Detection of ASA metabolites in plasma following 1 week of daily ASA exposure. Human subjects were each given ASA daily for one week, and tissue samples were obtained both before (pre) and after (post) this period. (A), Protocol for 325 mg dosing. (B), Levels of salicylate and salicylurate in plasma in the 325 mg cohort. * p < 0.0001, paired t-test. (C), Levels of gentisic acid and salicyl acyl glucuronide in plasma in the 325 mg cohort. * p < 0.0001, paired t-test. (D), Protocol for 81 mg dosing. (E), Levels of salicylate and salicylurate in plasma in the 81 mg cohort. * p < 0.0001, paired t-test. (F), Levels of gentisic acid and salicyl acyl glucuronide in plasma in the 81 mg cohort. * p = 0.04, ** p < 0.0001, paired t-tests.