Cipla, Glenmark Pharmaceuticals, Sun Pharma and Torrent Pharmaceuticals are the firms which are eagerly pursuing a larger share of the Indian obesity market, which is estimated at Rs 500 crore.

Cipla's drug, Obestat, came in December and it has been followed by Sibutrim produced by Glenmark Pharma. Sun Pharma and Torrent Pharmaceuticals are awaiting for the drug controller's permission to launch their versions of the drug.

Drugs to control obesity work by acting on appetite control centres in the brain and are used as part of a comprehensive weight-loss programme comprising exercise and diet control under the supervision of a qualified medical practitioner.

According to experts, a 10 mg capsule taken for atleast six months can help reduce excess weight of around 10 kg, provided it is aided by some exercise and diet control.

Knoll has been marketing its drug, which it imports, at Rs 115 for a 10 mg capsule. However, the Indian version launched by Cipla and Glenmark Pharma is available at Rs 15 for a 10 mg capsule and Rs 8 for a 5 mg capsule. Worldwide, the drug developed by Knoll Pharmaceuticals is marketed under the brand name `Merinda'. It is a patented drug in the US.

Since product patents are not applicable in India, the Indian companies have developed a similar drug with a different process and marketed it at a steep discount. One of the reasons for a huge price difference between the imported and the Indian version of the drug is the customs duty of 35 per cent plus the surcharge.

It is difficult to estimate the market size but it is safe to assume that 20 to 40 per cent adults suffer from obesity in India. Since there is a growing awarness of the health risks associated with obesity, an affordable drug would have a huge number of potential users.