Effect of Cross Linking Agent and Polymer on The Characteristics of Ovalbumin Loaded Alginater Microspheres

Objective: The aim of the present research was to investigate effect of polymer and cross linking agent on the characteristics of ovalbumin-loaded alginate microspheres. Ovalbumin was selected as a protein model antigen; barium chloride and calcium chloride were used as cross linking agent. Methods: Ionotropic gelation using aerosolisation and drop technique were applied in this study. The microspheres produce were characterized for the size, morphology, encapsulation efficiency, protein loading, yield and in vitro release. Release of the protein was also studied. Results: Ovalbumin-loaded alginate microspheres were successfully produced by aerosolisation with maximum encapsulation efficiency and loadings of about 89%. Smooth and spherical microspheres were shown for both alginate microspheres produced using Ca2+ and Ba2+ of the aerosolisation method with average sizes from 12 to 30µm. In case drop technique, bigger microspheres size was produced of around 1-3 mm. The in vitro release study revealed that protein release decreased by decreasing alginate concentration, whereas no significant differences of ovalbumin release by decreasing calcium chloride concentration. Interestingly, alginate microspheres produced using barium chloride resulted burst and faster release behaviour of ovalbumin in HCl pH 1.2 and PBS pH 7.4 release medium. Conclusion: This result suggested that modification of cross linking agent and polymer concentration were important for sustained release characteristics of ovalbumin-loaded alginate microspheres