Manufacture of gelatin/gelatin coacervate microcapsules

Abstract Microelectrophoretic mobility profiles of two oppositely charged gelatins were used to determine the optimum pH and ionic strength conditions for coacervation to occur between the gelatins. Coacervation of aqueous mixtures of the two gelatins was only detected when the temperature was reduced below the gelation temperature of the gelatins. Coacervate yield was dependent on: the final temperature of the mixture; the time allowed for equilibration; the concentration of the gelatin solutions; and the pH and ionic strength of the media. Microcapsules containing naproxen were prepared by complex coacervation of the gelatins. Those variables which affected gelatin/gelatin coacervate yield had similar effects on microcapsule yield.