Investigation into the production of calcium pectinate particles for oral delivery to the colon

Pectin can be cross linked with calcium ions forming calcium pectinate, a material that is ideal for delivery to the colon since it can be degraded by the colonic flora. To avoid drug loss before the colonic is reached, particles can be coated in pH responsive polymers. The production of calcium pectinate particles, loaded with 5 aminosalicylic acid (5-ASA) was explored. Their potential for controlled drug release to the colon was evaluated. Two production methods for the particles were explored; the ‘syringe droplet’ method and the ‘water in oil’ emulsion method. The characteristics of these particles were found to be dependent on the processing parameters selected. Loading of 5-ASA into the particles was investigated by loading the drug in solution and suspension. Due to the poor solubility of 5-ASA in water, encapsulation of the drug gave a 0% encapsulation efficiency. Therefore, the 5-ASA was re-encapsulated though a suspension. Particles were also subject to in vitro release in conditions simulating the gastrointestinal tract, where the 5-ASA was rapidly released though all simulations. The particles were finally subject to preliminary coating studies with a pH responsive polymer by a solvent evaporation method where it was believed some degree of coating was achieved