Synthesis, sciatic nerve block activity evaluation and molecular docking of fluoro-substituted lidocaine analogs as local anesthetic agents

Abstract

Thirty fluoro-substituted lidocaine analogs (10a–e, 11a–e, 14a–e, 15a–e, 18a–e and 19a–e) were synthesized, and their sciatic nerve block activity were evaluated as local anesthesia. Most of the compounds displayed significant potency, and compound 10a in particular was much more potent than the parent lidocaine. Fifteen analogs including 10a demonstrated pKa values of 7.5–7.8 suitable for local anesthesia. Compound 10a, 14e, and lidocaine were docked into three target receptors of local anesthetics by molecular docking studies to delineate structure-activity relationships and explain the differences in activities. Hydrophobic interactions and hydrogen bonds were identified key to molecular binding, suggesting that optimization of these interactions and/or trifluoro-substitution at the benzene ring of lidocaine could enhance the properties of lidocine analogs for local anesthesia.