Availability of salicylate from salsalate and aspirin

Publisher Website
Google Scholar
Abstract
Salicylate availability from salsalate (SSA) and aspirin (ASA) [antiinflammatory agents] was examined in 6 rheumatoid arthritis patients in a multiple-dose double-blind crossover study. Doses contained equimolar amounts of salicylic acid. After initial ASA treatment to achieve therapeutic salicylate levels (150-300 .mu.g/ml) the patients received equimolar doses of SSA or ASA. When steady state was achieved patients were hospitalized, and blood and urine specimens were obtained during 3 dosing intervals and during the washout period that followed. Patients were then placed on the alternate medication for at least 1 wk and the in-hospital pattern was repeated. Despite insignificant differences in absorption of the formulations as measured by urinary salicylate recovery, the plasma salicylic acid AUC [area under the plasma concentration time curve] was lower after SSA. Evidence indicates that this apparent lower availability of salicylate from SSA is due to incomplete hydrolysis to salicylic acid; the unhydrolyzed SSA was excreted mainly as glucuronide conjugates.