Development of Chitosan Hydrogel Containing PEG-PCL Micelles Loaded with Silibinin and Evaluation of its Anticancer Properties in B16 Melanoma Cells

Abstract

Introduction: Silibinin, a nontoxic flavonoid, has demonstrated anticancer, antioxidant, and liver protective effects. However, its effectiveness is limited due to its poor water solubility. Encapsulation of poorly water-soluble drugs in copolymeric micelles has successfully enhanced solubility and targeted delivery. Hydrogels, another drug delivery system with three-dimensional polymer networks, can improve drug half-life and patient compliance and decrease drug side effects. Aims: This study aimed to develop a hydrogel formulation dispersed with silibinin-loaded micelles to improve the biological half-life of silibinin and tumor-targeted delivery of this anticancer agent.Materials and Methods: Silibinin was encapsulated using PEG-PCL micelles via the co-solvent evaporation method. The resulting freeze-dried micelles were mixed with chitosan and added to DAS solution to form the hydrogel. The physicochemical properties of the micelles and hydrogels were examined. The cytotoxicity of the formulation on B16 melanoma cells was evaluated using MTT assay and live/dead staining.Results: The silibinin loading efficiency ratio was 85±5%, and all micellar formulation was less than 200 nm in size on average, with acceptable PDI. Hydrogels exhibited appropriate morphology and demonstrated satisfactory results in terms of gelation time, swelling, and degradation studies. The release profile indicated that nearly 98% of the drug was released into the environment after 72 hours. Biological tests, including MTT assay and live/dead staining, revealed that the free-drug hydrogel or micelle structure did not exhibit toxicity to B16 melanoma cells. However, drug-loaded micelles and hydrogels exhibited appropriate toxicity toward cancer cells.Conclusion: Based on this study, it is only feasible to incorporate a hydrophobic drug like Silibinin into a hydrogel with the aid of an amphiphilic structure such as nanoparticles. This formulation is considered suitable due to its high half-life and patient compliance, and it has the potential to produce positive outcomes in the clinic.