One-Pot Synthesis of Poly(glycerol- co-succinic acid) Nanogels for Dermal Delivery.

Polyglycerol nanogels are three-dimensional polymeric networks with a few hundred nanometer sizes and the ability to encapsulate and deliver cargos for a wide range of biomedical applications. However, time-consuming and multistep synthetic routes as well as milligram-scale production have hindered further development of these nanomaterials. In this work, we report on a straightforward synthetic method for the production of polyglycerol nanoarchitectures. Enzymatic ring-opening copolymerization of a mixture of glycidol and succinic anhydride resulted in polyglycerol nanogels with succinic acid segments in their backbone. Novozyme 435 was used as a dual catalytic agent to support ring-opening polymerization of the above-mentioned cyclic monomers as well as esterification of the produced oligomers to obtain nanogels. While succinic acid segments improved the biodegradability and loading capacity of nanogels, polyglycerol caused water solubility, high functionality, and biocompatibility. Nanogels were loaded with tacrolimus and photosensitizer 5,10,15,20-tetrakis(3-hydroxyphenyl)porphyrin (mTHPP)-a close congener of the approved photosensitizer temoporfin (mTHPC)-and their ability to improve the skin penetration of these therapeutic agents was investigated. mTHPP delivery experiments on human skin, which were quantified by fluorescence microscopy, showed that these nanogels deposit in the stratum corneum and release the loaded drug to viable epidermis of skin efficiently in comparison with commercially available base cream. Taking advantage of the straightforward synthesis as well as biodegradability, biocompatibility, high loading capacity, and efficient skin penetration, the synthesized nanogels could be used as future topical delivery systems.