High sensitive LC–MS/MS method for estimation of eluxadoline in human plasma and its application to pharmacokinetic study

Bioanalysis of bedaquiline in human plasma by liquid chromatography-tandem mass spectrometry: Application to pharmacokinetic study

Introduction

A sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for estimation of bedaquiline (BDQ) in human plasma using the deuterated analogue of the analyte, bedaquiline-d6 (BDQ-d6) as the internal standard.

Methods

The plasma sample of 50 µL was extracted by liquid-liquid extraction using methyl tertiary butyl ether (MTBE). The separation was achieved on Zodiac C18 (50 x 4.6 mm, 5 µm) column with a mobile phase consisting of methanol and 5 mM ammonium formate in 0.1 % formic acid (w/v) (90:10, v/v) at a flow rate of 1.0 mL/min. Protonated analyte and internal standard were detected on a triple quadrupole mass spectrometer using multiple reaction monitoring (MRM) mode.

Results

The linearity of the method was established in the concentration range of 5---1800 ng/mL with correlation coefficient, r2 ≥ 0.99. All the validated parameters were found well within the limits.

Discussion

The method was applied for the first time to evaluate the pharmacokinetic parameters after single oral dose of BDQ 100 mg under fed conditions in healthy human volunteers, and the results were further authenticated by incurred sample reanalysis.

Validation of the HPLC–PDA method for detection of eluxadoline and rifaximin in rat plasma and application in a pharmacokinetic study

Background

A precise, simple, accurate, and quick HPLC–PDA method for the determination of eluxadoline and rifaximin in rat plasma was developed and validated in this study. In this method, Loperamide hydrochloride was used as the internal standard and plasma samples were prepared using a liquid–liquid extraction technique for which acetonitrile was a solvent. An Agilent Symmetry C8 column (5 µm, 250 mm × 4.6 mm) at 283 nm and isocratic elution using HPLC grade acetonitrile and 7 mM TEA (pH 2.5) with a ratio of (40: 60 v/v) was used as a mobile phase and the flow rate employed was 1 mL min−1. A satisfactory chromatographic separation was accomplished.

Results

An HPLC–PDA method for the determination of eluxadoline and rifaximin with retention times of 3.06 and 7.82 min, respectively, was developed. The calibration curves appear linear for both eluxadoline and rifaximin in the range of 5–200 ng mL−1 and 10–400 ng mL−1, and the corresponding correlation coefficient values were found to be 0.9999 and 0.9998 respectively. Lower limits of quantification (LLOQ) for eluxadoline and rifaximin were evaluated to be 5.0 ng mL−1 and 10.0 ng mL−1, respectively. The accuracy and precision results in all validation experiments were within the acceptance limits of FDA guidelines.

Conclusion

The developed HPLC–PDA approach was fully validated to meet the USFDA guidelines for bioanalytical method validation in terms of precision, accuracy, and stability. The presented approach could be beneficial for the determination of ELX and RFX in rat plasma, according to validation parameters. This is one of the efficient method to study the pharmacokinetics of ELX and RFX in rats.

Graphical abstract