Phase separation induced in gelatin-base coacervation systems by addition of water-soluble nonionic polymers I: Microencapsulation.
A microencapsulation procedure in which water-soluble nonionic polymers (especially, polyethylene oxide or polyethylene glycol) were added to gelatin-base coacervation systems is described. The advantages of this method are: (a) The addition of a small amount of polyethylene glycol (PEG) or polyethylene oxide (PEO) to a complex coacervation system (e.g., gelatin-acacia) allows microencapsulation to occur over an expanded pH region (pH 2-9 in gelatin-acacia). (b) These polymers induce phase separation in an aqueous solution of gelatin alone and enable the preparation of gelatin-coated microcapsules not only in the vicinity of the isoelectric point (pH 9.0), but over a wide pH range (pH 5.5-9.5). (c) Spherical single-seeded microcapsules can be obtained.
D002214:Capsules; D002626:Chemistry, Pharmaceutical; D003102:Colloids; D005780:Gelatin; D006863:Hydrogen-Ion Concentration; D011108:Polymers; D012995:Solubility; D013501:Surface-Active Agents; D014783:Viscosity
D002214:Capsules; D003102:Colloids; D011108:Polymers; D013501:Surface-Active Agents; D005780:Gelatin