RESUMO
This study aimed to incorporate green-synthesized zinc oxide nanoparticles (ZnO NPs), functionalized with polyethylene glycol (PEG) and linked to doxorubicin (DOX), into various topical gel formulations (hydrogel, oleogel, and bigel) to enhance their dermal delivery. The ZnO NPs were produced using the aqueous extract of the root hair of Phoenix dactylifera. The optimized green-synthesized ZnO NPs, PEGylated and conjugated to DOX, demonstrated a particle size below 100 nm, low polydispersity index, and zeta potential between - 11 and - 19 mV. The UV-Vis spectroscopy analysis confirmed characteristic absorption peaks at 351 and 545 nm for ZnO and DOX, respectively. The transmission electron microscope (TEM) images revealed well-dispersed spherical nanoparticles without aggregation. Additionally, ZnO NPs-loaded gels exhibited uniformity, cohesion, no phase separation, pseudoplastic flow, and viscoelastic properties. The in vitro release studies showed that DOX-PEG-ZnO NPs hydrogel released 99.5% of DOX after 5 h of starting the release. Moreover, the penetration of DOX-PEG-ZnO NPs through excised rat skin was visualized by TEM. In conclusion, the hydrogel formulation containing green-synthesized DOX-PEG-ZnO NPs holds great promise for dermal administration in skin cancer treatment. Furthermore, the release rate and skin penetration of DOX from gels were varied based on the type of gel matrix and corroborated with their corresponding rheological properties.
RESUMO
This study aimed to develop and evaluate thermoresponsive in situ microgels for the local ocular delivery of prednisolone (PRD) (PRD microgels) to improve drug bioavailability and prolong ocular drug residence time. Lipid nanosystems of PRD microemulsions (PRD-MEs) were prepared and evaluated at a drug concentration of 0.25-0.75%. PRD microgels were prepared by incorporating PRD-MEs into 10 and 12% Pluronic® F127 (F127) or combinations of 12% F127 and 1-10% Kolliphor®P188 (F68). PRD microgels were characterized for physicochemical, rheological, and mucoadhesive properties, eye irritation, and stability. Results showed that PRD-MEs were clear, miscible, thermodynamically stable, and spherical with droplet size (16.4 ± 2.2 nm), polydispersity index (0.24 ± 0.01), and zeta potential (-21.03 ± 1.24 mV). The PRD microgels were clear with pH (5.37-5.81), surface tension (30.96-38.90 mN/m), size, and zeta potential of mixed polymeric micelles (20.1-23.9 nm and -1.34 to -10.25 mV, respectively), phase transition temperature (25.3-36 °C), and gelation time (1.44-2.47 min). The FTIR spectra revealed chemical compatibility between PRD and microgel components. PRD microgels showed pseudoplastic flow, viscoelastic and mucoadhesive properties, absence of eye irritation, and drug content (99.3 to 106.3%) with a sustained drug release for 16-24 h. Microgels were physicochemically and rheologically stable for three to six months. Therefore, PRD microgels possess potential vehicles for local ocular delivery.