Spherical calcium phosphate cement carriers were synthesized by water/oil emulsion. A 23 factorial design was employed in order to optimize the size and form of the microspheres. Stirring speed, liquid-to-powder ratio and cement paste-to-oil ratio were varied in two different levels and the response variable was the microsphere's sphericity. The results showed that cement's setting reaction was responsible for stabilizing the microspheres within the oil phase resulting in a low crystalline hydroxyapatite. The sizes varied from 6.29 to 64.23 µm. From the factors studied, the stirring velocity and the interaction between the L/P ratio with the P/O ratio are the ones that are more effective in controlling microspheres' sphericity. The results suggest that the methodology studied may provide microspheres with appropriate properties to deliver cells and/or drugs without inducing inflammatory reactions.
Keywords
calcium phosphate cement; microspheres; water/oil emulsion; alpha- tricalcium phosphate; factorial design
