Controlled release theophylline matrices prepared from co-spray dried theophylline-polymer-channeling agent

Abstract

Controlled release theophylline matrices containing various types and amounts of cellulose derivatives (ethylcellulose, hydroxyl propylmethylcellulose, hydroxypropylmethylcellulose phthalate) and/or channeling agent (PVP K30, lactose) were prepared using spray drying technique. The types and amounts of matrix additives affected the condition of spray drying process and the physical properties of co-spray dried powders. The release characteristics of theophylline from the matrices were different in acid and alkali medium. The release rate decreased with an increase in the amount of cellulose polymers. Type of channeling agent appeared to exert more effect on the release rate while altering the amount of these additives played a lower effect on drug release. Those matrices containing 3% ethyl cellulose and 25% lactose exhibited the most satisfactory release profiles. The release mechanisms and models of all prepared matrices were also assessed in comparison with the commercial products.