Effects of encapsulation process parameters of calcium alginate beads on Vitamin B12 drug release kinetics

Calcium alginate beads were prepared by ionotropic gelation of droplet of an alginate solution containing Vitamin B-12, followed by oven air drying at 70 degrees C. The beads were characterized by a light microscope and in vitro drug release in phosphate buffer saline (PBS) solution (pH 7.4) maintained at 37 degrees C in order to simulate intestinal fluid conditions. The effect of drug configuration within a bead, various process factors on the bead morphology and drug release properties was investigated. The experimental results indicated that altering the polymer to drug loading ratio, alginate, Vitamin B-12 concentration and flow rates affected the Vitamin B-12 release rates. The addition of chitosan to the polymer matrix was found to have a significant impact on the rate of release, as it slowed down the release of Vitamin B-12. It has also been found that some combinations of the parameters mentioned above, thermal effects in particular, were able to create the clear wall-core structures, and it is envisaged that one can apply those combinations or at least adopt the overall trend in a more advanced equipment to achieve controlled releasing drug micro-capsules. (C) 2009 Curtin University of Technology and John Wiley & Sons, Ltd.