PREFORMULATION OF ANTITUBERCULOUS DRUGS IN POLYMERIC BASED FILMS

Document Type : Original Article

Authors

1 Department of Pharmaceutics, Faculty of Pharmacy, Assiut University, Assiut, Egypt

2 Department of Microbiology and Immunology, Faculty of Medicine, Assiut University, Assiut, Egypt

Abstract

Controlled - release rifampicin (RP) and isoniazid (INH) polymeric films were cast from ethylene-vinyl acetate-copolymer (EVA), polyvinyl acetate (PVA) and cellulose acetate butyrate (CAB) polymeric solutions. Evaluation of the films was done by determining Young's modulus of elasticity, tensile strength and permeability parameters. Hard and brittle films were obtained with CAB films while, PVA and EVA form soft and tough films. The incorporation of drugs in either polymers resulted in a decrease in the modulus of elasticity. The rate of permeation depended on the hydrophilicity of the drug and the polymer type. The permeation rate of INH through EVA is higher than CAB films while RF has low permeability across both films. The effect of initial drug concentration on the release rate from films was determined for each drug. There was a linear relationship between released amount of drug per unit surface area and square-root of time. The release rate of RF from EVA and CAB polymeric films is lower than that of INH. The release rate of INH from EVA films was higher than from PVA films. While that of RF from EVA and PVA films was enhanced by incorporating different concentrations of ethylcellulose (EC) as a film component. The slow release of RF from polymeric films was attributed to the possible interaction of RF with the polymer used in the preparation of the film as indicated from infrared spectral studies. The effect of dimethyl formamide (DMF) as a solubility modifier for RF in the films was indicated by increasing the release rate of the latter from EVA rather than from CAB films. The enhancing effect of DMF on the release rate of RF from polymeric films was found to be dependent on the level of DMF incorporated in the film. The antibacterial effect of RF released from polymeric films was found to be greatest from EVA followed by PVA films. The results were promising for topical formulation of RF.