A rapid, simple, specific liquid chromatographic-electrospray mass spectrometry method for the determination of finasteride in human plasma and its application to pharmacokinetic study.
ABSTRACT A fast, accurate, sensitive, selective and reliable method using reversed-phase high-performance liquid chromatography-mass spectrometry coupling with an electrospray ionization interface was developed and validated for the determination of finasteride in human plasma. After deprotienation with acetonitrile, centrifugation, evaporation to dryness and dissolving in mobile phase, satisfactory separation was achieved on a Hypersil-Keystone C(18) reversed-phase column using a mobile phase consisting of acetonitrile-water (46:54, v/v), 0.1% acetic acid and 0.1% trifluoracetic acid. Carbamazepine (IS) was used as internal standard. This method involved the use of the [M+H](+) ions of finasteride and IS at m/z 373 and 237 with the selective ion monitoring (SIM) mode. The calibration curve was linear in the range of 0.2-120 ng ml(-1). The limit of quantification for finasteride in plasma was 0.2 ng ml(-1) with good accuracy and precision. The intra-assay precision and accuracy were in the range of 2.1-11.2% and -1.3% to 8.5%, respectively. The inter-assay precision and accuracy were in the order of 3.4-12.1% and -1.5% to 11.5%, respectively. The mean sample extract recoveries of the method were higher than 85% and 74% for finasteride and internal standard (IS), respectively. The assay has been successfully used to estimate the pharmacokinetics of finasteride after oral administration of a 5mg tablet of finasteride to 24 healthy volunteers.
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ABSTRACT: Benign prostatic hyperplasia and prostate cancer can be treated with the 5α-reductase inhibitors, finasteride and dutasteride, when pharmacodynamic biomarkers are useful in assessing response. A novel method was developed to measure the substrates and products of 5α-reductases (testosterone, 5α-dihydrotestosterone (DHT), androstenedione) and finasteride and dutasteride simultaneously by liquid chromatography tandem mass spectrometry, using an ABSciex QTRAP(®) 5500, with a Waters Acquity™ UPLC. Analytes were extracted from serum (500µL) via solid-phase extraction (Oasis(®) HLB), with (13)C3-labelled androgens and d9-finasteride included as internal standards. Analytes were separated on a Kinetex C18 column (150×3mm, 2.6µm), using a gradient run of 19min. Temporal resolution of analytes from naturally occurring isomers and mass +2 isotopomers was ensured. Protonated molecular ions were detected in atmospheric pressure chemical ionisation mode and source conditions optimised for DHT, the least abundant analyte. Multiple reaction monitoring was performed as follows: testosterone (m/z 289→97), DHT (m/z 291→255), androstenedione (m/z 287→97), dutasteride (m/z 529→461), finasteride (m/z 373→317). Validation parameters (intra- and inter-assay precision and accuracy, linearity, limits of quantitation) were within acceptable ranges and biological extracts were stable for 28 days. Finally the method was employed in men treated with finasteride or dutasteride; levels of DHT were lowered by both drugs and furthermore the substrate concentrations increased.Talanta 01/2014; · 3.50 Impact Factor
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ABSTRACT: A fast, accurate, sensitive, selective and reliable method using reversed-phase high performance liquid chromatography coupled to electrospray ionization ion trap mass spectrometry was developed and validated for the determination of ﬁnasteride in human plasma. After protein precipitation with perchloric acid, satisfactory separation was achieved on a Zorbax Eclipse® C8 analytical column using a mobile phase consisted of acetonitrile, 2 mM ammonium formate buffer (58:42, pH adjusted at 2.5 using formic acid); the flow rate was 0.25 mLmin-1 and the column oven was set to 50°C. Tamoxifen citrate was used as internal standard. This method involved the use of [M + H]+ ions of ﬁnasteride and IS at m/z 373 and 372 respectively with the selected ion monitoring (SIM) mode. The calibration curve was linear over the range of 0.1–60 ng mL−1. The limit of quantiﬁcation for ﬁnasteride in plasma was 0.1 ng mL−1. The intra-day and inter-day repeatability (precision) were 2.68-13.87% and 2.14-14.69% respectively. Intra-day and inter-day accuracy were 98-101.57% and 99.7-110%. The assay method has been successfully used to estimate the pharmacokinetics of ﬁnasteride after oral administration of a 5 mg tablet of ﬁnasteride in 12 healthy volunteers.Iranian journal of pharmaceutical research (IJPR) 01/2012; 11(7):59-67. · 0.51 Impact Factor
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ABSTRACT: A stability-indicating micellar electrokinetic chromatography method has been developed and validated for determination of finasteride. Analysis was performed by using 50 cm × 100 µm i.d. (effective length 42.8 cm) fused silica capillary and background electrolyte of 50 mM NaH2PO4 (pH 3) buffer containing 10 mM sodium dodecyl sulfate as surfactant. Applied potential was selected as − 15 kV at 25°C and the detection was at 210 nm. The calibration curve was linear in the range of 5-50 µg.mL. Effects of pH, capillary temperature, applied voltage and buffer concentration were investigated. Degradation studies were carried out under acidic (1.0 M HCl), basic (1.0 M NaOH), oxidative (%10 H2O2), thermal (60°C) and UV-light (254 nm) conditions and it was found that finasteride was degraded under acidic, basic and oxidative stress conditions. The method was successfully applied to the determination of finasteride in tablet formulations.Journal of Liquid Chromatography & Related Technologies 02/2013; 36(6):781-791. · 0.57 Impact Factor