Panacea Biotech, which has recently patented a modified drug release technology for anti-tuberculosis drugs combination (rifampicin + isoniazid), is all set to launch the product in the Indian market in January 2004. The company's research group that had 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 therapy, which has been in use ever since the WHO approved combination therapy for treatment of tuberculosis for better patient compliance in India, is in the eye of a storm as the bioavailability of rifampicin, the key drug, gets impaired in the presence of isoniazid. The rifampicin loss in the existing combinations is estimated in the range of 30 to 50 per cent. The rifampicin loss occurs when it gets released along with isoniazid simultaneously together in the stomach. The poor bioavailability of rifampicin is caused due to the reaction of isoniazid 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 other companies have attempted a new delivery route to get avoid this serious problem. However, it is learnt that, few more Indian companies had initiated NDDS projects on the anti-TB drugs as the poor bioavailability of the combination drug is found to be one of the causes for rampantly growing multi-drug resistant tuberculosis (MDR TB).
Confirming Panacea's new product launch plan, company sources 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 would 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 formulations such as three drug and four drug combinations. However, 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.