MICROENCAPSULATION OF PYRROLNITRIN FROM PSEUDOMONAS-CEPACIA USING GLUTEN AND CASEIN

For the formulation and sustained-release delivery of pyrrolnitrin, a biologically anti-fungal antibiotic, a microencapsulation technique us ing gluten and casein as the coating materials and employing simple co acervation was developed. The core materials were the dried fermentati on broth of Pseudomonas cepacia containing pyrrolnitrin (Powder A) and pyrrolnitrin-adsorbed Microken powder (Powder B). Irregular microcaps ules with particle sizes ranging from 5 to 80 mu m and possessing a sm ooth surface after hardening with glutaraldehyde were obtained. For th e encapsulation of Powder B, about 51-69% of pyrrolnitrin was retained in the microcapsules; compared with only 27-48% for the encapsulation of Powder A, These low yields were due to the decomposition of pyrrol nitrin, as well as to its release into the polymer-poor phase during t he coacervation process. Microcapsules prepared by each of the dispers ion systems conferred significant delayed-release of pyrrolnitrin, com pared to its rapid release from the core materials without encapsulati on. The sustained release properties depended on both the core-to-wad ratio and the dosage of hardening agent.