Influence of two dietary fibers in the oral bioavailability and other pharmacokinetic parameters of ethinyloestradiol

Dietary fibers are widely used in hypoglycaemic, hypolipidemic, slimming di ets. It is probable that their ingestion coincides with the oral administra tion of drugs and a modification of their pharmacokinetics can appear. In t he present study, the influence of two soluble fibers (guar gum and psylliu m) was evaluated on the pharmacokinetics of ethinyloestradiol (EE) when the y were administered together to female rabbits via the oral route. Three gr oups of rabbits were used. All animals received 1 mg/kg of EE; this compoun d was administered alone in the control group and with 3.5 g of guar gum or psyllium in the other two groups. When guar gum was administered, there wa s a decrease in the extent of EE absorbed, but no change was observed in th e rate of absorption. When psyllium was administered, the extent of EE abso rbed increased slightly and the rate of absorption was slower. (C) 2001 Els evier Science Inc. All rights reserved.