Nanogels obtained by electrostatic interactions; Formulation, characterization, and release studies.

Abstract

The nanomedicine sector has been booming since the development of nanovectors for encapsulating water-soluble or amphiphilic molecules for drug delivery. As the new therapeutic agents synthesized are increasingly lipophilic, the development of new nanoparticulate vectors for their transport and targeting is now a major challenge. Nanogels could be used in the pharmaceutical industry to protect active ingredients, to act as a reservoir for them, and to allow their controlled release thanks to their very high capacity for penetration. They can also increase the solubility and therapeutic index of PAs (reduced toxicity, increased efficacy).

In this study, we formulated mixed oil-in-water nanogels, a few tens of nanometers in diameter, stabilized by a surfactant layer composed of castor oil and stealth agents.  We have developed a new method for formulating nanogels using a lipophilic polymer (poly (Maleic anhydride-alt-1-Octadecene) PMAO which is inserted into the oil phase of a previously formed nano-emulsion and hydrophilic polymer chitosan solubilized in the water phase.

The new formulation method is based on electrostatic interactions with a positively charged polymer in the aqueous phase and carboxylate groups on the surface of the nanogel droplets.

The characterization was done by dynamic light scattering, zetametry, and UV spectrophotometry.  No instability phenomena were observed in any of the selected preparations. Concerning the size and the polydispersity index of the nanogels, we have shown that they depend on the percentage of Chitosan. The zeta potential evolves with the amount of Chitosan. The release of encapsulated Ketoprofen is compatible with the release of molecules at very low concentrations (like hormones). Indeed, we note that only 6% of releases after 210min.

Our study shows the possibility of formulating mixed nanogels with lipids and biocompatible and biodegradable polymers for use in therapeutics.