title: New liquid membrane electrode for determination of lidocaine in local anesthetic formulations.
abstract: A new lidocaine-responsive liquid membrane electrode based on the use of the lidocaine reineckate ion pair complex in nitrobenzene solvent has been developed. The electrode displays a linear response for 10(-2)-10(-5) M lidocaine over the pH range of 3-6.5. The response time varies from 35 s to 1 min depending on the lidocaine concentration. The life span of the electrode is at least 1 month. Excipients and diluents commonly used in local anesthetic formulations do not interfere. Determination of lidocaine in some pharmaceutical preparations gives results with an average recovery of 99% of the nominal values and a mean standard deviation of 1.7% which compare favorably with those obtained by the U.S. Pharmacopeia method.
mesh_terms: D000779:Anesthetics, Local / Q000032:analysis*; D004566:Electrodes; D008012:Lidocaine / Q000032:analysis*; D011199:Potentiometry
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine