Materials and methodsInhibition of palpebral reflex was evaluated after local application of test solutions to the rabbit cornea. Groups of six male New Zealand rabbits (2-2.5 kg) (Charles River) were immobilized in appropriate restrain cages and test solutions were applied in the right eye. Saline was applied in the left eye and was used as reference substance to determine basal reflex.100 ml of test solutions or saline were applied in both eyes and the corneas of each animal were stimulated by means of a plastic rod. To avoid the potential reflex due to the proximity of the rod, stimuli were carefully applied from the back. Six stimuli were thus applied and positive responses, denoted by the closing of the eyelid were recorded. Stimuli were applied 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50,55 and 60 minutes after dosing RESULTS.Figure 5 summarizes the results of this study. Mepivacaine 1% did not induce 100% anesthesia, being the maximum effect (80%) shown at 2 minutes and then decreasing rather rapidly. 20 minutes after application, no more anesthetic effects were evidenced.IQB-9302 (1%) exhibited a potent, long lasting anesthetic effect: 100% anesthesia was obtained from minute to minute 30, but some anesthetic effects were still evident 55- 60 minutes after dosing. The onset of the effect was almost the same as mepivacaine (60% IQB-9302 80% mepivacaine at minute 2). Calculation of area under curves
of anesthetic effects versus time revealed that IQB was 5.2 more active
than mepivacaine in this test.
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