SPL Set ID: 833cd52c-6470-49c4-937f-1393971f4db9

Lidocaine and prilocaine cream, 2.5%/2.5% is an emulsion in which the oil phase is a eutectic mixture of lidocaine and prilocaine in a ratio of 1:1 by weight. This eutectic mixture has a melting point below room temperature and therefore both local anesthetics exist as a liquid oil rather than as crystals. It is packaged in 30 gram tubes and 5 gram tubes for hospital use. Lidocaine is chemically designated as acetamide, 2-(diethylamino)- N -(2,6-dimethylphenyl), has an octanol: water partition ratio of 43 at pH 7.4, and has the following structure: Prilocaine is chemically designated as propanamide, N -(2-methylphenyl)-2-(propylamino), has an octanol: water partition ratio of 25 at pH 7.4, and has the following structure: Each gram of lidocaine and prilocaine cream, 2.5%/2.5% contains lidocaine 25 mg, prilocaine 25 mg, polyoxyethylene fatty acid esters (as emulsifiers), carbomer 934P (as a thickening agent), sodium hydroxide to adjust to a pH approximating 9, and purified water. Lidocaine and prilocaine cream, 2.5%/2.5% contains no preservative, however it passes the USP antimicrobial effectiveness test due to the pH. The specific gravity of lidocaine and prilocaine cream, 2.5%/2.5% is approximately 1.00. Structural Formula Structural Formula