Pharmacokinetics, Safety, and Bioequivalence of 2 Lopinavir/Ritonavir (200/50 mg) Tablets in Healthy Chinese Volunteers: Effect of Food on Absorption

Lopinavir/ritonavir is an important protease inhibitor for treating HIV-1 infection in patients aged >2 years in combination with other antiretrovirals. The antiviral activity of lopinavir/ritonavir in vivo is mainly derived from lopinavir, while ritonavir improves the bioavailability of lopinavir. This study compared the bioequivalence and safety of 2 lopinavir/ritonavir (200/50 mg) formulations under fasted and fed conditions in healthy Chinese volunteers and compared the pharmacokinetic parameters of lopinavir and ritonavir. A randomized, open-label, single-dose, 4-period, crossover bioequivalence was conducted in 72 subjects under fasted and fed conditions. Lopinavir and ritonavir plasma concentrations were analyzed using validated liquid chromatography with tandem mass spectrometry. Noncompartmental analysis was used to evaluate pharmacokinetic parameters. The 90% confidence intervals of test/reference geometric mean ratio for lopinavir and ritonavir area under the plasma concentration-time curve and maximum drug concentration meets the bioequivalence criteria based on the average bioequivalence method. A high-fat meal delayed the time to the maximum concentration of lopinavir and ritonavir. Therefore, these formulations were bioequivalent in healthy Chinese volunteers under fasting and fed conditions. Moreover, adverse events were more frequent in the fed state, but all were mild.