A rapid spectrophotometric assay of amide type dental anaesthetic agents

A spectrophotometric procedure for the determination of lignocaine in ointments was investigated and standardized for general application to local anaesthetic solutions of the amide type commonly used for dental injection, namely, lignocaine, prilocaine, mepivacaine, pyrrocaine and tolycaine. The method is based on the controlled formation of a copper complex and the Beer-Lambert law was found to be obeyed over a useful range. Results indicated that the method would be accurate, convenient and rapid, saving substantial time over wet-way methods conventionally used. For confirmation of the identify of the anaesthetic agent, infrared spectroscopy was shown to be a rewarding technique.