Figure 7.

(A) Schematic diagram of the in vitro tear-turnover apparatus. The model incorporates an insert containing iHCEC as a turnover chamber; the external basal side of the insert was sealed to avoid a down diffusion of material. The temperature of thermostat bath is 34°C (the temperature of human tear film). Two peristaltic pumps were used to control the inflow and outflow of simulated tears in the chamber. (B) Schematic diagram of the BH-Mt/CS NPs with positive charge could retain on the iHCEC (negative charge) by electrostatic interaction. (C) BH concentration in the cornea/tear film compartment after the instillation of BH solution and BH-Mt/CS NPs.

Abbreviations: BH, betaxolol hydrochloride; CS, chitosan; Mt, montmorillonite; NPs, nanoparticles; iHCEC, human immortalized cornea epithelial cells.