Hydrogels and nanogels: effectiveness in dermal applications

Abstract

Drug delivery systems (DDSs) are an important tool for obtaining medicines with improved physicochemical properties, especially for drugs with stability, absorption, and biodistribution impairments. Among the DDSs, we can highlight hydrogels and nanogels, which are easy to obtain, show good biocompatibility, and have several applications in the design of drug carriers for dermal and ocular administration. In this review, we introduce a brief concept on hydrogels, underlining compounds such as chitosan and alginate, and methods used for their preparation. Nanogels, with their attractive features, such as high drug encapsulation and penetration enhancer embedding, are also addressed. Finally, the application of these systems in dermal pathophysiological processes through the incorporation of drugs for enhancing skin permeation brings out promising prospects for innovation which may arise in the drug delivery field.

Keywords: cross-linking; drug delivery; formulation; nanogel; polymer.

Figure 1

Structure of hydrogels and nanogels of cross-linked polymers. Cross-linking is a technique for forming hydrogels, a process in which polymer chains are joined through covalent and noncovalent bonds, forming three-dimensional networks. The process allows polymers to be cross-linked intra- or intermolecularly by chemical bonds or physical interaction.

Figure 2

Nanogels as dermal drug delivery systems. Systems developed through the union between a polymer and a drug provide benefits by producing formulations that present increased encapsulation, increased delivery, and controlled drug release.