No abstract

Liraglutide is a glucagon-like peptide-1 (GLP-1) analog that has been utilized for the treatment of type 2 diabetes mellitus. Liraglutide at a higher dose also shows beneficial effects in weight loss, which prompted its widespread use as an anti-obesity drug. The potential of liraglutide to treat Alzheimer’s disease and cognitive impairment has also been suggested. Nevertheless, the pharmacokinetics of liraglutide, including its distribution to the brain, has not been fully characterized. Therefore, this study aimed to develop a simple and sensitive bioanalytical method using liquid chromatography–tandem mass spectrometry (LC–MS/MS) and determine the pharmacokinetics and brain distribution of liraglutide in rats. Liraglutide in the rat plasma and brain tissue homogenates was extracted by protein precipitation using methanol. A gradient elution profile was used for chromatographic separation with mobile phases comprising 0.3% formic acid in water and 0.3% formic acid in acetonitrile. The mass spectrometry was operated in the positive electrospray ionization with multiple reaction monitoring mode. The lower limit of quantification of the present LC–MS/MS was 1 ng/mL in the plasma and 2 ng/mL in the brain tissue. Following intravenous injection (0.05 mg/kg, n = 5), plasma concentrations of liraglutide decreased monoexponentially with an average half-life of 3.67 h. The estimated absolute bioavailability of liraglutide after subcutaneous injection was 13.16%. Brain distribution of liraglutide was not significant, with the tissue-to-plasma partition coefficient (Kp) of liraglutide less than 0.00031. However, the concentrations of liraglutide were significantly different in the different brain regions following IV injection. In the brain, liraglutide concentrations were the highest in the hypothalamus, followed by the cerebellum and cerebrum. The present LC–MS/MS assay and the pharmacokinetic results may be helpful to understand better the effect of liraglutide in the brain for further preclinical and clinical studies of liraglutide.

Evogliptin (EV) is a novel dipeptidyl peptidase‐4 inhibitor (DPP4i) for glycemic control in patients with type 2 diabetes mellitus (T2DM). This study evaluated the pharmacokinetic (PK) and pharmacodynamic (PD) interactions between EV and sodium glucose cotransporter‐2 inhibitors (SGLT2i) in healthy volunteers since combination therapy of DPP4i and SGLT2i has been considered as an effective option for T2DM treatment. A randomized, open‐label, multiple‐dose, two‐arm, three‐period, three treatments, two‐sequence crossover study was conducted in healthy Korean volunteers. In arm 1, subjects were administered 5 mg of EV once daily for 7 days, 25 mg of empagliflozin (EP) once daily for 5 days, and the combination once daily for 5 days (EV + EP). In arm 2, subjects were administered 5 mg of EV once daily for 7 days, 10 mg of dapagliflozin (DP) once daily for 5 days, and the combination once daily for 5 days (EV + DP). Serial blood samples were collected for PK analysis, and oral glucose tolerance tests were conducted for PD analysis. In each arm, a total of 18 subjects completed the study. All adverse events (AEs) were mild with no serious AEs. The geometric mean ratio and confidence interval of the main PK parameters (maximum concentration of the drug in plasma at steady state and area under the plasma drug concentration‐time curve within a dosing interval at a steady state) between EV and either EP or DP alone were not significantly altered by co‐administration. Administration of EV + EP or EV + DP did not result in significant PD changes, as determined by the glucose‐lowering effect. Administration of EV + EP or EV + DP had no significant effects on the PK profiles of each drug. All treatments were well‐tolerated.