Stimuli-responsive nanohydrogel as Fascinating Platform in Drug Delivery

Aim and Background: Hydrogels with 3D structure has emerged as promising nano- formulation in pharmaceutics especially in the field of drug delivery. Hydrogels have significant physicochemical properties, such as high water content capacity, permeability, porosity, physical interactions and some smart ones are capable to make response to environmental stimuli like temperature, pH and ionic strength. Sensitivity to temperature and pH are important factors in designing nanohydrogels for drug delivery platforms. Two polymeric matrixes made of poly vinyl caprolactam (PVCL) and poly (N-isopropyl acryamide) (PNIPAAm) are among the most extensively thermoresponsive studied structures. Nanohydrogels made of aforementioned structures has a continuous coil-to-globule phase transition behavior with the lower critical solution temperature (LCST) ranging from 32 to 50°C, which depends on polymeric diversity and molecular weight. pH responsivity could be dictated to system by implementing pH responsive polymeric segments, and pH responsive linkages. Doxorubicin and cisplatin are two highly applied anticancer agents with sever adverse effects. Designing drug delivery systems for these anticancer drugs are considered as noteworthy research topic. Methods: Nanohydrogels made of PVCL and PNIPAAm are made by reversible-addition fragmentation addition polymerization technique. Polyethyleneglycol diacrylate was used as cross-linking agent. The anticancer drug doxorubicin linked to the structure by Schiff-base linkage. In the case of cisplatin administration, the pH responsive linkage was constructed by coordination chemistry. Results and discussion: According to the results, well-structure defined smart pH and temperature responsive nano-hydrogel was prepared. The enhanced release rates are observed at acidic pH and elevated temperature. We have concluded that the doxorubicin or cisplatin conjugated nanoparticle results in higher cellular uptakes and more cytotoxicity. Conclusion: Smart nanohydrogels conjugated with anticancer drug have potential to be considered as efficient and biosafe therapeutic agents.