# Hydrogels—Advanced Polymer Platforms for Drug Delivery

## TL;DR

This paper reviews hydrogels as smart drug delivery systems that can release medicines in a controlled way based on body conditions.

## Contribution

The paper provides an integrated analysis of hydrogels for drug delivery, emphasizing their stimuli-responsive properties and integration with advanced technologies.

## Key findings

- Hydrogels can be tailored for controlled and targeted drug release through natural, synthetic, and hybrid polymers.
- Functionalization allows hydrogels to respond to physiological stimuli like pH, temperature, and enzymes.
- Integration with biosensors and wireless systems enables real-time drug delivery monitoring and control.

## Abstract

Optimizing drug administration remains a central challenge in the development of modern therapies, especially in the context of conditions that require spatiotemporal control of active substance release. In this context, hydrogels have been intensively investigated as polymeric platforms for drug delivery, through their three-dimensional hydrophilic structure, tunable properties, and compatibility with biological environments. This analysis presents an integrated approach to hydrogels used in drug administration, addressing the physicochemical fundamentals, the constitutive polymeric materials, and the mechanisms of response to relevant physiological stimuli. Recent experimental studies have been discussed, which highlight the use of hydrogels based on natural, synthetic, and hybrid polymers for controlled and targeted release, in correlation with various administration routes, including oral, injectable, transmucosal, and topical ones. Advanced functionalization strategies that allow adaptive responses to pH, temperature, glucose, enzymes, and reactive oxygen species are also analyzed. Furthermore, emerging directions integrating hydrogels with biosensors, microdevices, and wireless communication systems for real-time monitoring and on-demand release are highlighted. Overall, the analysis emphasizes the role of smart hydrogels as multifunctional platforms for complex therapeutic strategies while also underlining the current challenges associated with clinical translation and long-term performance.