Composite Hydrogel-Embedded Sucrose Stearate Niosomes: Unique Curcumin Delivery System

Abstract

Cold-set egg white-bovine gelatin composite hydrogels were evaluated as potential delivery vehicles for the encapsulation and subsequent release of sucrose stearate-based niosomes loaded with curcumin. The effects of loading blank-niosome or curcumin-niosome and their content (6 and 12 mL) on physicochemical and rheological properties of composite protein hydrogels were analyzed. The results showed that hydrogel protein solutions positive charge with a high volume of niosomal suspension irrespective of its type resulted in higher hardness value and improved storage modulus (G '). Subsequently, the composite hydrogels hardness increased significantly from 1102.95 +/- 35.80 g in samples containing 6 mL curcumin-niosomes to 3273 +/- 120.34 g in 12 mL curcumin-niosome-loaded ones (p < 0.01). Fourier transform infrared (FTIR) spectroscopy suggested hydrophobic and hydrogen bonding between niosomes and proteins. Furthermore, characteristic peaks related to alpha-helix structure (1659 cm(-1)) did not change due to niosome loading, whether blank or curcumin-loaded ones, into protein hydrogels. The most appropriate mathematical model which best represented curcumin release for hydrogels with different levels of curcumin-niosome in simulated gastrointestinal conditions and food simulants was the Korsmeyer-Peppas model, showing the prevalence of super case-II transport mechanism. In addition, increasing curcumin-niosome in hydrogel formulation resulted in slower curcumin release without model parameter alteration. Electronic microscopy indicated a less porous structure for the composite hydrogels loaded with a higher amount of niosomes regardless of their types. These results suggest that niosomal composite protein hydrogel with compact structure and elastic behavior can overcome niosome limitations (aggregation, fusion, and drug leakage) and provides a controlled delivery system for curcumin.