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The optimal design of novel microneedles (MNs) for the ocular delivery system is necessary and useful for improving the effectiveness of medication. The objective of this study was to design and develop the optimal fluconazole (FLUZ)-microemulsions (MEs)-loaded two-layered dissolving MNs as a potential treatment for fungal eye infection. The experimental designs using the simplex-lattice design were used to select the optimal formulation. The two-layered dissolving MNs were fabricated from 3% chitosan and 20% polyvinyl alcohol (PVA) in a weight ratio of 1:4 as an outer layer and FLUZ-loaded MEs containing eugenol, tween 80, PEG400, and water as an inner layer. The physical appearance, mechanical properties, penetration ability, dissolution time, in vitro/ex vivo ocular drug delivery, and antifungal activity were evaluated. From the results, the optimal two-layered dissolving MNs exhibited good physical properties, complete insertion, minimally invasive ocular tissue, and high stability at 4 °C and 25 °C for 3 months. Moreover, the optimal two-layered dissolving MNs showed significantly higher FLUZ permeation into the ocular tissue than other formulations, while providing highly potential antifungal activity. In conclusion, the optimal MEs-loaded two-layered MNs’ formulation had appropriate properties for ocular delivery of FLUZ, resulting in an improvement of fungal keratitis treatment.

Progesterone (P4) is a neurosteroid hormone synthesized in both males and females, it is widely used in reproductive health and hormone replacement therapy. The aim of this study was to develop microemulsions (ME) and optimization of P4 microemulsion using a simplex lattice mixture design for enhancing the transdermal delivery of P4. Pseudo-ternary phase diagrams were generated to find the optimal ratio of the microemulsion constituents. The solubilities of P4 in different oils, surfactants, and co-surfactants were determined. The ME formulations of P4 were then prepared and optimized by simplex lattice mixture design. Each ME formulation was characterized for size, PDI, zeta potential, drug content, in vitro permeation study, and drug permeation in porcine skin. The result showed that the optimal ME formulation composed of 34.97 %w/w eugenol as the oil phase, 18.35 %w/w Labrasol® as the surfactant, 36.69 %w/w ethanol as the cosurfactant, and 10.00% w/w water containing HPβCD (1.0 M). The optimized ME showed an appropriate size of about 178 ± 42 nm with a low polydispersity index (PDI) and almost neutral charge. The drug content of the optimized ME was about 19.9 ± 0.6 %w/w. The results of in vitro permeability showed that the optimized ME formulation was significantly higher than the drug suspension. Moreover, the P4 from the optimized ME was able to be deposited in the dermis (1.07 mg) at a higher extent than in the stratum corneum (0.65 mg). In conclusion, this study explored a formulation approach to improve the transdermal permeation of P4.

The aims of this study were to investigate the skin regeneration potential of bioactive placenta (deer placenta (DP), goat placenta (GP), and porcine placenta (PP)) and fabricate bioactive extract-loaded dissolving microneedles (DMNs) as a dermal delivery approach. The placentas were water-extracted, and the active compounds were evaluated. Bioactivity studies were performed in dermal fibroblasts and keratinocytes. DMNs were fabricated to deliver the potent bioactive placenta extract into the skin. All placental extracts expressed high amounts of protein, growth factors (EGF, FGF, IGF-1 and TGF-β1), and amino acids. These extracts were not toxic to the skin cells, while the proliferation of fibroblast cells significantly increased in a time-dependent manner. GP extract that exhibited the maximum proliferation, migration, and regeneration effect on fibroblast cells was loaded into DMN patch. The suitable physical properties of DMNs led to increased skin permeation and deposition of bioactive macromolecules. Moreover, GP extract-loaded DMNs showed minimal invasiveness to the skin and were safe for application to human skin. In conclusion, placental extracts act as potent bioactive compounds for skin cells, and the highest bioactive potential of GP-loaded DMNs might be a novel approach to regenerate the skin.

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