Pharmacokinetics of a new nitroderivative of acetylsalicylic acid after a single dose in rats.

The pharmacokinetics of a new ASA-nitroderivative compound, NCX 4016 (ASA-NO2), was evaluated using an HPLC method. After single equimolar doses of ASA (35 mg kg(-1)) or ASA-NO2 (65 mg kg(-1)), no detectable levels of these compounds have been observed in rat plasma samples. SA peak levels were obtained at 3 h and 6 h after ASA and ASA-NO2 administration respectively. The elimination rate constants of SA were similar after ASA and ASA-NO2, suggesting a similar elimination phase of this metabolite in rats. From these data it is evident that ASA-NO2 is slowly metabolized in ASA, which is rapidly converted to SA.