FORMATION AND CHARACTERIZATION OF POLYMER-DISSOLVING MICRONEEDLES FOR THE TRANSDERMAL DELIVERY SYSTEMS

Dissolving polymer microneedles based on hydroxypropyl methylcellulose (HPMC), sodium carboxymethylcellulose (Na-CMC), polyvinyl alcohol (PVA), and their binary hydrogel blends were fabricated using a micromolding technique and systematically characterized. The influence of polymer type, concentration, viscosity, and blending on microneedle formation, mechanical properties, and dissolution behavior was investigated. Successful microneedle formation was achieved using 4–5% HPMC, 4–5% Na-CMC, and 10% PVA hydrogels, while all binary polymer systems (HPMC/CMC, HPMC/PVA, and CMC/PVA) demonstrated improved mold filling, tip sharpness, and structural stability. FTIR analysis confirmed the presence of characteristic functional groups in HPMC, Na-CMC, and PVA and revealed pronounced intermolecular interactions in the polymer blends, primarily hydrogen bonding, dipole–dipole, and ion–dipole interactions, indicating enhanced molecular compatibility and structural integrity of the microneedle matrices. Mechanical testing showed that binary polymer systems exhibited improved mechanical properties compared with single-polymer microneedles. In particular, the HPMC/PVA blend demonstrated the highest tensile strength (98 MPa) and elongation at break (7%), indicating synergistic interactions between the polymers. The addition of glycerol as a plasticizer increased flexibility, with an optimal concentration of approximately 0.3 wt% providing a balanced combination of tensile strength and elongation. Dissolution studies performed using an agarose-based skin model demonstrated rapid hydration and progressive dissolution of HPMC/CMC microneedles, with near-complete dissolution occurring within 10 min after insertion. These findings indicate that HPMC, Na-CMC, and PVA hydrogels, particularly their binary blends, represent promising polymer matrices for the development of dissolving microneedle systems for transdermal drug delivery applications.