Pharmacokinetic study of phyllanthin and hypophyllanthin after oral administration to rats

Objective: The present study was carried out to develop a sensitive and cost effective HPLC method for the determination of bioactive lignans (phyllanthin and hypophyllanthin) and its application in a pharmacokinetic study. Methods: Identification of lignan compounds on C–18 column was monitored at a range of 199–400nm using photodiode array detector (PDA) with methanol-water (66:34, v/v) as mobile phase at a flow rate of 1ml/min. Carbamazepine was used as internal standard. Results: From the developed method LOD and LOQ values were found to be 56.14ng/ml and 169.99ng/ml for phyllanthin, and 56.04ng/ml and 169.82ng/ml for hypophyllanthin. The validated RP–HPLC method herein was applied for pharmacokinetic studies and C_max (ng/ml) values for administered three oral doses (2.5, 5 and 10mg/kg) of phyllanthin and hypophyllanthin were 0.28±0.06, 0.53±0.16, 0.98±0.22 and 0.68±0.76, 1.35±0.23, 2.45±0.33, respectively. Conclusion: In conclusion, developed HPLC–PDA method effectively determined the phyllanthin and hypophyllanthin in various solvent and plasma samples. This method was successfully applied in conducting their oral pharmacokinetic studies.

Key words:Phyllanthus amarus, phyllanthin, hypophyllanthin, HPLC–PDA, pharmacokinetics.