Received 26 January 2002 Revised 20 March 2002 Copyright # 2002 John Wiley & Sons, Ltd. Accepted 25 March 2002 BIOPHARMACEUTICS & DRUG DISPOSITION Biopharm. Drug Dispos. 23: 197–202 (2002) Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/bdd.310 Bioequivalence Evaluation of Two Brands of Gliclazide 80 mg Tablets (Glyzide 1 & Diamicron 1 ) } in Healthy Human Volunteers Naji Najib a , Nasir Idkaidek a , M. Beshtawi a , Mohammed Bader a , Isra’ Admour a , S. Mahmood Alam b , Q. Zaman b and Ruwayda Dham b, * a International Pharmaceutical Research Centre (IPRC), Amman - Jordan b Gulf Pharmaceutical Industries-Julphar, Dubai, United Arab Emirates ABSTRACT: A randomized, two-way, crossover, bioequivalence study in 24 fasting, healthy, male volunteers was conducted to compare two brands of gliclazide 80 mg tablets, Glyzide 1 (Julphar, UAE) as test and Diamicron 1 (Servier Industries, France) as reference product. The study was performed at the International Pharmaceutical Research Centre (IPRC), in joint venture with Speciality Hospital, Amman, Jordan. The drug was administered with 240 ml of 20% glucose solution after a 10 h overnight fasting. After dosing, serial blood samples were collected for a period of 48 h. Plasma harvested from blood was analyzed for gliclazide by validated HPLC method. Various pharmacokinetic parameters including AUC 0–t , AUC 0–/ , C max , T max , T 1=2 , and elimination rate constant were determined from plasma concentrations of both formulations. Statistical modules (ANOVA and 90% confidence intervals) were applied to AUC 0–t , AUC 0–/ , and C max for bioequivalence evaluation of the two brands which revealed no significant difference between them, and 90% CI fell within US FDA accepted bioequivalence range of 80–125%. Based on these statistical inferences, Glyzide 1 was judged bioequivalent to Diamicron 1 . Copyright # 2002 John Wiley & Sons, Ltd. Key words: gliclazide; bioequivalence; pharmacokinetics; HPLC; Julphar Introduction Bioequivalence of two formulations of the same drug comprises equivalence with respect to the rate and extent of its absorption. The area under concentration–time curve (AUC) generally serves as the characteristic of the extent of absorption while the peak concentration ðC max Þ and the time of its occurrence ðT max Þ, reflect the rate of absorption, especially in fast releasing drug formulations [1,2]. The present study was con- ducted to evaluate the bioequivalence of two brands of gliclazide 80 mg tablets in fasting, healthy human volunteers. Although several studies have been published on gliclazide phar- macokinetics, very few of them have focused on the proof of bioequivalence between two brands. Gliclazide is a second-generation sulfonylurea oral hypoglycaemic agent closely related to glyburide [3–6], effective in controlling blood glucose in type II diabetes mellitus. As for other second-generation sulfonylureas, the potency of gliclazide is greater than that of first-generation agents. It acts mainly by stimulating the islet tissue of the pancreas to secrete insulin and by increasing the sensitivity of peripheral tissues to insulin. Consequently, it is effective only when some residual pancreatic beta-cell activity is present [7]. Thus, hypoglycaemic mechanism of action of gliclazide is mainly related to * Correspondence to: Gulf Pharmaceutical Industries, Julphar, Twin Towers 1201, P.O. Box 42040, Dubai, UAE. E-mail: julphard@ emirates.net.ae