Plamen Katsarov

Indomethacin-loaded nanoparticles (IMC-NPs) were obtained by emulsifier-free radical polymerization of vinyl acetate (VAc) in the presence of indomethacin (IMC) in the aqueous solution of Carbopol® (Cbp) or chitozan (CH). The purpose of this study was to investigate the influence of nature and quantity of the added to the reaction system polymer on IMC loading and its kinetic release properties in terms of the future development of topical ophthalmic formulations. CH was chosen as a cationic polysaccharide and Cbp as an anionic crosslinked polymer. TEM and DLS were used to observe the morphology and to determine the average particle size which was in the range of 178.20÷297.90 nm and the polydispersity index (PDI) which was within 0.149÷0.339. A monomodal particle size distribution (PSD) was observed for the CH-coated NPs and bimodal PSD was observed in the models, obtained in the presence of Cbp. FTIR analysis showed that the models were a result of interactions with hydrogen bonds. UV-spectroscopy was used for the determination of IMC inclusion and in vitro release characteristics. The results of release kinetic analyses showed that IMC was released from the investigated models following the first order. The polymer shell (Cbp or CH) around the pVAc–core had an impact on the rate and degree of the released drug.