Tests conducted by the Ahmedabad based NGO Consumer Education & Research Centre (CERC) on 20 popular anti-diabetic tablets available in the Indian drug market have revealed that the drugs are of good quality and conforms to various quality parameters.

It said that the brands passed all the tests including active ingredient identification, assay and uniformity of weight, disintegration and uniformity of content, dissolution and label information.

According to CERC, it tested two kinds of anti-diabetic oral drugs, sulphonylurea and biguanide at its in-house laboratory. Sulphonylureas work by stimulating the pancreas to release more insulin. Non-obese patients with Type 2 diabetes (non-insulin dependent diabetes) are usually prescribed sulphonylureas. Biguanides work by increasing insulin sensitivity and glucose utilisation and reducing the amount of glucose produced by the liver. Obese patients with Type 2 diabetes are usually prescribed biguanides.

CERC tested five brands of each type of generic drug, all of which are national brands. The glibenclamide tablets tested were Daonil (Aventis Pharma), Diabetnil (Inga Pharmaceuticals Pvt. Ltd.), Euglucon (Nicholas Piramel), Glyboral (USV Ltd.) and Glinil (Cipla) which had 5 mg strength. Glycomet (USV), Gluformin Nicholas Piramel), Walaphage (Wallace Pharmaceuticals), Glyciphage (Franco-Indian pharmaceuticals) and Obimet (Abbot India) were metformin tablets and were of 500 mg. The glipizide tablets of 5 mg were Glynase (USV India), Diaglip (Sanofi India), Glide, Glucotrol (Pfizer) and Glibetic (Pharm Products) and the gliclazide tablets of 80 mg were Glycigon (Aristo Pharmaceutical Ltd), Reclide (Dr Reddy's Lab), Glizid (Panazea Biotech), Dianorm (Micro Labs) and Diamicron (Serdia Pharmaceuticals (India) Ltd).

CERC tested four generic drugs, glibenclamide, glipizide, gliclazide and metformin. Out of these, metformin is a biguanide and the other three are sulphonylureas. The glibenclamide and metformin tablets were tested as per the Indian Pharmacopoeia (IP). Glipizide and gliclazide tablets were tested as per the British Pharmacopoeia (BP) since tests for them were not specified in the IP. All the tablets were tested for four basic parameters - identification, assay, uniformity of weight and disintegration. CERC also tested glibenclamide for uniformity of content and metformin tablets for dissolution as specified. Though the test for uniformity of content was not specified for glipizide and gliclazide, the test for these drugs were done in the interests of the consumers, said CERC.

The study observed that as all the brands complied with the standards, a major criterion for preferring one brand to another is the price. Glibenclamide tablets cost between Rs. 5.50 and 8.00 for ten tablets. Metformin tablets cost between Rs. 7.20 and 13.10 for ten tablets whereas glipizide tablets cost around Rs. 4.65 to 6.65 for ten tablets. The gliclazide tablets were the costliest at between Rs. 29 and 63.70 for ten tablets. The variation in the price, apart from profit margin, could be due to the additives used in making the tablet such as for coating, binding, disintegration, dissolution and for increasing bulk. The additives also influence the efficiency of the tablets, noted the study.