Pharmacodynamic measurements to quantify the percutaneous penetration of compounds with local anesthetic potency

• Applicant: Professorin Dr. Claudia S. Leopold
• Subject Area: Pharmacy
• Term: from 2002 to 2003
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5387290

With cutaneously applied local anesthetic bases various effects may be observed, such as a decrease in pricking pain and a change in burning, itch, and thermal sensations. These effects occur after skin penetration and may be attributed to the action of the anesthetics on nociceptors andr thermoreceptors, i.e. on C and Ad nerve fibers respectively. As little is known about the pharmacodynamic response of nonionic surfactants with a potentially anesthetic action such as Polidocanol, this study characterizes nonionic surfactants pharmacodynamically by measuring thermal thresholds with a thermal sensory analyzer after cutaneous application. The results obtained with the nonionic surfactants were compared with data resulting from the cutaneous application of local anesthetic bases such as Mepivacaine, Bupivacaine, Prilocaine, Lidocaine, the 1:1-mixture of Lidocaine and Prilocaine contained in EMLA (reg.) and a triple mixture consisting of Lidocaine, Prilocaine and Tetracaine (1:1:1). The results show that none of the investigated surfactants affect thermal thresholds probably due to their high molecular weight. The same was observed with the anesthetics Mepivacaine and Bupivacaine. In contrast, Prilocaine, Lidocaine, the 1:1-mixture of Lidocaine and Prilocaine and the triple mixture consisting of Lidocaine, Prilocaine and Tetracaine (1:1:1) proved to be potent local anesthetics. However their pharmacodynamic responses do not differ significantly from each other.

• DFG Programme: Research Grants