Advances in Hydrogel-Based Drug Delivery Systems

Abstract

Hydrogels, with their distinctive three-dimensional networks of hydrophilic polymers, drive innovations across various biomedical applications. The ability of hydrogels to absorb and retain significant volumes of water, coupled with their structural integrity and responsiveness to environmental stimuli, renders them ideal for drug delivery, tissue engineering, and wound healing. This review delves into the classification of hydrogels based on cross-linking methods, providing insights into their synthesis, properties, and applications. We further discuss the recent advancements in hydrogel-based drug delivery systems, including oral, injectable, topical, and ocular approaches, highlighting their significance in enhancing therapeutic outcomes. Additionally, we address the challenges faced in the clinical translation of hydrogels and propose future directions for leveraging their potential in personalized medicine and regenerative healthcare solutions.

Keywords: drug delivery; hydrogel; injectable; ocular; oral; topical.

Figure 1

Illustration of hydrogel classification based on cross-linking methods and their biomedical applications.

Figure 2

Classification of hydrogels based on the cross-linking formation mechanisms.

Figure 3

Schematic of SHSe microbead delivery: Upon reaching the intestine, they release HA-Se to target colon inflammation, modulating immune responses and optimizing gut microbiota by altering cytokines, immune cells, and bacterial communities. Adapted with permission from [131]. Copyright © 2023, American Chemical Society.

Figure 4

Scheme of the hydrogel-based delivery system described by Hu et al. [146]. (A) Synthesis of OHA/HA-ADH-gels, highlighting their chemical versatility and ability to encapsulate SeNPs. (B) Osteoarthritis is characterized by selenium deficiency, oxidative stress, cartilage damage, and increased inflammatory cytokines. (C) The gels serve as an intra-articular platform for sustained SeNPs delivery to the inflamed joint. (D) They mitigate cartilage degeneration by restoring redox balance and inhibiting apoptosis via GPX1 activation. Copyright © 2023, Elsevier Ltd.

Figure 5

Scheme of the hydrogel-based delivery system described by Chen et al. [159]. Copyright © 2024, Springer Nature.