Identification and structure-activity relationship exploration of uracil-based benzoic acid and ester derivatives as novel dipeptidyl Peptidase-4 inhibitors for the treatment of type 2 diabetes mellitus.

Our previously reported carboxyl-containing DPP-4 inhibitors were highly potent but were poorly bioavailable. Esters of the carboxyl analogs exhibited a significant DPP-4 potency loss albeit with enhanced oral absorption. Herein, we described identification and structure-activity relationship (SAR) exploration of a novel series of benzoic acid and ester derivatives as low single-digit nanomolar DPP-4 inhibitors. Importantly, the esters displayed comparable activities to the acids counterparts. Molecular simulation revealed that ester adopts a similar binding mode to acid. Moreover, the selected esters and acids demonstrated high selectivity and low cytotoxicity, as well as good metabolic stability. And more importantly, the esters possessed excellent pharmacokinetic profiles for oral administration. The best compound ester 19b demonstrated long DPP-4 inhibition in vivo, and robustly improved the glucose tolerance in normal and db/db mice while ensuring glucose-lowering potency in chronic treatment. Our results supported that the compound 19b can be served as a potential candidate for the treatment of type 2 diabetes.

Development and validation of an ultrasensitive LC-MS/MS method for the quantification of cetagliptin in human plasma and its application in a microdose clinical trial.

This study established and validated an LC-MS/MS method for the ultrasensitive determination of cetagliptin in human plasma. Sample pretreatment was achieved by liquid-liquid extraction with ethyl acetate, and chromatographic separation was performed on an XB-C18 analytical column (50 × 2.1 mm, 5 µm) with gradient elution (0.1% formic acid in acetonitrile and 0.1% formic acid) at a flow rate of 1.0 mL/min. For mass spectrometric detection, multiple reaction monitoring was used, and the ion transitions monitored were m/z 421.2-86.0 for cetagliptin and m/z 424.2-88.0 for cetagliptin-d3. Method validation was performed according to the U.S. Food and Drug Administration Bioanalytical Method Validation Guidance, for which the calibration curve was linear in the range of 50.0-2000 pg/mL. All of the other results, such as selectivity, lower limit of quantitation, precision, accuracy, matrix effect, recovery, and stability, met the acceptance criteria. The validated method was successfully applied in a microdose clinical trial to systematically investigate the pharmacokinetic profile of cetagliptin in healthy subjects. Both rapid absorption and prolonged duration demonstrate the potential value of cetagliptin for diabetes treatment.

An HPLC-MS/MS method for quantitation of trelagliptin and application in a comparative pharmacokinetic study.

Aim: A sensitive HPLC-MS/MS approach was established to quantify trelagliptin and explore the pharmacokinetic characteristics in rats for up to 7 days. Meanwhile, the pharmacokinetic differences of trelagliptin were investigated for the first time. Results/methodology: The ion pairs of m/z 358.2→341.2 for trelagliptin and m/z 340.3→116.1 for alogliptin (internal standard) were detected in positive mode. Trelagliptin displayed a good linearity in the range of 4-4000 ng/ml (r2 = 0.9997) with a mean recovery rate of 86.9-94.1%. Discussion/conclusion: Compared with normal groups, the T1/2, apparent volume of distribution, area under the curve and bioavailability in model rats were significantly increased while the apparent plasma clearance decreased. The approach is proved to be straightforward and appropriate for quantitation of trelagliptin and application in pharmacokinetics studies.

Pharmacokinetic-pharmacodynamic (dipeptidyl peptidase-4 inhibition) model to support dose rationale in diabetes patients, including those with renal impairment, for once-weekly administered omarigliptin.

AIMS: To characterize the population pharmacokinetics (PK) and pharmacodynamics (PD) of the once-weekly dipeptidyl peptidase-4 (DPP-4) inhibitor omarigliptin in healthy subjects and patients with type 2 diabetes mellitus, and use these models to support the dosing recommendation for patient labelling including patients with renal impairment. METHODS: PK and PD were assessed from a total of 9827 omarigliptin concentrations collected from 1387 healthy subjects and patients participating in Phase 1, 2 and 3 studies examining single- or multiple-dose weekly administration of omarigliptin at doses ranging from 0.25 to 400 mg. Population PK and PD analyses were performed using nonlinear mixed effect modelling. RESULTS: A semi-mechanistic 2-compartment model with linear unbound clearance and concentration-dependent binding of omarigliptin to the DPP-4 enzyme in both the central and peripheral compartments adequately described omarigliptin PK. Key covariates on omarigliptin PK included reduced unbound clearance with renal impairment. A direct effect sigmoid maximum inhibitory efficacy model adequately described the relationship between omarigliptin plasma concentrations and DPP-4 inhibition. These models supported the current Japan label instructions that the approved omarigliptin 25-mg once-weekly dose be halved in patients with severe renal impairment and in those with end-stage renal disease. Also, if patients missed a dose, the next dose of omarigliptin should be taken as soon as remembered up to and including the day before the next scheduled dose. No other clinically important covariates were identified. CONCLUSION: The models in the present analysis adequately described PK and PD characteristics of omarigliptin and supported the dosing and administration section of the omarigliptin label.

Metabolites characterization of a novel DPP-4 inhibitor, imigliptin in humans and rats using ultra-high performance liquid chromatography coupled with synapt high-resolution mass spectrometry.

Imigliptin has been reported as a novel dipeptidyl-peptidase-IV (DPP-4) inhibitor to treat type 2 Diabetes Mellitus (T2DM), and is currently being tested in clinical trials. In the first human clinical study, imigliptin was well tolerated and proved to be a potent DPP-4 inhibitor. Considering its potential therapeutic benefits and promising future, it is of great importance to study the metabolite profiles in the early stage of drug development. In the present study, a robust and reliable analytical method based on the ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC/Q-TOF MS) method combined with MassLynx software was established to investigate the characterization of metabolites of imigliptin in human and rat plasma, urine and feces after oral administration. As a result, a total of 9 metabolites were identified in humans, including 6, 9 and 8 metabolites in human plasma, urine, and feces, respectively. A total of 11 metabolites were identified in rats, including 7, 10 and 8 metabolites in rat plasma, urine, and feces, respectively. In addition, 6 of the metabolites detected in humans and rats were phase I metabolites, including demethylation, carboxylation, hydroxylation and dehydrogenation metabolites, and 5 of the metabolites were phase II metabolites, including acetylation and glucuronidation. There was no human metabolite detected compared to those in rats. The major metabolites detected in human plasma (M1 and M2) were products resulting from acetylation, and hydroxylation followed by dehydrogenation. M1 was the major metabolite in rat plasma. M2 and the parent drug were the major drug-related substances in human urine. The parent drug was the major drug-related substances in rat urine. M2, M5 (hydroxylation product) and M6 (2 × hydroxylation and acetylation product) were the predominant metabolites in human feces. M2 and M5 were the major metabolites in rat feces. In addition, renal clearance was the major route of excretion for imigliptin.

Evaluation of pharmacokinetic and pharmacodynamic parameters following single dose of sitagliptin in healthy Indian males.

PURPOSE: Sitagliptin, a dipeptidyl peptidase (DPP)-IV inhibitor approved for the treatment of type 2 diabetes, is reported to be more efficacious in Indian patients than non-Indian patient population. The objective of the study was to evaluate pharmacokinetic and pharmacodynamic (PK/PD) parameters of single-dose sitagliptin 100 mg (Januvia) in healthy Indian male participants. METHOD: In a randomised, single-dose, open-label, three-treatment, three-period, three-sequence, crossover bioavailability study, 18 healthy male participants received single-dose of sitagliptin under fasted and fed conditions. PK parameters (Cmax, Tmax, AUC0-∞ and t1/2) were determined using Phoenix WinNonlin software. PD parameters [DPP-IV inhibition, active glucagon-like peptide-1 (GLP-1) and insulin] were determined using established methods. RESULTS: PK parameters expressed in mean (SD) were Cmax 491.7 (135.9) ng/mL; AUC0-∞ 4256.1 (509.9) ng· hr/mL, Tmax 2.9 (1.0) hr and t1/2 10.4 (3.0) hr. The weighted average (WA) plasma DPP-4 inhibition over 24 h was 89.6% and WA of plasma active GLP-1 over 2 h after standardised meal (geometric mean ratio) was 11.1 (9.9) pM/L which is two- to- four fold higher compared to that reported in other populations. The mean average (SD) AUC of plasma insulin over 2 h of standardised meal was 47.9 (24.9) µIU/mL. CONCLUSION: Although, there are differences in pharmacokinetic parameters, no clinically meaningful differences were observed with respect to DPP-IV inhibition between Indian and non-Indian population.

Use of Prohibited Medication, a Potentially Overlooked Confounder in Clinical Trials: Omarigliptin (Once-weekly DPP-4 Inhibitor) Monotherapy Trial in 18- to 45-year-olds.

PURPOSE: The objective of this clinical trial was to assess the efficacy and safety of omarigliptin monotherapy in young adult patients with type 2 diabetes mellitus (T2DM). Unexpected efficacy results in this trial led to a series of investigations that identified the use of prohibited medication by a substantial number of trial patients. METHODS: Patients with T2DM who were ≥18 to <45 years of age and either drug-naive or not on an antihyperglycemic agent for ≥12 weeks with inadequate glycemic control were randomized in a double-blind manner to receive omarigliptin 25 mg once weekly (n = 102) or placebo once weekly (n = 101) for 24 weeks. The objectives of the trial were to assess the effect of treatment with omarigliptin on glycemic parameters, including levels of glycosylated hemoglobin (HbA1c), 2-hour postmeal glucose, and fasting plasma glucose, and to assess the safety and tolerability of omarigliptin. Additional investigations into trial conduct included the measurement of drug levels for omarigliptin and metformin in blood samples collected for future biomedical research, available for approximately one half of the patients. FINDINGS: The mean age of trial participants was 39.2 years, approximately 60% were male, mean body mass index was 32.5 kg/m2, and mean duration of diabetes was 3.1 years. The mean baseline HbA1c value was 7.9% in the omarigliptin group and 8.1% in the placebo group. After 24 weeks, the least squares mean change (95% CI) in HbA1c value from baseline was -0.33% (-0.60 to -0.06) in the omarigliptin group and -0.45% (-0.72 to -0.18) in the placebo group, with a between-group difference of 0.12% (-0.26 to 0.49; P = 0.535). Similarly, no between-group difference was observed for the other glycemic parameters (2-hour postmeal glucose and fasting plasma glucose levels). No issues were identified in drug allocation, dispensing or supply, patient compliance with trial medication, sample handling or analysis, or site trial conduct that explained the observed results. Measurement of drug levels from future biomedical research samples uncovered the use, with no investigator knowledge, of an antihyperglycemic agent that was prohibited by the protocol (ie, metformin) by 42.4% (39 of 92) of patients. Metformin was used by more patients in the placebo group (57% [25 of 44]) than in the omarigliptin group (29% [14 of 48]). IMPLICATIONS: The use of prohibited metformin in a trial of a dipeptidyl peptidase-4 inhibitor, omarigliptin, introduced a confounding factor that invalidated the results of the trial. This behavior may have been encouraged in the trial by protocol-specified self-monitoring of blood glucose levels. Use of prohibited medication may be an underappreciated confounder in clinical trial research. TRIAL REGISTRATIONS: MK-3102-028 (US); ClinicalTrials.gov identifier, NCT01814748; EudraCT number, 2012-004303-12 (EU).

Sensitive and specific LC-ESI-MS/MS method for determination of ZYDPLA1, a novel long-acting dipeptidyl peptidase 4 inhibitor in rat plasma: An application for toxicokinetic study in rats.

A rapid and highly specific assay was developed and validated for the estimation of ZYDPLA1 in rat plasma using liquid chromatography coupled to tandem mass spectrometry with positive electrospray ionization. Method validation comprised of parameters such as specificity, matrix effect, precision, accuracy, recovery, stability, etc. The assay procedure involved a simple protein precipitation of ZYDPLA1 and alprazolam (internal standard) from rat plasma using acetonitrile. Chromatographic separation was achieved with a gradient mobile phase comprising: (A) 0.2% ammonia in purified water; (B) 0.1% formic acid in isopropyl alcohol/methanol (1: 1 v/v); and (C) acetonitrile at a flow rate of 1 mL/min on an ACE-5, C18 (4.6 × 50 mm) column with a run time of 5.5 min. The quantitation of ZYDPLA1 was achieved by the summation of four multiple reaction mode transitions (m/z 399.7 → 383.0, 399.7 → 276.10, 399.7 → 153.20 and 399.7 → 127.20), while that of the internal standard was by a single multiple reaction mode transition (m/z 309.10 → 281.00). The lower limit of quantitation achieved was 0.01 µg/mL and the method showed linearity from 0.01 to 25 µg/mL. The intra- and inter-day precision (%CV) of the quality control samples was within 8.81% and accuracy was ±10% of nominal values. This novel method was applied for evaluation of toxicokinetics of ZYDLA1 in rats.

Relative bioavailability of an empagliflozin 25-mg/linagliptin 5-mg fixed-dose combination tablet
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OBJECTIVE: This relative bioavailability study compared a fixed-dose combination (FDC) tablet of empagliflozin 25 mg/linagliptin 5 mg with the corresponding individual components. In addition, the effect of food on the bioavailability of the FDC was studied, and the standard-dissolving formulation FDC was compared with a slow-dissolving side batch. METHODS: An open-label, randomized, crossover study design was used (ClinicalTrials.gov Identifier NCT01189201). Healthy volunteers (n = 42) each received three single-dose treatments: FDC standard dissolution, individual tablets, and either FDC standard dissolution with food or FDC slow dissolution. Primary endpoints for relative bioavailability comparisons were area under the plasma concentration-time curve (AUC) over time 0 to the last time point with the plasma concentration above the quantification limit (AUC0-tz) for empagliflozin, AUC from 0 to 72 hours (AUC0-72) for linagliptin, and maximum plasma concentration (Cmax) for both drugs. RESULTS: In all three comparisons, the 90% confidence intervals for the ratios of AUCs were within the standard acceptance range (80 - 125%) for bioequivalence. Empagliflozin and linagliptin both showed reductions in Cmax after food compared with the fasted state, although overall exposure remained similar. The empagliflozin/linagliptin combinations were well tolerated. CONCLUSIONS: This study shows that the FDC of empagliflozin 25 mg/linagliptin 5 mg can be regarded as bioequivalent to the individual tablets. Administering the tablet after food or a tablet with a slow-dissolution profile did not have a clinically-relevant impact on the bioavailability of empagliflozin/linagliptin FDC tablets.
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Optimization of magnetic retention in the gastrointestinal tract: Enhanced bioavailability of poorly permeable drug.

Oral administration of low permeable drugs remains a challenge as they do not cross biological membrane efficiently and therefore exhibit a poor bioavailability. Herein, the effect of magnetic retention on the circulation and bioavailability of magnetic beads in the gastrointestinal tract in the presence of an external magnetic field is evaluated. Retention efficiency is imaged using magnetic resonance and near infrared techniques. The effect on bioavailability is then evaluated in a pharmacokinetic study. Iron oxide nanoparticles, the drug (dipeptidyl peptidase-IV inhibitor) and a fluorophore (Alexa Fluor-750) are co-encapsulated in chitosan-alginate core-shell beads. Retention of these beads is induced by the presence of an external permanent magnet on the abdomen of rats. After single administration of magnetic beads containing 20mg/kg of drug to fasted rats, a 2.5-fold increase in drug's bioavailability is observed in the presence of an external magnetic field, significantly higher than the same dose administered to rats without the field or for the drug in aqueous solution. Retention of the magnetic carriers in the presence of an external magnet proves to accumulate these carriers in a specific localization of the intestine leading to a significant improve in the drug's bioavailability.

Effects of renal impairment on the pharmacokinetics and pharmacodynamics of a novel dipeptidyl peptidase-4 inhibitor, evogliptin (DA-1229).

Evogliptin is a novel potent and selective dipeptidyl peptidase-4 (DPP-4) inhibitor. The aim of the present study was to evaluate the pharmacokinetic (PK) and pharmacodynamic (PD) characteristics of evogliptin in participants with renal impairment (RI). An open-label, parallel-group clinical study was conducted in participants with mild, moderate and severe RI and in matched participants with normal renal function (NRF). A single oral 5-mg dose of evogliptin was administered and serial blood and urine samples were obtained to assess the PK and PD characteristics of evogliptin. Baseline urine samples were collected to evaluate endogenous CYP3A metabolic markers. The plasma exposure to evogliptin and degree of DPP-4 activity inhibition increased with decreasing renal function. The mean areas under the concentration-time curves from 0 to 120 hours were increased 1.2-, 1.8- and 1.98-fold in the mild, moderate and severe RI groups, respectively, compared with the NRF group. The levels of CYP3A metabolic markers were lower in the RI group than in the NRF group. The increase in the plasma concentration of evogliptin is unlikely to result in changes in its efficacy or safety, considering the results of previous clinical studies.

Hepatic Dipeptidyl Peptidase-4 Controls Pharmacokinetics of Vildagliptin In Vivo.

The main route of elimination of vildagliptin, which is an inhibitor of dipeptidyl peptidase-4 (DPP-4), in humans is cyano group hydrolysis to produce a carboxylic acid metabolite M20.7. Our in vitro study previously demonstrated that DPP-4 itself greatly contributed to the hydrolysis of vildagliptin in mouse, rat, and human livers. To investigate whether hepatic DPP-4 contributes to the hydrolysis of vildagliptin in vivo, in the present study, we conducted in vivo pharmacokinetics studies of vildagliptin in mice coadministered with vildagliptin and sitagliptin, which is another DPP-4 inhibitor, and also in streptozotocin (STZ)-induced diabetic mice. The area under the plasma concentration-time curve (AUC) value of M20.7 in mice coadministered with vildagliptin and sitagliptin was significantly lower than that in mice administered vildagliptin alone (P < 0.01). Although plasma DPP-4 expression level was increased 1.9-fold, hepatic DPP-4 activity was decreased in STZ-induced diabetic mice. The AUC values of M20.7 in STZ-induced diabetic mice were lower than those in control mice (P < 0.01). Additionally, the AUC values of M20.7 significantly positively correlated with hepatic DPP-4 activities in the individual mice (Rs = 0.943, P < 0.05). These findings indicated that DPP-4 greatly contributed to the hydrolysis of vildagliptin in vivo and that not plasma, but hepatic DPP-4 controlled pharmacokinetics of vildagliptin. Furthermore, enzyme assays of 23 individual human liver samples showed that there was a 3.6-fold interindividual variability in vildagliptin-hydrolyzing activities. Predetermination of the interindividual variability of hepatic vildagliptin-hydrolyzing activity might be useful for the prediction of blood vildagliptin concentrations in vivo.

Determination of a novel dipeptidyl peptidase IV inhibitor in monkey plasma by HPLC-MS/MS and its application in a pharmacokinetics study.

A lot of attention has been given to novel diabetes treatment, which is used to replace injectable insulin. A novel dipeptidyl peptidase IV inhibitor (HWH-10d) for treating type 2 diabetes was previously determined to have comparable efficacy to the marketed drug (alogliptin) in ICR male mice. Therefore, a sensitive and rapid liquid chromatography-tandem mass spectrometric method was developed and validated for the further evaluation of HWH-10d in monkey. The analytes were extracted through a liquid-liquid extraction with ethyl acetate. The linear detection range for HWH-10d in monkey plasma was from 0.5 to 2000 ng/mL with the lower limit of quantification of 0.5 ng/mL. The relative standard deviation was measured to be less than 10.4% for determination of inter- and intra-day precisions, and the relative error was determined to be within ±7.2% for all accuracy measurements. The simple and rapid LC-MS/MS method for HWH-10d in monkey plasma could be used for the pharmacokinetics studies of HWH-10d in monkeys. The oral bioavailability of HWH-10d in monkeys is 57.8%.

Relative bioavailability study of linagliptin/metformin tablets in healthy Chinese subjects.

OBJECTIVE: To evaluate the relative bioavailability of single pill combination (SPC) tablets of linagliptin and metformin compared with separate tablets co-administered in healthy Chinese subjects. MATERIALS AND METHODS: This was an open-label, single-dose, randomized, two-period, crossover study in healthy Chinese subjects with two dose groups: linagliptin 2.5 mg/metformin 850 mg and linagliptin 2.5 mg/metformin 500 mg. Within each group (n=24), subjects received one dose of the SPC tablet in one period and one dose of the separate tablets in the other. Primary endpoints were area under the plasma concentration-time curve from 0 to 72 hours (AUC0-72) and maximum plasma concentration (Cmax) for linagliptin, and AUC from 0 to the last quantifiable concentration (AUC0-tz) and Cmax for metformin. RESULTS: With the linagliptin 2.5 mg/metformin 850 mg dose, the adjusted geometric mean ratio of the SPC to the separate tablets for linagliptin was 99.53% (90% confidence interval (CI): 94.75-104.55) for AUC0-72 and 101.93% (90% CI: 95.36-108.95) for Cmax; for metformin the ratio was 96.99% (90% CI: 90.62-103.81) for AUC0-tz and 94.64% (90% CI: 85.43-104.84) for Cmax. With the linagliptin 2.5 mg/metformin 500 mg dose, the ratio with linagliptin for AUC0-72 and Cmax was 100.81% (90% CI: 95.14-106.82) and 111.37% (90% CI: 100.40-123.54), respectively; the same statistical parameters with metformin for AUC0-tz and Cmax were 102.95% (90% CI: 96.24-110.12) and 102.46% (90% CI: 92.20-113.87), respectively. CONCLUSIONS: SPC tablets of linagliptin and metformin were bioequivalent to separate tablets co-administered in healthy Chinese subjects.

Population Pharmacokinetics and Pharmacodynamics of Linagliptin in Patients with Type 2 Diabetes Mellitus.

BACKGROUND AND OBJECTIVES: Linagliptin is a dipeptidyl peptidase (DPP)-4 inhibitor, used to treat type 2 diabetes mellitus (T2DM). Population pharmacokinetic and pharmacodynamic analyses were performed to characterize the impact of clinically relevant intrinsic/extrinsic factors (covariates) on linagliptin exposure and DPP-4 inhibition in patients with T2DM. METHODS: Linagliptin plasma concentrations and DPP-4 activities were obtained from four studies (two phase 1, two phase 2b). Non-linear mixed-effects modelling techniques were implemented using NONMEM software. The covariates that were studied comprised demographic information and laboratory values, including liver enzyme levels and creatinine clearance, as well as study-related factors such as metformin co-treatment. Covariate effects on parameters describing the pharmacokinetics and pharmacokinetic/pharmacodynamic relationship were investigated using stepwise forward inclusion/backward elimination. RESULTS: The pharmacokinetic analysis included 6,907 measurements of plasma linagliptin concentrations from 462 patients; the pharmacokinetic/pharmacodynamic analysis included 9,674 measurements of plasma DPP-4 activity and linagliptin plasma concentrations from 607 patients. The non-linear pharmacokinetics were described by a target-mediated drug disposition model accounting for the concentration-dependent binding of linagliptin to its target, DPP-4. The difference in exposure between the 5th and 95th percentiles of the covariate distributions and median was <20 % for each single covariate. Likewise, the impact of the covariates on both the half-maximum effect (EC50) and the concentration leading to 80 % DPP-4 inhibition was <20 %. CONCLUSION: These analyses show that the investigated factors do not alter the pharmacokinetics and DPP-4 inhibitory activity of linagliptin to a clinically relevant extent and that dose adjustment is not necessary on the basis of factors including age, sex and weight.

A fixed-dose combination tablet of gemigliptin and metformin sustained release has comparable pharmacodynamic, pharmacokinetic, and tolerability profiles to separate tablets in healthy subjects.

BACKGROUND: In type 2 diabetes mellitus, fixed-dose combination (FDC) can provide the complementary benefits of correction of multiple pathophysiologic defects such as dysfunctions in glycemic or metabolic control while improving compliance compared with separate tablets taken together. The objective of the study reported here was to compare the pharmacodynamic (PD), pharmacokinetic (PK), and tolerability profiles of gemigliptin and extended-release metformin (metformin XR) between FDC and separate tablets. METHODS: A randomized, open-label, single-dose, two-way, two-period, crossover study was conducted in 28 healthy male volunteers. Two FDC tablets of gemigliptin/metformin 25/500 mg or separate tablets of gemigliptin (50 mg ×1) and metformin XR (500 mg ×2) were orally administered in each period. Serial blood samples were collected up to 48 hours post-dose to determine dipeptidyl peptidase 4 (DPP-4) activity using spectrophotometric assay and concentrations of gemigliptin and metformin using tandem mass spectrometry. Geometric mean ratios (GMRs) of FDC to separate tablet formulations and their 90% confidence intervals (CIs) were calculated to compare the PD and PK parameters between the two formulations. Tolerability was assessed throughout the study. RESULTS: The plasma DPP-4 activity-time curves of the FDC and the separate tablets almost overlapped, leading to a GMR (90% CI) of the FDC to separate tablets for the plasma DPP-4 activity and its maximum inhibition of 1.00 (0.97-1.04) and 0.92 (0.82-1.05), respectively. Likewise, all of the GMRs (90% CIs) of FDC to separate tablets for the area under the plasma concentration-time curve and maximum plasma concentration of gemigliptin and metformin fell entirely within the conventional bioequivalence range of 0.80-1.25. Both the FDC and separate tablets were well tolerated. CONCLUSION: The PD, PK, and tolerability profiles of gemigliptin and metformin XR in FDC and separate tablets were found to be comparable. The FDC tablet of gemigliptin and metformin sustained release can be a convenient therapeutic option in patients with type 2 diabetes mellitus requiring a combination approach.

Human pharmacokinetic profiling of the dipeptidyl peptidase-IV inhibitor teneligliptin using physiologically based pharmacokinetic modeling.

Teneligliptin is a type 2 diabetes drug that has an inhibitory effect on dipeptidyl peptidase-4. The aim of this study was to establish a physiologically based pharmacokinetic (PBPK) model to elucidate in detail the pharmacokinetics of teneligliptin. A PBPK model of teneligliptin was developed using the population-based Simcyp simulator incorporating the results of in vitro and in vivo studies. Model validation was conducted by comparison of simulated teneligliptin plasma concentrations with those from clinical trials. Using the PBPK model, predicted drug-drug interactions with concomitant medication were examined. The robustness of the PBPK model was demonstrated by the accurate simulation of clinically measured plasma concentrations of teneligliptin after oral administration in different ethnic groups, in subjects belonging to different age groups and in patients with kidney or liver impairment; none of these factors were incorporated during model development. The fraction absorbed and intestinal availability of teneligliptin predicted by the model were 0.62 and 0.99, respectively. The predicted ratios of areas under the time-concentration curves (AUCs) in patients with moderate and severe renal impairment who were concomitantly administered ketoconazole, a potent inhibitor of P450 3A4, were, respectively, 2.1- and 2.2-fold those in healthy adults who were given teneligliptin alone. A robust PBPK model reflecting the pharmacokinetic properties of teneligliptin was constructed. The final optimized PBPK model enabled us to elucidate in detail the factors affecting the pharmacokinetics of teneligliptin and to predict changes in exposure in drug-drug interactions or in specific populations.

[Determination of yogliptin and its metabolite in Wistar rat plasma by liquid chromatography-tandem mass spectrometry].

A rapid, sensitive and simple liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the simultaneous determination of yogliptin and its metabolite in Wistar rat plasma. Linagliptin and dexamethasone were chosen as the internal standards of yogliptin and its metabolite, (R)-8-(3-hydroxypiperidine- -yl)-7-(but-2-yn-1-yl)-1-((5-fluorobenzo[d]thiazol-2-yl)methyl)-3-methyl- H-purine-2, 6 (3H, 7H)-dione, respectively. After a simple protein precipitation using acetonitrile as the precipitating solvent, both analytes and ISs were separated on a Grace Altima HP C18 column (2.1 mm x 50 mm, 5 microm) with gradient elution using methanol (containing 0.1% formic acid, 4 mmol x L(-1) ammonium acetate)-0.1% formic acid (containing 4 mmol x L(-1) ammonium acetate) as the mobile phase. A chromatographic total run time of 4.4 min was achieved. Mass spectrometric detection was conducted with electrospray ionization under positive-ion and multiple-reaction monitoring modes. Linear calibration curves for yogliptin and its metabolite were over the concentration range of 0.5 to 500 ng x mL(-1) with a lower limit of quantification of 0.5 ng x mL(-1). The intra- and inter- assay precisions were all below 14%, the accuracies were all in standard ranges. The method was used to determine the concentration of yogliptin and M1 in Wistar rat plasma after a single oral administration of yogliptin (27 mg x kg(-1)). The method was proved to be selective, sensitive and suitable for pharmacokinetic study of yogliptin and M1 in Wistar rat plasma.

Metabolism and disposition of the dipeptidyl peptidase IV inhibitor teneligliptin in humans.

1. The absorption, metabolism and excretion of teneligliptin were investigated in healthy male subjects after a single oral dose of 20 mg [(14)C]teneligliptin. 2. Total plasma radioactivity reached the peak concentration at 1.33 h after administration and thereafter disappeared in a biphasic manner. By 216 h after administration, ≥90% of the administered radioactivity was excreted, and the cumulative excretion in the urine and faeces was 45.4% and 46.5%, respectively. 3. The most abundant metabolite in plasma was a thiazolidine-1-oxide derivative (designated as M1), which accounted for 14.7% of the plasma AUC (area under the plasma concentration versus time curve) of the total radioactivity. The major components excreted in urine were teneligliptin and M1, accounting for 14.8% and 17.7% of the dose, respectively, by 120 h, whereas in faeces, teneligliptin was the major component (26.1% of the dose), followed by M1 (4.0%). 4. CYP3A4 and FMO3 are the major enzymes responsible for the metabolism of teneligliptin in humans. 5. This study indicates the involvement of renal excretion and multiple metabolic pathways in the elimination of teneligliptin from the human body. Teneligliptin is unlikely to cause conspicuous drug interactions or changes in its pharmacokinetics patients with renal or hepatic impairment, due to a balance in the elimination pathways.

Pharmacokinetics and safety of teneligliptin in subjects with hepatic impairment.

The pharmacokinetics of teneligliptin was compared in 3 groups of 8 subjects assigned according to their degree of hepatic impairment (mild, moderate, or matched healthy subjects). Hepatic impairment was associated with an increase in maximal plasma concentration (Cmax ) and overall exposure (AUC0-∞ ) to teneligliptin. Geometric least square mean ratios for Cmax in subjects with mild and moderate hepatic impairment were 25% and 38% higher than in healthy subjects, and those for AUC0-∞ were 46% and 59% higher than in healthy subjects, respectively. For both parameters, the upper limit of the 90% confidence intervals was outside the 80%-125% "no effect" limit, but below the FDA-recommended "dose-adjustment" boundary of 200%. The lower mean total clearance in subjects with mild (9.79 L/h) or moderate (8.57 L/h) hepatic impairment resulted in longer mean half-lives (27.9 and 30.9 hours, respectively) than in healthy subjects (clearance: 13.11 L/h, half life: 24.8 hours). Protein binding ranged between 36.9% and 47.5% in subjects with hepatic impairment and between 32.5% and 34.5% in healthy subjects. Overall, teneligliptin was well tolerated by subjects with hepatic impairment. These results may indicate that caution will be needed when administering teneligliptin to subjects with hepatic impairment.