Alginic Aldehyde-Gelatin Nanogel as Sustainable Drug Delivery System of Azithromycin: Development, Characterization and In Vitro Evaluation

The present study deals with the encapsulation of Azithromycin in alginic aldehyde and gelatin nanogel as an intestinal sitespecific and controlled therapeutic delivery system against gram-negative intracellular Salmonella Typhi, which is synthesized through inverse miniemulsion technique in three different drug to polymer ratios, and exploration the physicochemical properties and antibacterial activity of the system. The characterizations of the azithromycin-loaded nanogel were done by DLS and FT-IR. The hydrodynamic diameter of the azithromycin-loaded nanogel is 118±4 nm with negative zeta potential (-34.2±1.5 mV). We observed absolute transition from the crystalline form of the azithromycin to amorphous state while was loaded to the AA-Gel nanogel by FT-IR, and the FT-IR measurements demonstrate that there are not any detectable chemical and intramolecular interactions between AZM and nanogel network. The encapsulation efficiency of the loaded nanogels were influenced by the ratio of drug to polymer, which the highest value (86.3±2.3%) was demonstrated for the 1:3 formulation. In vitro azithromycin release profile from AA-Gel nanogels presents an initial burst release over a period of 4 hours that is followed by controlled release until the 24 hours. Nanogels showed significant bacteriostatic activities in comparison to free azithromycin. Our results indicate proper physicochemical, in vitro and ex vivo features of the azithromycin nanogel, which can be a worthy candidate for oral administration against Salmonella Typhi.