Quantification of Phosphonate Drugs by H-P HSQC Shows That Rats Are Better Models of Primate Drug Exposure than Mice.

The phosphonate group is a key pharmacophore in many antiviral, antimicrobial, and antineoplastic drugs. Due to its high polarity and short retention time, detecting and quantifying such phosphonate-containing drugs with LC/MS-based methods are challenging and require derivatization with hazardous reagents. Given the emerging importance of phosphonate-containing drugs, developing a practical, accessible, and safe method for their quantitation in pharmacokinetics (PK) studies is desirable.

The Drug-Drug Interaction Profile of Presatovir.

Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infections in young children. Presatovir (previously GS-5806) is a novel, orally administered RSV fusion inhibitor with a favorable safety profile and proven antiviral efficacy in preclinical and clinical studies. In vitro, presatovir is a substrate of the efflux transporters P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) and hepatic uptake transporters organic anion transporting polypeptide (OATP) 1B1 and OATP1B3 and is slowly metabolized by cytochrome P450 (CYP) 3A4 and CYP3A5.

Antiviral Efficacy of a Respiratory Syncytial Virus (RSV) Fusion Inhibitor in a Bovine Model of RSV Infection.

Respiratory syncytial virus (RSV) is the leading cause of bronchiolitis and pneumonia in infants. Effective treatment for RSV infection is a significant unmet medical need. While new RSV therapeutics are now in development, there are very few animal models that mimic the pathogenesis of human RSV, making it difficult to evaluate new disease interventions.

Optimization of Pharmacokinetics through Manipulation of Physicochemical Properties in a Series of HCV Inhibitors.

A novel series of HCV replication inhibitors based on a pyrido[3,2-d]pyrimidine core were optimized for pharmacokinetics (PK) in rats. Several associations between physicochemical properties and PK were identified and exploited to guide the design of compounds. In addition, a simple new metric that may aid in the prediction of bioavailability for compounds with higher polar surface area is described (3*HBD-cLogP).

RNase H active site inhibitors of human immunodeficiency virus type 1 reverse transcriptase: design, biochemical activity, and structural information.

Pyrimidinol carboxylic acids were designed as inhibitors of HIV-1 RNase H function. These molecules can coordinate to two divalent metal ions in the RNase H active site. Inhibition of enzymatic activity was measured in a biochemical assay, but no antiviral effect was observed.

Mechanism of active renal tubular efflux of tenofovir.

Tenofovir (TFV) undergoes renal elimination by a combination of glomerular filtration and active tubular secretion. While transporter-mediated uptake of TFV from the blood into proximal-tubule cells has been well characterized, comparatively little is known about the efflux system responsible for transporting TFV into the lumen during active tubular secretion. Therefore, members of the ATP-binding cassette family of efflux pumps expressed at the apical side of proximal-tubule cells were studied for the ability to transport TFV.

Lack of a metabolic and antiviral drug interaction between tenofovir, abacavir and lamivudine.

Objective: An anti-HIV regimen composed of the nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) tenofovir (TFV) disoproxil fumarate (TDF), abacavir (ABC) and lamivudine (3TC) has performed poorly in patients. This study evaluated the combination of TFV, ABC and 3TC for metabolic or antiviral antagonism in vitro.

Design: Procedures were developed to evaluate the in vitro metabolism and antiviral activity of drug combinations of TFV, ABC and 3TC in cell types relevant for HIV infection.