The subject invention provides useful and novel calcium channel blockers based upon mibefradil. The subject invention also provides methods for synthesizing the compounds of the invention. The invention also provides methods for the control or prevention of hypertension, angina pectoris, ischemia, arrhythmias, and cardiac insufficiency in a patient by administering a compound, or composition, of the invention to an individual in need of such treatment.

BRIEF SUMMARY OF THE INVENTION

The subject invention provides useful and novel calcium channel blockers. The subject invention also provides methods for synthesizing the compounds of the invention. The invention also provides methods for the control or prevention of hypertension, angina pectoris, ischemia, arrhythmias, and cardiac insufficiency in a patient by administering a compound, or composition, of the invention to an individual in need of such treatment.

Advantageously, the subject invention provides compounds which are readily metabolized by the physiological metabolic drug detoxification systems. Specifically, in a preferred embodiment, the therapeutic compounds of the subject invention contain an ester group, which does not detract from the ability of these compounds to provide a therapeutic benefit, but which makes these compounds more susceptible to degradation by hydrolases, particularly serum and/or cytosolic esterases. The subject invention further provides methods of treatment comprising the administration of these compounds to individuals in need of calcium channel blocking treatment

This invention is drawn to compounds which are more easily metabolized by the metabolic drug detoxification systems. This invention is also drawn to methods of treating disorders which can be treated by blocking calcium channels. Specifically, this invention provides analogs of drugs which have been designed to be more susceptible to degradation by hydrolases, particularly serum and/or cytosolic esterases and methods of treatment comprising the administration of these analogs to individuals.

DETAILED DISCLOSURE OF THE INVENTION

The subject invention concerns novel calcium channel blockers. Preferably, the calcium channel blocker can be deactivated to a primary inactive metabolite by hydrolytic enzymes. Compounds of the present invention can be advantageously used to treat individuals suffering from cardiovascular diseases as exemplified by hypertension, angina pectoris, ischemia, arrhythmias and congestive heart failure. Many of these individuals are taking multiple drugs, thus, the compounds of the subject invention would be much safer in view of the reduced or eliminated incidence of DDI, LFT, and/or TDP.

Verapamil, diltiazem, and nifedipine represent three different structural classes of calcium entry blockers and are all currently marketed in the United States. However, these compounds do not demonstrate the same kind of clinical benefit as mibefradil since they tend to decrease myocardial contractive force. Accordingly, in a preferred embodiment, the present invention provides novel mibefradil-based compounds that have been modified to provide for metabolism via endogenous hydrolytic enzymes. The novel compounds are referred to as soft calcium channel blockers, i.e. bioactive molecules having cardiovascular properties and undergoing deactivation to primary inactive metabolites by hydrolytic enzymes. FIGS. 3-9 (see Original Patent) provide exemplary metabolic degradation routes for exemplary compounds of the invention.

Additional modifications of the compounds disclosed herein can readily be made by those skilled in the art. Thus, analogs and salts of the exemplified compounds are within the scope of the subject invention. With a knowledge of the compounds of the subject invention skilled chemists can use known procedures to synthesize these compounds from available substrates. As used in this application, the term "analogs" refers to compounds which are substantially the same as another compound but which may have been modified by, for example, adding additional side groups. The term "analogs" as used in this application also may refer to compounds which are substantially the same as another compound but which have atomic or molecular substitutions at certain locations in the compound.

Analogs of the exemplified compounds can be readily prepared using commonly known, standard reactions. These standard reactions include, but are not limited to, hydrogenation, methylation, acetylation, and acidification reactions. For example, new salts within the scope of the invention can be made by adding mineral acids, e.g., HCl H.sub.2SO.sub.4, etc., or strong organic acids, e.g., formic, oxalic, etc., in appropriate amounts to form the acid addition salt of the parent compound or its derivative. Also, synthesis type reactions may be used pursuant to known procedures to add or modify various groups in the exemplified compounds to produce other compounds within the scope of the invention.

In a preferred embodiment, the subject invention provides compounds having the following formula -- see Original Patent.

The subject invention further pertains to enantiomerically isolated compounds, and compositions comprising the compounds, for calcium channel blocking. The isolated enantiomeric forms of the compounds of the invention are substantially free from one another (i.e., in enantiomeric excess). In other words, the "R" forms of the compounds are substantially free from the "S" forms of the compounds and are, thus, in enantiomeric excess of the "S" forms. Conversely, "S" forms of the compounds are substantially free of "R" forms of the compounds and are, thus, in enantiomeric excess of the "R" forms. In one embodiment of the invention, the isolated enantiomeric compounds are at least about in 80% enantiomeric excess. In a preferred embodiment, the compounds are in at least about 90% enantiomeric excess. In a more preferred embodiment, the compounds are in at least about 95% enantiomeric excess. In an even more preferred embodiment, the compounds are in at least about 97.5% enantiomeric excess. In a most preferred embodiment, the compounds are in at least 99% enantiomeric excess.

A further aspect of the subject invention pertains to the breakdown products which are produced when the therapeutic compounds of the subject invention are acted upon by hydrolytic enzymes, such as esterases. The presence of these breakdown products in urine or serum can be used to monitor the rate of clearance of the therapeutic compound from a patient.

Thus, the subject invention also provides antibodies that specifically react with metabolic breakdown products of the subject invention as wells as detection assays for the identification of metabolic breakdown products in the serum or urine of an individual. In some preferred embodiments, the antibodies specific for the metabolic breakdown products of the invention do not cross-react with the therapeutic compounds (i.e., soft calcium channel blockers) of the invention. Other embodiments provide for antibodies that do not specifically bind to metabolic breakdown products of the soft calcium channel blockers but which specifically bind to non-metabolized (intact) soft calcium channel blockers of the subject invention. In yet other embodiments, antibodies that specifically bind to both metabolic breakdown products and intact compounds of the invention are provided. The subject invention also provides for kits containing any combination of the antibodies discussed supra and/or containing soft calcium blockers of the invention and/or metabolic breakdown products of the invention. In some embodiments, the kits of the invention include assay substrates (e.g., immunoassay plates or substrates upon which lateral flow assays are performed) coated with antibodies or biosensors containing antibodies of the invention. Alternatively, assay substrates or biosensors can be coated with intact compounds or metabolic breakdown products of the inventive compounds. Other embodiments provide various combinations of antibodies, intact compounds, and metabolic breakdown products coated on assay substrates or biosensors.

The term "antibody" encompasses polyclonal and monoclonal antibody preparations, as well as preparations including hybrid antibodies, genetically altered antibodies (including antibodies modified to alter their physiochemical characteristics and antibodies subjected to affinity mutagenesis to increase or decrease their binding affinities (e.g., through alanine scanning mutagenesis)), F(ab').sub.2 fragments, F(ab) fragments, F.sub.v fragments, single domain antibodies, chimeric antibodies, diabodies, multispecific antibodies, humanized antibodies, and functional fragments thereof which exhibit immunological binding properties of the parent antibody molecule. Methods of making polyclonal, recombinant, and monoclonal antibodies, as well as antigen binding fragments of such antibodies, are well-known in the art.

Detection systems for the identification of metabolic breakdown products present in the serum or urine of an individual include ligand-receptor binding assays. Non-limiting examples of such assays can include antibody-based assays such as enzyme linked immunosorbent assays (ELISAs), radioimmunoassays (RIAs), lateral flow assays, automated flow assays, and assays utilizing antibody containing biosensors. The assays and methods for conducting the assays are well-known in the art. Ligand-receptor binding assays can be considered to be of four types: direct binding, sandwich assays, competition assays, and displacement assays. While the exact arrangement of ligands and receptors varies widely as does the type of readout system involved, the four types can be generally (but not exclusively) described as follows.

In a direct binding assay, either the ligand or receptor is labeled, and there is a means of measuring the number of complexes formed. In a sandwich assay, the formation of a complex of at least three components (e.g., receptor -ligand-labeled receptor) is measured. In a competition assay, labeled ligand and unlabelled ligand compete for binding to the receptor, and either the bound or the free component is measured. In a displacement assay, the labeled ligand is prebound to the receptor, and a change in signal is measured as the unlabelled ligand displaces the bound labeled ligand from the receptor.

Displacement assays and flow immunosensors useful for carrying out displacement assays are described in: (1) Kusterbeck et al., "Antibody-Based Biosensor for Continuous Monitoring," in Biosensor Technology, R. P. Buck et al., eds., Marcel Dekker, N.Y. pp. 345-350 (1990); Kusterbeck et al., "A Continuous Flow Immunoassay for Rapid and Sensitive Detection of Small Molecules," Journal of Immunological Methods, vol. 135, pp. 191-197 (1990); Ligler et al., "Drug Detection Using the Flow Immnosensor," in Biosensor Design and Application, J. Findley et al, eds., American Chemical Society Press, pp. 73-80 (1992); and Ogert et al., "Detection of Cocaine Using the Flow Immunosensor," Analytical Letters, vol. 25, pp. 1999-2019 (1992), all of which are incorporated herein by reference in their entireties. Displacement assays and flow immunosensors are also described in U.S. Pat. No. 5,183,740, which is also incorporated herein by reference in its entirety. The displacement immunoassay, unlike most of the competitive immunoassays used to detect small molecules, can generate a positive signal with increasing antigen concentration.

The subject invention further provides methods of synthesizing the unique and advantageous therapeutic compounds of the subject invention. Particularly, methods of producing less toxic therapeutic agents comprising introducing ester groups into therapeutic agents are taught. The ester linkage may be introduced into the compound at a site which is convenient in the manufacturing process for the compounds of the invention. Various exemplary synthetic routes for the preparation of the compounds of the subject invention are described in FIGS. 10-12 (see Original Patent). Additionally, the sensitivity of the ester linkage may be manipulated by the addition of side groups which hinder or promote the hydrolytic activity of the hydrolases or esterases responsible for cleaving the drug at the ester locus. Methods of adding such side groups, as well as the side groups themselves, are well known to the skilled artisan and can be readily carried out utilizing the guidance provided herein.

The term "individual(s)" is defined as a single mammal to which is administered a compound or composition of the present invention. The mammal may be, for example a mouse, rat, pig, horse, rabbit, goat, pig, cow, cat, dog, or human. In a preferred embodiment, the individual is a human.

The compounds of this invention have therapeutic properties similar to those of the unmodified parent compounds. Accordingly, dosage rates and routes of administration of the disclosed compounds are similar to those already used in the art and known to the skilled artisan. (See, for example, Physicians' Desk Reference. 54.sup.th Ed., Medical Economics Company, Montvale, N.J., 2000.)

The compounds of the subject invention can be formulated according to known methods for preparing pharmaceutically useful compositions. Formulations are described in detail in a number of sources which are well known and readily available to those skilled in the art. For example, Remington's Pharmaceutical Science by E. W. Martin describes formulation which can be used in connection with the subject invention. In general, the compositions of the subject invention are formulated such that an effective amount of the bioactive compound(s) is combined with a suitable carrier in order to facilitate effective administration of the composition.

In accordance with the subject invention, pharmaceutical compositions are provided which comprise, as an active ingredient, an effective amount of one or more of the compounds and one or more non-toxic, pharmaceutically acceptable carriers or diluents. Examples of such carriers for use in the invention include ethanol, dimethyl sulfoxide, glycerol, silica, alumina, starch, and equivalent carriers and diluents.

Further, acceptable carriers can be either solid or liquid. Solid form preparations include powders, tablets, pills, capsules, cachets, suppositories and dispersible granules. A solid carrier can be one or more substances that may act as diluents, flavoring agents, solubilizers, lubricants, suspending agents, binders, preservatives, tablet disintegrating agents or encapsulating materials.

The disclosed pharmaceutical compositions may be subdivided into unit doses containing appropriate quantities of the active component. The unit dosage form can be a packaged preparation, such as packeted tablets, capsules, and powders in paper or plastic containers or in vials or ampoules. Also, the unit dosage can be a liquid based preparation or formulated to be incorporated into solid food products, chewing gum, or lozenges.

All patents, patent applications, provisional applications, and publications referred to or cited herein are incorporated by reference in their entirety, including all figures and tables, to the extent they are not inconsistent with the explicit teachings of this specification.
 

Claim 1 of 10 Claims

1. A method for blocking a calcium channel in a patient in need of such blocking wherein said method comprises administering to said patient a calcium channel blocking compound wherein said compound has the following structure: ##STR00003## -- see Original Patent.

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