Novel class of nanofiber hydrogels based on the biodegradable amphiphilic copolymers poly(sarcosine) and poly(l-lactic acid) and prepared using alcohols

Abstract

Route of preparation can be an important step in producing safe and effective controlled-release drug vehicles. We now describe a novel class of hydrogels based on biodegradable amphiphilic polymers consisting of hydrophobic poly(l-lactic acid) and hydrophilic poly(sarcosine). The hydrogels were prepared by initially dissolving the polymers in methanol, ethanol, and butanol, which are also amphiphilic. Transmission electron microscopy revealed that the hydrogels consist of self-assembled nanofibers, with a dynamic modulus greater than the loss elastic modulus over a range of stress cycles at different frequencies. Differential scanning calorimetry indicated that the hydrogels contain stable poly(l-lactic acid) crystals. Importantly, the hydrogels did not elicit irritation in a 3D model of the human corneal epithelia, and suppressed, by more than 20%, the initial drug burst typically associated with controlled-release vehicles already on the market. Hence, the hydrogels show promise as a new class of controlled-release drug delivery systems.