title: An API LC/MS/MS quantitation method for ansamitocin P-3 (AP3) and its preclinical pharmacokinetics.
abstract: Ansamitocin P-3 (AP3) is a potent maytansinoid antitumor agent isolated from microorganisms and mosses. In this study, a highly sensitive and specific electrospray ionization (ESI) liquid chromatography-tandem mass spectrometry (LC/MS/MS) method for quantitation of AP3 was developed and validated. AP3 was extracted from rat plasma along with the internal standard, depsipeptide FK228 (NSC-630176, FR) with ethyl acetate. Components in the extract were separated on a 50mm x 2.1mm Betabasic C 85 microm stainless steel column by isocratic elution with 70% acetonitrile/0.9% formic acid. The liquid flow was passed through a pre-source splitter and 5% of the eluent was introduced into the API source. The components were analyzed in the multiple-reaction-monitoring (MRM) mode as the precursor/product ion pair of m/z 635.2/547.2 for AP3 and of m/z 541.5/424.0 for the internal standard FR. Linear calibration curves were obtained in the range 1-500 ng/mL using 0.2 mL rat plasma. The within-day coefficients of variation (CVs) were 12.9, 6.7, and 5.5% and the between-day CVs were 10.4, 6.5, and 6.4% (all n = 5) at 1, 10, and 200 ng/mL, respectively. A formulation based on normal saline and PEG300 was then developed and Sprague-Dawley male rats were given this formulated drug by i.v. bolus. Plasma drug concentrations were measured by this method and the pharmacokinetics were analyzed by standard techniques. Plasma concentration-time profiles were found to follow a triexponential decline and the terminal phase was nearly flat, suggesting that the drug distributed in deep tissue compartments or organs and then equilibrates slowly with the blood stream.
authors.affiliation: College of Pharmacy, The Ohio State University, 410 W. 12th Avenue, Columbus, OH 43210, USA.
authors.forename: Zhongfa
authors.initials: Z
authors.lastname: Liu
authors.forename: Heinz G
authors.initials: HG
authors.lastname: Floss
authors.forename: John M
authors.initials: JM
authors.lastname: Cassady
authors.forename: Jim
authors.initials: J
authors.lastname: Xiao
authors.forename: Kenneth K
authors.initials: KK
authors.lastname: Chan
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods; D004353:Drug Evaluation, Preclinical / Q000379:methods; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D008453:Maytansine / Q000031:analogs & derivatives* / Q000032:analysis* / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D008453:Maytansine; C015682:ansamitocins