Polymer-based thermoresponsive hydrogels for controlled drug delivery

Abstract

Introduction: Controlled drug delivery through hydrogels is generally limited by the poor barrier that polymeric network can create to diffusion mechanism. Stimuli responsive polymers can help in this way guaranteeing that delivery can be sustained and finely controlled using an external stimulus. Area covered: This review provides an overview of recent studies about the use of temperature as an external stimulus able to work as an efficient new route of drug's administration. Thermoresponsive hydrogels are discussed and compared in terms of physical properties and mechanism of drug release considering their classification in intrinsical (formed by thermosensitive polymers) and non-intrinsical (polymers with thermosensitive moieties) hydrogels. Expert opinion: Thermoresponsive hydrogels can be developed by using different polymers added or not with micro/nanoparticles of organic or inorganic origin. In both cases, the final system represents an innovative way for the local and sustained drug delivery in a specific site of the body. In particular, it is possible to obtain an on-demand release of drug by applying a local increase of temperature to the system.

Advancements in hydrogel-based drug delivery systems for the treatment of inflammatory bowel disease: a review

“…213 For instance, temperature-sensitive hydrogels may release drugs in response to external temperature changes or fever unrelated to inflammation, while light-sensitive hydrogels may release drugs in response to ambient light or accidental irradiation. [214][215][216]…”

Last Advances on Hydrogel Nanoparticles Composites in Medicine: An Overview with Focus on Gold Nanoparticles

“…Hydrogels are defined as hydrophilic networks characterized by the presence of a high amount of aqueous solution, which makes them a suitable environment to mimic biological fluids (e. g., extracellular matrix, ECM). [19] By selecting the polymeric materials, the crosslinking mechanism and density, as well as the final formulation, it is possible to finely tune the hydrogel features, obtaining a wide range of different behaviors tailored to specific applications. Hydrogel classification has been carried out according to different properties.…”

Recent advances on thermosensitive hydrogels-mediated precision therapy

“…Subsequently, as the ambient temperature goes up to the lower critical solution temperature (LCST) or higher, the hydrogen bonds break, and the micelles start to pack together tightly, which entraps water inside and causes sol-gel phase conversion. Therefore, the mechanisms of the gelation behavior of thermo-responsive hydrogel are the result of micellization, solution temperature, and micelle aggregation of thermos-gelling polymers [64] , [65] , [66] . The packing mechanism between different types of thermosensitive polymer micelles was approximately the same except for a slight difference.…”