Sustained release isoniazid tablets. I--Formulation and in vitro evaluation.

Isoniazid (INH) has been widely used in the preventive therapy of tuberculosis since the early 1950's. The aim in designing a sustained release tablet form was to attain in fast inactivators sustained blood concentrations similar to those produced by ordinary INH tablets in slow acetylators during chemotherapy. In the present paper, the release of INH incorporated into three different matrix materials, polymethylmethacrylates, polyvinyl chloride and carbomer were studied. The release rate of a unit dose of conventionally formulated INH tablets was used as a basis of comparison. The best sustained effect on the release rate of INH was obtained with 30% carbomer matrix tablets.