Development and Validation of an LC-MS/MS Method for Quantification of the Novel Antibacterial Candidate DA-7010 in Plasma and Application to a Preclinical Pharmacokinetic Study

Pharmacokinetics of the novel 5-HT4 receptor agonist, DA-6886, in dogs

The pharmacokinetics of a new 5-hydroxytryptamine receptor 4 agonist, DA-6886, intended for the treatment of constipation-predominant irritable bowel syndrome, were evaluated in beagle dogs following both intravenous and oral administration of DA-6886 (1-10 mg/kg). The study also examined the effects of gender and food on the pharmacokinetics of DA-6886 in dogs.DA-6886 demonstrated dose-proportional area under the plasma concentration-time curve (AUC) values and dose-independent clearance (21.0-24.6 mL/min/kg) after administration via both routes. The steady-state volume of distribution (Vss) for DA-6886 was dose-independent and relatively large (6.76-8.57 L/kg), aligning with its observed high distribution in rat tissues.No significant differences were observed in the pharmacokinetics of DA-6886 between male and female dogs. Post oral administration, extent of absolute oral bioavailability (BA) was relatively high (48.2-96.1%) in contrast to the rates observed in rats (18.9-55.0%).Dogs that were fed exhibited a significantly lower Cmax and a delayed Tmax in comparison to those that were fasted. However, the AUC values were similar between the two groups. The extended stomach transit time in the fed state may account for this delayed absorption of DA-6886 without substantial changes in AUC.

Pharmacokinetics of DA-6886, A New 5-HT4 Receptor Agonist, in Rats

DA-6886 is a novel serotonin (5-hydroxytrypamine [5-HT]) receptor 4 agonist for the potential treatment of constipation-predominant irritable bowel syndrome. The purpose of this study was to validate the quantitative assay of DA-6886 in rat plasma and to evaluate the pharmacokinetics and tissue distribution of DA-6886 in rats. The liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for the robust quantification of DA-6886 in rat plasma was successfully validated and applied to the pharmacokinetic studies in rats. The pharmacokinetic parameters of DA-6886 in rats were evaluated following single intravenous or oral administration at three dose levels (2, 10, and 20 mg/kg). DA-6886 exhibited a smaller dose-normalized area under the plasma concentration–time curve (AUC) values and faster clearances in the low-dose group than in the high-dose group following both intravenous and oral administration. The steady-state volume of distribution (V_ss) of DA-6886 was relatively large (4.91–7.84 L/kg), which was consistent with its high distribution to the liver, kidney, lung, and digestive tract, and was dose-independent. After oral administration, the extent of absolute bioavailability (F) tended to increase (18.9–55.0%) with an increasing dose. The slope of the log-transformed AUC and/or C_max values versus log dose was greater than unity and greater for oral administration (~1.9) than for intravenous administration (~1.1). Because the nonlinear pharmacokinetics of DA-6886 was more obviously observed after oral administration, it appears that the saturation of pre-systemic intestinal and/or hepatic first-pass extraction of DA-6886 at high doses occurred.