Nanostructured lipid carrier-based hydrogel formulations for drug delivery: a comprehensive review.

The scientific literature today provides several systems that can deliver active pharmaceutical ingredients (APIs) across the skin. These include reservoir matrices, matrix diffusion-controlled devices, multiple polymer devices and multilayer matrix assemblies. Among these, nanostructured lipid carriers (NLC) have emerged as novel systems composed of physiological lipid materials suitable for topical, dermal and transdermal administration. This review focuses on the design characteristics, production and composition of semi-solid formulations containing NLC as API carriers. One of the useful semi-solid systems are hydrogels, which can be used as vehicles to provide appropriate consistency for NLC formulations to be applied onto the skin. In the present review recent developments in the field are highlighted, including examples of APIs successfully entrapped within NLC now amenable for delivery via the skin. Further innovations in NLC composition and formulation, as well as in semi-solid hydrogel assemblies, are likely to expand the number of APIs available for topical, dermal and transdermal delivery.