Abstract/Summary

Microneedles (MNs) are promising drug delivery systems which enable the delivery of drugs of various physicochemical properties into and across the skin by breaching the skin barrier. Dissolving MNs are a type of MNs which release the incorporated drug by dissolving or degrading in the skin upon contact with the skin’s interstitial fluid. Polymers are commonly used to fabricate dissolving MNs, but their mechanical properties limit efficient skin insertion. Therefore, there is a need to identify additional polymers which can create high quality MNs and potentially broaden the applicability of dissolving MNs. This thesis investigated the feasibility of fabricating dissolving MNs from poly(2-ethyl-oxazoline) (PEOZ) of two molecular weights (50 kDa and 200 kDa) and used polyvinylpyrrolidone (PVP) MNs as a benchmark to evaluate the suitability of PEOZ for fabricating MNs. Findings from the characterisation studies suggest that PEOZ 200 kDa is a promising MN material with comparable performance to PVP whereas sole use of PEOZ 50 kDa is not suitable for MN fabrication. PEOZ 50 kDa was then blended with poly(vinyl alcohol) (PVA) to assess for miscibility between the polymers in order to improve PEOZ 50 kDa MNs by polymer blending. Polymer miscibility was evaluated by using a combination of various analytical techniques, providing useful insights into polymer miscibility and the potential applications of PEOZ-PVA blends. This thesis also showcases an innovative approach to treating cutaneous leishmaniasis (CL) by loading paromomycin into dissolving MNs and tailoring the MN composition to the disease. Characterisation studies suggest that the use of paromomycin-containing dissolving MNs is a promising approach to treating CL. Suggestions of additional studies are also proposed to further explore this drug delivery system. Studies towards developing a sensitive assay for quantifying paromomycin in MNs are also described, providing useful insights into paromomycin quantification by liquid chromatography and mass spectrometry.