Design and Evaluation of Novel Dosage Form of Rifampicin and Isoniazid with Improved Functionality

Abstract:

The aim of present investigation was to develop a novel dosage form of rifampicin and isoniazid to minimize degradation of rifampicin in acidic medium and to modulate the release of rifampicin in the stomach and isoniazid in intestine. Gastroretentive tablets of rifampicin were prepared by direct compression using polyethylene oxide, calcium carbonate and ascorbic acid. The powder blend and tablets of rifampicin were characterized. Isoniazid tablets, prepared by direct compression using dicalcium phosphate, were enteric coated using hydroxypropylmethylcellulose (HP-55S) and characterized. Two tablets each of rifampicin and isoniazid were put into a hard gelatin capsule (size 00) and characterized for in vitro drug release and in vitro drug degradation studies. Rifampicin was released over 4 h from the novel dosage form. Less than 8% of isoniazid was released from novel dosage form before reaching to intestinal pH 7.4. Complete drug release of isoniazid was observed within 90 m at pH 7.4. The degradation of rifampicin to 3-formyl rifampicin SV (3FRSV) in presence of isoniazid was arrested (less than 0.21% degradation of rifampicin at the end of 120 m) from novel dosage form because of the minimization of physical contact between the two drugs and controlled release of rifampicin in acidic medium.

Key words-Rifampicin, Gastroretentive tablets, Isoniazid, Hydroxypropylmethylcellulose phthalate, Degradation, Modified dissolution apparatus