In-vivo Kinetics of Silymarin (Milk Thistle) on Healthy Male Volunteers

Purpose: The study was aimed at evaluating the in vivo kinetics of silymarin tablets, a product with antihepatotoxic and free radical scavenging activities. Methods: Silimarin® (Amson Vaccines & Pharma Pvt Ltd) was used as the test product while another silymarin tablet brand, Silliver® (Abbott Laboratories Pak Ltd) was the reference product. The tablets were administered to healthy male volunteers orally at a dose of 200 mg following an overnight fast according to a randomized cross-over design. Scheduled blood samples were collected, centrifuged and the plasma assayed using a sensitive and validated reversed phase high performance liquid chromatographic (RP-HPLC) method. Various pharmacokinetic parameters were calculated based on the non-compartmental model. Results: Non-significant difference (p < 0.05) was observed in the area under the curve (AUC) of the two brands with values of 10.8 ± 0.4 μg h/ml and 11.2 ± 0.7 μg h/ml, respectively. There was, however, a significant difference (p < 0.05) in the Cmax of the two brands. Other pharmacokinetic parameters evaluated did not show any statistical difference (p < 0.05) between the two products except for mean residence time Conclusion: The test product can be used as an alternative to the brand, Silliver®-Abbot (reference), only in conditions where maximum plasma concentration (Cmax) is not an important consideration.