Abstract
This study evaluates the effect of Centella asiatica formulation on the pharmacokinetics of amitriptyline in rats. In this study, rats were randomly divided into two groups (n = 6 each) which were served as a control (amitriptyline alone) and treatment group (amitriptyline with C. asiatica), respectively. Rats were administered vehicle saline or C. asiatica (62.5 mg/kg, p.o.daily for 7 days), then administered a single amitriptyline dose (25 mg/kg, p.o.) on day 8. Plasma samples were analyzed for amitriptyline concentration using a developed and validated reversed-phase high-performance liquid chromatography (RPHPLC) method. Pharmacokinetic parameters were calculated using non-compartmental analysis. The co-administration of C. asiatica with amitriptyline resulted in increased plasma maximum concentration (C-max), area under the curve (AUC(0-24)) and elimination half-life (t(1/2)) by 14.34, 23, and 13.81%, respectively. The present study demonstrated that C. asiatica extract has the potential to alter the pharmacokinetics of amitriptyline by a significant reduction in amitriptyline clearance and an increase in its AUC, C-max and t(1/2).