Preparation and Properties of Sodium Carboxymethyl Cellulose Microspheres by Dropping Method

Sodium carboxymethyl cellulose (CMC) is the most extensively utilized derivative of cellulose. In this study, an innovative approach was employed to disperse a CMC aqueous solution into olive oil in the form of liquid droplets, resulting in the direct formation of CMC microspheres after drying. The effects of CMC concentration and needle aperture size on microsphere formation were systematically investigated, showing that the particle size of the microspheres decreased with an increase in CMC concentration and a decrease in needle aperture. The CMC-based microspheres exhibited a consistently uniform spheroid morphology with particle sizes ranging from 1.5 to 2.5 mm, and a three-dimensional uniform polymeric network structure. Furthermore, the drug loading efficiency of the CMC-based olive oil microspheres reached 82.18%, which was markedly superior to that of other cellulose-based microspheres for fat-soluble substances. The CMC-based vitamin C (VC) microspheres exhibited an ultimate drug loading efficiency of approximately 24%, and their maximum encapsulation efficiency was 78.57% at a VC concentration of 30%, which was significantly higher than that of starch-based VC microspheres. Additionally, the CMC-based VC microspheres realized a sustained and stable release rate in ethanol at 30 °C.