Effect of Stirring Speed on the Formation and Characteristic of Alginate Microspheres via Gelation/ Emulsification Method

Alginate microspheres are used for controlled drug delivery system; however, the formation and size control of alginate microspheres is necessary for these systems to be effective. Therefore, the influence of stirring speed on the characteristic of alginate microspheres (AMs) via emulsification/gelation method was evaluated. Alginate solution was emulsified into liquid paraffin oil to form water in oil emulsion and followed by cross-linked with Ca 2+ ions. The shape and surface characteristics of AMs were determined by scanning electron microscope (SEM). Morphological observation shows that at lower stirring speed, the alginate particles were irregularly shaped with a rough surface. Whereas, increasing stirring speed resulted in spherical microspheres with smoother surface. Particle size analysis by laser diffraction method showed a decreased in mean particle size and more homogeneous distribution as the stirring speed increased. The mean particle size of AMs was found to be in the range of 28.5-69.6 μm. Fourier transform infrared (FTIR) analysis shows that there was no shifting in peak positions in the transmittance spectrum of AMs. This study suggested that the formation of AMs can be synthesis via emulsification/gelation method and the size of the AMs can be tailor by varying the stirring speed.