Microcapsules for the controlled release of acetylsalicylic acid in the gastrointestinal environment

A process for the preparation of microcapsules for the controlled release of acetylsalicylic acid (ASA) in the gastrointestinal environment, said microcapsules being orally ingestible in a dose (D) and comprising particles of acetylsalicylic acid with a size of between 100 and 1000 .mu.m which are coated and designed so that, when ingested orally in a single administration of a dose D of between 75 and 320 mg of ASA, they induce moderate ASA absorption kinetics in vivo in man, extending over at least 24 hours, said ASA absorption being:

• less than or equal to 10% by weight of the absorbed fraction of D at a time t after ingestion of 0.4 hour,
• less than or equal to 50% by weight of the absorbed fraction of at t=3.9 hours, and
• less than or equal to 90% by weight of the absorbed fraction of D at t=23 hours, t being given to within .+-.10%, which process consists essentially in:
• a) preparing a coating composition by mixing a film-forming polymer (P.sub.1) insoluble in the gastrointestinal environment, a water-soluble polymer (P.sub.2), a solid lubricating filler and a hydrophobic plasticizer in a solvent system,
• b) applying the composition/solvent system mixture to particles of acetylsalicylic acid, and
• c) drying the resulting microcapsules.