Indomethacin and ketoprofen (non-steroidal anti-inflammatory drugs) were incapsulated with cellulose acetate trimellitate, enteric polymer, using a spray drying technique.Organic solutions of polymer and drug were prepared in different weight ratios and sprayed, achieving drug loaded microspheres.The obtained spray dried microparticles were characterized in terms of yield of production, shape, size, morphological characteristics and drug content.The in vitro drug release tests, carried out using a pH change method with a flow-through cell apparatus, show a typical delayed drug release due to the pH-dependent solubility of the polymer.