Pharmacokinetics and Pharmacodynamic Herb-Drug Interaction of Piperine with Atorvastatin in Rats.

Herbals that are widely consumed as therapeutic alternatives to conventional drugs for cardiovascular diseases, may lead to herb-drug interactions (HDIs). Atorvastatin (ATR) is drug of choice for hyperlipidemia and is extensively metabolized through CYP3A4 enzyme. Thus, we postulate that concomitant administration of ATR with piperine (PIP, potent inhibitor of CYP3A4 enzyme)/ridayarishta (RID, cardiotonic herbal formulations containing PIP) may lead to potential HDI. A simple, accurate, sensitive high-performance liquid chromatography-photodiode array detection method using Kromasil-100 C18 column, mobile phase acetonitrile: 30 mM phosphate buffer (55:45 v/v) pH 4.5 with flow rate gradient programming was developed to study the potential HDI in rats. Method was found to be linear (2-100 ng/mL) with Lower Limit of Detection (LLOD) 2 ng/mL. The precision (%CV < 15%), accuracy (-1.0 to -10% R.E) with recoveries above 90% from rat plasma of ATR and IS were obtained. The pharmacokinetic (PK) interactions studies on co-administration of ATR (8.4 mg/kg, p.o.) with PIP (35 mg/kg, p.o.), demonstrated a threefold increase in Cmax of ATR (P < 0.01) with significant increase in AUC0-t/AUC0-∞ compared to ATR alone indicating potential PK-HDI. However co-administration of RID (4.2 mL/kg, p.o.) showed less significant changes (P > 0.05) indicating low HDI. The pharmacodynamic effects/interactions study (TritonX-100 induced hyperlipidemic model in rats) suggested no significant alterations in the lipid profile on co-administration of PIP/RID with ATR, indicating that there may be no significant pharmacodynamic interactions.