Pharmaceutical compositions of 5-alpha-reductase inhibitors and methods of use thereof

Abstract

Non-occlusive compositions for transdermal delivery of 5-alpha-reductase inhibitors, and more particularly finasteride or dutasteride or pharmaceutically acceptable salts or derivatives thereof, and methods of making same. The composition may, for example, be a gel suitable for transdermal or transmucosal applications. The compositions of the present invention typically include a mixture of water and alcohol, and a solvent system having a mono alkyl ether of diethylene glycol and a glycol present in specified ratios and in specific amounts, wherein the pH of the gel is usually between about pH 4.5 and about pH 8. The compositions may include further components, for example, the hydroalcoholic vehicle may further include additional penetration enhancer(s), buffering agent(s), antioxidant(s), stabilizer(s) and / or gelling agent(s). Also, a method for the sustained delivery of 5-alpha-reductase inhibitors to treat a variety of conditions and disorders.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation-in-part of co-pending application Ser. No. 11 / 755,923, filed May 31, 2007, which is a continuation-in-part of application Ser. No. 11 / 371,042, filed Mar. 7, 2006, now U.S. Pat. No. 7,335,379, which in turn is a continuation of International application PCT / EP2004 / 011175 filed Oct. 6, 2004, which in turn claims the benefit of U.S. Provisional Application No. 60 / 510,613, filed Oct. 10, 2003. The content of each prior application is expressly incorporated herein by reference.TECHNICAL FIELD[0002]The present invention relates to novel transdermal or transmucosal pharmaceutical formulations, including compositions and dosage forms, of dutasteride and its pharmaceutically acceptable salts thereof, and a hydroalcoholic solvent system, wherein the solvent system includes monoalkyl glycol ethers and glycols in specific ratios.[0003]Described herein are formulations that are useful and efficacious for transdermal ...

AI Technical Summary

Benefits of technology

The formulation achieves higher transdermal flux and bioavailability of 5-alpha-reductase inhibitors, reducing skin irritation and contamination risks while allowing for once-daily dosing and prolonged drug release, effectively treating conditions like androgenetic alopecia and benign prostatic hyperplasia.

Problems solved by technology

However, despite its clear advantages, transdermal delivery also poses inherent challenges, in part because of the nature of skin.

But even with these methodologies, only a limited number of drugs can be administered transdermally without problems such as sensitization or irritation occurring.

The vehicle may also cause skin irritation or allergic reactions in some patients.

Because the non-occlusive dosage form is left uncovered, unwanted transfer of the pharmaceutical formulation to the clothing of the user or even to other individuals in close proximity to the user is unavoidable.

Other drawbacks of the non-occlusive dosage form include evaporation of the formulation, removal of the formulation from the skin or mucosa, for example, by bathing or by other activities, and the non absorption of the formulation through the skin, which is discussed below.

Thus, a vast majority of the active drug remains unabsorbed on the skin or mucosa surface.

Because the vast majority of the drug remains on the skin and does not penetrate the skin or mucosa surfaces, the bioavailability of the particular drug is not optimal, and also a high risk of contamination of other individuals in close proximity to the user is presented by the unwanted transfer of the pharmaceutical formulation in the non-occlusive dosage form.

Problems associated with the unwanted transfer of a particular pharmaceutical formulation to others are well documented.

However occlusive dosage forms also exhibit several major drawbacks.

For example, occlusive dosage forms present a high potential of local skin irritation caused by the prolonged contact on the skin of the drug, volatiles, vehicle excipients, and the adhesive used to attach the occlusive device, e.g., the patch, to the skin.

In addition, the occlusive nature of certain occlusive dosage forms, such as the patch device, also restrict the natural ability of the skin to “breathe,” and thereby increases the risk of irritation.

In addition to the aforementioned drawbacks of occlusive dosage forms, significant serious hazards have been documented regarding the high drug loading that is specific to patches.

USA) contains patient information that indicates the following warning: “Since the patch will still contain some oxybutynin, throw it away so that it can not be accidentally worn or swallowed by another person, especially a child.” The high level of active drug residues is thus a critical drawback of patches.

Although attempts have been made to overcome drawbacks associated with both occlusive and non-occlusive drug forms, such attempts have been futile.

For example, as noted above, one drawback of non-occlusive dosage forms is evaporation of the formulation, which is left open in the atmosphere.

The formulation of non-occlusive supersaturated systems could have achieved an ideal merge but transdermal formulations, which rely on supersaturation technologies, present a major drawback of formulation instability, both prior to and during application to the skin due to solvent evaporation.

Notably, extraordinary physicochemical changes occur with the evaporation of the solvent system, which result in modifications of the concentration of the active agent, which may even lead to drug precipitation, thereby altering the diffusional driving force of the formulation.

Further, transdermal delivery from semi-solid formulations faces opposite requirements.

Conversely, for a volatile vehicle which begins evaporating from the moment of application, the surface concentration of the chemical increases with time up to the point at which the solvent has disappeared; one is now left with a solid film of the chemical from which continued uptake into the stratum corneum may be very slow and dissolution-limited.

Inhibition of 5-alpha reductase results in decreased production of DHT, increased levels of testosterone and possibly increased levels of estradiol.