[Ropivacaine--a new local anesthetic with specific properties].

Ropivacaine is the (S)-enantiomer of 1-propyl-2',6'-pipecoloxylidide. In terms of its physicochemical properties, it is a long-acting local anesthetic (molecular weight of the base 274, pKa 8.07, protein-binding 92%). It shows a selective action on A delta and C fibers. This may be attributable to its relatively low partition coefficient (6.1 in n-heptane). The subcutaneous and intravenous acute toxicity (LD50) is lower than that of other long-acting local anesthetics. Because of its vasoconstrictor potency, its use as a vasoconstrictor-free solution is of particular interest.