EFFECT OF EGRET RIVER TEA (AN ANTIHYPERTENSIVE HERBAL SUPPLEMENT TEA) ON THE PHARMACOKINETIC PROFILE OF ORAL TELMISARTAN IN RABBITS

Kaneng Katherin Pam, Jacob A. Kolawole* and Emmanuel Taiwo Alemika

ABSTRACT

The study is aimed at investigating the effect of Egret River tea (an antihypertensive herbal supplement tea), on the pharmacokinetic profile of oral single dose telmisartan in rabbits. In the first phase, a dose of oral telmisartan (40mg/kg) was administered to rabbits after overnight fast. Blood samples (3.0 ml) were drawn from an indwelling catheter into EDTA bottles at 0.0, 0.5, 1, 2, 4, 6, 8, 10 and 24 hours. The blood samples were centrifuged at 3000rpm for 10 minutes and plasma harvested. In the second phase, the rabbits were allowed free access to their normal feeds for two weeks. The Egret River tea (150 ml) prepared by merceration of one tea bag in hot water was administered orally for three days. The rabbits were fasted overnight after the last dose of the tea and Telmisartan (40mg/kg) was administered to the rabbits orally. Blood samples were collected and treated as earlier. Telmisartan was analysed using UV-spectrophotometeric method after liquid-liquid extraction from plasma using diethyl-ether and dichloromethane (60:40 % v/v), at 238 nm. Method validation parameters found method to be efficient enough for the comparative pharmacokinetic work with linearity between 8-90μg/ml with a correlation coefficient (r²) of 0.994 and %Recovery of 96.95% with, RSD of 0.0098. Egret River tea significant (p<0.05) decrease Cmax, AUC0-24, AUCo - ∞ and t1/2β, while there was significant (p<0.05) increase in Vd. However Egret River tea did not statistically (p>0.05) affect the Tmax, Cl/F and the t1/2α.

Keywords: Telmisartan, Egret River tea, Green tea, Pharmacokinetics, Drug-drug interaction, Herb-drug interaction.