Microfluidic ocular formulation of voriconazole designed for hospital production

Fungal keratitis is a serious corneal infection with a limited therapeutic panel. Voriconazole, an azole antifungal, has been shown to be effective against many of the fungal strains involved in this type of infection. The absence of an ocular dedicated formulation on the market has led to the use of the sterile commercial cyclodextrin based formulation as a hospital preparation with some drawbacks. The aim of this study was to design a dedicated formulation for ocular delivery using oil-in-water nanoemulsion. A 0.4% voriconazole nanoemulsion was formulated with an oil and two surfactants, complying with the standards set by the authorities and literature. The nanoemulsion was produced using the phase inversion composition method. It was also formulated using microfluidic technology, suitable for hospital transposition. The mean droplets size was around 100 nm and zeta potential was negative. The pH and osmolality have been adjusted without destabilizing the nanoemulsion. Additionally, it was demonstrated that the formulation consists of two compartments: oil nanodroplets and residual micelles. Voriconazole was preferentially found in the micellar compartment. Finally, in vitro determination of minimal-inhibition-concentration tests were carried out on Aspergillus and Fusarium fungal species and compared to the 1% current hospital preparation. These tests showed that our formulation was no less effective than the hospital preparation.