Bioequivalence of a Generic Nateglinide Formulation in Healthy Chinese Volunteers under Fasting and Fed Conditions: A Randomized, Open-Label, Double-Cycle, Double-Crossover Study.

INTRODUCTION: Nateglinide or N-(trans-4-isopropylcyclohexyl-1-carbonyl)-D-phenylalanine is a drug with a rapid hypoglycemic effect that is mainly used in the treatment of type 2 diabetes. Very few studies have assessed bioequivalence based on feeding status. This study aimed to assess the pharmacokinetic bioequivalence and safety of nateglinide-containing tablets (0.12 g) in healthy Chinese volunteers under fasting and fed conditions. METHODS: The studies were performed in 2017-2018 in the Phase I Clinical Trial Ward of the Affiliated Hospital of Liaoning University of Traditional Chinese Medicine, China. Eligible Chinese volunteers received a single 0.12-g dose of the test or reference formulation, followed by a 7-day washout period and administration of the alternate formulation. Blood samples were collected at various time intervals, and plasma nateglinide concentrations were analyzed by liquid chromatography-tandem mass spectrometry. Then, the adverse events, laboratory test results, vital signs, and physical exam findings were compared between the 2 groups. RESULTS: The ratios of the geometric means of Cmax, AUC0-t, and AUC0-inf of the tested to reference preparations under fasting conditions were 105.03% (90% confidence interval [CI]: 99.53-110.83%), 104.02% (90% CI: 101.37-106.74%), and 104.04% (90% CI: 101.38-106.77%), respectively. The same ratios under fed conditions were 96.55% (90% CI: 85.80-108.65%), 103.08% (90% CI: 100.07-106.18%), and 103.07% (90% CI: 100.21-106.01%), respectively. The 90% CI values for Cmax, AUC0-t, and AUC0-inf fell within the accepted range of bioequivalence (80.00-125.0%). Common adverse events included hypoglycemia, heart rate increase, palpitation, sweating, dizziness, and diarrhea. CONCLUSIONS: The test formulation (0.12 g) met the CFDA's regulatory definition for bioequivalence to the reference formulation. Both formulations were well tolerated by healthy Chinese subjects. TRIAL REGISTRATION: This trial has been registered in the Chinese Clinical trial registry (ChiCTR2000030694), March 10, 2020.

Simultaneous Pharmacokinetics Estimation of Nateglinide and Pioglitazone by RP-HPLC: Computational Study to Unlock the Synergism.

Nateglinide (NAT) and Pioglitazone (PIO) are an antidiabetic drugs combination and currently under clinical trial in countries like Japan. In this study, an alternative, a simple, sensitive high-performance liquid chromatography method has been developed (limit of detection: 15 ng/mL and limit of quantification: 50 ng/mL) for simultaneous estimation of this drug combination in rat plasma. Most remarkably, bioavailability of NAT has been increased markedly on coadministration with PIO, than when it was administered alone. Thus, PIO is assumed to retard the catabolism of NAT by inhibiting metabolic liver-microsomal enzyme, especially CYP2C9. Using a Waters Nova-Pak C 18 column (150 × 3.9 mm, 4 µm) and a mobile phase of acetonitrile: 10 mM KH2PO4 (60: 40, V/V (volume by volume)) pH 3.5, the analysis was performed at 210 nm with a flow rate of 1.5 mL/min. In silico docking via molecular dynamics simulation revealed that NAT-CYP2C9 binding affinity may be reduced after PIO attachment, presumably due to the binding site overlapping of the two drugs. Thus, it has been proposed that NAT and PIO may be an efficient synergistic fixed dose combination against diabetes mellitus, and the above method can foster a simple but highly sensitive bioanalytical estimation for routine analysis.

QSPR Modeling of Biopharmaceutical Properties of Hydroxypropyl Methylcellulose (Cellulose Ethers) Tablets Based on Its Degree of Polymerization.

Quantitative structure-property relationship (QSPR) approach has been widely used in predicting physicochemical properties of compounds. However, its application in the estimation of formulation properties based on the polymer used in it to achieve desired formulation characteristics is an extremely challenging process. In the present research, predictive QSPR models were developed by correlating the physicochemical properties of varying grades of cellulose ethers (hydroxypropyl methylcellulose, HPMC) with those of nateglinide (NTG) containing tablets (in vitro and in vivo properties). Sustained release tablets of NTG were prepared by using different grades and concentrations of HPMC and subsequently characterized for in vitro as well as in vivo parameters. Further, QSPR models for individual formulation property were developed by correlating the polymeric physicochemical properties with the formulation characteristics. Subsequently, a true external validation method was used to validate the predictability of developed models. The dissolution study indicated Korsmeyer-Peppas as the best fit model following non-Fickian as drug transport mechanism extending the drug release up to 12 h. In vivo studies showed limited absorption of the NTG. Developed QSPR models showed promising validated predictability for formulation characteristics. The applicability of present work in formulation development could significantly reduce the time and cost expenditure on design trials without actually formulating a delivery system.

Niosomes for oral delivery of nateglinide: in situ-in vivo correlation.

Niosomes have been claimed to enhance intestinal absorption and to widen the absorption window of acidic drugs. This was reported after monitoring the intestinal absorption in situ. Accordingly, the aim of this work was to investigate the effect of niosomal encapsulation on intestinal absorption and oral bioavailability of nateglinide. This was conducted with the goal of correlation between in situ intestinal absorption and in vivo availability. The drug was encapsulated into proniosomes. The niosomes resulting after hydration of proniosomes were characterized with respect to vesicle size and drug entrapment efficiency. The in situ rabbit intestinal absorption of nateglinide was monitored from its aqueous solution and niosomes. Streptozotocin was used to induce diabetes in albino rats which were then used to assess the hypoglycemic effect of nateglinide after oral administration of aqueous dispersion and niosomal systems. The prepared vesicles were in the nanoscale with the recorded size being 283 nm. The entrapment efficiency depended on the pH of the formulation. The in situ intestinal absorption reflected non-significant alteration in the membrane transport parameters of the drug after niosomal encapsulation compared with the free drug solution. In contrast, niosomes showed significant improvement in the rate and extent of the hypoglycemic effect compared with the unprocessed drug. This discrepancy can be attributed to different transport pathway for the drug after niosomal inclusion with the vesicles undergoing translymphatic transport which can minimize presystemic metabolism. However, this requires confirmatory investigations. In conclusion niosomes can enhance oral bioavailability of nateglinide with the absorption being through nontraditional pathway.