Effect of Grapefruit Juice and Ritonavir on Pharmacokinetics of Lopinavir in Wistar Rats

• Published in: Phytotherapy research Vol. 26; no. 10; pp. 1490 - 1495
• Main Authors: Ravi, P. R., Vats, R., Thakur, R., Srivani, S., Aditya, N.
• Format: Journal Article
• Language: English
• Published: Chichester Blackwell Publishing Ltd 01-10-2012; Wiley
• Subjects: Animals; Beverages; Biological and medical sciences; Citrus paradisi - chemistry; drug interaction; Drug Synergism; Food-Drug Interactions; General pharmacology; grapefruit juice; HIV Protease Inhibitors - pharmacokinetics; Intestinal Absorption; Intestines - drug effects; lopinavir; Lopinavir - administration & dosage; Lopinavir - pharmacokinetics; Male; Medical sciences; Microsomes - drug effects; Pharmacognosy. Homeopathy. Health food; pharmacokinetics; Pharmacology. Drug treatments; Rats; Rats, Wistar; ritonavir; Ritonavir - administration & dosage; Ritonavir - chemistry; grapefruit juice; Antiretroviral agent; Rat; Enzyme; Pharmacognosy; Ritonavir; Lopinavir; Rodentia; Enzyme inhibitor; Fruit juice; Medicinal plant; Peptidases; Vertebrata; Mammalia; Animal; Plant origin; Hydrolases; Antiviral; Grapefruit; Drug interaction; Pharmacokinetics; Protease inhibitor
• ISSN: 0951-418X; 1099-1573
• DOI: 10.1002/ptr.4593

Lopinavir (LPV), a newer HIV protease inhibitor, has poor bioavailability being a substrate of both cytochrome P450 3A enzyme system (CYP3A) and permeability‐glycoprotein (P‐gp). Ritonavir (RTV) is a known inhibitor of both P‐gp and CYP3A and is co‐administered with LPV in anti‐HIV therapy. Grapefruit juice (GFJ) is known to inhibit CYP3A and has conflicting effects, ranging from activation to inhibition, on P‐gp. In this research work, the effects of GFJ and RTV on the pharmacokinetics of LPV were compared in rats. A mechanistic evaluation was undertaken using various in vitro and ex vivo studies to support the in vivo pharmacokinetic data. The plasma levels of LPV were found to increase significantly upon co‐administration with GFJ in single dose as well as multidose pretreatment studies. Similar, but marginally higher, results were observed upon co‐administration of LPV with RTV. No significant change in tmax was observed in the various treatment groups. The apparent permeability of LPV in the ileum increased significantly after the pre‐incubation with GFJ and RTV compared with no pre‐incubation. The GFJ and RTV showed a significant and similar inhibitory effect on rat intestinal microsomes in the metabolism of LPV. The GFJ was equally effective as RTV in increasing the bioavailability of LPV. Copyright © 2012 John Wiley & Sons, Ltd.