PLATELET AGGREGATION INHIBITOR
(SALICYLIC ACID DERIVATIVE)

FORMULATION:
Each tablet contains:
Aspirin,USP........…….............................................................……100 mg

DESCRIPTION:
Aspirin (Asaprim) is a violet to bluish-violet enteric coated tablet, biconvex and plain on both sides.

CLINICAL PHARMACOLOGY:
PHARMACODYNAMICS:
Aspirin is used for pain, fever, inflammation and the prevention of myocardial infarction and stroke. The antithrombotic activity of aspirin is due to its inhibitory effect on platelets which is mediated via irreversible acetylation of platelet cyclooxygenase with subsequent blockade of platelet thromboxane synthesis. The inhibitory effect of aspirin on platelet thromboxane production persists for the lifespan of the platelet, around 7 to 10 days. As a result, acetylation of platelet cyclooxygenase and consequent inhibition of thromboxane formation is cumulative on repeated dosing. Low doses of aspirin inhibit platelet aggregation and may be more effective than higher doses. Larger doses inhibit cyclooxygenase in arterial walls, interfering with prostacyclin production, a potent vasodilator and consequent inhibition of platelet aggregation.

PHARMACOKINETICS:
About 80% to 100% of an oral dose of aspirin is absorbed from the gastrointestinal tract. However, the actual bioavailability of the drug as
unhydrolyzed aspirin is lower since aspirin is partially hydrolyzed to salicylate in the gastrointestinal mucosa during absorption and on first pass through the liver. Food does not appear to decrease the bioavailability of unhydrolyzed aspirin; however, absorption is delayed and peak serum aspirin concentration may be decreased. Aspirin is rapidly and widely distributed into most body tissues and fluids. Aspirin’s volume of distribution is 0.15 to 0.2 L/kg. Aspirin is poorly bound to plasma proteins; the unhydrolyzed drug is 33% bound at a serum salicylate concentration of 120 mcg/mL.