Unveiling Pharmacokinetics and Drug Interaction of Linagliptin and Pioglitazone HCl in Rat Plasma Using LC-MS/MS.

The linagliptin (LIN) and pioglitazone HCl (PIO) combination, currently undergoing phase III clinical trials for diabetes mellitus treatment, demonstrated significant improvements in glycemic control. However, the absence of an analytical method for simultaneous determination in biological fluids highlights a crucial gap. This underscores the pressing need for sensitive bioanalytical methods, emphasizing the paramount importance of developing such tools to advance diabetes management strategies and enhance patient care. Herein, a sensitive reverse-phase high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry method was developed for simultaneous determination of LIN and PIO in rat plasma using alogliptin as an internal standard. Chromatographic separation was performed on an Agilent Eclipse Plus C18 (4.6 × 100 mm, 3.5 µm) using an isocratic mobile phase system consisting of ammonium formate (pH 4.5) and methanol using an acetonitrile-induced protein precipitation technique for sample preparation. Multiple reaction monitoring in positive ion mode was used for quantitation of the precursor to production at m/z 473.2 → 419.9 for LIN, 357.1 → 134.2 for PIO, and 340.3 → 116.1 for ALO. The linearity range was 0.5 to 100 and 1 to 2000 ng/mL for LIN and PIO, respectively. The developed method was validated as per US-FDA guidelines and successfully applied to clinical pharmacokinetic and drug-drug interaction studies with a single oral administration of LIN and PIO in rat plasma. Pharmacokinetic parameters of LIN were significantly influenced by the concomitant administration of PIO and vice versa. Molecular modeling revealed the significant interaction of LIN and PIO with P-glycoprotein. Therefore, the drug-drug interaction between LIN and PIO deserves further study to improve drug therapy and prevent dangerous adverse effects.

A Pharmacokinetic Drug Interaction Between Fimasartan and Linagliptin in Healthy Volunteers.

OBJECTIVE: Fimasartan, an angiotensin II type 1 receptor blocker, and linagliptin, a dipeptidyl-peptidase-4 inhibitor, are frequently coadministered to treat patients with hypertension and diabetes, respectively. This study sought to evaluate the pharmacokinetic interactions between fimasartan and linagliptin after co-administration in healthy Korean subjects. METHODS: The overall study was divided into two separate parts, with each part designed as an open-label, multiple-dose, two-period, and single-sequence study. In Part A, to investigate the effect of linagliptin on fimasartan, 25 subjects received 120 mg fimasartan alone once daily for seven days during Period I, and 120 mg fimasartan with 20 mg linagliptin for seven days during Period II. In Part B, to examine the effect of fimasartan on linagliptin, 12 subjects received only linagliptin once daily for seven days during Period I, followed by concomitant administration of fimasartan for seven days during Period II, at the same doses used in Part A. Serial blood samples were collected at scheduled intervals for up to 24 h after the last dose to determine the steady-state pharmacokinetics of both drugs. RESULTS: Thirty-six subjects completed the study. The geometric mean ratio and 90% confidence intervals for maximum plasma concentration at steady state (Cmax,ss) and area under the concentration-time curve at steady state (AUCτ,ss) of fimasartan with or without linagliptin were 1.2633 (0.9175-1.7396) and 1.1740 (1.0499-1.3126), respectively. The corresponding values for Cmax,ss and AUCτ,ss of linagliptin with or without fimasartan were 0.9804 (0.8480-1.1336) and 0.9950 (0.9322-1.0619), respectively. A total of eight adverse events (AEs) were reported and the incidence of AEs did not increase significantly with co-administration of the drugs. CONCLUSION: Our results suggest that there are no clinically significant pharmacokinetic interactions between fimasartan and linagliptin when co-administered. Treatments were well tolerated during the study, with no serious adverse effects. CLINICAL TRIAL REGISTRY: http://clinicaltrials.gov, NCT03250052.

Square-wave Adsorptive Anodic Stripping Voltammetric Determination of Antidiabetic Drug Linagliptin in Pharmaceutical Formulations and Biological Fluids Using a Pencil Graphite Electrode.

A simple, sensitive, low-cost, quick and reliable square-wave anodic stripping voltammetric method is described for the determination of the antidiabetic drug Linagliptin (LNG) in pure form, tablets, and spiked human urine and plasma samples. Using a pencil graphite electrode (PGE), cyclic voltammetry (CV) was applied to study the electrochemical behavior of LNG. In a Teorell-Stenhagen buffer (pH 5.5) containing 0.1 M NaClO4 as a supporting electrolyte, the LNG yields an irreversible well-defined oxidation peak at about 1.2 V vs. Ag/AgCl electrode. The various affecting factors, such as the pH, buffer type, supporting electrolyte, accumulation potential, scan rate and accumulation time, were tested and optimized. Also, square-wave adsorptive anodic stripping voltammetric (SWAdASV) studies show that the peak current various linearly over the LNG concentration range of 0.24 - 5.20 µg mL-1 (R2 = 0.9994). The detection and quantification limits were calculated to be 0.10 and 0.33 µg mL-1, respectively. The proposed procedure exhibits a good precision, selectivity, and stability and was applied successfully to determine the LNG in pharmaceutical formulations (tablets) and biological fluids (spiked human urine and plasma samples).

Novel spectrofluorimetric quantification of linagliptin in biological fluids exploiting its interaction with 4-chloro-7-nitrobenzofurazan.

Direct determination of linagliptin (LIN) using fluorimetry has been limited because LIN releases a very weak fluorescence signal. Accordingly, it should be derivatized first with a fluorogenic reagent to enhance its fluorescence and consequentially the sensitivity required for its bioanalysis. This is the first description of a spectrofluorimetric method for LIN quantification in human plasma. The suggested method exploits the nucleophilic nature of its amino group to react with 4-chloro-7-nitrobenzofurazan (NBD-Cl) in borate buffer at pH 8.5 to yield a strong fluorescent product with excitation and emission wavelengths of 459 and 529 nm, respectively. Experimental variables concerning the conditions of reaction and fluorescence intensity were carefully investigated and optimized. The linearity range was from 1.0-100 ng ml-1 with a lower detection limit and a lower quantification limit of 0.60 ng ml-1 and 1.82 ng ml-1 , respectively. Validation of the suggested method has been accomplished and the application to LIN analysis in commercial tablets as well as in human plasma resulted in a mean per cent recovery of 100.12 ± 1.57 and 99.65 ± 1.22, respectively. The developed method was proven to be a promising, simple and fast alternative bioanalytical method for LIN quantification in clinical and bioequivalence research.

Pharmacokinetic interaction between linagliptin and tadalafil in healthy Egyptian males using a novel LC-MS method.

Aim: Assessment of pharmacokinetic interaction between linagliptin (LNG) and tadalafil (TDL) in healthy males. Methods: First, a novel LC-MS method was developed; second, a Phase IV, open-label, cross-over study was performed. Volunteers took single 20-mg TDL dose on day 1 followed by wash out period of 2 weeks then multiple oral dosing of 5-mg/day LNG for 13 days. On day 13, volunteers were co-administered 20-mg TDL. Results: LNG and TDL single doses did not affect QTc interval. Smoking did not alter pharmacokinetics/pharmacodynamics of LNG and TDL. Co-administration of LNG with TDL resulted in TDL longer time to reach maximum plasma concentration (Tmax), decreased oral clearance (Cl/F) and oral volume of distribution (Vd/F), increased its maximum plasma concentration (Cmax), area under concentration-time curve (AUC), muscle pain and QTc prolongation. Conclusion: LNG and TDL co-administration warrants monitoring and/or TDL dose adjustment.

A validated LC-MS/MS method for simultaneous determination of linagliptin and metformin in spiked human plasma coupled with solid phase extraction: Application to a pharmacokinetic study in healthy volunteers.

Combination therapy has a pivotal role in type II diabetes mellitus management in patients unable to maintain normal glycemic level using metformin alone. Addition of linagliptin, dipeptidyl peptidase-IV inhibitor, to metformin improves glycemic control. This study is concerned with the development of an HPLC-MS/MS method for simultaneous quantification of linagliptin and metformin in spiked human plasma. The method was applied to evaluate the potential pharmacokinetic interactions between the cited drugs in healthy volunteers. Solid phase extraction was applied using Strata™ X cartridge. Separation was carried out on Symmetry® C18 column using methanol: 10 mM ammonium formate buffer (containing 0.2% formic acid) in a ratio of (95: 5, v/v) as mobile phase at flow rate 0.25 mL min-1. Quantification was performed with multiple reaction monitoring in positive ionization mode. The monitored transitions were set at m/z 473.24 → 419.94, 130.14 → 60.18 and 340.27 → 116.07 for linagliptin, metformin and alogliptin (internal standard), respectively. The method was validated according to FDA guidelines. The method showed excellent linearity over concentration ranges 0.25-10 and 25-2000 ng mL-1 for linagliptin and metformin, respectively. The validated HPLC-MS/MS method was successfully applied to pharmacokinetic study of linagliptin and metformin in healthy volunteers after oral administration of Jentadueto® tablets.

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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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.

[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.