Preparation, Characterization, and In Vitro Evaluation of Cream and Gel Formulations Containing Lidocaine and Tetracaine

The study developed and evaluated cream and emulgel formulations containing lidocaine and tetracaine (LT) as alternatives to EMLA® cream for topical anesthesia. The emulgel formulation demonstrated faster LT release and longer tetracaine release duration compared to the cream, with both formulations exhibiting shear thinning thixotropic behavior and maintaining suitable consistency and pH levels. The study concluded that these LT formulations could provide effective pain relief with a faster onset and longer duration of action without occlusion, making them suitable for superficial operations. Stability studies showed the formulations remained stable over 30 days, although pH levels increased slightly. Further in vivo and clinical investigations were suggested to confirm clinical benefits.