Relative bioavailability of rifampicin in four Chinese fixed-dose combinations compared with rifampicin in free combinations.

BACKGROUND: Decreases in the bioavailability of rifampicin (RFP) can lead to the development of drug resistance and treatment failure. Therefore, we investigated the relative bioavailability of RFP from one four-drug fixed-dose combination (FDC; formulation A) and three two-drug FDCs (formulations B, C, and D) used in China, compared with RFP in free combinations of these drugs (reference), in healthy volunteers. METHODS: Eighteen and twenty healthy Chinese male volunteers participated in two open-label, randomized two-period crossover (formulations A and C) or one three-period crossover (formulations B and D) study, respectively. The washout period between treatments was 7 days. Bioequivalence was assessed based on 90% confidence intervals, according to two one-sided t-tests. All analyses were done with DAS 3.1.5 (Mathematical Pharmacology Professional Committee of China, Shanghai, China). RESULTS: Mean pharmacokinetic parameter values of RFP obtained for formulations A, B, C, and D products were 11.42 ± 3.41 µg/ml, 7.86 ± 5.78 µg/ml, 13.05 ± 6.80 µg/ml, and 16.18 ± 3.87 µg/ml, respectively, for peak plasma concentration (C max ), 91.43 ± 30.82 µg·h-1·ml-1 , 55.49 ± 37.58 µg·h-1·ml-1 , 96.50 ± 47.24 µg·h-1·ml-1 , 101.47 ± 33.07 µg·h-1·ml-1 , respectively, for area under the concentration-time curve (AUC 0-24 h ). CONCLUSIONS: Although the concentrations of RFP for formulations A, C, and D were within the reported acceptable therapeutic range, only formulation A was bioequivalent to the reference product. The three two-drug FDCs (formulations B, C and D) displayed inferior RFP bioavailability compared with the reference (Chinese Clinical Trials registration number: ChiCTR-TTRCC-12002451).

Synthesis and antiviral activity of N-phenylbenzamide derivatives, a novel class of enterovirus 71 inhibitors.

A series of novel N-phenylbenzamide derivatives were synthesized and their anti-EV 71 activities were assayed in vitro. Among the compounds tested, 3-amino-N-(4-bromophenyl)-4-methoxybenzamide (1e) was active against the EV 71 strains tested at low micromolar concentrations, with IC50 values ranging from 5.7 ± 0.8-12 ± 1.2 µM, and its cytotoxicity to Vero cells (TC50 = 620 ± 0.0 µM) was far lower than that of pirodavir (TC50 = 31 ± 2.2 µM). Based on these results, compound 1e is a promising lead compound for the development of anti-EV 71 drugs.

Synthesis and antiviral activity of substituted bisaryl amide compounds as novel influenza virus inhibitors.

The influenza virus is a persistent cause of mortality and morbidity on an annual basis and thus presents itself as an important target for pharmaceutical investigation. In this work, substituted bisaryl amide compounds were found to be a new class of potential anti-influenza agents, and a series of substituted bisaryl amide compounds were synthesised and evaluated for their anti-influenza virus activities. The analysis of the results produced a preliminary structure-activity relationship study (SAR). Compounds 1a, 1g, 1h, 1j, 1l and 1n exhibited clear antiviral activities against the influenza A (A/Guangdong Luohu/219/2006, H1N1) virus with 50% inhibitory concentrations (IC(50)) for virus growth ranging from 12.5 to 59.0 µM. Specifically, compound 1j also possessed antiviral activity against both oseltamivir-resistant influenza (A/Jinnan/15/2009) virus and influenza B (B/Jifang/13/97) virus with IC(50) values of 9.2 µM and 21.4 µM, respectively. Compound 1j is thus worth further investigation as an anti-influenza virus candidate.

Host apolipoprotein B messenger RNA-editing enzyme catalytic polypeptide-like 3G is an innate defensive factor and drug target against hepatitis C virus.

UNLABELLED: Host cellular factor apolipoprotein B messenger RNA (mRNA)-editing enzyme catalytic polypeptide-like 3G (hA3G) is a cytidine deaminase that inhibits a group of viruses including human immunodeficiency virus-1 (HIV-1). In the continuation of our research on hA3G, we found that hA3G stabilizing compounds significantly inhibited hepatitis C virus (HCV) replication. Therefore, this study investigated the role of hA3G in HCV replication. Introduction of external hA3G into HCV-infected Huh7.5 human hepatocytes inhibited HCV replication; knockdown of endogenous hA3G enhanced HCV replication. Exogenous HIV-1 virion infectivity factor (Vif) decreased intracellular hA3G and therefore enhanced HCV proliferation, suggesting that the presence of Vif might be an explanation for the HIV-1/HCV coinfection often observed in HIV-1(+) individuals. Treatment of the HCV-infected Huh7.5 cells with RN-5 or IMB-26, two known hA3G stabilizing compounds, increased intracellular hA3G and accordingly inhibited HCV replication. The compounds inhibit HCV through increasing the level of hA3G incorporated into HCV particles, but not through inhibiting HCV enzymes. However, G/A hypermutation in the HCV genome were not detected, suggesting a new antiviral mechanism of hA3G in HCV, different from that in HIV-1. Stabilization of hA3G by RN-5 was safe in vivo. CONCLUSION: hA3G appears to be a cellular restrict factor against HCV and could be a potential target for drug discovery.