Hydroxypropyl methylcellulose phthalate beads containing a model non-steroid anti-inflammatory drug

When given orally to patients, non-steroid anti-inflammatory drugs (NSAIDs) can provoke mild to severe gastric irritation side effects. Reduction of gastrointestinal irritation caused by NSAIDs can be achieved using enteric beads which are preferable to coated tablets or capsules. The present work reports the studies of formulation of a model NSAID using a recently described method. Drug-loaded hydroxypropyl methylcellulose phthalate (HP50) beads were prepared using a technique which is based on the variation of HP50 solubility with pH. Studies carried out to characterise the formulations, such as density, crushing force and encapsulation efficiency, show that the beads are suitable for further pharmaceutical manipulation (e.g. capsule filling). The in vitro release studies confirmed the gastroresistance, and mathematical studies showed that the drug released followed a first order kinetic. (C) 1998 Elsevier Science B.V. All rights reserved.