MXPA00006079A - Topical carbamazepine formulations and methods of use - Google Patents

Abstract

A therapeutic formulation comprises a topically acceptable semisolid vehicle and carbamazepine, the vehicle consisting of components that are compatible with the carbamazepine, and the carbamazepine being in a concentration sufficient to permit a therapeutically effective amount of the carbamazepine to be absorbed from the formulation into the skin of a patient. The vehicle may be a cream, ointment, or gel. A method of treating a skin condition of a patient such as psoriasis comprises applying carbamazepine topically to the patient's skin until the condition improves. A method of administering carbamazepine to a patient comprises applying a formulation comprising carbamazepine topically to the patient's skin.

Description

FORMULATIONS OF TOPICAL CARBAMAZEPINE AND METHODS OF USE BACKGROUND OF THE INVENTION The invention relates to topical formulations of carbamazepine and its use to treat skin conditions such as psoriasis. Carbamazepine and its derivatives are well known as systemic bioactive agents useful as anticomvulsants. They are used to treat the central nervous system as epilepsy. A patent review with reference to carbamazepine reveals that there is ongoing research on oral formulations of carbamazepine, intravenous formulations, sustained release delivery systems, including a transdermal patch, and uses to treat other nervous system disorders, vertigo, syndromes Parkinson's, dependence on drugs such as alcoholism, and cocaine use. These formulations are all aimed at systemic applications, and the therapeutic objectives are essentially neurological diseases and essentially neurological states. The systemic use of drugs has disadvantages, such as the need for higher dosages, side effects in regions of the body not related to the affected tissue, toxicity to the liver or other organs, and slow or long-term results. Carbamazepine can cause neuropathy, adverse hematological effects, such as anemia, and hypersensitivity syndrome including dermatitis. The side effects can be so severe that they require the interruption of therapy in some patients. However, carbamazepine is believed to be a drug that is only effective in systemic applications. Their mechanisms of action and metabolism are not well understood. It would be desirable to find new ways to administer carbamazepine with reduced side effects. Psoriasis is a disease of poorly understood etiology. There has been a limited arsenal of useful therapeutic methods to treat the disease, including physical treatment (sun, local heat, mud treatment) and steroids. The beneficial effects of these approaches are limited. None is effective in all cases, and the failure rate is high. Any new effective method of treatment would be of enormous value in relieving the pain of people with psoriasis.

SUMMARY OF THE INVENTION According to the invention, the topical formulations of carbamazepine comprise a pharmaceutically acceptable carrier in which a convenient concentration of carbamazepine is dissolved or suspended, the drug and the vehicle interact so that the topically effective amount of carbamazepine can be transfer to the epidermal tissue to which the formulation is applied. The invention also encompasses a method of treating psoriasis which comprises applying an effective amount of a topical formulation of carbamazepine to the affected area until the condition is improved. This provides a new treatment modality using a new active agent. A therapeutic formulation comprises a topically acceptable semi-solid vehicle and carbamazepine, converting the vehicle into components that are compatible with carbamazepine, and carbamazepine being in a sufficient concentration to allow a therapeutically effective amount of carbamazepine to be absorbed from the formulation in the skin. of a patient. The vehicle can be a cream, ointment or gel. The method for treating the skin condition of a patient such as psoriasis comprises applying carbamazepine topically to the patient's skin until the condition improves. A method of administering carbamazepine comprises applying a formulation comprising carbamazepine locally in the affected area, preferably topically to the skin of a patient. Other objectives and advantages will become apparent from the consideration of the description and drawings.

Detailed description of the preferred embodiments In describing the preferred embodiments of the present invention and illustrate the drawings, specific terminology is used for the sake of clarity. However, the invention is not intended to be limited to the specific terminology thus selected, and it will be understood that each specific element includes technical equivalents that operate in a similar manner to carry out the same purpose. It was observed that an HIV positive patient suffering from psoriatic erythroderma exhibited improvement when he accidentally ingested 200-400 milligrams / days of Tegretol® carbamazepine for two weeks. The condition arose again when he stopped taking the medication. The condition improved again when he intentionally started taking the medication a second time. His mood was affected too. Smith and Skelton, New England Journal of Medicine. December 26, 1996, page 1999. According to the invention, similar effectiveness can be achieved in a topical formulation whose use minimizes the physiological and other side effects of carbamazepine administered systemically. This formulation is a semi-solid or non-solid suitable for dispersing over the affected tissue of a patient. The formulation may be a cream, ointment, gel, lotion, or liquid, and may be occlusive and moisturizing. An oil-in-water emulsion that provides an elegant cream base is most preferred. A liquid is desirable to treat the scalp. The components of the formulation are selected to be compatible, stable, topically acceptable and capable of supporting carbamazepine in a chemically stable state, and to be administered to the skin of a patient after application. Carbamazepine may be present as a suspension or a solution. A solution is preferred in order to facilitate the timely administration of the drug. Carbamazepine is practically insoluble in water, but it is soluble in alcohols, acetone and propylene glycol. In accordance with the foregoing, vehicles containing propylene glycol are preferred. Carbamazepine can be made into pharmaceutical compositions with appropriate pharmaceutically acceptable carriers or diluents and can be formulated in semisolid or liquid form. Methods known in the art can be used to control the release or absorption of the composition over time. A pharmaceutically acceptable formula should be employed that does not render the compositions of the present invention ineffective. The compositions can be used alone or in appropriate association, as well as in combination with other pharmaceutically active compounds. The formulation may further comprise anti-inflammatory components such as steroids, or non-steroidal compounds, and may comprise local anesthetics. The method of the composition of the invention can be used in combination or in rotation with other treatment regimens, to avoid the desensitization effect that occurs with psoriasis and other skin diseases. By "non-solid" is meant to exclude dosage forms such as tablets, and includes gels, creams, ointments, lotions, liquids and suspensions. The term "treatment" is intended to encompass the administration of compounds according to the invention prophylactically to prevent or suppress an undesired condition, and therapeutic administration to eliminate or reduce the degree of symptoms of the condition. Treatment according to the invention can be for a human for an animal having a disease in need of this treatment. The "effective amount" of the composition is such that it produces the desired effect in a host that can be monitored using various endpoints known to those skilled in the art. For example, a desired effect could include the reduction of psoriatic inflammation. These effects could be monitored in terms of a therapeutic effect, for example, relief of some symptom associated with the disease being treated, or particularized tests. These described methods are by no means totally inclusive, and other methods that satisfy the specific application will become apparent to the technician with ordinary experience. In addition, the amounts of each active agent included in the compositions employed in the examples described herein provide the general guidance and range of each component to be used by the practitioner after optimizing the method of the present invention for practice. either in vitro or in vivo. Moreover, these ranges in no way prevent the use of a higher or lower quantity of a component, as could be guaranteed in a particular application. For example, the current dose and schedule may vary depending on whether the compositions are administered in combination with other pharmaceutical compositions, or depend on interindividual differences in severity, pharmacokinetics, drug disposition, and metabolism. A person skilled in the art can easily make any necessary adjustment according to the needs of the particular situation. The concentration of carbamazepine in such a formulation is sufficiently high to allow administration of a therapeutically effective amount, but not so high as to cause undesired side effects. A preferred concentration is between about 0.05 percent and about 20 percent. A more preferable concentration is between about 1 percent and about 6 percent. Skin refers to any epidermal tissue in which psoriasis may occur, including that of the extremities, trunk, head, as well as mucosa, and so on. As used herein, carbamazepine is intended to mean 5-carbamoyl-5H-dibenz [b, f] azepine and pharmaceutically acceptable and stable salts and therapeutically effective derivatives thereof. Without pretending to be limited by the mode of action, it is believed that carbamazepine, applied topically, penetrates the skin from the outside to provide a therapeutic effect as when the systemic exposure of carbamazepine enters the skin from the fine capillaries. In one embodiment of the invention, an oil-in-water emulsion is prepared to form an elegant cream. The carbamazepine in pure powder form is dissolved in propylene glycol (for example up to about 95 percent). Alternatives of the aqueous phase include an alcohol such as ethanol or isopropanol, with an added thickener, for example Carbomer 934 or 940. The oil phase preferably includes mineral oil with petrolatum, cetyl alcohol and / or sterile alcohol. Emulsifiers such as polysorbate 80, sorbitan monostearate, or others known in the art can be used. Regulating agents, antioxidants, and gelling agents can be added to improve the characteristics of the formulation. In another embodiment, an ointment is prepared by micronising carbamazepine to provide particles with a size distribution mainly below 10 microns, and adding them to mineral oil to form a finely dispersed suspension, which is then mixed with petrolatum.

Example 1 A gel comprising the following ingredients is prepared. The concentrations are given in percent by weight. Carbamazepine 5% Propylene glycol 93% Carbomer 934 neutralized with 2% sodium hydroxide Example 2 A cream is prepared comprising the following ingredients. Carbamazepine 1% Propylene glycol 50% Cetostearyl alcohol 5% Sodium lauryl sulfate 1% Water 43% Example 3 An ointment is prepared with the following ingredients. Carbamazepine 3% Mineral oil 5% Petrolatum 92% Example 4 CCaarrbbaammaazzeeppiinnaa aall 55 %% eenn propylene glycol and the formulations of the previous examples are applied daily to the skin of a mouse with experimentally induced model of psoriasis induced by ultraviolet light. Based on observations of the size and number of lesions and plaques, topical carbamazepine treatment is more effective than a placebo for each vehicle lacking the carbamazepine used as control. The embodiments illustrated and discussed in this specification are intended only to show those skilled in the art the best known way for the inventors to make and use the invention. Nothing in this specification shall be considered as limiting the scope of the present invention. Modifications and variations of the above-described embodiments of the invention are possible without departing from the invention, as appreciated by those skilled in the art in light of the above teachings. It will therefore be understood that, within the scope of the claims and their equivalents, the invention can be practiced otherwise than as specifically described.

Claims (9)

1. A pharmaceutical formulation comprising a topically acceptable non-solid carrier and carbamazepine the vehicle consisting of components that are compatible with carbamazepine, and carbamazepine being in a sufficient concentration to allow a therapeutically effective amount of carbamazepine to be absorbed from the formulation in the skin of a patient.

2. A formulation according to the claim 1, wherein the vehicle is a cream, ointment, liquid, lotion or gel.

3. A formulation according to claim 1, wherein the carbamazepine has a sufficiently high concentration to be effective as applied, but not so high as to cause systemic side effects.

4. A formulation according to claim 1, wherein the carbamazepine has a concentration between about 0.05 percent and about 20 percent.

5. A formulation according to claim 1, wherein the carbamazepine has a concentration between about 1 percent and about 6 percent.

6. A method for treating a skin condition of a patient that comprises applying carbamazepine topically to the patient's skin repeatedly until the condition improves. The method of claim 6, wherein the condition is psoriasis. 8. A method of administering carbamazepine to a patient which comprises applying carbamazepine locally. 9. A method according to claim 8, comprising applying the carbamazepine in a topically acceptable vehicle and topically to the skin of the patient.