Abstract
To attain anesthesia of the skin without needle puncture, we developed a gel form mixture of lidocaine dissolved in propylene glycol and ethanol with glycyrrhetinic acid 3-0 hemiphtalate disodium salt as an absorption promoter along with an acid thikener and neutralizer. From the results of a patch test, slight was appeared in one person but did not cause any discomfort and clinically insignificant. The absorption was followed by measuring the concentrations of lidocaine in the general circulation at different time intevarls after application. When applied to normal skin, the serum concentrations of lidocaine were lower than those associated with toxicity. Cryotherapy of dermal melanocytosis by liquid N2 was performed in one patient under a topical anesthesia with this gel. The analgesia was sufficient and the patient rated the pain as slight. When this gel was applied on repetively freezed skin by cryotherapy, the drug were 30 times higher than those applied to normal skin. These results suggest that this gel would provide an effective local anesthesia for cryotherapy, currettage of molluscs, cutting of split skin grafts as well as for a number of other skin surgical procedures.
