A versatile method for evaluating the controlled-release performance of microcapsules

Sustained-release profile is an important component in the quality control of microcapsules. In the current study, we propose a reliable, convenient, and versatile strategy to assess the controlled-release performance of MCs under artificial, simulated conditions. Dissolution tests were performed using an experimental device equipped with syringe filters. The optimum experimental conditions utilized 80% v/v methanol (3 ml) as a release medium at each sampling point, Nylon 6 filters (13 mm diameter, 0.22 mu m pore size) as diffusion barriers, and a sampling regime based on predetermined changed intervals. Validation tests demonstrated that this strategy possessed favorable universality for three wall materials (polyurea, polyurethane and urea-formaldehyde) and three core materials (phoxim, pyraclostrobin and clomazone), as all sampling points had standard errors below 3.4%. Our proposed method also showed apparent advantages in experimental precision and the demand for a release medium compared with dynamic dialysis.