Matrix pellets based on the combination of waxes, starches and maltodextrins

Matrix pellets were produced combining microcrystalline waxes, pregelatinized starches and hydrolysed starches. Ibuprofen, sodium salicylate, benzoic acid, sodium benzoate and chloroquine phosphate were used as model drugs. Using a wax with a melting range between 68 and 72°C and increasing the wax concentration decreased the drug release rate. Pellets containing drum-dried corn starch failed to form matrix pellets. The slowest drug release was obtained for formulations containing waxy maltodextrin, releasing 95% of the incorporated ibuprofen after 48 h in vitro. Increasing the ibuprofen concentration decreased the drug release rate. Drug release was controlled by pore and matrix diffusion. The release of sodium salicylate and sodium benzoate from the wax-starch matrix pellets was characterised by an initial burst release followed by a block of the drug release.