Kinetics of Nirogacestat-Mediated Increases in B-cell Maturation Antigen on Plasma Cells Inform Therapeutic Combinations in Multiple Myeloma.

GSIs can enhance multiple myeloma therapies targeting BCMA by increasing mbBCMA on plasma cells. In response to the GSI nirogacestat, mbBCMA rapidly and robustly increased in vitro and in vivo. Elucidating nirogacestat's effects on BCMA kinetics will guide potential multiple myeloma dosing strategies.

Design and synthesis of spirocyclic compounds as HCV replication inhibitors by targeting viral NS4B protein.

Two novel series of spirocyclic piperidine analogs appended to a pyrazolo[1,5-a]pyridine core were designed, synthesized and evaluated for their anti-HCV activity. A series of piperidine ketals afforded dispiro 6p which showed excellent in vitro anti-HCV activities (EC50 of 1.5nM and 1.

Synthesis and pharmacokinetic profile of highly deuterated brecanavir analogs.

Several highly deuterated analogs of the HIV-1 protease inhibitor brecanavir have been prepared to study the effect of deuterium upon metabolic stability. The sites for deuterium incorporation were initially chosen to maximize the potential for a kinetic isotope effect; locations where C-H bond breaking is the rate limiting step. The analogs have been profiled in both in vitro and in vivo pharmacokinetic studies and the result will be described herein.

Evaluation of the metabolism of propranolol by linear ion trap technology in mouse, rat, dog, monkey, and human cryopreserved hepatocytes.

Propranolol is a widely used quality control and validation compound for liver microsome and hepatocyte metabolism studies. A multitude of literature reports describing the identification of propranolol metabolites exists today. However, no literature reports currently exist showing hepatocyte metabolism across the five species commonly used during pre-clinical drug discovery, namely mouse, rat, dog, monkey, and human.

Determination of zanamivir in rat and monkey plasma by positive ion hydrophilic interaction chromatography (HILIC)/tandem mass spectrometry.

A hydrophilic interaction chromatography (HILIC)/mass spectrometric assay was developed for the determination of zanamivir, a neuraminidase inhibitor used to treat influenza, in rat and monkey plasma. An organic solvent with hydrophilic properties, methanol, was used to precipitate proteins in plasma to assure the highly polar zanamivir of staying in solution. Chromatographic separation was obtained using a HILIC silica column with multiple reaction monitoring turboionspray positive ion detection.

The systemic exposure of an N-methyl-D-aspartate receptor antagonist is limited in mice by the P-glycoprotein and breast cancer resistance protein efflux transporters.

GV196771 [E-4,6-dichloro-3-(2-oxo-1-phenyl-pyrrolidin-3-glydenemethyl)-1H-indole-2 carboxylic acid] is a potent antagonist of the modulatory glycine site of the N-methyl-d-aspartate receptor. GV196771 has low oral bioavailability (<10%) and plasma clearance ( approximately 2 ml/min/kg) in rats. P-Glycoprotein (Pgp) and breast cancer resistance protein (Bcrp) are ATP-binding cassette (ABC) transporters that limit the oral absorption of drugs and dietary constituents.

P-glycoprotein influences the brain concentrations of cetirizine (Zyrtec), a second-generation non-sedating antihistamine.

Recent in vitro studies have suggested that P-glycoprotein (Pgp) and passive membrane permeability may influence the brain concentrations of non-sedating (second-generation) antihistamines. The purpose of this study was to determine the importance of Pgp-mediated efflux on the in vivo brain distribution of the non-sedating antihistamine cetirizine (Zyrtec), and the structurally related sedating (first-generation) antihistamine hydroxyzine (Atarax). In vitro MDR1-MDCKII monolayer efflux assays demonstrated that cetirizine was a Pgp substrate (B-->A/A-->B + GF120918 ratio = 5.