Characterization of biodegradable semi‐interpenetrating polymer based on poly(vinyl alcohol) and sodium alginate containing natural neem (Azadirachta indica) for controlled release application

A biodegradable novel semi‐interpenetrating polymer network based on poly(vinyl alcohol) (PVA) and sodium alginate containing neem (Azadirachta indica) in the presence of azadirachtin‐A (neem Aza‐A) as well as glutaraldehyde as a crosslinking agent was prepared for use in the controlled released of neem Aza‐A. This is necessary because neem Aza‐A is not stable in the environment. The neem Aza‐A‐containing beads were prepared using various experimental parameters, such as the extent of crosslinking and the amount of loading, in order to optimize the process variables. The chemical structure of the capsule wall was evaluated through X‐ray diffraction. In addition, the swelling behaviour of the capsules and their thermal stability were investigated. The strength of the capsule wall depended on the PVA in the matrix and the crosslinking density. Scanning electron microscopy, electron probe microanalysis and atomic force microscopy data indicated that the structure of the bead walls is rough and nonporous. Swelling results indicated that swelling of the polymeric beads decreases with increasing exposure time to the crosslinking agent. At particular intervals, the remaining concentration of neem Aza‐A was analysed using high‐performance liquid chromatography. The release data were fitted to an empirical equation to estimate the kinetic parameters. The degree of release of neem Aza‐A was controlled by the parameter conditions. Copyright © 2010 Society of Chemical Industry