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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.

This study aimed to evaluate the optimal conditions for crosslinked of PAMA/PVA microneedle (MN) arrays. Poly (acrylic acid-co-maleic acid) (PAMA)/poly (vinyl alcohol) (PVA) MN arrays were fabricated for the first time using the micromolding technique. The PAMA/PVA MN arrays at the polymer ratio of 1:4 were sharp, homogenous and perfectly formed with an elegant appearance. The successfully crosslinking MN arrays were determined using FTIR and water insolubilization. The results showed that increasing the crosslinking temperature and time, the degree of crosslinking also improved, which results in a decline in water uptake. The optimal crosslinking condition for PAMA/PVA MN arrays was 130°C for 1 h. Moreover, the highest swelling was observed from crosslinked PAMA/PVA MN arrays at 90°C for 0.5 h. These studies suggest that the combination of PAMA and PVA for fabrication of MN arrays could have a great potential to develop both hydrogel and dissolving MN devices for transdermal drug delivery.

Clindamycin (CM) is the one of antibacterial drugs that can be used to treat acne vulgaris. The commercial products in form of solutions, creams, and gels cannot provide the exact amount of the drug and constant drug release. Transdermal patches present an attractive point for reducing this limitation and there is no commercial transdermal patch containing CM available in the market nowadays. The purposes of this study were to develop CM loaded transdermal patches for the treatment of acne and to investigate the physical properties and drug release profile of the CM from the transdermal patches. The transdermal patch was prepared using 10% HPMC. The types and concentrations of additives (glycerin, polyethylene glycol(PEG) or propylene glycol (PG)), were varied to improve the properties of the patches. The physical appearances including the translucent, color thickness and weight of the patches were recorded. The mechanical properties and skin adhesion of the patches were determined by a texture analyzer. The polymorphism of CM in the patches and the release profile of CM from the patches were investigated by X-ray diffraction and Franz diffusion cell, respectively. CM transdermal patches were translucent. The weight and thickness of the patches increased as the amount of additive increased. Glycerin and PG decreased the strength of the patches, while PEG increased the hardness. Adding CM to the patches increased the hardness and decreased the elasticity of the patches. The internal structure of CM loaded into the patches was an amorphous form. The CM patches exhibited some adhesion properties when contacted with the porcine skin. The release of CM from the patches was found to be 71-108% within 60 minutes. The patch prepared from 10% HPMC, 15% Glycerin, and 5% PG displayed the highest release rate. In conclusion, the CM loaded HPMC patches presented desirable properties, which could be used as a transdermal patch for the treatment of acne.

The objective of this study was to optimize fabrication variables that affected desirable properties of dressings. Boesenbergia rotunda extract incorporated PVA hydrogels for wound dressings were fabricated by freeze-thaw method. The fabrication variables including PVA concentration (15, 17.5 and 20 % w/w), freeze-thaw cycle (2, 3 and 4 cycles) and extract loading (30, 40 and 50 % w/w) were studied and optimized. Effects of variables on the hydrogel wound dressing properties were determined by using Box-Behnken design and response surface method. Hydrogel properties such as tensile strength, elongation at break, Young’s Modulus, water content, swelling and erosion were measured and used as the designed responses. From statistical data analysis (p , the polynomial quadratic equation which indicated the significant effects of fabrication variables on the hydrogel properties was generated. In conclusion, desirable B. rotunda extract loaded PVA hydrogel dressing was favorably designed. The optimized PVA concentration, freeze-thaw cycle and extract loading were 17.07 % w/w, 3.86 cycles and 50 % w/w, respectively.