Lopinavir/ritonavir pharmacokinetics in HIV and hepatitis C virus co-infected patients without liver function impairment: influence of liver fibrosis.

BACKGROUND AND OBJECTIVE: To assess the influence of hepatitis C virus (HCV) co-infection and the extent of liver fibrosis on lopinavir/ritonavir pharmacokinetics in HIV-infected patients without liver function impairment. METHODS: Cross-sectional, comparative study enrolling HIV-infected adults receiving lopinavir/ritonavir (400 mg/100 mg twice daily). HIV/HCV co-infected patients were grouped as having advanced fibrosis (HCV+/FIB+, n=7) or not (HCV+/FIB-, n=8) based on the FIB-4 index. A full concentration-time profile was obtained for each patient, and blood samples were collected before (0), and 1, 2, 4, 6, 8, 10 and 12 hours after a lopinavir/ritonavir dose. Lopinavir and ritonavir concentrations in plasma were determined by high-performance liquid chromatography. Maximum and minimum plasma concentrations (Cmax and Cmin), area under the plasma concentration-time curve from 0 to 12 hours (AUC12), apparent oral clearance at steady state (CLss/F), and apparent volume of distribution after oral administration (Vd/F) were calculated for each individual using a non-compartmental approach. RESULTS: Twenty-six HCV- and 22 HCV+patients were enrolled. Lopinavir and ritonavir pharmacokinetics were comparable between HCV- and HCV+patients. However, the Vd/F of lopinavir was 125% higher in HCV+/FIB+patients than in HCV-patients (p=0.015) and 107% higher than in HCV+/FIB-(p=0.040) patients. The CLss/F of ritonavir was 40% lower in HCV+/FIB+patients than in HCV-patients (p=0.005) and 44% lower than in HCV+/FIB-patients (p=0.040). Thus, for ritonavir AUC12, Cmax and Cmin in HCV+/FIB+patients were 63%, 86% and 100% higher, respectively, when compared with those parameters in HCV-patients (p=0.005, p=0.012 and p=0.015, respectively), and 80%, 86% and 100% higher, respectively, when compared with levels in HCV+/FIB- patients (p=0.040, p=0.040 and p=0.029, respectively). CONCLUSION: Lopinavir exposure is similar in HIV-infected patients with or without HCV co-infection and without liver function impairment. However, ritonavir exposure may be higher in this setting, particularly in individuals with advanced liver fibrosis.

Variability in non-nucleoside reverse transcriptase and protease inhibitors concentrations among HIV-infected adults in routine clinical practice.

AIMS: The objective of this study was to assess interindividual variability in plasma trough concentrations of non-nucleoside reverse transcriptase inhibitors (NNRTI) and protease inhibitors (PI) among HIV-infected adults in an outpatient routine clinical practice setting. METHODS: The study included 117 patients who attended our clinic for routine outpatient blood tests and who were receiving antiretroviral therapy which included NNRTI or PI. Patients were not informed that drug concentrations were going to be assessed until blood sampling. The time of the last antiretroviral treatment intake and blood sampling were recorded. Drug concentrations were considered optimal if they were above the proposed minimum effective concentration. In addition, efavirenz, nevirapine and atazanavir concentrations were considered potentially toxic if they were higher than 4.0 mg l(-1), 6.0 mg l(-1), and 0.85 mg l(-1), respectively. RESULTS: Overall, interindividual variability in NNRTI and PI plasma concentrations was approximately 50%, and only 68.4% of the patients had drug concentrations within the proposed therapeutic range. Inappropriate adherence only explained 35% of subtherapeutic drug concentrations. CONCLUSION: Interindividual variability in trough concentrations of NNRTI and PI among HIV-infected adults is large in routine clinical practice, with drug concentrations being outside the therapeutic window in a significant proportion of patients. Therapeutic drug monitoring may be useful to guide antiretroviral therapy in clinical practice.

Variability in non-nucleoside reverse transcriptase and protease inhibitor concentrations among HIV-infected adults in routine clinical practice.

AIMS: The objective of this study was to assess interindividual variability in trough concentrations of plasma of non-nucleoside reverse transcriptase inhibitors (NNRTI) and protease inhibitors (PI) among HIV-infected adults in a routine outpatient setting. METHODS: One hundred and seventeen patients who attended our clinic for routine blood tests, and who were receiving antiretroviral therapy which included NNRTI or PI were studied. Patients were not informed that drug concentrations were going to be measured until blood sampling. The times of the last antiretroviral dose and of blood sampling were recorded. Drug concentrations were considered optimal if they were above the proposed minimum effective value. In addition, efavirenz, nevirapine and atazanavir concentrations were considered potentially toxic if they were > 4.0 mg l(-1), > 6.0 mg l(-1) and > 0.85 mg l(-1), respectively. RESULTS: Overall, interindividual variability of NNRTI and PI concentrations in plasma was approximately 50%, and only 68.4% of the patients had drug concentrations within the proposed therapeutic range. Poor adherence explained only 35% of subtherapeutic drug concentrations. CONCLUSION: Interindividual variability in trough concentrations of NNRTI and PI among HIV-infected adults is large in routine clinical practice, with drug concentrations being outside the therapeutic window in a significant proportion of patients. These findings provide further evidence that therapeutic drug monitoring may be useful to guide antiretroviral therapy in clinical practice.

Reaction of [Fe2(CO)8(mu-CF2)] with AsMe3 and other Lewis bases: syntheses, crystal structures of [Fe(CO)6(AsMe3)2(mu-CF2)] and [Fe(CO)5(AsMe3)3(mu-CF2)], and theoretical considerations.

The difluorcarbene complex [Fe2(CO)8(mu-CF2)] (2) reacts with AsMe3 under CO substitution to give the mu-CF2 containing complexes [Fe2(CO)6(AsMe3)2(mu-CF2)] (4) and [Fe2(CO)5(AsMe3)3(mu-CF2)] (5) which have an [Fe2(CO)9]-like structure as shown by X-ray analyses. In the solid state, 4 forms two isomers, 4a and 4b, in a 3 to 1 ratio, which differ in the position of the mu-CF(2) ligand; 4a has a local C(2) axis and 4b has C1 symmetry. The Fe-Fe distances in 4 and 5 are 2.47 A and are the shortest ones found in [Fe2(CO)9]-like compounds. Efforts were also undertaken to replace one or more CO groups in 2 by other ligands, such as N (bpy, phen, pzy, etc.) or P donors (dppe, dppm). With dppm, only the CF(2) free complex, [Fe2(CO)4(mu-Ph2PCH2PPh2)2(mu-CO)] (6), could be detected and characterized by X-ray analysis. Most of the reactions resulted in the formation of red-brown materials which were insoluble in the usual solvents and which could not be characterized. The use of CH2Cl2 during the attempts to crystallize a product from the reaction of 2 and phen gave [Fe(phen)3]Cl2 (7) in low yields. For 4 and 5, the electronic structures were analyzed using the atoms in molecules (AIM) theory. No electron density was found between the two iron atoms, and the short contacts can be interpreted in terms of a pi-interaction.