Development, Characterization, In Vitro, Ex Vivo, and Stability Evaluation of a Miconazole Nitrate Nanocrystal-loaded Hydrogel for Topical Application

Introduction: This study aimed to develop, characterize, optimize, and evaluate the in vitro ex vivo drug release and stability of miconazole nitrate (MN)-loaded nanocrystal for topical drug delivery. MN is an antifungal agent with poor oral bioavailability and significant first-pass metabolism, necessitating alternative administration routes. Nanoformulations with lipidic/polymeric nanoparticles can overcome conventional system formulation limitations. However, it resulted in controlled MN drug release for up to 48 h and greater skin flux than did a 1% MN solution. This study aimed to identify optimized, stable, and effective in vitro/ex vivo MN-loaded nanocrystal-based hydrogels for topical drug delivery. Methods: The nanocrystals (PN1-PN12) were developed via the precipitation method using Pluronic F-127 as a nonionic copolymer surfactant and stabilizer. The compatibility was evaluated via differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and Fourier transform infrared spectroscopy (FT-IR). With the help of the zetasizer, particle size, PDI, and Zeta Potential are determined. The drug in-vitro release was determined using the dialysis bag method. Carbopol 934-P and methylparaben were dissolved in distilled water with heat and constant stirring to prevent agglomeration. Permeation experiments used excised abdominal skin from Wistar rats euthanized by cervical dislocation. Results: The highest solubility was found in PF-127, followed by Pluronic F68. Nanocrystals were prepared via the antisolvent precipitation method. The new diffraction pattern of the nanocrystals confirms their crystalline nature and complexation with the polymer, supporting the DSC and FT-IR findings. The developed nanocrystal shows a subtle shift from 1587 to 1589 cm^-1, with no significant changes in the vibrational frequencies of the physical mixture. The PN5 formulation, with a small PS of 303.4 nm, a low PDI of 0.248, the highest drug content of 99.23 ± 5.23%, and a % cumulative drug release of 92.32 ± 3.27, was selected for further characterization. The PN5 formulations were stored under various conditions for 3 months, resulting in consistent particle sizes. SEM images revealed long, crystalline MN structures and needle-like nanocrystals. PN5 was optimized for developing a topical nanocrystal gel (PG1), which provided sustained drug release and retained significantly more drug than the other formulations did. PG1 remained stable during the 3-month storage. Conclusion: The PN5 formulation, optimized for developing a topical nanocrystal gel, resulted in consistent particle size, sustained drug release, and stability over 3 months.