Mass Spectrometry Method For Estimation Research Articles

Development and Validation of an Inductively Coupled Plasma Mass Spectrometry Method for Estimation of Elemental Impurities in Calcium Acetate Active Pharmaceutical Ingredient

A sensitive and selective method has been developed and validated for the simultaneous quantitative estimation of aluminum, magnesium, potassium, strontium and sodium in calcium acetate active pharmaceutical ingredient by inductively coupled plasma mass spectrometry. Inductively coupled plasma mass spectrometry is an advanced technique which is capable of analyzing multiple elements simultaneously with high selectivity, sensitivity and much lower detection limit. The test sample was prepared with microwave assisted acid digestion and introduced into optimized instrumental parameters for use of a quadrupole based Agilent 7800 inductively coupled plasma mass spectrometry instrument. Scandium is used as an internal standard in the study. The developed method was validated in terms of specificity, linearity, accuracy, precision, range, limit of detection, limit of quantitation and ruggedness. The results for recoveries of all elements were found between 85.3 to 103.9 %. The relative standard deviation for precision was within 15 %. Calibration plots were linear. The low relative standard deviation values and high recoveries of the method confirm the suitability of the method.

Dystonic opisthotonus: A rare phenotype of adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is a pan-ethnic disorder and affects approximately 1:20,000 males (Moser HW, Mahmood A, Raymond GV. X-linked adrenoleukodystrophy. Nat Rev Clin Pract Neurol 2007;3:140-51; Natarajan A, Christopher R, Netravathi M, Bhat M, Chandra SR. Liquid chromatography-tandem mass spectrometry method for estimation of a panel of lysophosphatidylcholines in dried blood spots for screening of X-linked adrenoleukodystrophy. Clin Chim Acta 2018;485:305-10). Phenotypes include the childhood cerebral form, which affects children who present with rapid cognitive decline. Adolescents and adults present with spastic paraparesis or adrenomyeloneuropathies and also as pure Addison's disease. The less common presentations are psychosis and cortical blindness. A 9-year-old boy presented with progressive cognitive decline, behavioral disturbance, extrapyramidal symptoms, and opisthotonic posturing. Magnetic resonance imaging of brain and blood levels of very long-chain fatty acids lysophosphatidylcholine confirmed X-ALD.

Liquid chromatography-tandem mass spectrometry method for estimation of a panel of lysophosphatidylcholines in dried blood spots for screening of X-linked adrenoleukodystrophy

BackgroundElevated C26:0-lysophosphatidylcholine (LPC) is used as a biomarker to screen newborns for X-linked adrenoleukodystrophy (X-ALD), an inherited peroxisomal disorder. Our aim was to develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based assay for estimating a panel of LPCs (C20:0, C22:0, C24:0 and C26:0) from dried blood spots (DBS) and to evaluate its sensitivity and specificity for identification of X-ALD in clinically suspected cases. MethodsLPCs (C20:0 - C26:0) were extracted from 3.2 mm DBS, spiked with an isotopically labelled internal standard (C26:0-d4-LPC) in a 96-well plate, and measured by LC-MS/MS in electrospray ionization positive, multiple reaction monitoring mode. The sensitivity and specificity of the method was evaluated in 21 patients diagnosed with X-ALD and 375 healthy controls. ResultsElevated C26:0 and C24:0-LPCs were 100% sensitive and specific for identification of X-ALD. The sensitivity and specificity of elevated C26:0/C20:0, C26/C22:0, C24:0/C20:0 and C24/C22:0-LPCs were > 80% and 70%, respectively. ConclusionThe LC-MS/MS method for estimating LPCs in DBS can be used to identify X-ALD in clinically suspected patients. Further large-scale studies to determine the pre-analytical variables and to define age- and gender-specific reference ranges in various ethnic groups are warranted before introducing this method for high-risk screening in India.

Liquid Chromatography/Tandem Mass Spectrometry Method for Estimation of Cholic Acid in Rat Plasma, Urine and its Application

Cholic acid is a primary bile acid synthesised from cholesterol in liver. Apart from being major catabolic products of cholesterol bile acids facilitates absorption of fats in intestine. A selective, sensitive MRM based liquid chromatography/ tandem mass spectrometry method has been developed and validated for the estimation of cholic acid in rat plasma and urine. Telmisartan was used as internal standard (IS). Electrospray ionization (ESI) probe with negative mode of operation was used for the ionisation of cholic acid and IS. Chromatographic separation was performed through X-bridge C18 column with the mobile phase of 0.1% formic acid in water (aqueous reservoir), 100% methanol (organic modifier). A short LC gradient of 3 minutes run time was used with flow rate of 0.7 mL/min. Charcoal stripped plasma and urine were used for the preparation of calibration standards and quality control samples. The analyte and IS were isolated from plasma and urine by a simple organic solvent based protein precipitation. The assay was linear in the concentration range of 31.26-10000 ng/mL. The method has been validated according to published FDA guidelines and showed excellent performance. The developed method was applied for the estimation of cholic acid in plasma and urine samples from liver toxicity experiment in rats. Liver toxicity was induced by intraperitoneal injection of carbon tetrachloride (CCl4).

Sensitive and rapid high‐performance liquid chromatography tandem mass spectrometry method for estimation of fulvestrant in rabbit plasma

A rapid and sensitive high-performance liquid chromatography and electrospray tandem mass spectrometry method was developed and validated for estimation of fulvestrant in rabbit plasma using liquid-liquid extraction. The separation and quantification of fulvestrant were achieved by reverse-phase chromatography on a Sunfire C18 column (50 x 2.1. i.d., 3.5 microm) with isocratic elution at a flow rate of 300 microL/min using norethistrone as an internal standard from 500 microL plasma sample. The method was validated over the concentration range from 0.092 to 16.937 ng/mL with a lower limit of detection of 0.023 ng/mL. The intra-day and inter-day accuracy and precision were within 10%. The recovery was 85 and 90% for fulvestrant and norethistrone respectively. The chromatographic run time was only 2.5 min.