Fabrication of N-acetyl-l-cysteine and l-cysteine functionalized chitosan-casein nanohydrogels for entrapment of hydrophilic and hydrophobic bioactive compounds

Abstract

In this work, we present self-assembly nanohydrogels (NGs) systems for controlled and sustained release of hydrophilic as well as hydrophobic bioactive compounds. Specifically, N-acetyl-l-cysteine (NAC) and l-cysteine (CYS) functionalized chitosan (CS) and NaOH modified casein (CA) were synthesized by layer-by-layer electrostatic interaction to enhance the bioavailability of egg white derived peptides (EWDP) and curcumin. The NAC–CS–CA NGs and CYS-CS-CA NGs exhibited pH-sensitive properties with the smallest particle size of 89 and 86 nm by dynamic light scattering, respectively. The NGs showed excellent storage stability for 21 days in room temperature. The entrapment efficiency (EE) of EWDP and curcumin ranges from 39 to 67% and 51–63% in NAC–CS–CA NGs, 45–58% and 48–63% in CYS-CS-CA NGs at different pH values. The NGs had been characterized by Fourier transform infrared (FTIR) spectroscopy to investigate chemical interactions as well as to evaluate the entrapment mechanism of the drug-loaded formulations. The in vitro release kinetics of EWDP and curcumin showed prolong drug release up to 56 h and 80 h from the NGs, respectively. Moreover, the NGs inhibited the burst release of EWDP and curcumin at gastric media and enhanced the sustained release at intestinal media. The current study exhibited the promising novel method for designing delivery systems for commercial production of encapsulated bioactive compounds with improved functional attributes.