Topical anesthesia of the skin by liposome-encapsulated tetracaine.

The potential of a liposomal local anesthetic formulation to provide topical anesthesia of the intact skin was investigated. Tetracaine base 0.5% was encapsulated into multilamellar phospholipid vesicles. The topical anesthetic effects of the liposomal and a control (Pontocaine cream) preparation were evaluated by pinprick technique in adult volunteers. Liposomal tetracaine-produced anesthesia, which lasted at least 4 hours after 1 hour application under occlusion. Pontocaine cream was ineffective. The liposomal formulation appeared to be suitable to provide long lasting anesthesia of the skin with low drug concentration.