Lopinavir

Lopinavir (also known as ABT-378) is a highly potent inhibitor of human immunodeficiency virus (HIV) protease that potently inhibits wild-type and mutant HIV protease with inhibition constant K_i values ranging from 1.3 to 3.6 pM. Lopinavir, a ritonavir analog designed to have a diminished interaction with Val82 in HIV protease, maintains a high potency inhibiting Val82 mutant HIV selected by ritonavir with 50% effective concentration EC₅₀ value lower than 0.06 μM. Although the antiviral activity of ritonavir is considerably attenuated by human serum, lopinavir is less affected by human serum proteins and is 10-fold greater in potency than ritonavir in the presence of human serum.

Reference

Sham HL, Kempf DJ, Molla A, Marsh KC, Kumar GN, Chen CM, Kati W, Stewart K, Lal R, Hsu A, Betebenner D, Korneyeva M, Vasavanonda S, McDonald E, Saldivar A, Wideburg N, Chen X, Niu P, Park C, Jayanti V, Grabowski B, Granneman GR, Sun E, Japour AJ, Leonard JM, Plattner JJ, Norbeck DW. ABT-378, a highly potent inhibitor of the human immunodeficiency virus protease. Antimicrob Agents Chemother. 1998 Dec;42(12):3218-24.

Comparative pharmacokinetic evaluation of lopinavir and lopinavir-loaded solid lipid nanoparticles in hepatic impaired rat model.[Pubmed:28317117]

J Pharm Pharmacol. 2017 Jul;69(7):823-833.

OBJECTIVE: Drug-induced hepatotoxicity is a major cause of concern in patients receiving HIV/TB co-treatment. Lopinavir (LPV), an anti-HIV drug, shows poor plasma exposure due to hepatic first-pass metabolism. In this study, we investigated the effect of hepatotoxicity on pharmacokinetics of free LPV and LPV-loaded solid lipid nanoparticles (LPV SLNs) in male Wistar rats. METHODS: Hepatic impairment model in rats was developed by injecting CCl4 (i.p., 2 ml/kg). Comparative pharmacokinetic (n = 5) and tissue distribution studies (n = 3) were conducted following oral administration (20 mg/kg) of free LPV and LPV SLNs in normal and hepatic impaired rats. Isolated perfused liver (IPL) model (n = 3) and cycloheximide intervened lymphatic uptake studies (n = 3) were conducted to appreciate disposition pattern of LPV. KEY FINDINGS: In contrary to free LPV, pharmacokinetic results demonstrated no significant (P > 0.05) difference in drug plasma profile of LPV SLNs in normal and impaired rats. IPL model demonstrated trivial role of liver in disposition of LPV SLNs. Tissue distribution studies of SLNs showed higher (P < 0.05) LPV accumulation in lymphoidal organs. Pretreatment of cycloheximide significantly (P < 0.05) reduced AUC and Cmax of LPV SLNs. CONCLUSION: From the results, we conclude that unlike conventional formulations of LPV, disposition characteristics of LPV SLNs were similar both in normal and hepatic impaired rats.

Simultaneous LC-MS-MS Determination of Lopinavir and Rifabutin in Human Plasma.[Pubmed:28334925]

J Chromatogr Sci. 2017 Jul 1;55(6):617-624.

Tuberculosis (TB) with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome represents the most common infectious diseases worldwide. Anti-TB drugs are used concurrently with antiretroviral drug for treatment of TB-HIV co-morbidities. Due to lower risk of interaction with protease inhibitors, rifabutin is preferred over rifampicin in treatment of HIV and TB co-morbidity. A simple and specific liquid chromatography tandem mass spectrometry method was developed for quantification of rifabutin (RBT) and Lopinavir (LPV) simultaneously in human plasma. Following extraction using 60% n-hexane in ethyl acetate, the processed samples were chromatographed on a Discovery HS C18 column (5 mum, 50 x 4.6 mm, id) using mobile phase [85% acetonitrile in ammonium acetate buffer (10 mM, pH 4.5)] at a flow rate of 0.7 mL/min. Mass spectrometric detection was performed in positive electrospray ionization mode using multiple reaction monitoring (RBT, m/z 847.7 --> 815.4; LPV, m/z 629.6 --> 447.4). Raloxifene and phenacetin were used as internal standards for RBT and LPV, respectively. Linearity was established in the range of 1-1,000 ng/mL and 0.5-10 microg/mL (R2 >/= 0.99) for RBT and LPV, respectively. The recovery of LPV and RBT were always >90 and >50%, respectively. The precisions and accuracies were well within the acceptable limits of variation.

Impact of lopinavir-ritonavir exposure in HIV-1 infected children and adolescents in Madrid, Spain during 2000-2014.[Pubmed:28350802]

PLoS One. 2017 Mar 28;12(3):e0173168.

BACKGROUND: The most-used protease-inhibitor in children is Lopinavir-ritonavir (LPV/r), which provides durable suppression of viral load and increases CD4+T-counts. This study describes the virological outcome of the HIV-1-infected paediatric population exposed to LPV/r during 15 years in Spain. METHODOLOGY: Patients from the Madrid Cohort of HIV-1-infected-children and adolescents exposed to LPV/r as different line therapy during 2000-2014 were selected. The baseline epidemiological-clinical features, viral suppression, changes in CD4+T-CD8+T cell counts and drug susceptibility were recorded before and during LPV/r exposure. Drug resistance mutations (DRM) were identified in viruses from samples collected until 2011. We predicted drug susceptibility to 19 antiretrovirals among those carrying DRM using the Stanford's HIVdb Algorithm. RESULTS: A total of 199 (37.3%) of the 534 patients from the cohort were exposed to LPV/r during 2000-2014 in first (group 1), second (group 2) or more line-therapies (group 3). Patients were mainly Spaniards (81.9%), perinatally infected (96.5%) with subtype-B (65.3%) and HIV-diagnosed before year 2000 (67.8%). The mean age at first LPV/r exposure was 9.7 years. After protease-inhibitor exposure, viral suppression was higher in groups 1 and 2 than in group 3. Viral suppression occurred in 87.5%, 68.6% and 64.8% patients from groups 1, 2 and 3, respectively. Among the 64 patients with available resistance data during LPV/r treatment, 27(42.3%) carried DRM to protease-inhibitor, 28 (58.3%) to reverse-transcriptase-inhibitors and 21 (43.7%) to non-reverse-transcriptase-inhibitors. Darunavir/ritonavir, atazanavir-ritonavir and tipranavir/ritonavir presented the highest susceptibility and nelfinavir the lowest. CONCLUSIONS: A better lymphocyte recovering occurred when protease-inhibitor was taken as part of a first-line regimen and a higher number of patients reached viral suppression. The least compromised antiretrovirals for rescue antiretroviral regimens, according to DRM in the LPV/r-exposed-paediatric cohort, were mainly the new protease inhibitors.