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.

Bioanalysis of trifluoperazine in human plasma by LC-MS/MS: Application to disposition kinetics.

A sensitive, selective and rapid bioanalytical method using liquid chromatography-tandem mass spectrometry has been developed for the quantification of trifluoperazine in human plasma. Trifluoperazine-D8 was used as the internal standard and the extraction from human plasma was performed by liquid-liquid extraction technique using tertiary butyl methyl ether as the solvent. Chromatographic separation was carried out on Zodiac C18 column (50 × 4.6 mm, 3 µm) employing a mixture of acetonitrile, methanol and 5 mm ammonium bicarbonate buffer in water (85:10:5, v/v/v) at a flow rate of 0.55 ml/min. The linearity was established within the concentration range of 5-1,250 pg/ml with r2 > 0.99. The results of all of the validation parameters as per the US Food and Drug Administration guidelines were within the acceptance limits. The pharmacokinetics of trifluoperazine after oral administration of a syrup of 1 mg dose under fasting conditions was determined by successful application of the present method.

Bioanalytical method for estimation of procyclidine in human plasma using liquid chromatography-tandem mass spectrometry: Application to pharmacokinetic study.

A rapid, selective and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for quantification of procyclidine hydrochloride in human plasma using Procyclidine D11 hydrochloride as internal standard. Liquid-liquid extraction technique with methyl tertiary butyl ether was used for the extraction of plasma samples. Chromatographic separation of the analyte and the internal standard from the endogenous components was done on Zodiac C18 column (50 × 4.6 mm, 5 µm) using a mixture of methanol and 0.1% formic acid in water (70:30, v/v) as mobile phase at a flow rate of 1 mL/min with the run time of 2 min. The detection of the eluents was done using multiple reaction monitoring (MRM) in positive ion mode. Linearity of the method was established in the concentration range of 0.5 to 120 ng/mL. Full validation of the method was done as per USFDA guidelines and the results were well within the acceptance limits. The successful application of the method was done on healthy human subjects under fasting conditions, proving it to be used for bioequivalence and bioavailability (BA/BE) studies of procyclidine.

Development and validation of ultra performance liquid chromatography-tandem mass spectrometry method for the simultaneous estimation of dolutegravir, lamivudine and tenofovir in bulk and tablet dosage form.

A simple, selective and rapid ultra performance liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous estimation of dolutegravir, lamivudine and tenofovir in bulk and tablet dosage form. Chromatographic separation was attained on Acquity Ethylene Bridged Hybrid (BEH) C18 column (50 × 2.1 mm, 3.5 µm), using a mixture of acetonitrile and 0.1% formic acid in water (60:40, v/v) as a mobile phase at a flow rate of 0.12 mL/min. The total run time of analysis was 3.5 min. The analytes were detected using tandem mass spectrometry, operating in positive ionization and multiple reaction monitoring modes. The method's linearity was determined to be in the range of 10-150 ng/mL with r2 > 0.99. The proposed method was validated as per the International Council for Harmonization (ICH) guidelines, and the results were found well within the acceptance limits. The method was successfully applied for the simultaneous quantification of all the three analytes in the combined tablet dosage form.

Development and validation of bioanalytical method for quantification of cycloserine in human plasma by liquid chromatography-tandem mass spectrometry: Application to pharmacokinetic study.

A selective, sensitive and high-throughput liquid chromatography-tandem mass spectrometry bioanalytical method has been developed for the estimation of cycloserine in human plasma, employing cytosine as the internal standard. The extraction of the analyte was facilitated by solid-phase extraction using 100 µL of human plasma. The separation was carried out on a BDS Hypersil C18 (150 × 4.6 mm, 5 µm) column using a mixture of 0.2% formic acid in HPLC-grade water, methanol and acetonitrile (70:15:15, v/v/v) as mobile phase at a flow rate of 1.0 mL/min. The method was linear over the range of 0.20-20 µg/mL with r2 > 0.99. Complete validation of the method was performed as per US Food and Drug Administration guidelines and the results met acceptance criteria. Applying the present method, the clinical pharmacokinetics of cycloserine following oral administration of 250 mg cycloserine was studied under fasting conditions. Assay reproducibility was also verified by incurred sample reanalysis.

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

A selective, sensitive and high throughput liquid chromatography - tandem mass spectrometry (LC-MS/MS) method was developed and validated for estimation of eluxadoline in human plasma. Plasma samples of analyte with internal standard (eluxadoline13CD3) were extracted using solid phase extraction on Orochem Panthera Deluxe cartridges. Chromatographic separation was performed on Ace Phenyl column (150 × 4.6 mm, 5 µm), using a mixture of buffer (2 mM ammonium acetate in 0.01% formic acid), acetonitrile and methanol (20:70:10, v/v/v) as mobile phase at a flow rate of 0.8 mL/min. The run time of analyte was 4.0 min. Tandem mass spectrometry, operating in positive ionization and multiple reaction monitoring modes was used for detection of analyte and internal standard. The method was established with a linear dynamic range of 25.0-5000 pg/mL for eluxadoline using 300 µL human plasma. The sample preparation procedure was consistent and reproducible (accuracy, 96.2-106.1%; precision (%CV), 0.8-6.6%), preventing the ex vivo hydrolysis of acyl glucuronide metabolite of eluxadoline to parent drug. The method was applied successfully to a clinical pharmacokinetic study in six healthy South Indian male subjects under fed conditions and the results were authenticated by incurred sample reanalysis.

Development and validation of bioanalytical liquid chromatography-tandem mass spectrometry method for the estimation of pentoxifylline in human plasma: Application for a comparative pharmacokinetic study.

A method for bioanalysis of pentoxifylline in human plasma was developed using liquid chromatography-tandem mass spectrometry, which is simple, specific, and sensitive. Pentoxifylline D5 was used as the internal standard. Employing only 100 µl of human plasma, processing was done with solid-phase extraction technique. The analyte and the internal standard were separated from endogenous components on Ace phenyl column using a mixture of 5 mM ammonium acetate buffer and high performance liquid chromatography grade acetonitrile (60:40, v/v) as mobile phase at a flow rate of 1 ml/min. The linearity of the method was in the range of 3-1200 ng/ml with r2 > 0.99. Positive ion MRM mode was used for the detection of the analyte and the internal standard. The method was validated as per the US Food and Drug Administration guidelines and the results were within the acceptance limits. The proposed method was applied for comparative pharmacokinetic study of pentoxifylline after oral administration of 400 and 600 mg tablets to South Indian male subjects under fed conditions.