Preparation and stabilization of heparin/gelatin complex coacervate microcapsules.
The aims of this study are to optimize conditions for the preparation, stabilization, and harvesting of heparin/gelatin microcapsules prepared by complex coacervation. Microelectrophoresis and dry coacervate weight were used to determine the optimum conditions of pH and ionic strength for maximum heparin/gelatin coacervate yield. Heparin/gelatin microcapsules were formed by complex coacervation in the presence and absence of poly(1-vinyl-2-pyrrolidone) (PVP), which was used as a stabilizer. The microcapsules were collected using a spray-drying technique. Microcapsule particle size was analyzed using an AccuSizer optical sizer. Optimized conditions for maximum coacervate yield were pH 2.6, ionic strength 10 mM, and a 1:2 heparin/gelatin A ratio. PVP stabilized the heparin/gelatin coacervate droplets and reduced droplet aggregation during spray-drying. The mean particle diameter of the spray-dried coacervate droplets was lower in the presence of PVP and was unaffected by PVP concentration (in the range 0.5-2.0% w/w). Heparin/gelatin microcapsules, prepared under conditions optimized for maximum coacervate yield, were stabilized without the use of chemical cross-linking agents. Stabilization was achieved by a combination of the addition of PVP and spray-drying.
Tsung
M
M
Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs 06269-2092, USA.
Burgess
D J
DJ
D004337:Drug Carriers; D004586:Electrophoresis; D005780:Gelatin / Q000737:chemistry*; D006493:Heparin / Q000737:chemistry*; D008956:Models, Chemical; D010316:Particle Size
D004337:Drug Carriers; D005780:Gelatin; D006493:Heparin