Emulsion-coaxial electrospinning: designing novel architectures for sustained release of highly soluble low molecular weight drugs

In drug therapy, most therapeutic drugs are of low molecular weight and could freely diffuse in the biological milieu depending on the administration route applied. The main reason for the development of polymeric drug carriers is to obtain desired effects such as sustained therapy, local and controlled release, prolonged activity and reduction of side effects. Alternatively, polymeric carriers can be made bioerodible in order to be eliminated by natural ways after a certain time of therapy. Core-shell fibres from coaxial spinneret or emulsion electrospinning are good candidates for the development of such devices; however difficulties remain especially in controlling the release over a sustained period. Here, we present a novel technique combining coaxial and emulsion electrospinning to produce micro-structured core-shell fibres. The design of drug microreservoirs of variable size within the bulk of the fibre combined with a tailored diffusive barrier allows modulating the release kinetics of these novel carriers. A nearly constant and linear release of the model drug Levetiracetam (M w ≈ 170 g mol -1) from PLGA emulsion-coaxial electrospun fibres is observed over 20 days. This device is aimed to be implanted into the brain for the treatment of epilepsy and is an example of the new capabilities and the promising potential that emulsion-coaxial electrospinning can provide towards the development of future drug carriers.