Pharmacokinetics of Phosphate Retagliptin Tabletin in Patients with Renal Dysfunction

Objective To compared the differences in pharmacokinetics of phosphate retagliptin tablets in patients with varying degrees of renal dysfunction. Methods A total of 32 patients were categorized into five groups according to their renal function: normal, mild dysfunction，moderate dysfunction, severe dysfunction, and end stage renal dysfunction (ESRD). All of the patients took a single dose of 50 mg phosphate retagliptin tablet. Their plasma and urinary concentrations of phosphate retagliptin (SP2086) and phosphate retagliptin acid (SP2086 acid) were determined using LC-MS/MS methods. The plasma pharmacokinetic parameters were calculated using WinNolin 6.1 software. Results Peak concentrations (Cmax) of SP2086 reached at (1.07±0.35) h in the patients with mild renal dysfunction, (1.50±0.89) h in the patients with moderate renal dysfunction, (1.67±2.16) h in the patients with severe renal dysfunction, (2.42±2.15) h in the patients with ESRD, and (1.75±1.21) h in the normal participants, with a clearance (CL/F) of （23.50±6.01）,（12.90±4.34）,（6.70±1.55）,（3.10±0.48） , and （30.50±10.70） L/h, respectively. With the increasing damages in renal function presented an incease in Cmax, time to reach Cmax (Tmax), and area under curve (AUC),a decrease in CL/F,of SP2086 and SP2086 acid. The 0-96 hurine cumulative excretion percentage (Ae%) of SP2086 ranged from 0.441% to 4.530%. The Ae% of SP2086 acid reached （71.7±14.3）% in the patients with mild renal dysfunction, （59.5±22.7）% in the patients with moderate renal dysfunction, （63.3±13.9）% in the patients with severe renal dysfunction, （34.1±20.0）% in the patient with ESRD, and （74.2±14.6）% in the normal participants，with a renal clearance (CL/R) of (220.0±51.2), (105.0±64.5), (54.5±7.6), (13.5±7.8), and (289.0±73.7) mL/min, respectively. Compared with the participants with normal renal function, the AUCs of SP2086 and SP2086 acid were 1.44 times and 2.32 times higher in the patients with moderate renal dysfunction, 2.20 times and 4.39 times higher in the patients with severe renal dysfunction，and 2.83 times and 9.28 times higher in the patients with ESRD. Conclusion The dosage of phosphate retagliptin tablet is recommended at 100 mg/d for patients with normal renal function and those with mild renal dysfunction, at 50 mg/d for patients with moderate renal dysfunction, and at 25 mg/d for patients with severe renal dysfunction. No phosphate retagliptin tablet is recommended for patients with ESRD.