A new drug-loading technique with high efficaciency and sustained-releasing ability via the Pickering emulsion interfacial assembly of temperature/pH-sensitive nanogels

pNIPAM nanogels, which exhibited rich sol–gel transition behavior, have been used extensively in the biomedical fields such as drug delivery, blood vessel embolization and tissue-engineering Owing to their limitation of 3D networks, pNIPAM nanogels have low drug-loading amount and poor sustained releasing properties. In the present research, Pickering emulsion combined with solvent evaporation (PESE) is developed firstly as a new drug-loading technique of pNIPAM nanogels in our knowledge. The entrapment efficiency (EE%) reached nearly 100%, and DOX loading amount (DL%) could reach 15%. Owing to ionic bonding interaction of DOX molecules and sulfonamide groups, DOX loaded PNS nanogels by PESE (PNS-D nanogels) show a slow releasing behavior, only 13.2% for 48   h in pure water, without any burst release. As the ionic strength of media increased, the DOX-releasing amount from PNS-D-10 nanogels increased to 29.5%, 41.6% and 48.0% respectively in 0.9   wt%, 3.0   wt% and 5.0   wt% of NaCl solutions for 48   h. The loading DOX has significant effect on the rheologic behavior of nanogel dispersions. PESE technique is hopeful to be developed as a universal hydrophobic drug loading method of nanogels, and will be extensively applied in drug delivery and tissue engineering.