Novel calcium phosphate-based starter pellets were used to develop a biphasic-release multiple-unit pellet system (MUPS) with diclofenac sodium as a model drug in the form of hard gelatin capsules. For comparative purposes, corresponding formulations based on the inert cores made of microcrystalline cellulose, sucrose and isomalt were prepared. The developed system consisted of two types of drug-layered pellets attaining different release patterns: delayed-release (enteric-coated) and extended-release. Dissolution characteristics were examined using both compendial and biorelevant methods, which reflected fed and fasting conditions. The results were collated with an equivalent commercial product but prepared with the direct pelletization technique.
