Indomethacin sustained release from alginate-gelatin or pectin-gelatin coacervates

Gastrointestinal side effects may interrupt essential therapy with indomethacin, a non-steroidal anti-inflammatory drug. Formulation of this drug into sustained release form may reduce some of these side effects by avoiding contact of drug crystals with gastrointestinal mucosa at high concentrations, as may happen with immediate release dosage forms. Indomethacin (IMC) sustained release microparticles (pellets) were prepared from pectin-gelatin or alginate-gelatin hydrocolloid coacervate systems under controlled pH and temperature conditions. Delayed release up to 14 h was obtained with pectin-gelatin or alginate-gelatin systems of varying composition. With the pectin-gelatin systems a low drug to hydrocolloid ratio and low pectin to gelatin ratio was the most optimal composition for sustained release. Incorporation of additives such as carnauba wax was essential for diffusion controlled mechanisms to operate in the alginate-gelatin systems. Additives also showed improvements in particle shape, size distribution and flow properties. The results of this study offer an inexpensive alternative form of sustained release IMC.