Impact of food administration on lopinavir-ritonavir bioequivalence studies.

A bioequivalence study in 16 Caucasian healthy volunteers (eight male, eight female), comparing plasma drug concentrations after a single oral dose of lopinavir and ritonavir (400 and 100mg, respectively), was carried out following a two-period, two-sequence, two-treatment, randomized crossover design. Formulations were given 15 min after a moderate-fat breakfast in order to diminish both the intrinsic highly-variable performance and the sex differences observed in bioequivalence trials under fasting conditions. Ninety percent confidence intervals for the Test/Reference (T/R) ratio of geometric means for area under concentration-time curve (AUC) and maximum concentration (C(MAX)), either for lopinavir or ritonavir, were within the range of 0.80-1.25. Coprandial administration of formulations not only reduced the number of subjects required for bioequivalence assessment, reducing both ethical and economic cost of the trial, but also the sex differences in the T/R ratio of means.

The impact of SLCO1B1 polymorphisms on the plasma concentration of lopinavir and ritonavir in HIV-infected men.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: * There is large interindividual variability in the pharmacokinetics of protease inhibitors (PIs) among human immunodeficiency virus (HIV)-infected individuals under highly active antiretroviral therapy. * Protease inhibitor have been recently reported to be substrates of the SLCO1B1/OATP1 drug transporter. * A single nucleotide polymorphism (SNP) in the SLCO1B1 gene (521T-->C) was associated with plasma levels of lopinavir in HIV-infected individuals. WHAT THIS STUDY ADDS: * Data on the impact of three SLCO1B1 SNPs (521T-->C, 388A-->G, 463C-->A) on the trough plasma concentration of lopinavir and ritonavir in a cohort of 99 adult HIV-infected Brazilian men under stable highly active antiretroviral therapy. * Evidence that carriers of the 521C allele display significantly higher lopinavir, but not ritonavir plasma concentrations relative to the wild-type TT genotype. * No effect of either 388A-->G or 463C-->A SNPs on lopinavir or ritonavir plasma concentrations. * Further studies are required to confirm the clinical significance of the association between the SLCO1B1521T-->C polymorphism and lopinavir pharmacokinetics. AIMS: To investigate possible associations between three SLCO1B1 single nucleotide polymorphisms (388A-->G, 463C-->A, 521T-->C) and lopinavir/ritonavir plasma concentrations. METHODS: The study included 99 human immunodeficiency virus-infected men on stable highly active antiretroviral therapy containing lopinavir/ritonavir. Trough concentrations of lopinavir and ritonavir in plasma were quantified using liquid chromatography-tandem mass spectrometry. Genotyping of SLCO1B1388A-->G, 463C-->A and 521T-->C polymorphisms was performed by allelic discrimination using real-time polymerase chain reaction. RESULTS: The trough concentration of lopinavir in plasma is significantly associated with SLCO1B1521T-->C genotypes (P= 0.03). There is a significant trend for increasing concentrations of lopinavir from TT to TC to CC genotypes (P= 0.02). Carriers of the 521C allele display significantly higher lopinavir plasma concentrations relative to the wild-type TT genotype (P= 0.03). CONCLUSIONS: Reduced uptake of lopinavir by hepatocytes in carriers of the 521C allele may account for these results, but further studies to confirm the clinical importance of SLCO1B1 polymorphisms in lopinavir pharmacokinetics are warranted.

ABCB1 polymorphisms and the concentrations of lopinavir and ritonavir in blood, semen and saliva of HIV-infected men under antiretroviral therapy.

INTRODUCTION: Lopinavir and ritonavir are frequently included in highly active antiretroviral therapy (HAART) regimens for HIV infection. These drugs are substrates, and may also inhibit and/or induce the P-glycoprotein (ABCB1) transporter, encoded by the polymorphic ABCB1 gene. We investigated the impact of three common exonic ABCB1 polymorphisms on the concentrations of lopinavir and ritonavir in blood, semen and saliva of HIV-infected men under stable HAART containing ritonavir-boosted lopinavir. MATERIALS & METHODS: Blood, semen and saliva samples were collected from 113 subjects, 30-35 minutes before the scheduled morning dose of lopinavir/ritonavir, and trough drug concentrations were measured using LC/MS/MS. The 1236C>T, 2677G>T/A and 3435C>T polymorphisms were genotyped using the single base extension-termination method and ABCB1 haplotypes were statistically inferred. RESULTS: Median (25th-75th percentile) trough concentrations (ng/ml) of lopinavir in plasma, semen and saliva were 6326 (4070-8617), 286.0 (128.4-475.5) and 72.7 (38.0-119.6), respectively. The corresponding concentrations (ng/ml) for ritonavir were 261.8 (172.2-398.6), 17.7 (9.2-27.6) and 5.3 (3.2-9.0), respectively. Univariate and multivariate regression analysis revealed no influence of ABCB1 genotypes or haplotypes on the concentrations of lopinavir and ritonavir in plasma, semen and saliva of HIV-infected men under stable HAART treatment. CONCLUSION: The ABCB1 1236C>T, 2667G>T/A and 3435C>T genotypes and haplotypes are not predictors of lopinavir and ritonavir concentrations in blood plasma, semen or saliva of HIV-infected men under stable HAART treatment. The concentrations of lopinavir and ritonavir in saliva are not reliable predictors of the concentration of these drugs in semen.

Determination of lopinavir and ritonavir in blood plasma, seminal plasma, saliva and plasma ultra-filtrate by liquid chromatography/tandem mass spectrometry detection.

A method based on liquid-liquid extraction followed by high-performance liquid chromatography (HPLC) with positive ion electrospray ionization tandem mass spectrometry (ESI-MS/MS) detection was developed for the simultaneous determination of lopinavir (LPV) and ritonavir (RTV) in human blood, semen and saliva samples. The acquisition was performed in multiple reaction monitoring (MRM) mode, monitoring the transitions: m/z 629 > 447.1 for LPV, 721.18 > 268.02 for RTV and m/z 747.22 > 322.03 for the internal standard (IS). The limit of quantification was 1 ng/mL for both analytes in all matrices. The method was linear in the studied range (1-2000 ng/mL for LPV and 1-200 ng/mL for RTV), with r2 > 0.99 for each drug, and the run time was 4.5 min. The intra-assay precisions (%) were in the ranges of 0.1-14.2 (LPV) and 0.4-12.7 (RTV), the inter-assay precisions were in the ranges of 2.8-15.3 (LPV) and 1.1-12.8 (RTV) and the intra-and inter-assay recoveries were >85% for both drugs. The extraction efficiencies were 73.5-118.4% for LPV and 74.4-126.2% for RTV. The analytical method was applied to measure LPV and RTV concentrations in blood plasma (total and unbound fraction), saliva and semen of six HIV+ individuals under stable treatment with Kaletra soft gel capsules. The results were consistent with previously published data.

CYP3A5 genotype has no impact on plasma trough concentrations of lopinavir and ritonavir in HIV-infected subjects.

CYP3A5 genotype has no impact on the trough plasma concentrations of lopinavir and ritonavir in human immunodeficiency virus (HIV)-infected individuals on stable highly active antiretroviral therapy (HAART). This is ascribed to a drug interaction, such that ritonavir by inhibiting CYP3A activity, may occlude the pharmacokinetic consequences of functional polymorphisms in the CYP3A5 gene. In the clinical setting, where lopinavir and ritonavir are always combined, CYP3A5 genotype is of no consequence on the trough plasma concentrations of these drugs.

Limited penetration of lopinavir and ritonavir in the genital tract of men infected with HIV-1 in Brazil.

The concentrations of lopinavir and ritonavir in seminal and blood plasma and the seminal human immunodeficiency virus (HIV) viral load were quantified by HPLC and the Nuclisens assay, respectively, in a cross-sectional study of 16 HIV-1-infected Brazilian men under stable treatment with a lopinavir/ritonavir containing antiretroviral regimen. Semen and blood samples were collected on 2 occasions: at 6 to 60 minutes before ("trough"), and 5 to 6 hours after ("peak") ingestion of regular doses of lopinavir/ritonavir. Median seminal lopinavir levels were 120.6 ng/mL (range, <20-1481.8 ng/mL) and 233.1 ng/mL (range, 48.4-1133.4 ng/mL) at trough and peak points, respectively. The corresponding values for ritonavir were 9.2 ng/mL (range, <5-47 ng/mL) and 17.1 ng/mL (range, 6.6-66.7 ng/mL). The median concentrations of lopinavir and ritonavir in semen were, respectively, 1.9% to 3% and 3.7% to 4.4% of those measured in blood plasma samples collected within 30 minutes. HIV-1 viral load was detectable in the semen of 2 and in the blood of 6 of 16 patients. These results may have implications for drug-resistant HIV-1 evolution and transmission.