Transdermal Delivery of Catechin Using Dissolving Poly(vinyl alcohol)-Based Microneedles: Effect of Microneedle Composition on Drug Release

The use of dissolving microneedles presents a highly desirable approach for transdermal drug delivery, offering enhanced patient safety and adherence. This study aimed to assess the release rate of catechin when combined with various constituents in a poly(vinyl alcohol) (PVA) microneedle patch. The impact of incorporating 2% dimethyl sulfoxide (DMSO), 5% carboxymethyl cellulose (CMC), 5% fructose, and 5% sucrose into the PVA microneedle patch was investigated. The manufactured microneedles underwent comprehensive characterization through techniques such as thermogravimetric analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, measurement of thickness, evaluation of antioxidant activity, determination of swelling ratio, assessment of content uniformity, investigation of dissolving capability in skin, analysis of erosion, and release studies. An ex vivo investigation was conducted by using porcine skin and Franz diffusion cells to determine the release rate. The CMC-based microneedle patch displayed the highest catechin release (86.62 ± 4.69%) and swelling ratio (283.85 ± 3.21%). The analyses revealed that sugar enhances the microneedle structure effectively, although it renders the structure brittle and results in lower drug release compared with sugar-free microneedles. Consequently, the CMC-based formulation emerged as the optimal choice for the PVA microneedle patch.