title: Simultaneous quantification of simvastatin and simvastatin hydroxy acid in blood serum at physiological pH by ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC/MS/MS).
abstract: Simvastatin attenuates airway inflammation and hyperreactivity, hallmarks of asthma, in allergen-challenged mice. As such, it is under consideration as a novel therapeutic, thus it is important to quantify the levels of simvastatin and its pharmacologically active and interconvertible metabolite, simvastatin hydroxy acid, that can be attained in the body. Methods exist to measure the concentrations of these compounds in biological media; however they do not maintain a physiological pH, and as a result do not accurately measure the ratio of these two compounds that exists in vivo. We developed a new method to measure simvastatin and simvastatin hydroxy acid more accurately in serum from mice by ultra high performance liquid chromatography-tandem mass spectrometry. We minimized the time that the compounds were in aqueous solution, and buffered samples to a physiological pH value of 7.4. Limits of quantification (LOQ) were 0.16 ng mL(-1) extract (1.3 ng mL(-1) serum) for simvastatin, and 8.3 ng mL(-1) extract (66 ng mL(-1) serum) for simvastatin hydroxy acid, respectively. No interconversion was observed, based on spike-and-recovery experiments of solutions containing both compounds. The method was applied using biological samples from mice challenged with house dust mite extract and simultaneously treated with subcutaneous simvastatin injection. Simvastatin hydroxy acid concentrations became significantly increased after a 2 week pre-treatment regime, whereas simvastatin concentrations were below the LOQ for all serum samples.
authors.affiliation: Department of Environmental Studies and Sciences, Richardson College for the Environment, The University of Winnipeg, Winnipeg, MB, Canada, R3B 2E9; Department of Chemistry, Richardson College for the Environment, The University of Winnipeg, Winnipeg, MB, Canada, R3B 2E9.
authors.forename: Hilary J
authors.initials: HJ
authors.lastname: Bews
authors.affiliation: Department of Environmental Studies and Sciences, Richardson College for the Environment, The University of Winnipeg, Winnipeg, MB, Canada, R3B 2E9; Department of Chemistry, Richardson College for the Environment, The University of Winnipeg, Winnipeg, MB, Canada, R3B 2E9.
authors.forename: Jules C
authors.initials: JC
authors.lastname: Carlson
authors.affiliation: Department of Physiology, University of Manitoba, Winnipeg, MB, Canada, R3E 0J9; Biology of Breathing Group, Manitoba Institute of Child Health, 513-715 McDermot Ave., Winnipeg, MB, Canada, R3E 3P4.
authors.forename: Aruni
authors.initials: A
authors.lastname: Jha
authors.affiliation: Department of Physiology, University of Manitoba, Winnipeg, MB, Canada, R3E 0J9; Biology of Breathing Group, Manitoba Institute of Child Health, 513-715 McDermot Ave., Winnipeg, MB, Canada, R3E 3P4.
authors.forename: Sujata
authors.initials: S
authors.lastname: Basu
authors.affiliation: Department of Physiology, University of Manitoba, Winnipeg, MB, Canada, R3E 0J9; Department of Internal Medicine, University of Manitoba, Winnipeg, MB, Canada, R3T 2N2; Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, MB, Canada, R3T 2N2; Biology of Breathing Group, Manitoba Institute of Child Health, 513-715 McDermot Ave., Winnipeg, MB, Canada, R3E 3P4.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Halayko
authors.affiliation: Department of Environmental Studies and Sciences, Richardson College for the Environment, The University of Winnipeg, Winnipeg, MB, Canada, R3B 2E9; Department of Chemistry, Richardson College for the Environment, The University of Winnipeg, Winnipeg, MB, Canada, R3B 2E9; Biology of Breathing Group, Manitoba Institute of Child Health, 513-715 McDermot Ave., Winnipeg, MB, Canada, R3E 3P4. Electronic address: wong.charles.shiu@alum.mit.edu.
authors.forename: Charles S
authors.initials: CS
authors.lastname: Wong
mesh_terms: D000818:Animals; D000924:Anticholesteremic Agents / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005260:Female; D006863:Hydrogen-Ion Concentration; D051379:Mice; D008807:Mice, Inbred BALB C; D044967:Serum / Q000737:chemistry; D019821:Simvastatin / Q000031:analogs & derivatives* / Q000097:blood*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D000924:Anticholesteremic Agents; C532833:simvastatin hydroxyacid; D019821:Simvastatin
keywords: Interconversion; Simvastatin; Simvastatin hydroxy acid; UHPLC/MS/MS