Abstract

EFFECT OF TWO POLYHERBAL BITTERS ON THE PHARMACOKINETICS OF GLIBENCLAMIDE AND METFORMIN IN RATS

*Etim, E.I., Silas L.M., Umoh, U.F., Akwaowo, A.E. and Udodok, I. N

ABSTRACT

Polyherbal bitters are herbal products which are commonly used by diabetic patients, because they are claimed to have antidiabetic potentials. Promoters of the bitters claim that being a natural product it could be co-administered with other therapeutic drugs with no adverse effects. This research was aimed at assessing the effect(s) or otherwise of the co-administration of two popular polyherbal bitters in Nigeria market (S-bitter SB and Y-bitter YB) on the pharmacokinetics of two widely used antidiabetic drug glibenclamide (GLI) and metformin (MET) using rats. Two hundred and eighty seven rats of both sexes weighing between 180g and 240g were divided into eight groups of thirty five each and the ninth group control with seven. Therapeutic doses of the bitters alone and in combination with glibenclamide and metfomin corresponding to the body weight of the animals were administered orally to different groups. At intervals of 0.5, 1, 3, 6, 8, 12 and 24 hours, five rats from each group were sacrificed and blood collected by cardiac puncture. The blood was centrifuged and the plasma collected was analyzed using UV visible spectrophotometer for the concentrations of metfomin and glibenclamide respectively. The results obtained indicated that co-administration of metformin with SB decreased ka from 0.578 to 0.349h-1, increased Tmax from 1.0 to 6.0 hours, but had no significant effect on AUC, Cmax and t1/2. Co-administration of metformin with YB cause on increase in from 4 to 6.2 hours, AUC from 12.55 to 18.086μ g/h/mL and Tmax from 1.0 to 6.0 hours. There was also a decrease in Kel from0.173 to 0.111 h-1 but with no effect on Cmax. Co-administration of glibenclamide with SB increases Tmax from 3 to 6 hours Cmax from 200 to 250μg/ml, t½el from 9.6 to 14.5 hours and a decrease in kel from 0.0721 to 0.0477086μg/h/mL. Co-administration glibenclamide with YB had no significant effect on any of the pharmacokinetic parameters measured. We concluded that it is not advisable to administer any of the bitters with therapeutic drugs since the effect on their pharmacokinetic parameters is erratic.

Keywords: Polyherbal bitters, Pharmacokinetics, Glibenclamide, Metfomin.