The penetration of local anesthetics into phosphatidylcholine monolayers

Abstract

The penetration of tetracaine into monolayers of phosphatidylcholine and trioctanoin at different surface pressures, and the penetration of dibucaine, tetracaine, butacaine, lidocaine, and procaine into monolayers of didecanoylphosphatidylcholine at Π = 10 mN/m was determined by the use of a modified Gibbs adsorption equation. These data were shown to fit a geometric model and compared favorably with data determined by a method based on the geometric model. The penetration of tetracaine into phosphatidylcholine monolayers was pressure dependent. At Π = 10 mN/m, the local anesthetics penetrate into a phosphatidylcholine monolayer in the order: dibucaine > tetracaine > butacaine > lidocaine > procaine. This correlates with their potencies in blocking nerve conduction and inhibiting phospholipase A2.

Keywords

• dibucaine
• tetracaine
• butacaine
• lidocaine
• procaine