A quantitation method for XXXX .

@entity35 @entity1037 @entity15 @entity2996
A new quantitation method for @entity2996 ( @entity2996 ) with matrix-assisted laser desorption/ionization (MALDI) has been developed. In this method, drug concentrations were determined by tissue homogenization of five 10   m tissue sections adjacent to those analyzed by @entity2996 . Drug levels in tissue extracts were measured by liquid chromatography coupled to tandem mass spectrometry (LC/ @entity15 / @entity15 ). The integrated @entity2996 response was correlated to the LC/ @entity15 / @entity15 drug concentrations to determine the amount of drug detected per @entity2996 ion count. The study reported here evaluates @entity1037 in liver tissue. Tissue samples containing a range of concentrations were created from liver harvested from @entity35 administered a single dose of @entity1037 at 0, 1, 4, 8, 16, 30, or 100 mg/kg. The liver samples were then analyzed by MALDI- @entity2996 and LC/ @entity15 / @entity15 . The MALDI- @entity2996 and LC/ @entity15 / @entity15 correlation was determined for tissue concentrations of ~300 to 60,000 ng/g and yielded a linear relationship over two orders of magnitude (R(2) = 0.9792). From this correlation, a conversion factor of 6.3    0.23 fg/ion count was used to quantitate @entity2996 responses at the pixel level (100   m). The details of the method, its importance in pharmaceutical analysis, and the considerations necessary when implementing it are presented.
