Title: Methods for treating multiple sclerosis employing desmethylselegiline
United States Patent: 6,699,495
Issued: March 2, 2004
Inventors: Blume; Cheryl D. (Tampa, FL); DiSanto; Anthony R. (Dade City, FL)
Assignee: Somerset Pharmaceuticals, Inc. (Tampa, FL)
Appl. No.: 026159
Filed: December 21, 2001
Methods and pharmaceutical compositions for using desmethylselegiline. In particular, the present invention provides novel compositions and methods for using desmethylselegiline for selegiline-responsive diseases and conditions. Diseases and conditions responsive to selegiline include those produced by neuronal degeneration or neuronal trauma and those due to immune system dysfunction. Desmethylselegiline is the R-(-) enantiomer of N-methyl-N-(prop-2-ynyl)-2-aminophenylpropane. Claimed compositions include both the R-(-) isomer and mixtures of the R-(-) and S(+) isomers. Pharmaceutically acceptable acid addition salts may also be used. Effective dosages are a daily dose of at least about 0.015 mg/kg of body weight.
SUMMARY OF THE INVENTION
The present invention is based upon the surprising discovery that both desmethylselegiline ("DMS" or "R(-)DMS") and its enantiomer (ent-desmethylselegiline, abbreviated as "ent-DMS" or "S(+)DMS") are useful in providing selegiline-like effects in subjects, notwithstanding dramatically reduced MAO-B inhibitory activity and an apparent lack of enhanced selectivity for MAO-B compared to selegiline. It has been discovered that desmethylselegiline, ent-desmethylselegiline and their isomeric mixtures provide a more advantageous way of obtaining selegiline-like therapeutic effects in selegiline-responsive diseases or conditions. This is particularly true for diseases or conditions characterized by neuronal degeneration, neuronal trauma or which are hypodopaminergic in nature, i.e. diseases or conditions characterized by reduced dopamine release and formation
Thus, the present invention provides novel pharmaceutical compositions in which desmethylselegiline, either alone or in a racemic mixture with ent-desmethylselegiline, is employed as the active ingredient and novel therapeutic methods involving the administration of desmethylselegiline. Specifically, the present invention provides:
(1) An improved method for obtaining selegiline-like therapeutic effects in a subject suffering from a selegiline-responsive disease or condition, which comprises: administering to said subject desmethylselegiline in a dosage regime effective to produce said selegiline-like therapeutic effect.
(2) A non-oral pharmaceutical composition comprising an amount of desmethylselegiline such that one or more unit doses of said composition administered on a periodic basis is effective to treat one or more selegiline-responsive diseases or conditions in a subject to whom said unit dose or unit doses are administered.
The pharmaceutical composition may contain desmethylselegiline in a substantially enantiomerically pure state or, alternatively, the composition may contain a racemic mixture of enantiomers that are together present in an amount sufficient for one or more unit doses of the composition to be effective in treating a selegiline-responsive disease or condition. The composition may be designed in such a way as to make it suitable for sublingual, buccal, parenteral or transdermal administration and may be adapted for effecting neuronal rescue or protection. The composition may also be adapted for restoring or improving immune system function in a human.
In addition, the present invention is directed to a therapeutic package for dispensing to, or for use in dispensing to, a patient being treated for a neuronal-protective or neuronal-regenerative selegeline-responsive disease or condition. The package contains one or more unit doses, each such unit dose comprising an amount of desmethylselegiline such that periodic administration is effective in treating the patient's selegeline-responsive disease or condition. The therapeutic package also comprises a finished pharmaceutical container containing the unit doses of desmethylselegiline and further containing or comprising labeling directing the use of the package in the treatment of the selegiline-responsive disease or condition. The unit doses may be adapted for oral administration, e.g. as tablets or capsules, or may be adapted for non-oral administration.
The invention is also directed to a method of dispensing desmethylselegiline to a patient being treated for a neuronal-protective or neuronal-regenerative selegeline-responsive disease or condition. The method comprises providing patients with a therapeutic package having one or more unit doses of desmethylselegiline in an amount such that periodic administration to the patient is effective in treating their selegeline-responsive disease or condition. The package also comprises a finished pharmaceutical container containing the desmethylselegiline and having labeling directing the use of the package in the treatment the selegeline-responsive disease or condition. The unit doses in the package may be adapted for either oral or non-oral administration.
As used herein the term "selegiline-responsive disease or condition" refers to any of the various diseases or conditions in mammals, including humans, for which selegiline is disclosed in the prior art as being useful. In particular, a "selegiline-responsive disease or condition" refers to the various diseases and conditions described above, e.g., Alzheimer's disease, cognitive dysfunction, neuronal rescue, and the like. The term also refers to the use of selegiline as an appetite suppressant. Similarly, the term "selegiline-like therapeutic effect" refers to one or more of the salutary effects reported as being exerted by selegiline in subjects being treated for a selegiline-responsive disease or condition.
The selegiline-responsive diseases or conditions related to neuronal degeneration or trauma which respond to the present methods include Parkinson's disease, Alzheimer's disease, depression, glaucoma, macular degeneration, ischemia, diabetic neuropathy, attention deficit disorder, post polio syndrome, multiple sclerosis, impotence, narcolepsy, chronic fatigue syndrome, alopecia, senile dementia, hypoxia, cognitive dysfunction, negative symptomatology of schizophrenia, amyotrophic lateral sclerosis, Tourette's syndrome, tardive dyskinesia, and toxic neurodegeneration.
The present invention also encompasses the restoration or improvement of immune system function by R(-)DMS or mixtures of R(-)DMS and S(+)DMS. Such improvement or restoration has been reported to occur when selegiline is administered to animals. The conditions or diseases treatable include age-dependent immune system dysfunction, AIDS, infectious diseases and immunological loss due to cancer chemotherapy.
Desmethylselegiline may be administered either by a route involving gastrointestinal absorption or by a route that does not rely upon gastrointestinal absorption. Depending upon the particular route employed, desmethylselegiline is administered in the form of the free base or as a physiologically acceptable non-toxic acid addition salt. Such salts include those derived from organic and inorganic acids such as, without limitation, hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid, methanesulphonic acid, acetic acid, tartaric acid, lactic acid, succinic acid, citric acid, malic acid, maleic acid, sorbic acid, aconitic acid, salicylic acid, phthalic acid, embonic acid, enanthic acid, and the like. The use of salts, especially the hydrochloride, is particularly desirable when the route of administration employs aqueous solutions, as for example parenteral administration; use of delivered desmethylselegiline in the form of the free base is especially useful for transdermal administration. Accordingly, reference herein to the administration of DMS or ent-DMS or to mixtures thereof encompasses both the free base and acid addition salt forms.
The optimal daily dose of desmethylselegiline, or of a combination of R(-)DMS and S(+)DMS, useful for the purposes of the present invention is determined by methods known in the art, e.g., based on the severity of the disease or condition being treated, the condition of the subject to whom treatment is being given, the desired degree of therapeutic response, and the concomitant therapies being administered to the patient or animal. Ordinarily, however, the attending physician or veterinarian will administer an initial dose of at least about 0.015 mg/kg, calculated on the basis of the free secondary amine, with progressively higher doses being employed depending upon the route of administration and the subsequent response to the therapy. Typically the daily dose will be about 0.5 mg/kg and may extend to about 1.0 mg/kg of the patient's body weight depending on the route of administration. Again, all such doses should be calculated on the basis of the free secondary amine. These guidelines further require that the actual dose be carefully titrated by the attending physician or veterinarian depending on the age, weight, clinical condition, and observed response of the individual patient or animal.
The daily dose can be administered in a single or multiple dosage regimen. Either oral or non-oral dosage forms may be used and may permit, for example, a continuous release of relatively small amounts of the active ingredient from a single dosage unit, such as a transdermal patch, over the course of one or more days. This is particularly desirable in the treatment of chronic conditions such as Parkinson's disease, Alzheimer's disease, and depression. Alternatively, it can be desirable in conditions such as ischemia or neural damage to administer one or more discrete doses by a more direct systemic route such as intravenously or by inhalation. In still other instances such as glaucoma and macular degeneration, localized administration, such as via the intraocular route, can be indicated.
Pharmaceutical compositions containing desmethylselegiline and/or ent-desmethylselegiline can be prepared according to conventional techniques. For example, preparations for parenteral routes of administration for desmethylselegiline, e.g., intramuscular, intravenous and intraarterial routes, can employ sterile isotonic saline solutions. Sterile buffered solutions can also be employed for intraocular administration.
Transdermal dosage unit forms of desmethylselegiline and/or ent-desmethylselegiline can be prepared utilizing a variety of previously described techniques (see e.g., U.S. Pat. Nos. 4,861,800; 4,868,218; 5,128,145; 5,190,763; and 5,242,950; and EP-A 404807, EP-A 509761, and EP-A 593807). For example, a monolithic patch structure can be utilized in which desmethylselegiline is directly incorporated into the adhesive and this mixture is cast onto a backing sheet.
Alternatively desmethylselegiline, and/or ent-desmethylselegiline, can be incorporated as an acid addition salt into a multilayer patch which effects a conversion of the salt to the free base, as described for example in EP-A 593807.
Desmethylselegiline and/or ent-desmethylselegiline can also be administered by a device employing a lyotropic liquid crystalline composition in which, for example, 5 to 15% of desmethylselegiline is combined with a mixture of liquid and solid polyethylene glycols, a polymer, and a nonionic surfactant, optionally with the addition of propylene glycol and an emulsifying agent. For further details on the preparation of such transdermal preparations, reference can be made to EP-A 5509761.
Since the term "ent-desmethylselegiline" refers to the S(+) isomeric form of desmethylselegiline, reference above to mixtures of desmethylselegiline and ent-desmethylselegiline includes both racemic and non-racemic mixtures of optical isomers.
Subjects treatable by the present preparations and methods include both human and non-human subjects for which selegiline-like therapeutic effects are known to be useful. Accordingly, the compositions and methods above provide especially useful therapies for mammals, especially domesticated mammals. Thus, the present methods and compositions are used in treating selegiline-responsive diseases or conditions in canine and feline species.
Successful use of the compositions and methods above requires employment of an effective amount of desmethylselegiline, or mixtures of desmethylselegiline and ent-desmethylselegiline. Although both desmethylselegiline and ent-desmethylselegiline are dramatically less potent than selegiline as inhibitors of MAO, employment of these agents, or a mixture of these agents, for neuroprotection does not require a commensurately increased dosage to obtain a selegiline-like therapeutic response. Surprisingly, dosages necessary to attain a selegiline-like therapeutic appear to be on the same order as the known doses of selegiline. Accordingly, because both desmethylselegiline and ent-desmethylselegiline exhibit a much lower inhibition of MAO-A at such dosages, desmethylselegiline and ent-desmethylselegiline provide a substantially wider margin of safety with respect to MAO-A associated toxicity compared to selegiline. In particular, the risk of the adverse effects of MAO-A inhibition, e.g., hypertensive crisis, are minimized due to the 40-70 fold reduced potency for MAO-A inhibition.
As described above and notwithstanding its demonstrably inferior inhibitory properties with respect to MAO-B inhibition, desmethylselegiline and its enantiomer appear to be at least as effective as selegiline in treating certain selegiline-responsive conditions, e.g., conditions resulting from neuronal degeneration or neuronal trauma. Although the oral route of administration will generally be most convenient, drug may be administered by the parenteral, topical, transdermal, intraocular, buccal, sublingual, intranasal, inhalation, vaginal, rectal or other routes as well.
As noted above, the present invention encompasses the additional discovery that desmethylselegiline can be employed either alone or in mixture with desmethylselegiline.
Claim 1 of 36 Claims
What is claimed is:
1. A method of treating Multiple Sclerosis in a subject suffering from Multiple Sclerosis which comprises administering to the subject a pharmaceutical composition comprising substantially enantiomerically pure R(-)-desmethylselegiline or a pharmaceutically acceptable salt thereof, wherein the composition comprises a pharmaceutically acceptable carrier, employing a single or multiple dosage regimen effective to treat the Multiple Sclerosis.