Abstract
We compared a 7% lidocaine cream (Preparation C) prepared at our hospital using a commercially available 5% dental xylocaine ointment (Preparation K) for application as a lacal anesthesia for skin patients when employing a laser beam for stability and anesthetic performance. Both preparations did not show any water separation or color change at 5°C, 25°C, 40°C at RH 75% with a 95% or more residual rate. Furthermore, water evaporation in both preparations was not observed and was within the limit of measurement error. Significant change was not recognized in the expansibility of the preparation. The results of the viable cell count study according to Standard Plate-Counting Method and Specific Plate-Counting Method under the four conditions were negative (10 bacteria or less/g) with no observation of bacterial colonies. The anesthetic effect lasted 120 min for Preparation C with the 60-min application, while Preparation K only showed diminution of pain for 30 min.
