Title:  Method for delivering beneficial compositions to hair follicles

United States Patent:  6,224,901

Assignee:  AntiCancer, Inc. (San Diego, CA)

Filed:  May 20, 1997

The present invention is directed to introduce a replacement pigment into the hair shaft through the hair follicle using a formulation of a replacement pigment in a liposomal composition.

SUMMARY OF THE INVENTION

It has now been discovered that liposomes can selectively target the hair follicle with potentially beneficial compounds. The invention describes the unexpected results obtained by the inventors that liposomes selectively deliver compounds to the hair follicle thus is enabling the compounds to cross the stratum corneum and be delivered to the cells in the hair follicle without delivery of the compounds to the surrounding skin cells.

The present invention provides compositions and methods which are useful for the specific delivery of beneficial compounds to hair follicle cells to, for example, improve hair color or condition, prevent alopecia, or to stimulate hair growth.

This invention describes methods for preparing liposomes, incorporating beneficial compounds into the liposomes either during formation of the liposomes or thereafter, and applying the liposomes to the skin areas requiring treatment in patients requiring such beneficial treatment. According to the present methods, liposomes preferentially deliver the beneficial compounds to the hair follicles where the compounds enter into the follicle cells. By virtue of the selectivity of the liposome-mediated delivery method, the administered compounds are not delivered substantially to the dermis or internally to the circulation, thereby minimizing undesirable side effects that the administered compound might exert on such dermis tissue or systemically in the circulation.

Thus, the invention provides a method of delivering beneficial compounds to the hair follicle and thus to the cells in the hair follicle. The invention provides a method of delivering any compound to the hair follicle by the use of liposomes. Although particular liposome compositions are specifically used as examples herein, the invention provides for the use of potentially any liposome to deliver the beneficial compound. Those of ordinary skill in the art will readily appreciate that any liposome may be used and that the invention is not limited to the particular types of liposomes described herein.

Thus, in a first aspect, the invention provides a method of directly and selectively delivering a beneficial compound to hair follicles of a mammal comprising the step of applying a liposome composition topically to skin areas of a mammal having a plurality of hair follicles, wherein the liposome composition comprises a liposome containing an effective amount of at least one selected beneficial compound, the liposome is capable of selectively delivering the beneficial compound to the hair follicle and the beneficial compound is preferentially transmitted to the hair follicle and enters into the hair follicle without substantially entering into the cells external to the hair follicle.

By "substantially" is meant that the compound is not appreciably delivered to the surrounding skin cells. Generally, approximately 5-20% of the compound in the liposome composition that is topically applied enters into the cells of the treated skin tissue. More commonly, 10% of the liposome composition topically applied enters the cells of the treated skin tissue. By "substantially" is meant that not more than 10% of the compound that enters the cells is delivered to the cells external to the hair follicle. More preferably, not more than 1% of the compound that enters the cells is delivered to the cells external to the hair follicle cells. In especially preferred embodiments, not more than 0.1-0.5%, preferably 0.1%, of the compound that enters the cells is delivered to cells external to the hair follicle.

Thus, one advantage of the invention is that beneficial compounds may be directly and selectively delivered to cells in the hair follicle without entering into other cells, such as other cells in the skin or the blood stream.

By "directly and selectively" is meant that the invention delivers the compound preferentially to the hair follicle and does not substantially deliver the compound to the cells surrounding the hair follicle that are not hair follicle cells or to the systemic circulatory system.

The present invention thus yields the surprising result that beneficial compositions may be directly and selectively delivered to hair follicles without transmission to the cells external to the hair follicles. The mechanism by which this selective transmission may take place may be, for example, but not by way of limitation, due to an attraction of the liposome compositions to the oil secreted by the sebaceous glands associated with the hair follicles.

Typically, the present methods are practiced on the skin of a mammal requiring treatment according to the present methods, such as a human. Thus, the methods can be practiced in vivo.

In order to determine the effectiveness of the hair follicle-specific treatment method of the present invention, an in vitro method of testing particular liposome agents has been developed, utilizing novel histoculturing techniques.

As mentioned above, it is known that a number of compounds, typically dyes and the like, when applied to the skin are more rapidly absorbed in heavily follicularized areas. However, many macromolecular or lipophobic substances cannot cross the plasma membrane or other lipid barriers into the follicle and follicle cells. In the present invention, it has been discovered that when incorporated into liposomes, those macromolecular compounds are successfully transported into the follicle cells, and furthermore can be selectively transferred across the stratum corneum into the follicle without entry to the circulation or the adjacent skin tissue, which has great potential efficacy as well as safety advantages.

Thus, the invention describes in one embodiment a liposome composition comprising a liposome containing an effective amount of a beneficial compound. The liposome utilized in the liposome composition is capable of selectively delivering the beneficial compound to hair follicles as described further herein. The beneficial compound to be administered can be a macromolecule or lipophobic molecule that is not capable of passage through the stratum corneum or cell membrane and requires the liposome-mediated delivery system to selectively and preferentially enter the hair follicle, or is a lipophilic molecule having undesirable effects on cells external to the hair follicles, and requires the selectivity of the liposome-mediated delivery system to preferentially deliver the lipophilic molecule to the hair follicle.

The liposome compositions can be utilized for a variety of applications, as described herein, and therefore may contain any of a variety of beneficial compounds, including hair color-restoring or modifying agents such as melanin, hair dye, tyrosinase, or a nucleic acid which is capable of expressing human tyrosinase, hair growth stimulating or hair fortifying agents, agents which inhibit sensitivity to chemo-therapeutics, other agents which prevent all forms of alopecia and the like beneficial compounds. These beneficial compounds may therefore be, for example, but are not limited to, proteins, peptides, nucleic acids, polymers, macromolecules, or dyes.

A liposome composition can comprise any of a variety of liposomes designed to selectively target hair follicles, including pH-sensitive liposomes, liposomes comprising a phospholipid selected from the group consisting of s phosphatidylcholine (PC), egg phosphatidylcholine (EPC), dioleoylphosphatidylcholine (DOPC), dipalmitoylphosphatidyl choline (DPPC), phosphatidylethanolamine (PE), dioleoylphosphatidylethanolamine (DOPE) and cholesterol, liposomes further comprising a cationic phospholipid selected from the group consisting of D282, D378, D383, D3886, D3897 and D3899, (obtainable from Molecular Probes Catalog, Eugene, Oregon) and the like formulations.

The invention also describes a method for restoring hair color to the hair of a mammal, comprising applying a therapeutically effective amount of a liposome composition to a skin area on said mammal having a plurality of hair follicles, where the liposome composition of the present invention comprises a liposome containing an effective amount of at least one selected hair color-restoring agent. Preferred hair color-restoring agents include melanin, hair dye, tyrosinase, and a nucleic acid capable of expressing human tyrosinase in hair follicle cells, more preferably, the nucleic acid encodes human tyrosinase including the amino acid residue sequence characteristics of the tyrosinase protein sequence SEQ ID NO 1.

The invention further describes a method of directly and selectively delivering a beneficial compound to hair follicles of a mammal comprising the step of applying a liposome composition of this invention topically to skin areas of a mammal having a plurality of hair follicles, wherein the liposome composition comprises a liposome containing an effective amount of at least one selected beneficial compound and wherein the beneficial compound is a macromolecule, a lipophobic molecule or a lipophilic molecule having undesirable effects on cells external to said hair follicles. The liposome composition may be applied to the skin area of a mammal having a plurality of hair follicles either in vivo, or in vitro, using explanted skin tissue. The explanted skin tissue may be grown, for example, as described herein, in skin histoculture. In preferred embodiments, the beneficial compound is a hair color-restoring agent such as melanin, hair dye, or tyrosinase. In related embodiments, the beneficial compound is a hair growth stimulator such as cyclosporin-A, or related compounds, finesteride, or an antisense nucleic acid molecule that would block a gene conferring a negative effect to the hair. Techniques of designing antisense molecules are well known to those of ordinary skill in the art. Hair growth stimulating compounds may have undesirable side effects when delivered systemically, one advantage of the present invention provides compounds for and a method of directly and selectively delivering the compounds to the hair follicle cells without substantially delivering the compound to the bloodstream, thus avoiding such undesirable side effects. In another related embodiment, the beneficial compound is a nucleic acid capable of expressing an effective amount of a replacement therapy protein. Particularly preferred are nucleic acid molecules capable of expressing tyrosinase or hair-growth stimulating proteins or the multi-drug resistance proteins conferring resistance to chemotherapy-induced alopecia.

In other embodiments, the invention contemplates the use of the present liposome compositions according to the present methods for inhibiting chemotherapy-induced alopecia. The liposome compositions contain compounds which reduce in the hair follicle the toxicity of the chemotherapy treatment.

Claim 1 of 8 Claims

What is claimed is:

1. A method to introduce a pigment into the hair shaft through the hair follicle cells associated with said hair shaft directly and selectively which method comprises

topically applying to the skin containing hair follicles of a subject in need of said pigment a formulation consisting essentially of liposomes that have incorporated therein an amount of pigment sufficient to effect hair color, wherein said formulation is free of pigment which is not incorporated in said liposomes;

wherein said formulation delivers said pigment selectively and directly into the hair follicle cells and said formulation does not substantially deliver the pigment to the cells surrounding the hair follicles that are not hair follicle cells or to the systemic circulatory system.

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