Characterization, In Vitro Evaluation and Stability Studies of Indomethacin-Loaded Polyzwitterionic Copolymer Nanoparticles

Abstract

The aim of the study was to investigate the influence of the nature and composition of the monomer feed, added to the reaction system indomethacin/vinyl acetate/3-dimethyl (methacryloyloxyethyl) aminopropyl sulfonate (IMC/VAc/DMAPS) and the characteristics of the obtained polymer latexes on indomethacin In-situ loading, its kinetic release properties, and drug stability. Indomethacin loaded nanoparticles were obtained by an emulsifier-free emulsion radical copolymerization of the monomers, in presence of the drug. Transmission electron microscopy, Attenuated Total Reflection Fourier Transform Infrared spectroscopic analyses, Particle size distribution and zeta potential analysis were carried out to characterize the In-situ loaded nanocarriers. High-performance liquid chromatography and UV/VIS spectroscopic analyses were applied to determine the drug loading, In vitro release properties and stability studies of the drug used. High yield of 90 to 96% was obtained for the tested In-situ loaded nanocarriers. They possess a spherical shape with diameter ranging from 100 to 900 nm and zeta potential from -3.25 mV to -20.3 mV. Mono-modal and bi-modal particle size distribution was observed depending on monomer feed, added to the reaction system. It also influenced the drug loading and its release characteristics. Indomethacin was released from the investigated patterns following first order release. The nature and composition of the monomer feed, added to the reaction system IMC/VAc/DMAPS are an effective factors for the control of the indomethacin loading and also affect the rate and extent of drug-releasing but do not influence the kinetic model and drug transport mechanism. Stability studies indicated the stabilizing role of the polymer carrier on the In-situ included indomethacin.