Adsorption and desorption of insulin on porous hydroxyapatite microspheres

In this study, porous hydroxyapatite microspheres with the size range 9-80 mu m have been prepared by a spray-drying method and the possibility using this kind of microspheres as carrier for peptides has been investigated with insulin being chosen as a model drug. In adsorption experiment, many factors (i.e., incubation temperature, incubation duration, pH and concentration of insulin solution) had influences on insulin adsorption on obtained microspheres. More than 90% insulin in solution could be loaded with optimal combination of these factors and drug loading of more than 3% could be achieved. In desorption experiment, the concentration of dipotassium hydrogen phosphate solution in many effecting factors had greatest influence on insulin release from insulin-adsorbed microspheres. More than 90% loaded-insulin could be released at dipotassium hydrogen phosphate solution at concentration around 10 mM. All these results suggested that there was possibility of fabrication of proteinic drug delivery system with porous hydroxyapatite microspheres.