The development of a liquid chromatography/tandem mass spectrometric assay for the quantitative analysis of the novel tubulin inhibitor D-24851 in human plasma and urine is described. D-24851 and the deuterated internal standard were extracted from 250 microL of plasma or urine using hexane/ether (1:1, v/v). Subsequently, 10-microL aliquots of reconstituted extracts were injected onto an Inertsil ODS analytical column (50 x 2.0 mm i.d., 5 microm particle size). An eluent consisting of methanol/5 mM ammonium acetate, 0.004% formic acid in water (80:20, v/v) was pumped at a flow rate of 0.2 mL/min. An API 365 triple quadrupole mass spectrometer was used in the multiple reaction monitoring mode for sensitive detection. For human plasma a dynamic range of 1-1000 ng/mL was validated, and for human urine a range of 0.25-50 ng/mL. Validation was performed according to the most recent FDA guidelines and all results were within requirements. The assay has been successfully applied to support a phase I clinical trial with orally administered D-24851.

Introduction Vildagliptin and metformin are two well-established oral antidiabetics with a complementary mechanism of action. Two new generic products, vildagliptin and its fixed-drug combination (FDC) with metformin, were tested for bioequivalence versus the approved originator reference products (Galvus® and Eucreas®). Methods Three randomized studies with two-treatment, two-period, two-sequence crossover design were conducted in healthy adults. One study evaluated vildagliptin 50 mg tablets as single dose under fasting conditions. Vildagliptin–metformin FDC tablet strengths of 50/850 mg and 50/1000 mg were evaluated in separate studies as single dose under fed conditions, given 30 min after a standardized high-fat, high-calorie breakfast following 10 h overnight fasting. Blood samples for analysis were collected until 24 h after dosing in each study period. Bioequivalence between test ( T ) and reference ( R ) products required 90% confidence interval (CIs) for the geometric least square (LS) mean T / R ratio to be within 80–125% for the pharmacokinetic parameters, maximum plasma concentration ( C max ), and area under the curve (AUC 0– t ). Results The 90% CIs of geometric LS means of T / R ratio for C max and AUC 0– t with vildagliptin tablets of 50 mg were 92.22–103.94% and 99.00–102.66%, respectively; corresponding results with FDC tablets for 50/850 mg tablets were 94.81–115.41% and 95.28–106.00% for vildagliptin and 90.87–101.18% and 90.56–100.09% for metformin; for 50/1000 mg tablets C max and AUC 0– t were 105.56–122.30% and 98.30–107.55%, respectively, for vildagliptin and 92.14–103.73% and 94.60–101.81%, respectively, for metformin. Other parameters such as AUC 0–∞ , time to maximum concentration ( T max ), and terminal half-life ( t 1/2 ) were comparable between test and reference products. Adverse events (AEs), mainly vomiting, were reported without relevant difference between test and reference products in each study. AEs were generally mild and transient. No severe or serious AEs occurred. Conclusions The new generic drug products of vildagliptin and the FDCs of vildagliptin and metformin demonstrated bioequivalence to the approved originator products and are therefore expected to provide similar therapeutic effects.

Introduction Three studies compared the bioequivalence (BE) of new generic tablet formulations of sitagliptin (100 mg; fasting) and the fixed-dose combination (FDC) of sitagliptin/metformin (50/850 mg, 50/1000 mg; both fed) in healthy volunteers with the same tablet strengths of the reference products Januvia and Janumet. Methods The study design was open-label, single-dose, randomized with two-way crossover periods. Blood sampling was performed for 72/48 h in the sitagliptin/FDC studies, respectively. Primary pharmacokinetic (PK) parameters for sitagliptin and metformin were area under the plasma concentration–time curve from time 0 to last timepoint of measurable concentration (AUC 0–t ) and maximum plasma concentration ( C max ). Test (T) and reference (R) formulations proved bioequivalent if 90% confidence interval (CI) of geometric least-squares mean ratio for AUC 0–t and C max were within BE acceptance range of 80.00–125.00%. Safety evaluations included vital signs, clinical laboratory tests, and adverse events (AEs). Results Treated/evaluable volunteers for BE per study were: 30/28 (sitagliptin 100 mg), 26/25 (FDC 50/850 mg), and 26/24 (FDC 50/1000 mg). The 90% CI of the geometric means of T/R ratios for primary PK parameters were within predefined BE limits: CI for AUC 0–t and C max were 95.83–100.37% and 91.85–109.56% (sitagliptin 100 mg); 100.84–103.69% and 93.44–105.10% (FDC 50/850 mg), and 101.26–105.20% and 98.71–112.89% (FDC 50/1000 mg); respective values for metformin were 94.23–101.89% and 91.66–99.38% (FDC 50/850 mg) and 98.45–104.89% and 96.79–105.62% (FDC 50/1000 mg). All AEs were nonserious, transient, and mostly mild. Safety evaluations did not reveal any relevant difference between T and R formulations. Conclusions The new generic tablet formulations of sitagliptin 100 mg and the FDCs sitagliptin/metformin 50/850 mg and 50/1000 mg demonstrated bioequivalence to originator reference products. Therefore, the new products are expected to provide efficacy and tolerability similar to those of the reference products in the treatment of patients with type 2 diabetes (T2D). Trial registration EudraCT EU Clinical Trials Registry (2014-005437-31); ClinicalTrials.gov Registry (NCT05549570 and NCT05549583, both retrospectively registered on 20 September 2022).