In vitro corneal retention study

Comparative in vitro corneal retention of bromfenac through marketed eyedrops and ChS-CS-NPs was performed in goat cornea according to previous reports with slight modifications.[14,36] Initially, cornea was fixed between donor and receiver compartment of Franz diffusion cell and allowed to stabilize for 15 min into prewarmed simulated tear fluid (32^°C) for 15 min; subsequently, STF of donor chamber was replaced with 100 μL of marketed eyedrops/equivalent amount of NPs suspension in STF. After 2 h, cornea was taken out and softly rinsed with STF. Rinsed cornea was homogenized in an equivalent amount of STF followed by extraction in methanol. Resultant homogenate was centrifuged at 10,000 rpm for 10 min. The supernatant was passed through membrane filter (0.45 μM) and quantitatively analyzed at absorption maxima (λ_max) 270 nm by UV-VIS spectrophotometer (double beam, Shimadzu, Japan).