Effects and pharmacokinetics of oral glibenclamide and glipizide in Caucasian and Chinese patients with type-2 diabetes

The effects and kinetics of oral glibenclamide (Gb) and glipizide (Gz) were studied in Caucasian and Chinese patients (ten in each group) with type-2 diabetes. In randomised order, 2.5 mg Gb, 2.5 mg Gz or placebo was given or ally before the administration of 75 g oral glucose. Concentrations of insu lin and proinsulin were determined using radioimmunoassay (RIA) without cro ss-reactivities, and sulphonylurea concentrations were determined using hig h-performance liquid chromatography (HPLC). There were no significant inter ethnic differences in Gb or Gz effects whether on glucose, insulin or proin sulin/insulin ratio at any time point. Following Gz, however, Chinese patie nts had greater increments of serum proinsulin at 10-30 min compared with C aucasians. Apart from the maximum plasma concentration (C-max) and area und er the plasma concentration-time curve (AUC) of Gz being higher among the C hinese, no significant interethnic differences in pharmacokinetics were fou nd. It appears that the same dosage principles could be used for Caucasian and Chinese patients with type-2 diabetes when Gb or Gz are prescribed.