title: A liquid chromatography-tandem mass spectrometry method for the quantitation of actarit in rabbit plasma: application to pharmacokinetics and metabolic stability.
abstract: Actarit (ATR), 4-acetylaminophenylacetic acid is an orally effective disease-modifying anti-rheumatic drug widely prescribed for the treatment of rheumatoid arthritis. The present study demonstrates the first report on a selective and sensitive liquid chromatography-tandem mass spectrometry method for the quantification of ATR in rabbit plasma using p-coumaric acid as an internal standard (IS). Following liquid-liquid extraction, chromatographic separation of the reconstituted samples was achieved isocratically on a Syncronis-C18 column with a mobile phase consisting of aqueous ammonium acetate (10 mM, pH 4)- methanol and acetonitrile mixture (8 : 92, v/v) at a flow rate of 0.6 ml/min. ATR and IS were detected using electrospray ionization operated in negative multiple reaction monitoring mode. The calibration curve was linear (r(2)  ≥ 0.990) over the concentration range of 1-4000 ng/ml with a lower limit of quantitation of 1 ng/ml. The mean extraction recovery of ATR and IS from rabbit plasma was greater than 85%. The method complied well with US Food and Drug Administration guidelines for selectivity, sensitivity, accuracy, precision, matrix effect, dilution integrity, carry-over effect and stability. The method was successfully applied to in vitro metabolic stability (using rabbit liver microsomes) and in vivo pharmacokinetic study after oral administration of ATR at a dose of 10 mg/kg in New Zealand rabbits. Copyright © 2015 John Wiley & Sons, Ltd.
authors.affiliation: Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow, 226031, India.|Academy of Scientific and Innovative Research, New Delhi, 110001, India.
authors.forename: Rachumallu
authors.initials: R
authors.lastname: Ramakrishna
authors.affiliation: Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow, 226031, India.|Academy of Scientific and Innovative Research, New Delhi, 110001, India.
authors.forename: Manisha
authors.initials: M
authors.lastname: Bhateria
authors.affiliation: Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow, 226031, India.|Academy of Scientific and Innovative Research, New Delhi, 110001, India.
authors.forename: Santosh Kumar
authors.initials: SK
authors.lastname: Puttrevu
authors.affiliation: Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow, 226031, India.
authors.forename: Yarra
authors.initials: Y
authors.lastname: Durga Prasad
authors.affiliation: Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow, 226031, India.
authors.forename: Rajbir
authors.initials: R
authors.lastname: Singh
authors.affiliation: Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow, 226031, India.|Academy of Scientific and Innovative Research, New Delhi, 110001, India.
authors.forename: Rabi Sankar
authors.initials: RS
authors.lastname: Bhatta
mesh_terms: D000284:Administration, Oral; D000818:Animals; D018501:Antirheumatic Agents / Q000008:administration & dosage / Q000097:blood* / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003373:Coumaric Acids / Q000737:chemistry; D057230:Limit of Detection; D059625:Liquid-Liquid Extraction / Q000379:methods; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D010648:Phenylacetates / Q000008:administration & dosage / Q000097:blood* / Q000378:metabolism; D011422:Propionates; D011817:Rabbits; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D018501:Antirheumatic Agents; D003373:Coumaric Acids; D010648:Phenylacetates; D011422:Propionates; C052562:4-(acetylamino)benzeneacetic acid; C495469:p-coumaric acid
keywords: LC-MS/MS; actarit; metabolic stability; pharmacokinetics; rabbit plasma; rheumatoid arthritis