The Study On The Properties Of Chitosan/Pectin Polyelectrolyte Complex And Research On BSA Delivery

Hydrogel complex is formed by electronic interaction between chitosan and pectin,which is pH sensitive. This paper was focused on exploring chitosan/pectin complexprocessing factors, such as molecular weight and deacetylation degree of chitosan,esterification of pectin, pH value, ions and ion concentration in environment. Severalproperties of chitosan/pectin polyelectrolyte complexes (PEC), such as pH sensitiveness,swelling behavior, loading and releasing of bovine serum albumin (BSA) were studied. Mainresults are:1. The prior ratio of chitosan to pectin remained around5:5when chitosan molecular wassmall (50kDa,150kDa and250kDa), while the ratio (3:7and2:8) of pectin increased incomplexes with high molecular weight of chitosan (350kDa and500kDa). As chitosanmolecular weight increased, the complex yield decreased. pH-turbidity results showed thatmolecular weight of chitosan had little effect on critical pH value. Swelling results showedthat all the complexes reached swelling balance in4to6hours, while different molecularweight of chitosan resulted in different swelling degrees.2. Chitosan deacetylation degree of85%and90%, had little effect on chitosan pectinratio and critical pH value. As deacetylation degree increased from85%to90%, free amino inchitosan/pectin complex increased, thus increased swelling degree.3. As esterification degree of pectin reduced from70%to60%, chitosan pectin ratioincreased. Esterification degree of pectin had little effect on critical pH value. Swelling resultsshowed, pectin with esterification degree of60%could have more cross-linking than70%,and chitosan/pectin complex with60%esterification degree of pectin had lower swellingdegree.4. When the pH value was2, the yields of chitosan/pectin complexes increased as theratio of chitosan in complexes gained, but the yields were low. When pH value was3, theyields increased as the ratio of pectin in complexes gained. When pH value was4, the yieldsincreased then decreased as the ratio of chitosan in complexes gained. chitosan/pectincomplex behaved different swelling patterns as it was affected by hydrophilic groups, cross-linking degrees and the ratio of pectin in complexes.5. With various ions, the optimal ratio of chitosan to pectin changed, and critical pHvalue switched from6to7. FT-IR analysis indicated that ions had no effect on the interactionbetween chitosan and pectin. SEM results showed that the chitosan/pectin PECs formed asponge-morphic microstructure, and the layer became more thick and smooth with theinteraction of ion. While the porosity was different between PECs composed with differentions.6. The swelling degrees of chitosan/pectin complexes with different ions in water were asfollows: FeCl3>CaCl2>Na2SO4>MgSO4>NaCl≈Fe2(SO4)3. The swelling degrees instimulated environment were: MgSO4>FeCl3>Na2SO4>NaCl>CaCl2>FeCl3. Chitosan/pectincomplex with all kinds of ions owned good pH sensitive. The swelling degrees were largest insimulated gastric environment, least in simulated colon environment. Chitosan/pectin swelledin simulated gastric and simulated small intestine environment, while it occurred erosion insimulated colon environment.7. Chitosan/pectin polyelectrolyte complex contained sodium chloride, sodium sulfate,ferric chloride were tested on loading BSA. The encapsulation efficiency reached75%,loading efficiency ranged from5%to15%. All complex had good pH sensitivity both insingle and continuous simulated environment. In single simulated environment,chitosan/pectin complex acquired distinctive drug release differences. In continuous simulatedenvironment, the BSA accumulative release rate was less than20%in simulated gastricenvironment, and it was higher than50%in simulated intestine environment. In singlesimulated environment, the release behavior belonged to Fick diffusion, which was mainlycontrolled by BSA concentration in complex. In continuous simulation environment, therelease behavior belonged to non-Ficken diffusion, BSA release was affected by acombination of factors, such as swelling or erosion of complex, BSA concentration. With theexistence of pectinase, the BSA release rate accelerated, resulted in BSA accumulative releaseof30%to50%in simulated colon environment and weakened slow release rate. In conclusion, chitosan/pectin complex with ions could be used as drug carrier for colon delivery.