Effect of herb-drug interactions of Bacopa monnieri Linn. (Brahmi) formulation on the pharmacokinetics of amitriptyline in rats

ABSTRACT Interactions between herbs and drugs may increase or decrease the pharmacological or toxicological effects of either component. Experimental data on the pharmacokinetic interactions between herbal products and drugs are limited. This study attempted to investigate the effect of Bacopa monnieri Linn. (Brahmi) 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 B. monnieri), respectively. Rats in the treatment group received B. monnieri (31 mg/kg/day) whereas the control group received normal saline by oral gavage for seven days before a single intragastric administration of 25 mg/kg amitriptyline. Plasma concentrations of amitriptyline were measured up to 24 h after its administration by a developed and validated high-performance liquid chromatography method. Pretreatment with B. monnieri produced a significant increase in the maximum plasma concentration (Cmax), area under the curve (AUC0-t) and elimination half-life (t1/2) of amitriptyline by 16.8%, 26.5%, and 15.5%, respectively, compared to amitriptyline alone. Moreover, oral clearance and volume of distribution (Vss) were decreased by 26.2% and 15.5% respectively. This study concluded that B.monnieri significantly enhanced the oral bioavailability of amitriptyline in rats.

Method Development and Validation of Levosalbutamol in Pure and Tablet Dosage Form by RP-HPLC.

A simple, rapid and accurate RP-HPLC method was developed for the determination of levosalbutamol in pure and tablet dosage form by RP-HPLC method using C18 BDS column (Phenomenex, 250 x 4.6 mm, 5 μm) in isocratic mode. The mobile phase consisted of Acetonitrile and buffer in the ratio of 20:80 (v/v) was used and maintain the pH 3. The flow rate was maintained at 1 mL/min and the injection volume was 20 μL . Detection wavelength with UV detector at 276 nm and run time was kept 10 min. The retention time of levosalbutamol was 5.4 min. The method was linear over the concentration range 7-12 μg/ml. The recovery was found to be 100.44± 0.27%. The validation of method was carried out utilizing ICH-guidelines. The described HPLC method was successfully employed for the analysis of pharmaceutical formulations.