All indications refer to quickly absorbed, unhydrolized aspirin. The latter is quickly metabolized (in part presystemically) to salicylic acid. Salicylic acid reaches peak plasma level in 1 to 2 hours, it has a dose dependent half-life (2-30 hours), and is partially eliminated hepatically.
*The "ideal" dose is not known. For coronary heart disease 100 mg/day or less suffice; for other angiopathies higher doses (300-500 mg/day) have often been administered.