Urea-formaldehyde nanocapsules for the controlled release of diclofenac sodium

Urea-formaldehyde (UF), polymerized in situ in aqueous media, is a rigid polymer that can be used in the controlled release of bioactive molecules. During the process of polymerization, liquid neem seed oil (NSO) was encapsulated at three different loadings, which was then replaced by diclofenac sodium (DS), the presence of which was confirmed by FTIR spectra. The nanocapsules thus prepared were evaluated for percentage loading of the drug, particle size and release characteristics. Thermal analysis and x-ray data were obtained to understand the physical nature of the encapsulated drug. The surface characteristics of the nanocapsules were studied using a scanning electron microscope. Particles in the size range around 500 nm were obtained. The percentage loading efficiency of NSO was approximately 90-95, whereas for DS, the loading efficiency was only 50-60%. Complete release of the drug from the matrices occurred in 24 h, whereas, at 8 h only 60% of the drug was released.