Stimuli responsive emulsion-based micro/nanospheres for the delivery of lipophilic therapeutics

INTRODUCTION: Hydrogel micro/nanospheres are of great interest in the field of drug and gene delivery. They can be applied to overcome the limitations of traditional drug administration in terms of therapeutic efficiency and patient compliance. In this work, advanced multi-responsive hydrogel micro and nano-spheres were developed using an emulsion prepared with sodium alginate and N-isopropyl-acrylamide (NIPAM) at different concentrations of stable ozonides (Ozoile) produced in a patented process. Ozoile acts as a biological inducer, regulating the main metabolic pathways and stimulating the endogenous defense system, and promotes tissue regeneration and damage-injury repair through the regulation of gene transcription [1]. EXPERIMENTAL: Ozoile was dispersed in the alginate solution forming an emulsion by high-intensity ultrasound (HIU) method. The micro/nano-spheres were prepared from an alginate-NIPAM-based emulsion with different concentrations of Ozoile (from 10 to 50 wt%). The emulsification process was optimized by varying the types and concentrations of surfactants and stabilizers. For the fabrication of the spheres, the extrusion-dripping technique followed by ion gelation crosslinking was used [2]. Next, the micro/nano spheres were optimized by a chitosan coating to improve the stability. The chemical composition, swelling behavior and microstructure of the spheres were evaluated using FTIR spectroscopy and optical microscopy. Differential scanning calorimetry (DSC) was used to investigate the thermo-responsive properties. Due to the response to specific internal or external triggers, these microspheres can increase the drug targeting efficacy, and at the same time, they can reduce the side effects/toxicities of payloads, which are the key factors for improving the patient compliance.