Fabrication And Application Study Of Chitosan Gel Beads By Piercing-solidifying Method

Chitosan is a natural polysaccharide, possesing a very rich reserve, with excellentphysical, chemical and biological properties, including excellent biocompatibility,biodegradability, non-toxicity, procoagulant property, soluble in dilute acid or dilutehydrochloric acid.when dissolved, it becomes a positively charged polyelectrolyte, with alarge number of active amino and hydroxyl groups etc on the molecular chain, and there istremendous value in its pharmaceutical application. However, the applications of the chitosangel to a greater extent are still in the research stage, and the procedures of applying thoseresearch are too complex, some products involve the use of toxic reagents during preparation,which would influence the biocompatibility to some extent.In this study,chitosan gel beads were prepared by Piercing-Solidifying Method,the effectof process parameters on the preparation of chitosan gel beads morphology and size werediscussed,and mechanical properties of the chitosan gel beads was characterized.Itsdrug(bovine serum albumin) loading and release properties were studied.Based on thechitosan gel beads,multi-porous structure was introduced by phase separation method,itsadsorption properties for bovine serum albumin solution was studied under differentconditions.The influence of dropping height,dropping speed,stirring speed,chitosan type,chitosansolution concentration,coagulation bath concentration,the pinhole aperture size on chitosangel beads’ morphology and size were discussed in this study.The best process parameters weredetermined by Orthogonal Experimental Design as:dropping height15cm, dropping speed1drop/2s,stirring speed C150type magnetic stirr120rpm,low viscosity chitosan,15mg/mLchitosan/1%acetic acid solution,1M aqueous sodium hydroxide solution as a coagulationbath,a pinhole aperture of0.9mm. Wherein the average particle size was impacted mostobviously by the viscosity type of chitosan material,the diameter would be larger with theincrease of the viscosity type of chitosan;the size uniformity and morphology were bothinfluenced most largely by the coagulation bath concentration,the chitosan beads with most uniform size were prepared with0.1M aqueous sodium hydroxide solution,while the mostspherical chitosan beads would be produced with1M aqueous sodium hydroxidesolution.Chitosan gel beads have excellent mechanical strength,it is insoluble in hydrochloricacid solution with pH≥3,while it will become soluble in hydrochloric acid solution at a lowerpH,dissolution behavior accelerated with pH decreasing and temperature increasing.The chitosan gel beads could be applied as drug delivery system in stomach with pH-sensitive release property.The loading efficiency for bovine serum albumin could be up to63.52%.In accordance with the chitosan gel beads dissolution behavior,rapid release of bovineserum albumin was detected because of the dissolution of the beads,sustained release wouldhappen in the release medium at a pH which is too high to dissolve the chitosan gel beads.With Tween80/liquid paraffin dispersed in chitosan solution uniformly as oil phase, thechitosan gel beads containing oil droplets were prepared, then oil phase was removed inchloroform, finally the multiporous chitosan gel beads was formed after purification,it couldadsorpt considerate amount of bovine serum albumin from relative solution,and also showshigh desorbtion efficiency.