In Vitro Safety Assessment and Permeation Study of Topical Lidocaine Solution for Ocular Administration

In this research, topical lidocaine solution for ocular administration was assessed for biocompatibility as a non-invasive anesthetic drug delivery. The study aimed to investigate the cytotoxicity against human corneal epithelial cells (HCECs) and to evaluate drug permeation. In the case of cytotoxicity, HCECs were treated with drug solution, analyzed for percent viability. For permeation study, the modified-franz diffusion method was used to study permeation partition coefficient of lidocaine solution; moreover, the drug retained on the sclera was also determined. HCECs were treated with lidocaine solutions with the concentration range of 0.781 -100 g/L. Significantly decrease in cell viability with the concentration above 12 g/L was detected by Resazurin metabolic rate assay. The permeation coefficient of lidocaine hydrochloride solution could not be determined because of drug absence in the receptor chamber. The entire drug loaded remained in the donor chamber and adsorbed on the surface of sclera tissue. The results suggested that topical lidocaine solution showed reasonably safe and lidocaine drops did not absorbed through the sclera. In present study, local topical anesthetic delivery of lidocaine was considered safe for ophthalmologic treatment.