Evaluation of Eutectic Temperature and Eutectic Composition of Some of The Binary Mixtures of Local Anesthetics and Terpenes and Their Pharmaceutical Application

摘要

The phase diagrams were constructed for the following binary mixtures, benzocaine:lmenthol, benzocaine:lidocaine, tetracaine:lidocaine and tetracaine:camphor using differential scanning calorimetry (DSC) and an effort was made to evaluate their eutectic composition and eutectic temperature. The eutectic temperature ranged from 15.9 °C for tetracaine:lidocaine to 40.41 °C for benzocaine:l-menthol. The melting point depression of the topical drugs has already been correlated with enhanced transdermal permeation of the drug. In conclusion, DSC can be a useful screening tool for selecting appropriate permeation enhancers that form eutectics with the drugs.