Biopharmaceutical evaluation of a tablet dosage form made from ethyl cellulose encapsulated aspirin particles

Ethyl cellulose encapsulated aspirin particles, suitable for preparation of direct compression tablets were prepared by the solvent evaporation method. Ethyl acetate was used as a solvent for the polymer in combination with a saturated solution of aspirin as the dispersing medium to prevent partitioning and drug loss. This resulted in a high yield of free-flowing, non-aggregated particles. In vitro-in vivo evaluations of the experimental aspirin tablets (made by direct compression of ethyl cellulose encapsulated particles) and three different commercial aspirin products (a conventional tablet, a timed-release tablet, and a timed-release caplet) were undertaken. Comparison of the dissolution in acidic media at pH 1.2 showed different release profiles for these products. While the conventional tablet and the timed-release caplet showed the highest and the lowest rate of release, respectively; the timed-release tablet and the experimentally made tablet revealed an intermediate rate and very similar release profiles. The cumulative urinary excretion data collected in a complete crossover study, using five healthy subjects further indicated that the experimental tablet has an in vivo availability identical to that of the timed-release tablet.