Polymeric nanoparticles for hydrophilic drug delivery prepared by a novel pH-dependent method

Different types of nanocarriers are extensively studied for the treatment and prevention of diseases. Polymeric nanoparticles (PN) can be used to encapsulate and deliver hydrophilic molecules and biomolecules. However, they have some limitations for this use, such as the need for aggressive organic solvents to solubilize the polymers and lipophilic components to form the nanostructure. This study developed for the first time in the literature nanoparticles of Eudragit® L30-D55 — containing babassu oil and without aggressive organic solvent — by a novel pH-dependent nanoprecipitation method to overcome some limitations of conventional PN. The nanoparticles without the drug (NP) and containing a model hydrophilic drug (diclofenac sodium - NPD) were physicochemically characterized by different techniques. Particles with a size distribution exclusively in the nanometric range and with low polydispersity over 60 days of analysis (NP size <144 nm and NPD size <190 nm) were obtained with acidic pH (∼2.5) and negative zeta potential. The pH dependence of the particles was demonstrated with the increase in particle size and separation of the polymer chains proportional to the increase in the pH of the medium. Preliminary data showed a possibility of process scale up to obtain PN using this novel methodology. A high association efficiency of 98 % of diclofenac sodium with the nanoparticles was maintained throughout the 60 days. The NPD showed a pH-dependent drug release profile. In acidic pH media, there was less drug release when compared to drug release at a pH near neutral. Therefore, an innovative polymeric nanoparticle of Eudragit® L30-D55 containing a model hydrophilic drug was successfully developed using a novel methodology. Future work aims to investigate the incorporation of biomolecules into these nanostructures.