Controlled release of albumin from chitosan-alginate microcapsules.
A polymeric delayed-release protein delivery system was investigated with albumin as a model drug. The polysaccharide chitosan was reacted with sodium alginate in the presence of calcium chloride to form microcapsules with a polyelectrolyte complex membrane. Variables believed to be important for membrane formation were examined; these included reaction time, chitosan molecular weight, alginate concentration, chitosan concentration, and solution pH. An alginate-chitosan reaction time, in the range of 10 to 45 min, had no effect on the release of albumin. Increasing the alginate concentration, however, resulted in a decreased rate of release of albumin (from 37% release at 4 h with 1.5% alginate to 20% release with 2.5% alginate). Another key variable was the chitosan molecular weight. The molecular weight of chitosan was varied from 1.25 x 10(6) to 0.25 x 10(6) through a nitrite oxidation reaction with sodium nitrite. Decreasing the molecular weight increased the release of albumin (from 37% release at 4 h with high molecular weight chitosan to 77% release with low molecular weight chitosan). The pH of the extracapsular environment was found to affect the release of albumin significantly (15% release over 24 h at a pH 3.0 and 73% release at pH 8.0). Capsules produced with high molecular weight chitosan and a combination of high and low molecular weight chitosan gave the best results for reducing elution of albumin in the first 4 h and increasing elution in the following 20 h.
Polk
A
A
Department of Chemical Engineering, Queen's University, Kingston, Ontario, Canada.
Amsden
B
B
De Yao
K
K
Peng
T
T
Goosen
M F
MF
D000418:Albumins / Q000008:administration & dosage / Q000737:chemistry*; D000464:Alginates / Q000737:chemistry*; D002122:Calcium Chloride / Q000494:pharmacology; D002214:Capsules; D002686:Chitin / Q000031:analogs & derivatives* / Q000737:chemistry; D048271:Chitosan; D003692:Delayed-Action Preparations; D004058:Diffusion; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D008970:Molecular Weight; D012995:Solubility
D000418:Albumins; D000464:Alginates; D002214:Capsules; D003692:Delayed-Action Preparations; D002686:Chitin; D048271:Chitosan; D002122:Calcium Chloride