Schematic representation of casting and crosslinking of the super swelling hydrogel films (A), microneedle preparation (B), Texture Analyser set-up for investigation of physical properties of microneedles (C) and Franz cell set-up for <i>in vitro</i> transdermal drug release studies (D).

<p>Panel (<b>E</b>) shows a diagrammatic representation of the measurements recorded from the optical coherence tomographic images of microneedle penetration into excised neonatal porcine skin <i>in vitro</i>, namely; (a) the distance between the lower microneedle base plate and the <i>stratum corneum</i>, (b) the depth of microneedle penetration into the skin and (c) the width of the micropore created in the skin.