Preparation of Mesalamine Nanoparticles Using a Novel Polyurethane- Chitosan Graft Copolymer

Chitosan nanoparticle, a potential vehicle, is used as a hydrophilic carrier system since it can deliver drugs to specific sites and also control the drug release rate. Moreover, controlled release systems are designed to minimize systemic absorption and to achieve optimum delivery of the biologically active mesalamine to the distal small intestine and the colon.

The current study investigated the development of new nanoparticulate drug delivery systems based on polyurethane-chitosan copolymers. The copolymer shows good biodegradablity and biocompatiblity properties and thus can be considered as a potential carrier for drug delivery systems.

In this work, Polyurethane was obtained from the condensation reaction between polypropylene glycol (PPG) as prepolymerpolyol, 1, 4-butanediol (BD) as diol, dimethylol propionic acid (DMPA) as chain extender and also isophoronediisocyanate (IPDI). The synthesized polyurethane was grafted onto the prepared chitosan through a covalent binding and preparation of nanoparticles was done further through a coprecipitation process. The particle size of the prepared samples was evaluated with dynamic light scattering (DLS) technique.

The obtained particle size of the samples was 80±0.05 nm. Characterization of the synthesized chitosan-polyurethane copolymer was performed by FT-IR spectroscopy, 13CNMR and 11HNMR spectroscopy. The morphology of the synthesized polyurethane-chitosan copolymers and the amount of the loaded drug were also examined using SEM images and UV-visible spectroscopy, respectively. Moreover, drug release behavior was examined in PBS (pH 7.4) at 37°C. It was concluded that the mesalamine release from polyurethane-chitosan was sustained and no initial burst release (burst effect) was observed and the percentage of mesalamine released from nanoparticles was 92.19±0.2% within 72 hrs.

The results of the drug loaded nanoparticles showed that the drug loading process was performed successfully. As a result, polyurethane-chitosan copolymer can be a good candidate for drug delivery systems.