SPL Set ID: 5900691d-8b50-7752-e053-2991aa0a5c5c

Lidocaine 2.5% and Prilocaine 2.5%, a topical anesthetic agent, 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 15 gram and 30 gram tubes. 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 2.5% and prilocaine 2.5% cream contains lidocaine 25 mg, prilocaine 25 mg, carboxypolymethylene (as a thickening agent), polyoxyethylene fatty acid esters (as emulsifiers), purified water to 1 gram, and sodium hydroxide to adjust pH (pH range 9.0-9.4). Lidocaine 2.5% and prilocaine 2.5% cream contains no preservative, however it passes the USP antimicrobial effectiveness test due to the pH. The specific gravity of lidocaine 2.5% and prilocaine 2.5% cream is 1.00. Lidocaine Structural Formula Prilocaine Structural Formula