This study explores developing and optimizing a nanoemulsion (NE) system loaded with dipyridamole and roflumilast, aiming to improve skin penetration and retention. The NE formulation was further transformed into a nanoemulgel to enhance its application as a topical treatment for psoriasis. Solubility studies were conducted to select the oil, surfactant, and co-surfactant. Phase diagrams were constructed using the aqueous phase titration method. All the formulations were in nanoscale, and Formula (F2) (which contains oleic acid oil as the oil phase, a mixture of Surfactant Tween 80 and co-surfactant (ethanol) at a ratio of 1:2 in addition to distilled water as an aqueous phase in a ratio of 1:5:4, respectively) was the selected formula depending on the particle size, PDI, and zeta potential. Formula (F2) has the best ratio because it gives the smallest nanoemulsion globule size (particle size average of 167.1 nm), the best homogenicity (lowest PDI of 0.195), and the highest stability (higher zeta potential of −32.22). The selected formula was converted into a nanoemulgel by the addition of 0.5% (w/w) xanthan gum (average particle size of 172.7 nm) and the best homogenicity (lowest PDI of 0.121%) and highest stability (higher zeta potential of −28.31). In conclusion, the selected formula has accepted physical and chemical properties, which enhanced skin penetration.

(1) Background: The present study aimed to assess the antifungal effectiveness of a topical innovative formulation containing the association of an antifungal agent, voriconazole (VCZ), and the essential oil of Pinus sylvestris L. (PSEO). (2) Methods: Pseudo-ternary phase diagram and D-optimal mixture design approaches were applied for the development and the optimization of the o/w nanoemulsion. The optimized formulation (NE) was subjected to physicochemical characterization and to physical stability studies. In vitro permeation studies were carried out using the Franz cell diffusion system. The antimycotic efficacy against Microsporum canis was carried out in vitro. (3) Results: Optimal nanoemulsion showed great physical stability and was characterized by a small droplet size (19.015 nm ± 0.110 nm), a PDI of 0.146 ± 0.011, a zeta potential of −16.067 mV ± 1.833 mV, a percentage of transmittance of 95.352% ± 0.175%, and a pH of 5.64 ± 0.03. Furthermore, it exhibited a significant enhancement in apparent permeability coefficient (p < 0.05) compared to the VCZ free drug. Finally, NE presented the greatest antifungal activity against Microsporum canis in comparison with VCZ and PSEO tested alone. (4) Conclusions: These promising results suggest that this topical innovative formulation could be a good candidate to treat onychomycosis. Further ex vivo and clinical investigations are needed to support these findings.

In this study, we focused on quetiapine fumarate (QTF), a class II BCS drug. QTF is an atypical antipsychotic used in the treatment of schizophrenia and bipolar disorders. Our objective was to develop a new QTF-loaded self-emulsifying drug delivery system (SEDDS) to improve the dissolution and absorption of the drug. An experimental design approach was used to develop and optimize QTF-loaded SEDDS. The optimized formulation was characterized for droplets size, zeta potential, PDI, and stability. It was then evaluated using an in-vitro combined test for dissolution and Everted gut sac technique. Mathematical modeling and Transmission electron microscopy (TEM) were used to elucidate the mechanism of release. The optimal formulation was type IIIB SEDDS, constituted of 9.1% of oleic acid, 51.6% of Tween (R) 20, and 39.3% of Transcutol (R) P. It showed a droplets size of 144.8 +/- 4.9nm with an acceptable PDI and zeta potential. For in-vitro evaluation tests, we noticed an enhancement of the dissolution rate of the optimal QTF-loaded SEDDS compared to the free drug (98.82 +/- 1.24% for SEDDS after 30 min compared to 85.65 +/- 2.5% for the pure drug). The release of QTF fitted with the Hopfenberg model indicating the drug was released by water diffusion and erosion mechanism. This result was confirmed by TEM images which showed a smaller droplet size after release. We also found an amelioration of the permeability of QTF of 1.69-fold from SEDDS compared to the free drug. Hence, the SEDDS formulation represented a new way to improve the dissolution and absorption of QTF.