Pharmacokinetic-pharmacodynamic equivalence of three gliclazide formulations in healthy human male subjects.

AIMS To find out the pharmacokinetic (PK) and pharmacodynamic (PD) parameters for assessing the bioequivalence of three marketed products. To study the relationship between the pharmacokinetics of gliclazide and pharmacodynamic effect in healthy male volunteers. METHODS This was an open label, balanced, randomized, 3-treatment, 3-sequence, 3 period, single-dose, cross-over bioavailability study in which 18 healthy adults were randomized to receive gliclazide 80 mg with 7 days wash out between treatments. The drug was administered with 240 ml of 20% glucose solution after a 10 h overnight fasting. Pharmacokinetic parameters like t(max), C(max), AUC(0-t), AUC(0-∞), AUC(0-t) / AUC(0-∞) and t(1/2) and pharmacodynamic parameters like maximum effect (minimum glucose level in the body, C(minglu)), time to minimum glucose level in the body (T(cminglu)) and partial AUC were calculated for all the products. RESULTS The values for mean ± SD for age, height and weight of the volunteers were 28.00 ± 22.68, 165.78 ± 5.56 and 56.78 ± 13.37 respectively. There were total 4 withdrawn subjects and 1 drop out. Within batch accuracy of the method were in the range of 95.5 - 101.7%, 99.1 - 106.1% and 96.2 - 104.2% for three consecutive batches. The 90% CI for log transformed data of the PK and PD were within the acceptance range of 80.0 - 125.0%. CONCLUSIONS This population PKPD analysis has characterized the relationship between the exposure to gliclazide and its hypoglycemic effect. The test products A & B compared to reference product R were bioequivalent on the basis of pharmacokinetic and pharmacodynamic parameters. Finally it is recommended that the more costly product R can be safely switched with less costly products i.e. A and B.