Development and validation of a liquid-chromatography tandem mass spectrometry method to determine in vitro and in vivo XXXX release.

@entity1 @entity6115 @entity6189 @entity112 @entity35 @entity15 @entity2021
@entity112 is an important biogenic @entity6115 involved in regulating numerous physiological and pathophysiological processes in @entity1 and animals. To date, there have been very few studies focused on developing and validating sensitive liquid-chromatography-tandem mass spectrometric (LC- @entity15 / @entity15 ) assays capable of quantitative trace level @entity112 analysis in biological matrices. In the present study, a rapid and sensitive LC- @entity15 / @entity15 assay, amenable to high throughput analysis was developed and validated to characterize in vitro and in vivo @entity112 release. The LC- @entity15 / @entity15 procedure incorporating @entity6189 labeled internal standards provides rapid resolution of @entity112 with excellent sensitivity, precision, and accuracy. @entity112 eluted at 1.5min and was well separated from endogenous plasma peaks. The total run time of the assay was 8.0min. A linear (r(2)>= 0.99) instrument response over the entire concentration range of 1.0-1000ng/mL was observed. Excellent accuracy (error  3.4%) and precision (CV  10%) of the assay was demonstrated, with the lower limit of quantitation (LLOQ) at 15.6ng/mL. The validated LC- @entity15 / @entity15 assay was applied to determine @entity112 release in both in vitro and in vivo models. Peritoneal mast cells treated with prototypical degranulating agents (Compound 48/80 and Teicoplanin) showed that the two chemicals caused approximately 40% @entity112 release. In @entity35 , using this assay, basal @entity112 plasma levels were typically under 100ng/mL. Treatment with an agent suspected of causing anaphylactic type reactions resulted in plasma @entity112 levels to increase above 3000ng/mL. The LC- @entity15 / @entity15 assay presented in this study can be applied to further characterize the physiological and pathophysiological role of @entity112 release in complex in vitro and in vivo models. Importantly, the LC- @entity15 / @entity15 assay may be useful in assessing active pharmaceutical ingredient-mediated degranulation and @entity2021 as part of either a pre-market or a post-market assessment of drug products.
