Drug Delivery from Stimuli-Responsive Poly(N-isopropylacrylamide-co-N-isopropylmethacrylamide)/Chitosan Core/Shell Nanohydrogels

Andrés Ortega-García; Bryan Giovanny Martínez-Bernal; Israel Ceja; Eduardo Mendizábal; Jorge Emilio Puig-Arévalo; Lourdes Adriana Pérez-Carrillo

doi:10.3390/polym14030522

Drug Delivery from Stimuli-Responsive Poly(N-isopropylacrylamide-co-N-isopropylmethacrylamide)/Chitosan Core/Shell Nanohydrogels

Polymers (Basel). 2022 Jan 27;14(3):522. doi: 10.3390/polym14030522.

Authors

Andrés Ortega-García¹, Bryan Giovanny Martínez-Bernal¹, Israel Ceja², Eduardo Mendizábal³, Jorge Emilio Puig-Arévalo¹, Lourdes Adriana Pérez-Carrillo¹

Affiliations

¹ Chemical Engineering Department, University Center of Exact Sciences and Engineering (CUCEI), University of Guadalajara (UdG), Guadalajara 44100, Jalisco, Mexico.
² Physics Department, University Center of Exact Sciences and Engineering (CUCEI), University of Guadalajara, Guadalajara (UdG), Guadalajara 44100, Jalisco, Mexico.
³ Chemistry Department, University Center of Exact Sciences and Engineering (CUCEI), University of Guadalajara (UdG), Guadalajara 44100, Jalisco, Mexico.

Abstract

The synthesis of stimulus-responsive poly(N-isopropylacrylamide-co-N-isopropylmethacrylamide)/chitosan core/shell nanohydrogels made by batch emulsion polymerization in the presence of chitosan (CS) micelles is reported. The ratio of monomers required to obtain copolymers with a volume phase transition temperature (T_VPT) in the range of the temperatures observed in the human body in response to an infection (38 to 40 °C) was estimated with the Fox equation. The conversion was determined by gravimetry; mean particle size, size distribution, and thermal response were measured by quasi-elastic light scattering (QLS). The core/shell structure was confirmed by TEM, and FTIR showed the presence of N-isopropyl acrilamide (NIPA), N-isopropyl methacrylamide (NIPMA), and CS in the nanohydrogels. The nanohydrogels were loaded with the drug doxycycline hyclate, and their release kinetic profile was determined at pH = 2.0 and 7.4 at their volume phase transition temperatures (T_VPT). A higher amount of drug was released at acidic pH. Some mathematical models described in the literature were used to fit the experimental drug release data.

Keywords: core-shell polymers; drug delivery; nanohydrogels; stimuli-responsive polymers.