LC–MS/MS method for determination of geldanamycin derivative GM-AMPL in rat plasma to support preclinical development

A LC–MS/MS method for determining the concentration of the small molecule Hsp90 inhibitor, GM-AMPL, has been developed and validated in rat plasma to support preclinical development. 17-[2-(morpholine-4-yl)ethyl]amino-17-demethoxygeldanamycin (GM-AMPL) and the internal standard 17-allylamino-17-demethoxygeldanamycin (17-AAG) were sufficiently separated on a Venusil MP C18 column that was eluted with 80% methanol in water at 40 °C. Quantification studies were performed with a multiple reaction monitoring (MRM) transition of m/z 657.3→614.3 and 584.3→541.3 for GM-AMPL and IS, respectively, in the negative ion mode. The present method exhibited good linearity (R > 0.999) over the concentration range of 2–600 ng/mL for GM-AMPL in rat plasma with a lower limit of quantification (LLOQ) of 2 ng/mL. The intra-batch and inter-batch assay coefficients of variation (CV) were in range of 1.56–6.84% and 1.62–6.98%, respectively. The plasma samples were extracted with methanol to precipitate protein with extraction recovery in range of 84.09–95.25%. The matrix effect was determined as internal substance (IS) normalized matrix factor of 1.09, 1.18 and 1.05 for samples with three concentration levels of 4, 40 and 400 ng/mL, respectively. This validated method was further applied to successfully determine the pharmacokinetic parameters and oral availability of GM-AMPL in Sprague-Dawley rats following intravenous injection and oral administration.

► First report on oral bioavailability of novel Hsp90 inhibitor GM-AMPL.
► The sensitive and reliable LC–MS/MS method for determination of GM-AMPL in rat plasma.
► Simple and stable extraction procedure of analytes from plasma samples.
► Validated method feasible to future pharmacokinetic study.