Evaluation of Quercetin's Bioenhancing Effect on Oral Pharmacokinetics of Rosuvastatin in Wistar Rats Using RP-HPLC Method.

Background: The absolute oral bioavailability of rosuvastatin (RST), a secondgeneration statin, is low i.e. 20% and only 10% is recovered as metabolite N-desmethy l rosuvistatin. Since it is a hydrophilic statin, RST relies on the organic anion transporting polypeptide- 1B1 (OATP-1B1), as the key mechanism for active transport into hepatocytes. Quercetin (QUE) being a bio enhancer and inhibitor of OATP1B1 can augment the bioavailability and pharmacokinetics of RST.

Objectives: The present study includes the development of a simple and validated bioanalytical Reverse Phase High-Performance Liquid Chromatography (RP-HPLC) method for the estimation of RST and to study the effect of co-administration of QUE as a bio enhancer on its bioavailability.

Methods: An analytical column of Kromasil 100, C18 (250 mm × 4.6 mm, 5 μm), was used for chromatographic separationand acetonitrile (ACN): acetic acid buffer pH 3.0 adjusted with glacial acetic acid (55:45 Vol. %) as mobile phase with flow rate 1.0 ml/min monitored at 242 nm. The ACN: methanol (50:50 Vol. %) was employed as the final solvent for extraction. The developed method has been successfully applied in a study on the pharmacokinetics of the drug RST in rats after co-administration of QUE, which was carried out using non-compartmental analysis in order to estimate the blood concentration of the drug.

Results: The pharmacokinetics of RST was found to be altered significantly (highest concentration of RST in the blood (C_max) = 67.3 ng/ml to 122.2 ng/ml) (p < 0.001), area under curve (AUC)_0-t (p < 0.0001) and AUC_0-inf (p = 0.0005) when co-administered with QUE at 120 min (t_max).

Conclusion: The results are in accordance with the fact that QUE increases plasma levels in rats through herb-drug interactions.