Optimization of Process Conditions for Preparing an Iron-polysaccharide Complex by Response Surface Methodology

The synthetic process of an iron-polysaccharide complex drug substance was improved to make it more suitable for industrial scale production. The complex was synthesized by reacting FeCl3 and syrup in basic solution followed by separation and purification by ethanol precipitation and low speed centrifugation. Process conditions were optimized using response surface methodology (RSM) based on the central composite design (CCD). A quadratic polynomial equation was developed, which indicated the effect of variables on the yield of the complex. The optimal conditions were 20 % Na2CO3 aqueous solution 51.7 g, concentration of FeCl3 · 6H2O w = 30.3 % , and the temperature of the ferric hydroxide synthesis 6.5 °C. Under these conditions, the experimental yield was 40.1 %, which was agreed closely with the predicted value (38.9 %). The results of scale-up experiments indicated that the optimized process conditions could also improve the yield at larger scales.