Pharmacokinetic analysis
Liquid chromatography with tandem mass spectrometry was used to analyze plasma evogliptin, evogliptin M7, evogliptin M8, glimepiride, and glimepiride M1 and urine evogliptin concentrations. In blank human plasma and urine, no interference of endogenous compounds was observed. The calibration curves of undiluted samples were linear over the range of concentration from 0.1 μg/L to 60 μg/L for plasma evogliptin; from 10 ng/L to 10000 ng/L for plasma evogliptin M7 and evogliptin M8; from 5 μg/L to 2000 μg/L for plasma glimepiride; from 0.5 μg/L to 500 μg/L for plasma glimepiride M1; from 5 to 50000 μg/L for urine evogliptin. The within-run accuracy and precision were 97.2 - 105.5 % and 0.8 - 7.2 % for plasma evogliptin; 94.9 - 103.2 % and 0.2 - 6.9 % for plasma evogliptin M7; 86.7 -106.3 % and 0.1 - 11.2 % for plasma evogliptin M8; and for plasma glimepiride; and for plasma glimepiride M1; 97.5 - 104.6 % and 3.3 - 6.5 % for urine evogliptin.
The individual PK parameters were determined via noncompartmental methods using Phoenix WinNonlin® software version 8.0 (Certara, Princeton, NJ, USA). The maximum concentration at steady-state (Cmax,ss) and Tmax at steady state (Tmax,ss) were determined by observing the plasma concentration-time data. The half-life at steady state (T1/2,ss) was determined by fitting a linear regression for evogliptin, evogliptin M7, evogliptin M8, glimepiride, and glimepiride M1. The area under the plasma concentration-time curve over dosing interval at steady-state (AUCτ,ss) and the total apparent clearance at steady-state (CLss) were determined using the linear-log trapezoidal method.
The fraction excreted unchanged in urine over dosing interval at steady-state (feτ,ss) was determined by dividing the amount excreted unchanged in urine over dosing interval at steady-state (Aeτ,ss) by the total dose given on the day of urine collection. The renal clearance at steady-state (CLR,ss) was determined as Aeτ,ss divided by the AUCτ,ss for evogliptin.