Release Characteristics and Kinetics of Artemisinin Micron- and Submicron-Sized Granules for Sustained Algae Inhibition Under Different Media Conditions

This study describes two kinds of artemisinin sustained-release granules (ASGs), in which the particle size of the improved ASGs prepared by ionic cross-linking method combined with micro/nanotechnology was 1189.5 nm, and the encapsulation efficiency was as high as 52.4%. Moreover, both granules had a good inhibitory effect on Microcystis aeruginosa , with no algae growth within 30 days after adding 10 g L -1 of ASGs, and the same effect was achieved by adding 0.2 g L -1 of the improved ASGs. Both granules progressively released the loading dose (artemisinin) after a thorough research using varied temperature, ionic strength, and pH in the release medium, demonstrating a controlled release behavior by the chitosan/sodium alginate shell. For 30 days, ASGs (10g L -1 ) released about 75.33 percent artemisinin, but the improved ASGs in Lake Taihu water released 71.85 percent artemisinin continuously with no drug burst effect. The non-Fickian diffusion of ASGs was seen in the investigation on drug release mechanism, and the matrix corrosion of improved ASGs was better characterized by the Korsemeyer-Peppas model. As a result, the improved ASGs have a lot of potential as a sustained-release algae inhibitor with a continuous algae inhibition.