(lidocaine and prilocaine) Periodontal Gel
Oraqix (lidocaine and prilocaine periodontal gel,) 2.5%/2.5% is a microemulsion 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; therefore, both local anesthetics exist as liquid oils rather than as crystals. Oraqix contains poloxamer excipients, which show reversible temperature-dependent gelation. Together with the lidocaine-prilocaine 1:1 mixture, the poloxamers form a low-viscosity fluid system at room temperature and an elastic gel in the periodontal pocket. Oraqix is administered into periodontal pockets, by means of the supplied special applicator. Gelation occurs at body temperature, followed by release of the local anesthetics, lidocaine and prilocaine. The Oraqix single-use glass cartridges deliver up to 1.7g (1.7mL) of gel (42.5 mg of lidocaine and 42.5 mg of prilocaine). Prilocaine base and lidocaine base are both relatively hydrophilic amino-amides. The structural formulas are:
Lidocaine is chemically designated as 2-(diethylamino)-N-(2,6-dimethylphenyl)-acetamide and has an octanol:water partition ratio of 43 at pH 7.4. The pKa of lidocaine is 7.86. Prilocaine is chemically designated as N-(2-methyl-phenyl)-2 (propylamino)-propanamide and has an octanol:water partition ratio of 25 at pH 7.4. The pKa of prilocaine is 7.89. Each gram of Oraqix contains 25-mg lidocaine base and 25-mg prilocaine base. The gel also contains thermosetting agents (poloxamer 188 purified, poloxamer 407 purified), hydrochloric acid (pH adjustment), and purified water. The pH of Oraqix is 7.5-8.0.
Last reviewed on RxList: 8/17/2012
This monograph has been modified to include the generic and brand name in many instances.
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