The New Delhi-based Panacea Biotech, has patented the modified drug release technology for the currently controversial anti-tuberculosis drugs combination-- rifampicin, isoniazid capsules. The company's research group that has been working on the osmotically controlled delivery systems and gastroretentive systems to improve bioavailability of drugs in collaboration with NIPER and various other institutions, had filed this patent in India, Nigeria and Sudan last year.

The rifampicin-isoniazid combination, which has been in use ever since the WHO approved combination therapy for treatment of tuberculosis for better patient compliance in India, has been in the eye of a storm as the bioavailability of rifambicin, the key drug, gets impaired in the presence of isoniazid (). The rifampicin loss is currently estimated in the range of 30 to 50 per cent when the two drugs are released together in the stomach. The poor bioavailability of rifampicin is caused due to the reaction of INH with rifampicin in the acidic condition of the stomach.

Although, the existing manufacturers resort to different arguments on the impaired bioavailability and the following consequences such as drug resistant tuberculosis, prolonged treatments etc, no companies have attempted a new delivery route to get rid of the problem. However, it is learnt that, of late few more Indian companies had also initiated NDDS projects on the anti-TB drugs.

Confirming Panacea's new product launch plan, a highly placed source in the company told Pharmabiz that the company has already set up a new production line in the capsulation plant. Though drug experts are of the view that the dosage of rifampicin can be reduced in the new delivery system as it can provide the optimum bioavailability, the company sources said that it will continue with existing dosage of 250 mg of rifampicin as per the WHO guideline. The company will have all the variants of the combi-therapy such as the three drug and four drug combinations.

This is the first time Panacea is planning a rifampicin combination in the anti-TB segment. At present the company has two products-Myser (cycloserine 250 mg capsule) and Myobid (ethionamide 250 mg tablet), in the anti tuberculosis segment.