Fabrication of novel ultradeformable bilosomes for enhanced ocular delivery of terconazole: In vitro characterization, ex vivo permeation and in vivo safety assessment.

The objective of this work was to encapsulate terconazole (TCZ), a water insoluble antifungal drug, into novel ultradeformable bilosomes (UBs) for achieving enhanced ocular delivery. In addition to the constituents of the conventional bilosomes; namely, Span 60, cholesterol, and the bile salts, UBs contain an edge activator which imparts extra elasticity to the vesicles and consequently hypothesized to result in improved corneal permeation. In this study, TCZ loaded UBs were prepared utilizing ethanol injection method according to 2 full factorial design. The investigation of the influence of different formulation variables on UBs properties and selection of the optimum formulation was done using Design-Expert software. The selected UBs formulation (UB1; containing 10mg bile salt and 5mg Cremophor EL as an edge activator) showed nanosized spherical vesicles (273.15±2.90nm) and high entrapment efficiency percent (95.47±2.57%). Results also revealed that the optimum UBs formulation exhibited superior ex vivo drug flux through rabbit cornea when compared with conventional bilosomes, niosomes, and drug suspension. Furthermore, in vivo ocular tolerance and histopathological studies conducted using male albino rabbits proved the safety of the fabricated UBs after topical ocular application. Overall, the obtained results confirmed that UBs could be promising for ocular drug delivery.