Experimental Study of Local Anesthetic Activity and Acute Toxicity of a Combined Gel

Results from studies of the local anesthetic activity of a gel for surface anesthesia that was developed at A. S. Sadykov Institute of Bioorganic Chemistry of the Academy of Sciences of the Republic of Uzbekistan are presented. DF Skincaine gel (Korea) and 5% lidocaine solution were used as reference drugs. A model of terminal anesthesia of rabbit-eye cornea showed that the test gel had a local anesthetic effect with a Rainier index of 950; DF Skincaine gel, 680; 5% lidocaine solution, 480. The new gel had a longer anesthetic effect than DF Skincaine (75 ± 6.4 and 45 ± 3.8 mins or 66.7% longer) and shorter latent period (4 and 6 min or 37% less). The studies showed that instillation into the conjunctival sac of the anesthetic gel did not cause adverse local reactions. Conversely, use of 5% lidocaine solution as an anesthetic agent led to the appearance of signs of local irritation as hyperemia of the conjunctivae and edge of the eyelids. Results of acute toxicity tests after subcutaneous injection to mice showed that the anesthetic gel was seven times less toxic than 5% lidocaine solution. The LD₅₀ values of the compounds were lidocaine 274.6 ± 7.4 mg/kg; DF Skincaine, ≥2000; and the new anesthetic gel, ≥2500.