Quantitative determination of BMS186716, a thiol compound, in dog plasma by high-performance liquid chromatography-positive ion electrospray mass spectrometry after formation of the methyl acrylate adduct

As it is extremely unstable in blood, the thiol compound BMS186716 was stabilized by the addition of methyl acrylate (MA) to blood samples, The blood samples were then kept in ice for 10-15 min for completion of the Michael addition reaction to occur between the thiol group of BMS186716 and MA, after which the plasma was separated by centrifugation under refrigeration. For sample analysis, the standard and quality control samples were prepared by spiking blank plasma with the BMS186716-MA adduct. After addition of the internal standard, BMS188035-MA, each sample was acidified with HCl and then extracted with methyl tert.-butyl ether. Each reconstituted extract was injected into a high-performance liquid chromatography-positive ion electrospray ionization mass spectrometric system, The electrospray condition was chosen to enhance the [M+NH4](+) signal at the expense of the [M+H](+) signal. Monitoring the [M+NH4](+) signal, a lower limit of quantitation of 2.5 ng/ml was achieved, with 0.5 ml plasma. We have thus shown that a sulfhydryl compound (BMS186716) in blood can successfully be stabilized by reacting it with MA and that the adduct produced is adequately stable in blood and plasma to allow the development of a rugged quantitative bioanalytical method.