Experimental Design Approach in Erythropoietin-alginate Microsphere Preparation with Different Concentrations of Drug and Polymer

Abstract

Background: Microspheres as drug delivery system has been selected to increase stability ofErythropoietin (EPO) to achieve efficacy. Aim: Aim of this research was to determine effect of polymer andEPO concentrations on the characteristics. Materials and Method: Microspheres involved sodium alginateas polymer and CaCl2 as a crosslinker. The concentrations of sodium alginate used were 2% and 3%, andEPO were 5000 IU and 10000 IU. Formula of microspheres which consist of 2% and 3% of alginate and5000 IU EPO were called F1 and F2 respectively, whereas microspheres using 2 and 3% alginate and10000 IU EPO was named F3 and F4 respectively. Characterization including morphology, particle size,swelling index, and yield of microspheres prepared by ionotropic gelation aerosolization technique. Designof Experiment (DoE) was used to analyze the formula. Results: Results showed that particle sizes ofEPO-alginate microspheres were 3.36 ± 0.126μm, 3.42 ± 0.098μm, 3.88 ± 0.131μm and 3.95 ± 0.151μmfor F1, F2, F3 and F4 respectively. The swelling index measurement based on mass and particle size ofmicrospheres of all formulas showed an index of less than 10. Respectively, yield was 77.84 ± 0.290%,86.65 ± 0.191%, 91.89 ± 0.210%, and 94.65 ± 0.252% for F1 to F4. Using the ANOVA factorial design,it was found that increasing sodium alginate concentration significantly increased yield, while increasingEPO concentration significantly increased particle size and yield of microspheres. Both sodium alginateand EPO concentrations did not affect swelling index of microspheres. Range concentrations of sodiumalginate and EPO that produced optimal characteristics of microspheres can be observed in the feasible areaof design space overlaid contour plot generated from DoE study. Conclusion: EPO-alginate microspheresdemonstrated the prospective as carrier and DoE is potential for further optimized formulations.