Preparation of chitosan microspheres by emulsion/polymerization method using tripolyphosphate (TPP) and glutaraldehyde (GLT)

Chitosan microspheres are promising candidates in controlled release drug delivery especially for instable and sensitive drugs. Among various methods of microspheres preparation emulsion/polymerization method based on ion cross-linking is thought to be suitable for chitosan microspheres technology because of its simplicity and mild characteristic. In this paper, chitosan microspheres preparation by the emulsion/polymerization method using tripolyphosphate (TPP) and glutaraldehyde (GLT) as cross-linkers was described. The in uence of the type of oil phase, water/oil ratio, surfactant, pH, TPP concentration and additional cross-linking with GLT was evaluated. It was found that type of oil is very important in microspheres formation. Liquid para n seems to be inappropriate due to di culties with puri cation of microspheres, therefore less viscous Miglyol 812 could be more suitable. Crucial factors for microspheres preparation were both pH solution before and after cross-linking. TPP/chitosan microspheres had much poorer mechanical strength compare to GLT/chitosan microspheres. In addition, water/oil volume ratio and surfactant concentration less importantly a ected the microspheres preparation.