Abstract: This invention relates to pharmaceutical formulations administered via parenteral methods, which provide a prolonged localized analgesic effect. More particularly, the present invention concerns a pharmaceutically acceptable biocompatible biodegradable carrier containing a local anesthetic and the parenteral administration of such carrier in a manner such that a localized analgesic effect is attained for a prolonged period of time.

Abstract: A formulation for inducing sustained regional local anesthesia in a patient comprising a substrate comprising a local anesthetic and an effective amount of a biocompatible, biodegradable, controlled release material prolonging the release of the local anesthetic from the substrate to obtain a reversible local anesthesia when implanted or injected in a patient, and a non-toxic augmenting agent effective to prolong the duration of the local anesthesia for a time period longer than that obtainable from the substrate without the augmenting agent. In preferred embodiments, the controlled release material is a low molecular weight, acid-terminated polymer. A further aspect of the invention is directed to such formulations which release the local anesthetic in two phases, the first a rapid “bolus” to initiate anesthesia and a second, slower release to maintain anesthesia.