Thorough QT/QTc Evaluation of the Cardiac Safety of Enarodustat (JTZ-951), an Oral Erythropoiesis-Stimulating Agent, in Healthy Adults.

This study evaluated the effect of enarodustat on cardiac repolarization in healthy subjects. Enarodustat (20 and 150 mg [supratherapeutic dose]), placebo, and moxifloxacin (positive control, 400 mg) were administered orally to males and females (N = 54) in a crossover fashion. Continuous 12-lead Holter electrocardiogram (ECG) data were obtained before and after dosing, and blood samples were obtained for pharmacokinetic assessments of enarodustat, its circulating metabolite (R)-M2, and moxifloxacin. Central tendency analysis was performed for relevant ECG parameters, the relationship between individual-corrected interval from beginning of the QRS complex to end of the T wave in the frontal plane (QTcI, the primary end point) and plasma concentrations of enarodustat and (R)-M2 were assessed, and ECG waveforms were evaluated for morphological changes. The supratherapeutic dose resulted in 7- and 9-fold higher geometric mean maximum concentrations for enarodustat and (R)-M2, respectively, than the 20 mg dose. Based on time point analysis, the upper bound of the 2-sided 90% confidence interval (CI) for QTcI did not exceed 10 milliseconds at any of the time points for either dose. Based on QTcI-concentration analysis, the slopes for enarodustat and (R)-M2 were not statistically different than 0, and the upper bounds of the 2-sided 90% CI for QTcI at the geometric mean maximum concentrations for the supratherapeutic dose were 1.97 and 1.68 milliseconds for enarodustat and (R)-M2, respectively. The lower bound of the 2-sided 90% CI for moxifloxacin was ≥5 milliseconds, demonstrating assay sensitivity. The study demonstrated no clinically relevant effect of enarodustat and (R)-M2 on cardiac repolarization. There was no evidence of any clinically significant effect on the PR interval and QRS duration, and ECG waveforms showed no new clinically relevant morphological changes.

Determination of metformin in rat plasma by HILIC-MS/MS combined with Tecan automation and direct injection.

Metformin is a well-known oral antihyperglycemic drug used in treatment of type II diabetes. Analysis of metformin in biological fluids is a challenge owing to its high polarity and small molecular size, which lead to poor retention of metformin on reversed-phase liquid chromatographic columns. A high-throughput method was developed and validated for the determination of metformin in rat plasma in support of preclinical toxicology studies, using hydrophilic interaction liquid chromatography tandem mass spectrometry (HILIC-MS/MS) and Tecan automated sample preparation. Extracted samples were directly injected onto the unbounded silica column with an aqueous-organic mobile phase. This HILIC-MS/MS method was validated for accuracy, precision, sensitivity, stability, matrix effect, recovery and calibration range. Acceptable intra-run and inter-run assay precision (coefficient of variation ≤ 3.9%) and accuracy (99.0-101.8%) were achieved over a linear range of 50-50,000 ng/mL. Metformin is stable in rat plasma for at least 6 h at room temperature, 147 days at -70°C and through three freeze (-70°C) and thaw cycles. Metformin is also stable in rat whole blood for at least 2 h at room temperature and in an ice-water bath. The validated method was successfully used in support of several preclinical studies where metformin is dosed together with an investigational drug substance. The ruggedness of the validated method was demonstrated by the incurred sample reproducibility test.