Effect of guar gum on glipizide absorption in man

The effect of 4.75 g guar gum, a fibre preparation, on the absorption of 2.5 mg glipizide has been studied in 10 healthy volunteers given a standard breakfast. Three different experimental protocols were used: glipizide without guar gum (Treatment 1), glipizide with guar gum (Treatment 2) and guar gum 30 min after the drug together with breakfast (Treatment 3). The serum glipizide at 30 minutes was higher during Treatment 2 than Treatment 3 (p less than 0.01), but neither differed from the control treatment. The AUCs for glipizide were calculated up to 8 hours. They did not differ significantly between the treatment, although there was a non-significant trend to lower values during Treatment 3. Serum insulin and blood glucose levels were determined up to 3 h. Corresponding to differences in the glipizide concentration, serum insulin was highest and blood glucose lowest at 30 minutes during Treatment 2. According to this single dose study, guar gum does not have any substantial deleterious effect on the absorption of glipizide. The lack of effect may be due to the complete gastrointestinal absorption of glipizide.