Urea-formaldehyde nanocapsules for the controlled release of diclofenac sodium

Urea-formaldehyde (UF), polymerized in situ in aqueous media, is a rigid po lymer that can be used in the controlled release of bioactive molecules. Du ring the process of polymerization, liquid neem seed oil (NSO) was encapsul ated at three different loadings, which was then replaced by diclofenac sod ium (DS), the presence of which was confirmed by FTIR spectra. The nanocaps ules thus prepared were evaluated for percentage loading of the drug, parti cle size and release characteristics. Thermal analysis and x-ray data were obtained to understand the physical nature of the encapsulated drug. The su rface characteristics of the nanocapsules were studied using a scanning ele ctron microscope. Particles in the size range around 500 nm were obtained. The percentage loading efficiency of NSO was similar to 90-95, whereas for DS, the loading efficiency was only 50-60%. Complete release of the drug fr om the matrices occurred in 24 h, whereas, at 8 h only 60% of the drug was released.