The aim of this study was to develop a thermal crosslinkable microneedle (MN) array. Gantrez S-97 was employed as the MN-forming polymer. The MNs were successfully fabricated by micromolding method. The MNs were thermally crosslinked at different times (0.5, 1, 2, 3 h) and temperatures (110, 130, 150°C). The morphology of the MN was observed using a digital microscope. The successful crosslink was confirmed by Fourier transform infrared spectroscopy. The percentages of swelling and MN remaining after being soaked in water were also investigated. Fully formed, sharped MN with desirable morphology was obtained at the Gantrez S-97 concentration of 30 %w/v. The FT-IR spectra confirmed the successful crosslink of the MN. The crosslinked Gantrez MN arrays could absorb massive amount of water, and exhibited excellent swelling capability. Increasing the crosslinking time and temperature resulted in the decrease in the swelling capability but increase in the water insolubilization. The MNs crosslinked at 150°C for 3 h demonstrated almost hundred percent of water insolubilization which desirable for developing hydrogel-forming MN. Therefore, 30% w/v Gantrez S-97 MN could be crosslinked by thermal process, and could provide desirable swelling properties and percentage of water insolubility, and therefore, may be an alternative for fabrication of hydrogel-forming MN for transdermal drug delivery.
Optimizing microneedle arrays for transdermal drug delivery: Extension to non-square distribution of microneedles