Biomaterial-Based Sustained-Release Drug Formulations for Localized Cancer Immunotherapy

Abstract

Cancer immunotherapy has revolutionized clinical cancer treatments by taking advantage of the immune system to selectively and effectively target and kill cancer cells. However, clinical cancer immunotherapy treatments often have limited efficacy and/or present severe adverse effects associated primarily with their systemic administration. Localized immunotherapy has emerged to overcome these limitations by directly targeting accessible tumors via local administration, reducing potential systemic drug distribution that hampers drug efficacy and safety. Sustained-release formulations can prolong drug activity at target sites, which maximizes the benefits of localized immunotherapy to increase the therapeutic window using smaller dosages than those used for systemic injection, avoiding complications of frequent dosing. The performance of sustained-release formulations for localized cancer immunotherapy has been validated preclinically using various implantable and injectable scaffold platforms. This review introduces the sustained-release formulations developed for localized cancer immunotherapy and highlights their biomaterial-based platforms for representative classes, including inorganic scaffolds, natural hydrogels, synthetic hydrogels, and microneedle patches. The design rationale and other considerations are summarized for further development of biomaterials for the construction of optimal sustained-release formulations.

Clinical Applicable Carboxymethyl Chitosan with Gel-Forming and Stabilizing Properties Based on Terminal Sterilization Methods of Electron Beam Irradiation

“…Hydrogels, which can be categorized into natural and synthetic hydrogels, have gained a great deal of attention in the field of tissue engineering, , wound dressings, implants, and other medical materials because of their good biocompatibility and unique three-dimensional cross-linked network structure . Compared with synthetic hydrogels, natural hydrogels are composed of chitosan, sodium alginate, hyaluronic acid, cellulose, and other natural polysaccharides that have the advantages of high stability, nontoxicity, good biocompatibility, and biodegradability . Among them, chitosan is the only alkaline polysaccharide with an amino group on its monomer in nature, which has excellent biocompatibility and biodegradability, making it widely researched in the biomedical field. , While chitosan is only soluble in moderately acidic environments due to the protonation of amino groups at pH < 6.5, it thus limits many of its potential applications .…”

“… 6 Compared with synthetic hydrogels, natural hydrogels are composed of chitosan, 7 sodium alginate, 8 hyaluronic acid, 9 cellulose, 10 and other natural polysaccharides that have the advantages of high stability, nontoxicity, good biocompatibility, and biodegradability. 11 Among them, chitosan is the only alkaline polysaccharide with an amino group on its monomer in nature, which has excellent biocompatibility and biodegradability, making it widely researched in the biomedical field. 12 , 13 While chitosan is only soluble in moderately acidic environments due to the protonation of amino groups at pH < 6.5, it thus limits many of its potential applications.…”