A novel microencapsulation of neem (Azadirachta Indica A. Juss.) seed oil (NSO) in polyelectrolyte complex of κ‐carrageenan and chitosan

Microcapsules containing neem (Azadirachta Indica A. Juss.) seed oil (NSO) were prepared by encapsulation of natural liquid pesticide NSO in a polyelectrolyte complex of κ‐carrageenan and chitosan. The optimum ratio between carrageenan and chitosan to form a stable polyelectrolyte complex was found as 1 : 0.36. The microencapsulation method for NSO loading was also optimized. SEM study demonstrated that the surface of the microcapsules became more irregular as oil loading increased. The release rates of NSO were studied by varying the percentage of oil loading, concentration of cross‐linking agent, and polymer concentration. Fourier transform infrared spectroscopy (FTIR) study confirmed the complex formation between κ‐carrageenan and chitosan. Differential scanning calorimetry (DSC) and FTIR study indicated the absence of any significant interaction between polyelectrolyte complex of κ‐carrageenan ‐chitosan and NSO. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009