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.

A Novel Mutation in Neurodegeneration with Brain Iron Accumulation - A Case Report.

Neurodegeneration with brain iron accumulation (NBIA), previously called Hallervorden Spatz disease, is a group of disorders which share the hallmark of iron deposition in the brain. They are collectively characterized by extrapyramidal movement disorders, particularly those of parkinsonism, dystonia, cognitive regression, neuropsychiatric abnormalities, pyramidal features, optic atrophy, and retinal abnormalities. There is aberrant brain iron metabolism, with large amounts of iron deposited in the globus pallidus and the substantia nigra pars reticulata. NBIA displays a marked genetic heterogeneity, and 10 genes have been associated with different NBIA subtypes at present. We present a 12-year-old boy with a one and a half-year history of a slow, progressive gait disturbance. An MRI of his brain revealed T2, FLAIR bilateral symmetrical hypointensities in globus pallidus and substantia nigra s/o NBIA. His genetic analysis revealed a novel homozygous missense variation in exon 2 of the C19orf12 gene (chr19:30199203; A>C) that results in the amino acid substitution of valine for phenylalanine at codon 51 (p.F51V; ENST00000392278). This is consistent with the MPAN (mitochondrial membrane protein-associated neurodegeneration) subtype.

Liquid chromatography-tandem mass spectrometric assay for eltrombopag in 50µL of human plasma: a pharmacokinetic study.

Eltrombopag is a thrombopoietin receptor agonist, used in the treatment of thrombocytopenia. This paper describes a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay method for the determination of eltrombopag in human plasma samples using eltrombopag 13C4 as internal standard (IS). Analyte and the IS were extracted from 50µL of human plasma using protein precipitation technique with no drying, evaporation and reconstitution steps. The chromatographic separation was achieved on a C18 column by using a mixture of 10mM ammonium formate (pH3) and acetonitrile (10:90, v/v) as the mobile phase at a flow rate of 1.0mL/min. The linearity of the method was established in the concentration range 50.0-10007ng/mL with r(2)≥0.99. The intra-day and inter-day precision and accuracy results in four validation batches across five concentration levels were well within the acceptance limits. The proposed method was found to be applicable to pharmacokinetic studies.

A rapid and sensitive liquid chromatography-tandem mass spectrometric assay for cycloserine in 50µL of human plasma: Its pharmacokinetic application.

This paper describes a simple, rapid and sensitive liquid chromatography/tandem mass spectrometry assay for the determination of cycloserine in human plasma using carbamazepine as internal standard (IS). Analyte and the IS were extracted from the 50µL of human plasma via protein precipitation using acetonitrile. The chromatographic separation was achieved on a C(18) column by using a mixture of acetonitrile-0.5% formic acid buffer (60:40, v/v) as the mobile phase at a flow rate of 0.8mL/min. The calibration curve obtained was linear (r(2)≥0.99) over the concentration range of 50-15,000ng/mL. Method validation was performed as per FDA guidelines and the results met the acceptance criteria. A run time of 2.5min for each sample made it possible to analyze more number of samples in short time, thus increasing the productivity. The proposed method was found to be applicable to pharmacokinetic studies.

Simultaneous determination of atorvastatin, metformin and glimepiride in human plasma by LC-MS/MS and its application to a human pharmacokinetic study.

A simple, rapid and sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay method has been developed and fully validated for the simultaneous quantification of atorvastatin, metformin and glimepiride in human plasma. Carbamazepine was used as internal standard (IS). The analytes were extracted from 200 µL aliquots of human plasma via protein precipitation using acetonitrile. The reconstituted samples were chromatographed on a Alltima HP C18 column by using a 60:40 (v/v) mixture of acetonitrile and 10 mM ammonium acetate (pH 3.0) as the mobile phase at a flow rate of 1.1 mL/min. The calibration curves obtained were linear (r2 ≥0.99) over the concentration range of 0.50-150.03 ng/mL for atorvastatin, 12.14-1207.50 ng/mL for metformin and 4.98-494.29 ng/mL for glimepiride. The API-4000 LC-MS/MS in multiple reaction monitoring (MRM) mode was used for detection. The results of the intra- and inter-day precision and accuracy studies were well within the acceptable limits. All the analytes were found to be stable in a battery of stability studies. The method is precise and sensitive enough for its intended purpose. A run time of 2.5 min for each sample made it possible to analyze more than 300 plasma samples per day. The developed assay method was successfully applied to a pharmacokinetic study in human male volunteers.

A rapid and sensitive liquid chromatography-tandem mass spectrometric assay for duloxetine in human plasma: Its pharmacokinetic application.

This paper describes a simple, rapid and sensitive liquid chromatography-tandem mass spectrometry assay for the determination of duloxetine in human plasma. A duloxetine stable labeled isotope (duloxetine d5) was used as an internal standard. Analyte and the internal standard were extracted from 100 µL of human plasma via solid phase extraction technique using Oasis HLB cartridges. The chromatographic separation was achieved on a C18 column by using a mixture of acetonitrile-5 mM ammonium acetate buffer (83:17, v/v) as the mobile phase at a flow rate of 0.9 mL/min. The calibration curve obtained was linear (r2≥0.99) over the concentration range of 0.05-101 ng/mL. Multiple-reaction monitoring mode (MRM) was used for quantification of ion transitions at m/z 298.3/154.1 and 303.3/159.1 for the drug and the internal standard, respectively. Method validation was performed as per FDA guidelines and the results met the acceptance criteria. A run time of 2.5 min for each sample made it possible to analyze more than 300 plasma samples per day. The proposed method was found to be applicable to clinical studies.

Simultaneous Determination of Atorvastatin and Aspirin in Human Plasma by LC-MS/MS: Its Pharmacokinetic Application.

A simple, rapid, and sensitive liquid chromatography tandem mass spectro-metric (LC-MS/MS) assay method has been developed and fully validated for the simultaneous quantification of atorvastatin and aspirin in human plasma using a polarity switch. Proguanil and furosemide were used as the internal standards for the quantification of atorvastatin and aspirin, respectively. The analytes were extracted from human plasma by the liquid-liquid extraction technique using methyl tert-butyl ether. The reconstituted samples were chromatographed on a Zorbax XDB Phenyl column by using a mixture of 0.2% acetic acid buffer, methanol, and acetonitrile (20:16:64, v/v) as the mobile phase at a flow rate of 0.8 mL/min. Prior to detection, atorvastatin and aspirin were ionized using an ESI source in the multiple reaction monitoring (MRM) mode. The ions were monitored at the positive m/z 559.2→440.0 transition for atorvastatin and the negative m/z 179.0→136.6 transition for aspirin. The calibration curve obtained was linear (r(2) ≥ 0.99) over the concentration range of 0.20-151 ng/mL for atorvastatin and 15.0-3000 ng/mL for aspirin. The method validation was performed as per FDA guidelines and the results met the acceptance criteria. A run time of 3.0 min for each sample made it possible to analyze more than 300 human plasma samples per day. The proposed method was found to be applicable to clinical studies.

Simultaneous determination of atorvastatin and niacin in human plasma by LC-MS/MS and its application to a human pharmacokinetic study.

A rapid, simple, sensitive and selective LC-MS/MS method has been developed and validated for quantification of the atorvastatin (AT) and niacin (NA) in 250 µL human plasma. The analytical procedure involves a liquid-liquid extraction method using nevirapine as an internal standard (IS). The chromatographic separation was achieved on a Hypurity Advance (4.6 × 50 mm, 5 µm) column using a mobile phase consisting of 0.1% formic acid buffer-acetonitrile (20:80, v/v) at flow rate of 0.8 mL/min. The API-4000 LC-MS/MS was operated in the multiple-reaction monitoring mode using electrospray ionization. The total run time of analysis was 3 min and elution of AT, NA and IS occurred at 1.06, 1.84 and 0.92 min, respectively. A detailed validation of the method was performed as per the US Food and Drug Administration guidelines and the standard curves found to be linear in the range of 0.10-30.0 ng/mL for AT and 20.2-6026 ng/mL for NA, with a coefficient of correlation of ≥ 0.99 for both the compounds. AT and NA were found to be stable in a battery of stability studies, viz. bench-top, autosampler, re-injection, wet-extract and repeated freeze-thaw cycles. The developed assay method was successfully applied to a pharmacokinetic study in humans.