DETERMINATION OF CAPECITABINE-AN ANTICANCER DRUG IN DRIED BLOOD SPOT BY LC-ESI-MS/MS

Objective: Capecitabine (Cape), the first oral prodrug which belongs to the group of fluoro pyrimidines is the most frequently prescribed anticancer drug for the treatment of metastatic breast and colorectal cancers. The article describes a selective and robust method for determination of Cape in dried blood spots (DBS) by liquid chromatography-tandem mass spectrometry (LC-MS/MS).Methods: Cape fortified DBS was punched and extracted with ethyl acetate using capecitabine-d11 as the internal standard (IS). Chromatographic separation of Cape and IS from endogenous matrix was performed on Phenomenex Gemini C18 (150 × 4.6 mm, 5mm) column under isocratic condition using acetonitrile: 2 mmol ammonium formate (pH 3.0, adjusted with 0.1 % formic acid) (80:20, v/v) as the mobile phase. Detection and quantification were carried on a triple quadrupole mass spectrometer, using electro spray ionization technique in the positive ionization mode.Results: The method was established over a concentration range of 10-10000 ng/ml. Accuracy, precision, selectivity, recovery, matrix effect and stability of the analyte were also estimated and the results were within the acceptance criteria. Further, precise results were obtained using an optimum spot volume of 10 µl with good spot homogeneity. Blood samples with hematocrit values varying from 24 % to 45 % gave acceptable results with good accuracy and precision.Conclusion: The efficiency of dried blood spot sample preparation, short analysis time and high selectivity permits estimation of Cape in a small blood volume. The validation results suggest that the method is precise, accurate, and reproducible and can be useful in therapeutic drug monitoring of Cape.Â

Development of a sensitive and rapid method for quantitation of (S)-(â)- and (R)-(+)-metoprolol in human plasma by chiral LCâESIâMS/MS

A selective, sensitive and high throughput liquid chromatography-tandem mass spectrometry (LCâESIâMS/MS) method has been developed for separation and quantification of metoprolol enantiomers on a chiral Lux Amylose-2 (250mmÃ4.6mm, 5μm) column. Solid phase extraction of (S)-(â)- and (R)-(+)-metoprolol and rac-metoprolol-d6 as an internal standard (IS) was achieved on Lichrosep DVB HL cartridges employing 200μL human plasma. Both the analytes were chromatographically separated with a resolution factor of 2.24 using 15mM ammonium acetate in water, pH 5.0 and 0.1% (v/v) diethyl amine in acetonitrile (50:50, v/v) as the mobile phase within 7.0min. The precursorâproduct ion transitions for the enantiomers and IS were monitored in the multiple reaction monitoring and positive ionization mode. The method was validated over the concentration range of 0.500â500ng/mL for both the enantiomers. Matrix effect was assessed by post-column analyte infusion experiment and the mean extraction recovery was greater than 94.0% for both the enantiomers at all quality control levels. The stability of analytes was evaluated in plasma and whole blood under different storage conditions. The method was successfully applied to a clinical study in 14 healthy volunteers after oral administration of 200mg metoprolol tablet under fasting conditions. The assay reproducibility is shown by reanalysis of 68 incurred samples. The suitability of the developed method was assessed in comparison with different chromatographic methods developed for stereoselective analysis of metoprolol in biological matrices. Keywords: S-(â)-metoprolol, R-(+)-metoprolol, Chiral column, Chromatographic separation, LCâESIâMS/MS, Human plasm

Determination of cilostazol and its active metabolite 3,4-dehydro cilostazol from small plasma volume by UPLCâMS/MS

A simple, rapid and sensitive ultra performance liquid chromatography-tandem mass spectrometry (UPLCâMS/MS) method has been developed for the simultaneous determination of cilostazol and its pharmacologically active metabolite 3,4-dehydro cilostazol in human plasma using deuterated analogs as internal standards (ISs). Plasma samples were prepared using solid phase extraction and chromatographic separation was performed on UPLC BEH C18 (50 mmÃ2.1 mm, 1.7 µm) column. The method was established over a concentration range of 0.5â1000 ng/mL for cilostazol and 0.5â500 ng/mL for 3,4-dehydro cilostazol. Intra- and inter-batch precision (% CV) and accuracy for the analytes were found within 0.93â1.88 and 98.8â101.7% for cilostazol and 0.91â2.79 and 98.0â102.7% for the metabolite respectively. The assay recovery was within 95â97% for both the analytes and internal standards. The method was successfully applied to support a bioequivalence study of 100 mg cilostazol in 30 healthy subjects. Keywords: Cilostazol, 3,4-dehydro cilostazol, UPLCâMS/MS, Sensitive, High throughpu