Bioadhesive nanoparticulate compositions, comprising active agent particles and one or more cationic surface stabilizers, are described. The cationic surface stabilizers prevent aggregation of the nanoparticles and increase bioadhesion of the nanoparticles to biological substrates, such as an insect, teeth, bone, nails, chitin, feathers, scales, mucous, skin, hair, plant tissue, etc. The particles may consist of pharmacologically active compounds (e.g., drug compounds for human or veterinary use), agricultural chemicals (pesticides, herbicides, fertilizers, and the like), cosmetic agents, consumer products (coloring agents, flavors, or fragrances), or other materials which function by interacting with biological substrates. In addition, the invention relates to methods of preparing and using such bioadhesive nanoparticulate compositions.

SUMMARY OF THE INVENTION

The present invention is directed to stable bioadhesive nanoparticulate compositions comprising an active agent and at least one cationic surface stabilizer. The active agent can be either crystalline, semi-crystalline, or amorphous, or liquid at or near room temperature. The active agent particles can be dissolved or dispersed in a liquid medium or used in dry form.

In one embodiment, described are stable bioadhesive nanoparticulate compositions comprising particles of a poorly water-soluble active agent and, adsorbed to the surface of the agent, at least one cationic surface stabilizer. The active agent can be either crystalline, semi-crystalline, or amorphous. The active agent particles of the nanoparticulate composition have an effective average particle size of less than about 4000 nm. The active agent particles can be dispersed in a liquid medium or used in dry form.

In yet another embodiment, described are stable bioadhesive nanoparticulate compositions comprising particles of a water-soluble active agent and, adsorbed to the surface of the agent, at least one cationic surface stabilizer. The active agent can be either crystalline, semi-crystalline, or amorphous. The active agent particles of the nanoparticulate composition have an effective average particle size of less than about 4000 nm. The active agent particles can be dispersed in a liquid medium or used in dry form.

In a further embodiment, described are stable bioadhesive nanoparticulate compositions comprising liquid particles of a poorly water-soluble active agent and, adsorbed to the surface of the liquid particles, at least one cationic surface stabilizer. The active agent is in a liquid state at or near room temperature. In this embodiment, the nanoparticulate composition is in the form of an emulsion. The active agent emulsion droplets of the nanoparticulate composition have an effective average particle size of less than about 4000 nm. The active agent emulsion droplets are dispersed in a liquid medium in which they are poorly soluble, such as water.

In a further embodiment, described are stable bioadhesive nanoparticulate compositions comprising liquid particles of a water-soluble active agent and, adsorbed to the surface of the liquid particles, at least one cationic surface stabilizer. The active agent is in a liquid state at or near room temperature. In this embodiment, the nanoparticulate composition is in the form of an emulsion. The active agent emulsion droplets of the nanoparticulate composition have an effective average particle size of less than about 4000 nm. The active agent emulsion droplets are dispersed in a liquid medium in which they are poorly soluble, such as mineral oil, vegetable oils (corn, safflower, olive, etc.), or a hydrocarbon.

Also described are stable bioadhesive nanoparticulate compositions comprising active agent particles dissolved or dispersed in liquid droplets of a poorly water-soluble liquid and, adsorbed to the surface of the liquid droplets, at least one cationic surface stabilizer. For this composition, the liquid droplets comprising active agent are dispersed in a liquid medium in which they are poorly soluble, such as water. In addition, the liquid droplets comprising active agent have an effective average particle size of less than about 4000 nm.

Yet another composition encompassed by the invention is a stable bioadhesive nanoparticulate composition comprising active agent particles dissolved or dispersed in liquid droplets of a water-soluble liquid and, adsorbed to the surface of the liquid droplets, at least one cationic surface stabilizer. For this composition, the liquid droplets comprising active agent are dispersed in a liquid medium in which they are poorly soluble, such as mineral oil, vegetable oils (corn, safflower, olive, etc.), or a hydrocarbon. In addition, the liquid droplets comprising active agent have an effective average particle size of less than about 4000 nm.

Another aspect of the invention is directed to pharmaceutical compositions comprising one or more nanoparticulate compositions of the invention. The pharmaceutical composition preferably comprises a nanoparticulate composition described above and a pharmaceutically acceptable carrier, as well as any desired excipients.

This invention further discloses methods of making nanoparticulate compositions according to the invention. A first method comprises contacting a nanoparticulate active agent with at least one cationic surface stabilizer for a time and under conditions sufficient to provide a stable nanoparticulate composition in which the cationic surface stabilizer is adsorbed to the surface of the active agent particles. The cationic surface stabilizer can be contacted with the active agent either before, during, or after size reduction of the active agent. The agent can be either crystalline, semi-crystalline, amorphous, or a mixture thereof. The active agent particles of the nanoparticulate composition have an effective average particle size of less than about 4000 nm. The effective average particle size can be achieved by wet milling techniques (such as described in the '684 patent), by controlled precipitation methods, by homogenization, or by other suitable size reduction methods.

In cases where the active agent is in a liquid state at or near room temperature, the nanoparticulate composition is in the form of an emulsion. In such cases, a method of making the emulsion comprises combining the liquid active agent with an emulsifying agent and a liquid non-solvent and processing the resultant mixture with a homogenizer, high-shear mixer, rotor-stator type device, Microfluidizer.RTM., or other such equipment which is suitable for preparing emulsions and is well known to those skilled in the art. For this composition, the cationic surface stabilizer is adsorbed to the surface of the liquid active agent of the emulsion.

The invention also encompasses variations of this nanoparticulate emulsion formulation. For example, an active agent can be dissolved in a liquid droplet of an emulsion, or the active agent can be dispersed as a solid particle within a liquid droplet of an emulsion. In the first type of formulation, the liquid droplet in which the active agent is dissolved is dispersed within a liquid in which the liquid droplet is insoluble. In the second type of formulation, the active agent is dispersed within a liquid droplet of the emulsion; i.e., the active agent is insoluble in the liquid droplet of the emulsion. Moreover, the liquid droplets comprising the solid particles of the active agent are dispersed within a second liquid in which the liquid droplets are insoluble.

For these types of emulsion formulations, if the active agent nanoparticles are insoluble within the liquid droplets of the emulsion, then at least one cationic surface stabilizer is adsorbed to the surface of the active agent nanoparticles, the surface of the liquid emulsion droplets comprising the active agent particles, or a combination thereof. If, however, the active agent nanoparticles are soluble within the liquid droplets of the emulsion, then at least one cationic surface stabilizer is adsorbed to the surface of the liquid droplets comprising the active agent nanoparticles. The cationic surface stabilizers may be present during the emulsification process or may be added after the emulsion has been formed.

In a third method, aqueous nanoparticulate dispersions of water-soluble active agents may be prepared by encapsulating the active agent particles with a suitable coating and then dispersing them in water. The water-soluble nanoparticles may be prepared by wet milling in liquid nonsolvents, controlled precipitation, or other methods known to those in the art. After removal of the nonsolvents by evaporation, the nanoparticles may be treated with a protective coating, such as ethylcellulose, and subsequently dispersed in an aqueous vehicle. At least one cationic surface stabilizer is adsorbed to the encapsulated nanoparticles.

The present invention is further directed to methods of treatment comprising administering to an animal in need a therapeutically effective amount of a nanoparticulate therapeutic active agent/cationic surface stabilizer composition according to the invention. The active agent can be administered via any biological surface of the animal.

Yet another aspect of the invention is directed to the application of the described bioadhesive nanoparticulate compositions to any biological surface of an animal. Such application encompasses, for example, the application of nanoparticulate compositions useful as cosmetics, perfumes, shampoos, cleansers, moisturizers, deodorants, topical creams, ointments, nail polish, hair cosmetic compositions, etc.

The compositions of the invention can also be applied to plant tissue. Such methods include applying nanoparticulate compositions useful as fertilizers, pesticides, herbicides, etc. to a biological surface of a plant.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to the discovery that nanoparticulate compositions, comprising an active agent and having one or more cationic surface stabilizers adsorbed to the surface of a liquid or solid active agent, adsorbed to a liquid droplet of an emulsion comprising dissolved or suspended active active agent, adsorbed to a solid active agent within a liquid droplet of an emulsion, or a combination thereof, exhibit exceptional bioadhesion to biological surfaces, such as hair, mucous, skin, plant tissue, etc. The active agent can be either soluble or insoluble. In addition, the active agent can be either crystalline, semi-crystalline, amorphous, in a liquid state at or near room temperature, or a combination thereof.

The active agent particles of the nanoparticulate composition, when in either a solid or a liquid state, have an effective average particle size of less than about 4000 nm. If the active agent is dissolved or dispersed in a liquid droplet of an emulsion, then the liquid droplet has an effective average particle size of less than about 4000 nm. The active agent particle, or liquid droplet of an emulsion comprising active agent, can also have an effective average particle size of less than about less than about 3500 nm, less than about 3000 nm, less than about 2500 nm, less than about 2000 nm, less than about 1500 nm, less than about 1000 nm, less than about 800 nm, less than about 700 nm, less than about 600 nm, less than about 500 nm, less than about 400 nm, less than about 300 nm, less than about 250 nm, less than about 200 nm, less than about 100 nm, and less than about 50 nm. The active agent particles can be dispersed in a liquid medium or used in dry form.

In a first embodiment, the active agent is a poorly water-soluble compound in a crystalline, semi-crystalline, an amorphous state, or a combination thereof. The stable bioadhesive nanoparticulate composition comprises the poorly water-soluble active agent and, adsorbed to the surface of the agent, at least one cationic surface stabilizer.

In a second embodiment, the active agent is a poorly water-soluble compound which is in a liquid state at or near room temperature. The stable bioadhesive nanoparticulate composition comprises the liquid poorly water-soluble active agent and, adsorbed to the droplet surface of the liquid agent, at least one cationic surface stabilizer. The liquid active agent droplets are dispersed in a liquid medium in which they are poorly soluble, such as water.

In a third embodiment, the active agent is a water-soluble compound in a crystalline, semi-crystalline, an amorphous state, or a combination thereof. The stable bioadhesive nanoparticulate composition comprises the water-soluble active agent and, adsorbed to the surface of the agent, at least one cationic surface stabilizer.

In a fourth embodiment, the active agent is a water-soluble compound which is in a liquid state at or near room temperature. The stable bioadhesive nanoparticulate composition comprises the liquid water-soluble active agent and, adsorbed to the droplet surface of the liquid agent, at least one cationic surface stabilizer. The active agent liquid droplets are dispersed in a liquid medium in which they are poorly soluble, such as mineral oil, ethanol, vegetable oils (corn, safflower, olive, etc.), or a hydrocarbon.

In a fifth embodiment, the active agent particles are dissolved or dispersed in liquid droplets of a poorly water-soluble liquid, such as mineral oil, vegetable oils (corn, safflower, olive, etc.), or a hydrocarbon. At least one cationic surface stabilizer is adsorbed to the surface of the liquid droplets. For this composition, the liquid droplets comprising active agent are dispersed in a liquid medium in which they are poorly soluble, such as water. In addition, the liquid droplets comprising active agent have an effective average particle size of less than about 4000 nm. In a variation of this composition, active agent particles dispersed in the liquid droplets have at least one cationic surface stabilizer adsorbed to the surface of the active agent, and at least one cationic surface stabilizer is also adsorbed to the surface of the liquid droplet comprising the active agent. The two cationic surface stabilizers can be the same or different. The liquid droplets comprising the active agent have an effective average particle size of less than about 4000 nm.

In a sixth embodiment, active agent particles are dissolved or dispersed in liquid droplets of a water-soluble liquid, such as water. At least one cationic surface stabilizer is adsorbed to the surface of the liquid droplets. For this composition, the liquid droplets comprising active agent are dispersed in a liquid medium in which they are poorly soluble, such as mineral oil, vegetable oils (corn, safflower, olive, etc.), or a hydrocarbon. In addition, the liquid droplets comprising active agent have an effective average particle size of less than about 4000 nm.

Another aspect of the invention is directed to pharmaceutical compositions comprising one or more nanoparticulate compositions of the invention. The pharmaceutical composition preferably comprises a nanoparticulate composition described above and a pharmaceutically acceptable carrier, as well as any desired excipients.

A. Summary of Bioadhesion

The term bioadhesion refers to any attractive interaction between two biological surfaces or between a biological and a synthetic surface. In the case of bioadhesive nanoparticulate compositions, the term bioadhesion is used to describe the adhesion between the nanoparticulate compositions and a biological substrate (i.e. gastrointestinal mucin). There are basically two mechanisms which may be responsible for this bioadhesion phenomena. These are mechanical or physical interactions and chemical interactions. The first of these, mechanical or physical mechanisms, involves the physical interlocking or interpenetration between a bioadhesive entity and the receptor tissue, resulting from a good wetting of the bioadhesive surface, swelling of the bioadhesive polymer, penetration of the bioadhesive entity into a crevice of the tissue surface, or interpenetration of bioadhesive composition chains with those of the mucous or other such related tissues. The second possible mechanism of bioadhesion, chemical, incorporates strong primary bonds (i.e., covalent bonds) as well as weaker secondary forces such as ionic attraction, van der Waals interactions and hydrogen bonds. It is this chemical form of bioadhesion which is primarily responsible for the bioadhesive properties of the nanoparticles described in this patent. However, physical and mechanical interactions may also play a secondary role in the bioadhesion of such nanoparticles.

Because of the character of biological surfaces, the cationic surface stabilizers of the invention result in bioadhesive formulations. Surprisingly, the bioadhesive property of cationic particles diminishes as the particle size of the active agent increases, as noted in more detail below.

B. Applications of the Nanoparticulate Compositions of the Invention

The bioadhesive nanoparticulate compositions are useful in any situation in which it is desirable to apply an active agent to a biological surface. For example, the bioadhesive nanoparticulate compositions of the invention can be used in pharmaceuticals, including biologics such as proteins and peptides, organic compounds, such as therapeutic small molecules, agricultural agents, cosmetic agents, hair compositions, and others. The bioadhesive nanoparticulate compositions of the invention coat the targeted surface in a continuous and uniform film which is invisible to the naked human eye.

The bioadhesive compositions can be applied to any plant or animal surface. For example, insects or pests can be treated with insecticides, plants can be treated with herbicides, etc.

The adhesion exhibited by the inventive compositions means that the active agent nanoparticles are not easily washed off, rubbed off, or otherwise removed from the biological surface for an extended period of time. The period of time in which a biological cell surface is replaced is the factor that limits retention of the bioadhesive nanoparticles to that biological surface. For example, skin cells are replaced every 24-48 hours. Thus, the nanoparticulate composition would have to be reapplied to the skin every 48 hours. Mucous cells shed and are replaced about every 5-6 hours. Other biological surfaces, such as chitin, hair, teeth, and bone, do not routinely shed cells and, therefore, repeat applications may not be necessary.

C. Nanoparticulate Compositions

1. Active Agents

The nanoparticles of the invention comprise an active agent. The active agent exists in a crystalline phase, semi-crystalline phase, in an amorphous phase, in a liquid state at or near room temperature, or a combination thereof. The crystalline phase differs from a non-crystalline or amorphous phase can which result from precipitation techniques, such as those described in EP Patent No. 275,796. If the agent is poorly soluble, it is preferably dispersible in at least one liquid medium. By "poorly soluble" it is meant that the agent has a solubility in the liquid dispersion medium of less than about 10 mg/mL, and preferably of less than about 1 mg/mL. By "soluble," it is meant that the active agent has a solubility in the liquid dispersion medium of greater than about 10 mg/mL.

The active agent can be a drug, which is preferably present in an essentially pure form. A drug can be selected from a variety of known classes of drugs, as provided in U.S. Pat. No. 5,145,684, including, for example, proteins, peptides, nutriceuticals, anti-obesity agents, corticosteroids, elastase inhibitors, analgesics, anti-fungals, oncology therapies, anti-emetics, analgesics, cardiovascular agents, anti-inflammatory agents, anthelmintics, anti-arrhythmic agents, antibiotics (including penicillins), anticoagulants, antidepressants, antidiabetic agents, antiepileptics, antihistamines, antihypertensive agents, antimuscarinic agents, antimycobacterial agents, antineoplastic agents, immunosuppressants, antithyroid agents, antiviral agents, anxiolytic sedatives (hypnotics and neuroleptics), astringents, beta-adrenoceptor blocking agents, blood products and substitutes, cardiac inotropic agents, contrast media, cough suppressants (expectorants and mucolytics), diagnostic agents, diagnostic imaging agents, diuretics, dopaminergics (antiparkinsonian agents), haemostatics, immunological agents, lipid regulating agents, muscle relaxants, parasympathomimetics, parathyroid calcitonin and biphosphonates, prostaglandins, radio-pharmaceuticals, sex hormones (including steroids), anti-allergic agents, stimulants and anoretics, sympathomimetics, thyroid agents, vasodilators and xanthines.

Drugs to be administered in an aerosol formulation are preferably selected from the group consisting of proteins, peptide, bronchodilators, corticosteroids, elastase inhibitors, analgesics, anti-fungals, cystic-fibrosis therapies, asthma therapies, emphysema therapies, respiratory distress syndrome therapies, chronic bronchitis therapies, chronic obstructive pulmonary disease therapies, organ-transplant rejection therapies, therapies for tuberculosis and other infections of the lung, fungal infection therapies, respiratory illness therapies associated with acquired immune deficiency syndrome, an oncology drug, an anti-emetic, an analgesic, and a cardiovascular agent.

A description of these classes of drugs and a listing of species within each class can be found in Martindale, The Extra Pharmacopoeia, Twenty-ninth Edition (The Pharmaceutical Press, London, 1989), specifically incorporated by reference. The drugs are commercially available and/or can be prepared by techniques known in the art.

a. Active Agents Useful in Dermal Applications

The active agents according to the present invention include but are not limited to active agents which can be used in dermal applications, e.g., sunscreens, cosmetics, topical application of pharmaceuticals to the dermis (acne medication, anti-wrinkle drugs, such as alpha-hydroxy formulations), nail polish, moisturizers, deodorant, etc.

Cosmetic compositions are generally defined as compositions suitable for application to the human body. Cosmetic compositions such as creams and lotions are used to moisturize the skin and keep it in a smooth, supple condition. Pigmented cosmetic compositions, such as makeup, blush, lipstick, and eye shadow, are used to color the skin and lips. Since color is one of the most important reasons for wearing cosmetics, color-containing cosmetics must be carefully formulated to provide maximum wear and effect.

One of the long standing problems with pigmented cosmetic compositions, such as face makeup, lipstick, mascara, and the like, is the tendency of the cosmetic to blot or transfer from the skin or lashes onto other surfaces, such as glassware, silverware, or clothing. This blotting not only creates soiling but it also forces the cosmetic user to reapply cosmetic at fairly short intervals.

Traditional pigmented cosmetic compositions are either water and oil emulsions containing pigments, or they are anhydrous systems containing waxes, oils, and pigments. These formulations are applied and blended into the skin to provide color and to correct skin topography to provide an even, smooth appearance. The films are simply deposited on the surface of the skin and if touched with fingers the product may transfer or become blotchy and uneven. Perspiration or sebum will break through the film and cause running or smearing. If skin comes into contact with clothing, the clothing may become soiled.

Other areas which benefit from the present invention include coloring agents, flavors and fragrances. Coloring agents or pigments are used in cosmetic applications as well as in fabric applications. Suitable pigments can be inorganic and/or organic. Also included within the term pigment are materials having a low color or luster, such as matte finishing agents, and also light scattering agents. Examples of suitable pigments are iron oxides, acylglutamate iron oxides, ultramarine blue, D&C dyes, carmine, and mixtures thereof. Depending upon the type of cosmetic composition, e.g., foundation or blusher, a mixture of pigments will normally be used.

Bioadhesive nanoparticulate cosmetic compositions satisfy a long-felt need for cosmetic compositions that strongly adhere to the biological surface to which they are applied.

Fragrances and odiferous compounds are also suitable for use in the present inventive compositions. Fragrances or perfumes are usually prepared from volatile oils distilled or extracted from the leaves, flowers, gums, or woods of plant life (occasionally from animal life). These include, for example, linalyl acetate from citral, jasmine, cedar, lavender, and attar of rose. A typical fragrance may consist of many volatile components blended to create a pleasant sensory experience to the person wearing the fragrance and also impart a pleasant sensory experience to the people around that person. These blended oils, however, are typically too potent or too expensive to wear without being diluted in an appropriate solvent. Present perfumeries use lower molecular weight alcohol, e.g., methanol or ethanol, and more typically ethanol, to prepare a variety of "perfume" products, such as eau de cologne, perfume, eau de parfum, eau de toilette, splash cologne, and eau fraiche for the consumer. Bioadhesive nanoparticulate compositions comprising a fragrance or odiferous compound as an active agent could provide prolonged sensory stimulation following application; ie., for up to 48 hours following application to the skin.

b. Active Agents Useful in Mucous Applications

Exemplary active agents to be applied to mucous include dental applications, such as oral bioadhesive nanoparticulate lidocain formulations, bioadhesive nanoparticulate fluoride treatments, application to the lungs, throat, GIT, application to wounds, etc.

Also included is application to the throat using a liquid containing a bioadhesive nanoparticulate formulation containing, for example, menthol or other numbing compound for treatment of coughs or sore throats. The stomach and GIT can also be treated using bioadhesive formulations. This is particularly useful for treatment of diseases associated with the mucous of the gastrointestinal tract, such as Crohn's Disease.

Other pharmaceutical therapeutic methodologies include oral dosing, nasal administration, vaginal administration, ocular administration, colonic, and subcutaneous administration.

The compositions of the invention also encompass food products. For example, spice, oleoresin, flavor oil, color, or chemicals are often added during food processing to produce the desirable flavors, taste, and appearance. These agents can be included in a bioadhesive nanoparticulate composition of the present invention for increased adhesion to biological surfaces. Bioadhesive nanoparticulate flavoring agents could be used in products such as gums to produce prolonged flavor.

c. Active Agents Useful in Hair Applications

Biological substrates such as the hair are also encompassed by the scope of the invention. Bioadhesive nanoparticulate compositions can be used in hair conditioner formulations, hair dyes, hair sprays, hair cosmetics, hair cleansers, depilatories, etc.

d. Active Agents Useful in Plant Tissue Applications

Yet another area of applicability of the present invention includes bioadhesive nanoparticulate compositions that can be applied to plant tissue. Because of the difficulty in solubilizing some agricultural agents (i.e., some agricultural agents are applied as insoluble powders), the present invention provides a superior application method for plants as compared to prior art plant application methods.

Bioadhesive nanoparticulate compositions can be used for applications of pesticides, insecticides, fertilizers, etc.--any substance to be applied to the surface of a plant. All plants, such as grass, trees, commercial farm crops (such as corn, soybeans, cotton, vegetables, fruit, etc), weeds, etc., are encompassed by the scope of this invention.

In one embodiment of the invention, the active agent of the bioadhesive nanoparticulate composition is an insecticidal ingredient applied to seeds, plants, trees, harvested crops, soil, and the like. The insecticide ingredient can be selected from a wide variety of organic compounds or mixtures which are known and used in agriculture and horticulture applications, such as those listed in W. T. Thomson, Agricultural Chemicals, Book I, Insecticides (Thomson Publications, Fresno, Calif. 1989).

The general categories of insecticidal-active organic compounds include chlorinated hydrocarbon derivatives, phosphorated derivatives, pyrethroids, acylureas, and the like. Chlorinated hydrocarbon insecticides usually act as stomach and contact poisons affecting the nervous system. They are persistent in the environment and tend to accumulate in animal fatty tissue, as exemplified by DDT and chlordane.

Illustrative of other insecticidal compounds are chlorfluazuron, chlorpyrifos, chlorpyrifos methyl, bromophos, diazinon, malathion, trichlorfon, dimethoate, phorate, lindane, toxaphene, diflubenuron, methomyl, propoxur, carbaryl, cyhexatin, cypermethrin, permethrin, fenvalerate, dicofol, tetradifon, propargite, and the like. Other examples of insecticides include the pyrethroid insecticides, such a Fenvalerate.TM. [.alpha.-cyano-3-phenoxybenzyl-2-(4-chlorophenyl)-3methylvalerate] and Pyrethroid.TM. [cyano(4-fluoro-3-phenoxyphenylmethyl-3-(2,2-dichloroethenyl)-2,2-dimethy- l cyclopropanecarboxylate]; organophosphorus insecticides, such as DDVP.TM. (2,2-dichlorovinyldimethyl phosphate), Sumithion.TM. (dimethyl-4-nitro-m-tolylphosphorothionate), Malathone.TM. {S-[1,2-bis(ethoxycarbonyl)ethyl]dimethyl-phosphorothiol thionate}, Dimethoate [dimethyl-S-(N-methylcarbamoylmethyl)-phosphorothios thionate), Elsan.TM. {S-[.alpha.-(ethoxycarbonyl)benzyl]dimethylphosphorothiol thionate), and Baycid.TM. [O,O-dimethyl-O-(3-methyl-4methylmercaptophenyl)thiophosphate]; carbamate; insecticides such as Bassa.TM. (O-butylphenyl methylcarbamate), MTMC.TM. (m-tolyl methylcarbamate), Meobal.TM. (3,4-dimethylphenyl-N-methylcarbamate), and NAC.TM. (1-naphthyl-N-methylcarbamate); as well as Methomyl.TM. {methyl-N[(methylcarbamoyl)oxy]thioacetimide} and Cartap.TM. {1,3-bis(carbamolythio)-2-(N,N-dimethylamino)propane hydrochloride}.

Examples of other agricultural agents include acaricides such as, but not limited to, Smite.TM. {2-[2-(p-tert-butylphenoxy)isopropoxy]isopropyl-2-chloroethyl sulfide}, Acricid.TM. (2,4-dinitro-6-sec-butylphenyl dimethylacrylate), Chlormit.TM. (isopropyl 4,4-dichlorobenzylate), Acar.TM. (ethyl 4,4-dichlorobenzylate), Kelthane.TM. [1,1-bis(p-chlorophenyl)-2,2,2-trichloroethanol], Citrazon.TM. (ethyl O-benzoyl-3-chloro-2,6-dimethoxybenzohydroxymate), Plictran.TM. (tricyclohexyltin hydroxide), and Omite.TM. [2-(p-tert-butylphenoxy)cyclohexyl-2-propinyl sulfite].

Examples of germicides include organosulfur germicides, such as Dithane.TM. (zinc ethylenebisdithiocarbamate), Maneo.TM. (manganese ethylenebis-dithiocarbamate), Thiuram.TM. [bis(dimethylthiocarbamoyl) disulfide], Benlate.TM. [methyl 1-(butylcarbamoyl)-2-benzimidazole carbamate], Difolatan.TM. (N-tetrachloroethylthio-4-cyclohexane-1,2-dicarboxyimide), Daconol.TM. (tetrachloroisophthalonitrile), Pansoil.TM. (5-ethoxy-3-trichloromethyl-1,2,4-thiadiazole), Thiophanate-methyl[1,2-bis(3-methoxycarbonyl-2-thioureido)benzene], Rabcide.TM. (4,5,6,7-tetrachlorophthaloid), Kitazin P.TM. (O,O-diisopropyl-S-benzyl phosphorothioate), Hinonsan.TM. (O-ethyl-S,S-diphenyldithiophosphate), and Propenazol.TM. (3-allyloxy-1,2-benzothiazole 1,1-dioxide).

Example of plant growth regulating agents include, but are not limited to, MH.TM. (maleic acid hydrazide) and Ethrel.TM. (2-chloroethylphosphonic acid).

Examples of herbicides include, but are not limited to Stam.TM. (3,4-dichloropropionanilide), Saturn.TM. [S-(4-chlorobenzyl) N,N-diethylthiolcarbamate), Lasso (2-chloro-2',6'-diethyl-N-(methoxymethyl)acetanilide), Glyphosate.TM. [N-(phosphonomethyl)glycine isopropylamine salt], DCMU [3-(3,4-dichlorophenyl)-1,1-dimethylurea), and Gramoxone.TM. (1,1'-dimethyl-4,4'-dipyridium dichloride].

Other herbicides contemplated for use in the present invention include auxin transport inhibitors, e.g., naptalam; growth regulators, including benzoic acids, e.g., dicamba; phenoxy acids, such as (i) acetic acid type, e.g., 2,4-D, MCPA, (ii) propionic acid type, e.g., 2,4-DP, MCPP, and (iii) butyric acid type, e.g., 2,4-DB, MCPB; picolinic acids and related compounds, e.g., picloram, triclopyr, fluroxypyr, and clopyralid.

Photosynthesis inhibitors are also herbicides useful in the compositions of the invention. Such compounds include but are not limited to (a) s-triazines, such as (i) chloro substituted, e.g., atrazine, simazine, and cyanazine, (ii) methoxy substituted, e.g., prometon, (iii) methylthio substituted, e.g., ametryn and prometryn; (b) other triazines, such as hexazinone, and metribuzin; (c) substituted ureas, such as diuron, fluometuron, linuron, tebuthiuron, thidiazuron, and forchlorfenuron; (d) uracils, such as bromacil and terbacil; and (e) others, such as bentazon, desmedipham, pheninedipham, propanil, pyrazon, and pyridate.

Pigment inhibitors are also herbicides useful in the compositions of the invention. Such compounds include but are not limited to pyridazinones, such as norflurazon; isoxazolones, such as clomazone; and others, such as amitrole and fluridone.

In yet another aspect of the invention, growth inhibitors are herbicides useful in the compositions of the invention. Such compounds include but are not limited to (a) mitotic disruptors, such as (i) dinitroanilines, e.g., trifluralin, prodiamine, benefin, ethalfluralin, isopropalin, oryzalin, and pendimethalin; and (ii) others, such as DCPA, dithiopyr, thiazopyr, and pronamide; (b) inhibitors of shoots of emerging seedlings, such as (i) thiocarbamates, e.g., EPTC, butylate, cycloate, molinate, pebulate, thiobencarb, triallate, and vernolate; (c) inhibitors of roots only of seedlings, such as bensulide, napropamide, and siduron; and (d) inhibitors of roots and shoots of seedlings, including chloroacetamides, such as alachlor, acetochlor, metolachlor, diethatyl, propachlor, butachlor, pretilachlor, metazachlor, dimethachlor, and cinmethylin.

Amino acid synthesis inhibitors are herbicides useful in the compositions of the invention. Such compounds include, but are not limited to, (a) glyphosate, glufosinate; (b) sulfonylureas, such as rimsulfuron, metsulfuron, nicosulfuron, triasulfuron, primisulfuron, bensulfuron, chlorimuron, chlorsulfuron, sulfometuron, thifensulfuron, tribenuron, ethametsulfuron, triflusulfuron, clopyrasulfuron, pyrazasulfuron, prosulfuron (CGA-152005), halosulfuron, metsulfuron-methyl, and chlorimuron-ethyl; (c) sulfonamides, such as flumetsulam (a.k.a. DE498); (d) imidazolinones, such as imazaquin, imazamethabenz, imazapyr, imazethapyr, and imazmethapyr.

Lipid biosynthesis inhibitors are herbicides useful in the compositions of the invention. Such compounds include, but are not limited to, (a) cyclohexanediones, such as sethoxydim and clethodim; (b) aryloxyphenoxys, such as fluazifop-(P-butyl), diclofop-methyl, haloxyfop-methyl, and quizalofop; and (c) others, such as fenoxaprop-ethyl.

Cell wall biosynthesis inhibitors are herbicides useful in the compositions of the invention. Such compounds include, but are not limited to, dichlobenil and isoxaben.

Rapid cell membrane disruptors are herbicides useful in the compositions of the invention. Such compounds include, but are not limited to, (a) bipyridiliums, such as paraquat, and diquat; (b) diphenyl ethers, such as acifluorfen, fomesafen, lactofen, and oxyfluorfen; (c) glutamine synthetase inhibitors, such as glufosinate; and (d) others, such as oxadiazon.

Miscellaneous herbicides useful in the compositions of the invention include, but are not limited to, (a) carbamates, such as asulam; (b) nitriles, such as bromoxynil and ioxynil; (c) hydantocidin and derivatives; and (d) various other compounds, such as paclobutrazol, ethofumesate, quinclorac (a.k.a. BAS514), difenzoquat. endothall, fosamine, DSMA, and MSMA.

Other herbicides useful in the compositions of the invention include, but are not limited to, triketones and diones of the type described in U.S. Pat. Nos. 5,336,662 and 5,608,101, the contents of each of which are incorporated herein by reference, and in EP-A-338-992; EP-A-394-889; EP-A-506,967; EP-A-137,963; EP-A-186-118; EP-A-186-119; EP-A-186-120; EP-A-249-150; and EP-A-336-898. Examples of such triketones and diones are sulcotrione (MIKADO.TM.), whose chemical designation is 2-(2-chloro-4-methanesulfonylbenzoyl)-1,3-cyclohexanedione: 2-(4-methylsulfonyloxy-2-nitrobenzoyl)-4,4,6,6-tetramethyl-1,3-cyclohexan- e dione; 3-(4-methylsulfonyloxy-2-nitrobenzoyl)-bicyclo[3,2,1]octane-2,4-d- ione3-(4-methylsulfonyl-2-nitrobenzoyl)-bicyclo[3,2]octane-2,4-dione; 4-(4-chloro-2-nitrobenzoyl)-2,6,6-trimethyl-2H-1,2-oxazine-3,5(4H,6H)dion- e; 4-(4-methylthio-2-nitrobenzoyl)-2,6,6-trimethyl-2H-1,2-oxazine-3,5(4H,6- H)-dione; 3-(4-methylthio-2-nitrobenzoyl)-bicyclo[3,2,1]octane-2,4-dione; 4-(2-nitro-4-trifluoromethoxybenzoyl)-2,6,6-trimethyl-2H-1,2-oxazine-3,5(- 4 H,6H)-dione.

Herbicidal compounds useful in the nanoparticulate compositions of the invention are described in U.S. Pat. No. 5,506,192; EP-A-461,079; EP-A-549,524; EP-A-315,589 and PCT Appln. No. 91/10653. The contents of all of the cited references are incorporated herein by reference; including for example 3-[(4,6-dimethoxy-2-pyrimidinyl)hydroxymethyl]-N-methyl-2-pyridine carboxamide; 4,7-dichloro-3-(4,6-dimethoxy-2-pyrimidinyl)-3-hexanoyloxyphthalide; 3-[(4,6-dimethoxy-2-pyrimidinyl)carbonyl]-N,N-dimethyl-2-pyridine carboxamide; 3,6-dichloro-2-[(4,6-dimethoxy-2-pyrimidinyl)carbonyl]benzoic acid; 6-chloro-2-[(4,6-dimethoxy-2-pyrimidinyl)thio]benzoic acid (a.k.a. DPX-PE350 or pyrithiobac) and salts thereof.

e. Agents Useful in Miscellaneous Applications

Other exemplary uses of the novel bioadhesive formulations are provided: teeth can be treated with teeth whiteners or fluoride bioadhesive compositions; bones can be treated with calcium bioadhesive compositions; nails can be treated with color or strengthening bioadhesive formulations; insects or pests can be treated with insecticides or other toxic compositions to the pest. In sum, the compositions are useful in treating any biological surface, or a surface derived from a biological material. Feathers and scales of animals can be treated, as well as other animal biological surfaces such as chitin.

2. Surface Stabilizers

Surface stabilizers useful herein physically adhere to the surface of the nanoparticulate active agent, or liquid emulsion droplet comprising the active agent, but do not chemically react with the active agent or itself. Individually adsorbed molecules of the surface stabilizer are essentially free of intermolecular crosslinkages. The surface stabilizers are commercially available and/or can be prepared by techniques known in the art. Examples of useful cationic surface stabilizers include but are not limited to polymers, biopolymers, polysaccharides, cellulosics, alginates, phospholipids, and nonpolymeric compounds, such as zwitterionic stabilizers, poly-n-methylpyridinium, anthryul pyridinium chloride, cationic phospholipids, chitosan, polylysine, polyvinylimidazole, polybrene, polymethylmethacrylate trimethylammoniumbromide bromide (PMMTMABr), hexyldesyltrimethylammonium bromide (HDMAB), and polyvinylpyrrolidone-2-dimethylaminoethyl methacrylate dimethyl sulfate.

Other useful cationic stabilizers include, but are not limited to, cationic lipids, sulfonium, phosphonium, and quarternary ammonium compounds, such as stearyltrimethylammonium chloride, benzyl-di(2-chloroethyl)ethylammonium bromide, coconut trimethyl ammonium chloride or bromide, coconut methyl dihydroxyethyl ammonium chloride or bromide, decyl triethyl ammonium chloride, decyl dimethyl hydroxyethyl ammonium chloride or bromide, C.sub.12-15dimethyl hydroxyethyl ammonium chloride or bromide, coconut dimethyl hydroxyethyl ammonium chloride or bromide, myristyl trimethyl ammonium methyl sulphate, lauryl dimethyl benzyl ammonium chloride or bromide, lauryl dimethyl (ethenoxy).sub.4 ammonium chloride or bromide, N-alkyl (C.sub.12-18)dimethylbenzyl ammonium chloride, N-alkyl (C.sub.14-18)dimethyl-benzyl ammonium chloride, N-tetradecylidmethylbenzyl ammonium chloride monohydrate, dimethyl didecyl ammonium chloride, N-alkyl and (C.sub.12-14) dimethyl 1-napthylmethyl ammonium chloride, trimethylammonium halide, alkyl-trimethylammonium salts and dialkyl-dimethylammonium salts, lauryl trimethyl ammonium chloride, ethoxylated alkyamidoalkyldialkylammonium salt and/or an ethoxylated trialkyl ammonium salt, dialkylbenzene dialkylammonium chloride, N-didecyldimethyl ammonium chloride, N-tetradecyldimethylbenzyl ammonium, chloride monohydrate, N-alkyl(C.sub.12-14) dimethyl 1-naphthylmethyl ammonium chloride and dodecyldimethylbenzyl ammonium chloride, dialkyl benzenealkyl ammonium chloride, lauryl trimethyl ammonium chloride, alkylbenzyl methyl ammonium chloride, alkyl benzyl dimethyl ammonium bromide, C.sub.12, C.sub.15, C.sub.17 trimethyl ammonium bromides, dodecylbenzyl triethyl ammonium chloride, poly-diallyldimethylammonium chloride (DADMAC), dimethyl ammonium chlorides, alkyldimethylammonium halogenides, tricetyl methyl ammonium chloride, decyltrimethylammonium bromide, dodecyltriethylammonium bromide, tetradecyltrimethylammonium bromide, methyl trioctylammonium chloride (ALIQUAT 336.TM.), POLYQUAT 10.TM., tetrabutylammonium bromide, benzyl trimethylammonium bromide, choline esters (such as choline esters of fatty acids), benzalkonium chloride, stearalkonium chloride compounds (such as stearyltrimonium chloride and Di-stearyldimonium chloride), cetyl pyridinium bromide or chloride, halide salts of quaternized polyoxyethylalkylamines, MIRAPOL.TM. and ALKAQUAT.TM. (Alkaril Chemical Company), alkyl pyridinium salts; amines, such as alkylamines, dialkylamines, alkanolamines, polyethylenepolyamines, N,N-dialkylaminoalkyl acrylates, and vinyl pyridine, amine salts, such as lauryl amine acetate, stearyl amine acetate, alkylpyridinium salt, and alkylimidazolium salt, and amine oxides; imide azolinium salts; protonated quaternary acrylamides; methylated quaternary polymers, such as poly[diallyl dimethylammonium chloride] and poly-[N-methyl vinyl pyridinium chloride]; and cationic guar.

Such exemplary cationic surface stabilizers and other useful cationic surface stabilizers are described in J. Cross and E. Singer, Cationic Surfactants: Analytical and Biological Evaluation (Marcel Dekker, 1994); P. and D. Rubingh (Editor), Cationic Surfactants: Physical Chemistry (Marcel Dekker, 1991); and J. Richmond, Cationic Surfactants: Organic Chemistry, (Marcel Dekker, 1990).

Particularly preferred nonpolymeric primary stabilizers for crystalline active agents are any nonpolymeric compound other than benzalkonium chloride. Such compounds can be a carbonium compound, a phosphonium compound, an oxonium compound, a halonium compound, a cationic organometallic compound, a quarternary phosphorous compound, a pyridinium compound, an anilinium compound, an immonium compound, a hydroxylammonium compound, a primary ammonium compound, a secondary ammonium compound, a tertiary ammonium compound, and quarternary ammonium compounds of the formula NR.sub.1R.sub.2R.sub.3R.sub.4.sup.(+). For compounds of the formula NR.sub.1R.sub.2R.sub.3R.sub.4.sup.(+): (i) none of R.sub.1-R.sub.4 are CH.sub.3; (ii) one of R.sub.1-R.sub.4 is CH.sub.3; (iii) three of R.sub.1-R.sub.4 are CH.sub.3; (iv) all of R.sub.1-R.sub.4 are CH.sub.3; (v) two of R.sub.1-R.sub.4 are CH.sub.3, one of R.sub.1-R.sub.4 is C.sub.6H.sub.5CH.sub.2, and one of R.sub.1-R.sub.4 is an alkyl chain of seven carbon atoms or less; (vi) two of R.sub.1-R.sub.4 are CH.sub.3, one of R.sub.1-R.sub.4 is C.sub.6H.sub.5CH.sub.2, and one of R.sub.1-R.sub.4 is an alkyl chain of nineteen carbon atoms or more; (vii) two of R.sub.1-R.sub.4 are CH.sub.3 and one of R.sub.1-R.sub.4 is the group C.sub.6H.sub.5(CH.sub.2).sub.n, where n>1; (viii) two of R.sub.1-R.sub.4 are CH.sub.3, one of R.sub.1-R.sub.4 is C.sub.6H.sub.5CH.sub.2, and one of R.sub.1-R.sub.4 comprises at least one heteroatom; (ix) two of R.sub.1-R.sub.4 are CH.sub.3, one of R.sub.1-R.sub.4 is C.sub.6H.sub.5CH.sub.2, and one of R.sub.1-R.sub.4 comprises at least one halogen; (x) two of R.sub.1-R.sub.4 are CH.sub.3, one of R.sub.1-R.sub.4 is C.sub.6H.sub.5CH.sub.2, and one of R.sub.1-R.sub.4 comprises at least one cyclic fragment; (xi) two of R.sub.1-R.sub.4 are CH.sub.3 and one of R.sub.1-R.sub.4 is a phenyl ring; or (xii) two of R.sub.1-R.sub.4 are CH.sub.3 and two of R.sub.1-R.sub.4 are purely aliphatic fragments.

Such compounds include, but are not limited to, behenalkonium chloride, benzethonium chloride, cetylpyridinium chloride, behentrimonium chloride, lauralkonium chloride, cetalkonium chloride, cetrimonium bromide, cetrimonium chloride, cethylamine hydrofluoride, chlorallylmethenamine chloride (Quaternium-15), distearyldimonium chloride (Quaternium-5), dodecyl dimethyl ethylbenzyl ammonium chloride(Quaternium-14), Quaternium-22, Quaternium-26, Quaternium-18 hectorite, dimethylaminoethylchloride hydrochloride, cysteine hydrochloride, diethanolammonium POE (10) oletyl ether phosphate, diethanolammonium POE (3)oleyl ether phosphate, tallow alkonium chloride, dimethyl dioctadecylammoniumbentonite, stearalkonium chloride, domiphen bromide, denatonium benzoate, myristalkonium chloride, laurtrimonium chloride, ethylenediamine dihydrochloride, guanidine hydrochloride, pyridoxine HCl, iofetamine hydrochloride, meglumine hydrochloride, methylbenzethonium chloride,7 myrtrimonium bromide, oleyltrimonium chloride, polyquaternium-1, procainehydrochloride, cocobetaine, stearalkonium bentonite, stearalkoniumhectonite, stearyl trihydroxyethyl propylenediamine dihydrofluoride, tallowtrimonium chloride, and hexadecyltrimethyl ammonium bromide. All of these nonpolymeric surface stabilizers can be used with semi-crystalline and amorphous active agents, as well as crystalline active agents.

All of these stabilizers can be used for amorphous, semi-crystalline, or any combination of amorphous, semi-crystalline, and crystalline active agents.

Secondary non-cationic surface stabilizers can also be added to the compositions of the invention. Benzalkonium chloride (BKC) is useful as a secondary stabilizer for crystalline compounds. BKC is useful as a primary stabilizer for amorphous, semi-crystalline, or mixtures of amorphous, semi-crystalline, and/or crystalline compositions.

3. Nanoparticulate Active Agent/Surface Stabilizer Particle Size

The compositions of the invention contain active agent nanoparticles which have an effective average particle size of less than about 4 microns, less than about 3.5 microns, less than about 3 microns, less than about 2.5 microns, less than about 2 microns, less than about 1.5 microns, less than about 1 micron, less than about 800 nm, less than about 700 nm, less than about 600 nm, less than about 500 nm, less than about 400 nm, less than about 300 nm, less than about 200 nm, less than about 100 nm, or less than about 50 nm, as measured by light-scattering methods, microscopy, or other appropriate methods.

If the active agent is dissolved or dispersed in a liquid droplet of an emulsion, then the liquid droplet comprising the active agent has a particle size of less than about 4 microns, less than about 3.5 microns, less than about 3 microns, less than about 2.5 microns, less than about 2 microns, less than about 1.5 microns, less than about 1 micron, less than about 800 nm, less than about 700 nm, less than about 600 nm, less than about 500 nm, less than about 400 nm, less than about 300 nm, less than about 200 nm, less than about 100 nm, or less than about 50 nm, as measured by light-scattering methods, microscopy, or other appropriate methods.

By "an effective average particle size of "less than about 4 microns," it is meant that at least 50% of the active agent particles, or liquid droplets comprising active agent, have a weight average particle size of less than about 4 microns when measured by light scattering techniques, microscopy, or other appropriate methods. Preferably, at least 70% of the active agent particles, or liquid droplets containing active agent, have an average particle size of less than about 4 microns, more-preferably at least 90% of the active agent particles, or liquid droplets containing active agent, have an average particle size of less than about 4 microns, and even more preferably at least about 95% of the particles or liquid droplets have a weight average particle size of less than about 4 microns.

It was unexpectedly discovered that the bioadhesive property of the nanoparticulate compositions of the invention is dependent upon the particle size of the active agent, or liquid droplets comprising active agent, present in the nanoparticulate composition. Optimal bioadhesive characteristics are observed with the effective average particle size of the active agent present in the nanoparticulate composition or liquid droplets comprising active agent, is less than about 1 micron. However, the bioadhesive property is still present, but minimal, up to about 6 microns. Larger particles do not exhibit strong bioadhesive properties. This is demonstrated by the results given in the examples in which large micron-sized drugs combined with cationic stabilizers did not exhibit bioadhesive properties.

4. Concentration of Nanoparticulate Active Agent and Surface Stabilizer

The relative amount of active agent and one or more surface stabilizers can vary widely. The optimal amount of the one or more surface stabilizers can depend, for example, upon the particular active agent selected, the hydrophilic lipophilic balance (HLB), melting point, and water solubility of the surface stabilizer, and the surface tension of water solutions of the surface stabilizer, etc.

The amount of stabilizer present is from about 0.001 to about 99.999% w/v, preferably from about 0.25 to about 25% w/v, more preferably from about 0.5 to about 15% w/v, and most preferably from about 1 to about 10% w/v, based on the total weight of the composition.

The concentration of the active agent can vary from about 99.99% to about 0.01% w/v, preferably from about 90% to about 0.1% w/v, more preferably from about 70% to about 1% w/v, more preferably from about 60% to about 2% w/v, and most preferably from about 50% to about 5% w/v, by weight based on the total weight of the composition.

D. Methods of Making Nanoparticulate Compositions

This invention further discloses methods of making nanoparticulate compositions according to the invention. A first method comprises contacting a nanoparticulate active agent with at least one cationic surface stabilizer for a time and under conditions sufficient to provide a stable nanoparticulate composition in which the cationic surface stabilizer is adsorbed to the surface of the active agent particles. The cationic surface stabilizer can be contacted with the active agent either before, during, or after size reduction of the active agent. The agent can be either crystalline, semi-crystalline, or amorphous. The active agent particles of the nanoparticulate composition have an effective average particle size of less than about 4 microns, less than about 3.5 microns, less than about 3 microns, less than about 2.5 microns, less than about 2 microns, less than about 1.5 microns, less than about 1 micron, less than about 800 nm, less than about 700 nm, less than about 600 nm, less than about 500 nm, less than about 400 nm, less than about 300 nm, less than about 200 nm, less than about 100 nm, or less than about 50 nm. The effective average particle size can be achieved by wet milling techniques, by controlled precipitation methods, or by other suitable size reduction methods, such as by homogenization. Exemplary milling, precipitation, and homogenization methods of making nanoparticulate compositions are described in U.S. Pat. Nos. 5,145,684; 5,518,187; 5,718,388; 5,862,999; 5,510,118; and 5,766,635.

Microprecipitation is a method of preparing stable dispersions of the active agents in the presence of one or more surface stabilizers free of any trace toxic solvents or solubilized heavy metal impurities. Such a method comprises, for example: (1) dissolving the active agent in a suitable solvent; (2) adding the formulation from step (1) to a solution comprising at least one cationic surface stabilizer to form a clear solution; and (3) precipitating the formulation from step (2) using an appropriate non-solvent. The method can be followed by removal of any formed salt, if present, by dialysis or diafiltration and concentration of the dispersion by conventional means. The resultant nanoparticulate dispersion can be utilized in solid or liquid formulations.

In cases where the active agent is a liquid at or near room temperature, or where the active agent is dissolved or dispersed in either a water-soluble or water-insoluble liquid, the nanoparticulate composition is in the form of an emulsion. In such cases, a method of making the emulsion comprises combining the active agent with an emulsifying agent and a liquid non-solvent and processing the resultant mixture with a homogenizer, high-shear mixer, rotor-stator type device, Microfluidizer.RTM., or other such equipment which is suitable for preparing emulsions and is well known to those skilled in the art.

If the active agent is present as droplets within an emulsion, then the active agent nanoparticles also comprise at least one cationic surface stabilizer adsorbed to the surface of the liquid active agent particles. If the active agent is solubilized in the liquid droplets of the emulsion, then the liquid droplets comprising the active agent have at least one cationic surface stabilizer adsorbed to the surface of the liquid droplets. If the active agent is insoluble in the liquid droplets of the emulsion, then the active agent nanoparticles comprise at least one cationic surface stabilizer adsorbed to the surface of the particles, the liquid droplets comprising the active agent comprise at least one cationic surface stabilizer adsorbed to the surface of the liquid droplets, or the particulate active agent in the liquid droplets and the liquid droplets comprise at least one cationic surface stabilizer adsorbed to the surface of the active agent particles and liquid emulsion droplets. The cationic surface modifiers may be present during the emulsification process or may be added after the emulsion has been formed. Exemplary microfluidization methods for making nanoparticulate compositions are described in U.S. Pat. No. 5,510,118.

If the active agent is a liquid at or near room temperature, or if the active agent particles are solubilized or dispersed in the liquid droplets of the emulsion, then the liquid droplets of the emulsion comprising the active agent (in either a pure, solubilized, or particulate state) have an effective average particle size of less than about 4 microns, less than about 3.5 microns, less than about 3 microns, less than about 2.5 microns, less than about 2 microns, less than about 1.5 microns, less than about 1 micron, less than about 800 nm, less than about 700 nm, less than about 600 nm, less than about 500 nm, less than about 400 nm, less than about 300 nm, less than about 200 nm, less than about 100 nm, or less than about 50 nm.

In a third method, aqueous nanoparticulate dispersions of water-soluble active agents can be prepared by encapsulating the active agent particles with a suitable coating and then dispersing them in water. The water-soluble nanoparticles can be prepared by wet milling in liquid nonsolvents, controlled precipitation, or other methods known to those in the art. After removal of the nonsolvents by evaporation, the nanoparticles can be treated with a protective coating, such as ethylcellulose, and subsequently dispersed in an aqueous vehicle. At least one cationic surface modifier is adsorbed to the surface of the encapsulated nanoparticles. The encapsulated nanoparticles have an effective average particle size of less than about 4 microns, less than about 3.5 microns, less than about 3 microns, less than about 2.5 microns, less than about 2 microns, less than about 1.5 microns, less than about 1 micron, less than about 800 nm, less than about 700 nm, less than about 600 nm, less than about 500 nm, less than about 400 nm, less than about 300 nm, less than about 200 nm, less than about 100 nm, or less than about 50 nm.

E. Methods of Using the Nanoparticulate Compositions

The nanoparticulate compositions of the present invention can be administered to biological surfaces, such as mucous and skin, of humans and animals either orally, rectally, parenterally (intravenous, intramuscular, or subcutaneous), intracisternally, intravaginally, intraperitoneally, locally/topically (powders, ointments or drops), or as a buccal or nasal spray.

The compositions can be applied to the biological surface of hair by spraying or soaking, as well as by other techniques known to those skilled in the art. The compositions can be applied to plant tissue by spraying, soaking, soil drench, pre-emergence and post-emergence, as well as by other techniques known to those skilled in the art.

Compositions suitable for parenteral injection may comprise physiologically acceptable sterile aqueous or nonaqueous dispersions, suspensions or emulsions and sterile powders for reconstitution into sterile injectable solutions or dispersions. Examples of suitable aqueous and nonaqueous carriers, diluents, solvents, or vehicles include water, ethanol, polyols (propyleneglycol, polyethyleneglycol, glycerol, and the like), suitable mixtures thereof, vegetable oils (such as olive oil), and injectable organic esters such as ethyl oleate.

Proper fluidity can be maintained, for example, by the use of a coating such as lecithin, by the maintenance of the required particle size in the case of dispersions, and by the use of surfactants. The nanoparticulate compositions may also contain adjuvants, such as preserving, wetting, emulsifying, and dispersing agents. Prevention of the growth of microorganisms can be ensured by various antibacterial and antifungal agents, such as parabens, chlorobutanol, phenol, sorbic acid, and the like. It may also be desirable to include isotonic agents, such as sugars, sodium chloride, and the like. Prolonged absorption of an injectable pharmaceutical form can be brought about by the use of agents delaying absorption, such as aluminum monostearate and gelatin.

Solid dosage forms for oral administration of a pharmaceutical active agent include capsules, tablets, pills, powders, and granules. In such solid dosage forms, the active compound is admixed with at least one of the following: (a) one or more inert excipients (or carrier), such as dicalcium phosphate; (b) fillers or extenders, such as starches, lactose, sucrose, glucose, mannitol, and silicic acid; (c) binders, such as carboxymethylcellulose, alignates, gelatin, polyvinylpyrrolidone, sucrose and acacia; (d) humectants, such as glycerol; (e) disintegrating agents, such as agar-agar, calcium carbonate, potato or tapioca starch, alginic acid, certain complex silicates, and sodium carbonate; (f) solution retarders, such as paraffin; (g) absorption accelerators, such as quaternary ammonium compounds; (h) wetting agents, such as cetyl alcohol and glycerol monostearate; (i) adsorbents, such as kaolin and bentonite; and (j) lubricants, such as talc, calcium stearate, magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate, or mixtures thereof. For capsules, tablets, and pills, the dosage forms may also comprise buffering agents.

Liquid application forms include emulsions, suspensions, syrups, and elixirs. In addition to the active compounds, the liquid dosage forms may comprise inert diluents commonly used in the art, such as water or other solvents, solubilizing agents, and emulsifiers. Exemplary emulsifiers are ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propyleneglycol, 1,3-butyleneglycol, dimethylformamide, oils, such as cottonseed oil, groundnut oil, corn germ oil, olive oil, castor oil, and sesame oil, glycerol, tetrahydrofurfuryl alcohol, polyethyleneglycols, fatty acid esters of sorbitan, or mixtures of these substances, and the like.

Besides such inert diluents, the composition can also include adjuvants, such as wetting agents, emulsifying and suspending agents, sweetening, flavoring, and perfuming agents.

Actual application levels of active ingredients in the nanoparticulate compositions of the invention may be varied to obtain an amount of active ingredient that is effective to obtain a desired response for a particular composition and method of application. The selected dosage level therefore depends upon the desired therapeutic effect, on the route of administration, on the desired duration of treatment, and other factors. In addition, the formulations of the present invention can be administered in combination with other pharmaceutical agents in the form of a solution, suspension, syrup or elixir or as formulated for solid dose administration.

The total daily amount of the active agent included in the inventive composition can be applied to a host in single or divided doses. Individuated units may contain such amounts of such submultiples thereof as may be used to make up the daily dose. It will be understood, however, that the specific dose level for any particular patient will depend upon a variety of factors, for example, when the host is a patient, such factors include the body weight, general health, sex, diet, time and route of administration, rates of absorption and excretion, combination with other drugs and the severity of the particular disease being treated.

Claim 1 of 81 Claims

1. A stable bioadhesive nanoparticulate composition which adsorbs to a biological surface and which comprises: (a) active agent particles in a crystalline state, wherein the active agent particles have an effective average particle size of less than about 4000 nm; and (b) adsorbed to the surface thereof at least one cationic surface stabilizer selected from the group consisting of a polymer, a biopolymer, a polysaccharide, a cellulosic, an alginate, and a nonpolymeric compound, wherein: (i) the nonpolymeric compound is not benzalkonium chloride; and (ii) the composition does not comprise a phospholipid; and (c) wherein the cationic surface stabilizer is in an amount effective to cause nanoparticles of the stable bioadhesive nanoparticulate composition to adhere to a biological surface.

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