Investigation of the effect of Graphene oxide concentration on the final properties of Aspirin loaded PLA filaments for drug delivery systems

It is well established that Polylactic acid (PLA) based biodegradable implants have several advantages over nonbiodegradable implants. PLA based implants can be used for controlled drug release as well as for mechanical functions and they break down in vivo into nontoxic by-products that are naturally eliminated from the body. Unlike permanent implants, no additional surgical procedure is required for their removal. Despite the benefits, currently PLA based implants are used in limited applications compared to e.g., titanium-based implants. The issues associated with PLA based implants are their lower tensile strength, poor hydrophobicity, and poor bioactivity. Graphene oxide (GO) which is a 2D material, possess several unique features which can potentially be used to overcome these issues. Due to its high surface area, GO can enhance the mechanical properties of PLA. Furthermore, GO is rich with oxygen containing functional groups, so when used as a drug carrier it can enhance the biocompatibility of the drug, as well as the bioavailability and dissolution rate. One of the challenges associated with current drug delivery systems is limitations in the achievable drug loadings. The lamella structure of GO can facilitate higher loading of drug and can be used in applications where high loadings are essential e.g., cancer treatment. This work aims to investigate whether different loadings of GO can enhance the mechanical properties of a PLA-drug matrix along with investigating the effect of GO loadings on the drug dissolution rate. In this work, Aspirin was used as a model drug with PLA, and GO was used in three different loadings (0.25 wt.%, 0.5 wt.% and 1 wt.%). PLA-Aspirin and GO were processed using hot melt extrusion process. After processing, the effect of GO loadings on the mechanical properties, and drug release profile was studied. Scanning electron microscope (SEM) testing of the samples was carried out to investigate the dispersion of drug for different loadings of GO. GO tends to agglomerate into larger particles and this affects the mechanical properties and dissolution rate.