BIOCOMPOSITES AND/OR GRAFT COPOLYMERS FOR DRUG DELIVERY AND COSMETICS. In: CURRENT AND FUTURE CHALLENGES IN ADVANCED MATERIALS, SUSTAINABILITY, HEALTH AND NANOMEDICINE

"Smart" and "stimuli" responsive materials can be widely used in controlled-release systems. Some of these materials final properties, e.g. water affinity, may be change, in response to an external stimulus such as temperature or pH. Responsive polymers (i.e. films, capsules and hydrogels) have been widely investigated in nano/biotechnology and they can have potential applications in several fields, such as drug delivery, cosmetics and aerospace. [1,2]. Graft copolymerization might be among the best methods to obtain both synthetic and natural polymers, preserving the properties of biodegradability and bioactivity characteristic to develop "smart" or "stimuli" responsive biopolymers. By changing the molar ratio of used polymers and/or their copolymerization conditions, it is possible to study the structure-property correlation potentially tailoring the final performances of the developed advanced materials. [3,4]. Preliminary activity was carried out to synthesize pH-sensitive cross-linked composites by direct reaction of chitosan (CS) and D, L-lactic acid (LA) to achieve graft-copolymers with hydrophobic synthetic side chains and hydrophilic natural main chains. The CS/LA copolymers were chemical-physically characterized and loaded with non-steroidal anti-inflammatory drugs (NSAIDs) solutions to study the kinetic release in simulated intestinal fluid (SIF) at pH 6.8 and 37°C. Graft copolymers, which form pH-sensitive hydrogels in aqueous solution, are of general interest for biomedical applications, such as artificial muscles or switches, in biochemical separation and in controlled-release systems.