Pharmacokinetics and pharmacodynamics of extended-release glipizide GITS compared with immediate-release glipizide in patients with type II diabetes mellitus

This study was designed to compare the pharmacokinetic and short-term pharmacodynamic profile of extended-release glipizide GITS (Glucotrol XL(R)) given in a dosage of 20 mg once daily with that of immediate-release glipizide (Glucotrol(R)) 10 mg twice daily in patients with typr II diabetes mellitus. In an open-label, randomized, two-way crossover study, each glipizide formulation was administered for 5 days. Serial blood samples were drawn at baseline and on the 5th day of each treatment phase for measurement of glipizide, glucose, insulin, and C-peptide concentrations, At steady state, the mean C-max after immediate-release glipizide was significantly greater than after glipizide GITS, and the t(max) was considerably shorter. Although the mean C-min with glipizide GITS was about 80% higher than with immediate-release glipizide, the mean AUC(0.24) was significantly lower, Despite the lower plasma concentrations with glipizide GITS in this short-term study, the two formulations had similar effects on serum concentrations of glucose, insulin, and C-peptide. The absence of a pronounced peak plasma concentration with the GITS formulation might confer advantages in terms of maintaining clinical effectiveness and reducing the potential to cause adverse effects. (C) 2002 the American College of Clinical Pharmacology.