Flow rate effect on partially modified potato starch microspheres formation process

Natural biopolymers are the most likely choice for biomedical applications, and starches can be considered the best materials for such applications. This comes from the fact of their natural origin and their high biodegradable behavior. Native starches have weak hydrogen bonding and a leaching behavior – making it a candidate for drug delivery application. Still, to make starch useful as a drug delivery carrier, this hydrogen bonding must be strengthened. In this work, native sweet potato starch was used, and the hydrogen bonding between starch molecules was enhanced by introducing glycerol as a hydrogen bonding source and sodium alginate (SA) as a thickener. This blend was tested by means of FTIR and DSC, and based on the test results, improved hydrogen bonding had taken place. Furthermore, potato starch microspheres were successfully produced at different flow rates. In the work, a microfluidic capillary device was harnessed to form microsphere generating total flow rates ranging between (0.00031 and 0.00054) cm³/sec. Herein, a starch/sodium alginate/glycerol mixture was used as a dispersed phase and PVA+tween 80 was used as continuous phase. At high flow rates (0.00062-0.00054) cm³/sec, the microspheres took an oval shape. At flow rates (0.00034-0.00048) cm³/sec, the microspheres took a spherical shape. At very low flow rate (0.00031) cm³/sec, the microspheres shell was weak and caused core oozing. In this work, starch microspheres were successfully formed with diameter ranging from (151-263) µm.