Microencapsulation of water‐soluble herbicide by interfacial reaction. II. Release properties of microcapsules

Chitosan microcapsules containing the water‐soluble herbicide 3‐hydroxy‐5‐methylisoxazole were fabricated at different fabrication conditions by a new microencapsulation process established in the previous work. Selecting chitosan as a capsule wall could be justified because chitosan not only has a biodegradable characteristic but also enhances the fertility of soil after degradation in the ground. The microcapsules prepared at an agitation speed of higher than 12,000 rpm were smaller than 5 μm in diameter, and the release of the active material from the capsules into pure water was sustained for 80–160 h, depending on the agitation speed used in microencapsulation. The effects of fabrication variables were discussed on the capsule size and release properties of the fabricated microcapsules.