Wenqia Wang

Pharmacokinetics of lipoyl vildagliptin, a novel dipeptidyl peptidase IV inhibitor after oral administration in rats

The pharmacokinetics of lipoyl vildagliptin, a novel dipeptidyl peptidase IV (DPP IV) inhibitor, was studied in rats after oral administration for developing it as an antidiabetic agent. A liquid chromatography-tandem mass spectroscopy (LC-MS/MS) method was developed to determine lipoyl vildagliptin in rat plasma. After an overnight fasting, rats were orally given lipoyl vildagliptin. Following a single oral dose of 25, 50, and 100 mg·kg−1, Tmax values were from 1.25 to 1.84 h, CL/F values were around 100 l h−1 kg−1. In the dose range, Cmax values (63.9–296 μg·l−1) and AUC0–∞values (260–1214 μg·h·l−1) were proportional to the doses. In conclusion, this LC-MS/MS method for the determination of lipoyl vildagliptin in rat plasma was selective and sensitive. In rats, lipoyl vildagliptin displayed linear pharmacokinetics after a single oral dose in the range of 25–100 mg·kg−1. Lipoyl vildagliptin might have very high CL/F values and Vd/F values, which indicated that the bioavailability of this drug might be low or lipoyl vildagliptin might distribute extensively or accumulate in tissues in view of its high liposolubility.

Numerical analysis of the second-order characteristic FEM for nonlinear aerosol dynamic equations

Aerosol modeling is very important to study the behavior of aerosol dynamics in atmospheric environment. In this paper we consider the nonlinear aerosol dynamic equations on time and particle size, which involve the advection-condensation process and the nonlinear coagulation process. For solving accurately the multiple sharp log-normal aerosol distributions, we study and analyze the second order characteristic finite element method for the aerosol dynamic equations. We strictly prove that the developed method has second-order accuracy in time. The scheme improves the first-order accuracy in time comparing to the classical characteristic method. Numerical experiments for the multiple log-normal aerosol distributions are further given to confirm the theoretical results.