Amlodipine Ocular Delivery Restores Ferning Patterns and Reduces Intensity of Glycosylated Peak of Carrageenan-Induced Tear Fluid: An Flexible Docking with IL-β1.

Background: The tear ferning test can be an easy clinical procedure for the evaluation and characterization of the ocular tear film.

Objective: The objective of this study was to examine the restoration of tear ferning patterns and reduction of glycosylation peak after amlodipine application in carrageenan-induced conjunctivitis.

Methods: At the rabbit's upper palpebral region, carrageenan was injected for cytokine-mediated conjunctivitis. Ferning pattern and glycosylation of the tear fluid were characterized using various instrumental analyses. The effect of amlodipine was also examined after ocular instillation and flexible docking studies.

Results: Optical microscopy showed a disrupted ferning of the tear collected from the inflamed eye. FTIR of the induced tear fluid exhibited peaks within 1000-1200 cm, which might be due to the protein glycosylation absent in the normal tear spectrogram. The glycosylation peak reduced significantly in the tear sample collected from the amlodipine-treated group. Corresponding energy dispersive analysis showed the presence of sulphur, indicating protein leakage from the lacrimal gland in the induced group. The disappearance of sulphur from the treated group indicated its remedial effect. The flexible docking studies revealed a stronger binding mode of amlodipine with Interleukin-1β (IL-1β). The reduction in the intensity of the glycosylated peak and the restoration offering are probably due to suppression of IL-1β.

Conclusion: This study may be helpful in obtaining primary information for drug discovery to be effective against IL-1β and proving tear fluid as a novel diagnostic biomarker.