European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences
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Comparative Study
Bupivacaine containing dry emulsion can prolong epidural anesthetic effects in rabbits.
To assess the prolongation of epidural bupivacaine by a novel lipid formulation, a physically stabilized bupivacaine containing dry emulsion was prepared by spray-drying. Bupivacaine release from the oil-in-water emulsion was studied using an in vitro two-phase stirred model, then the pharmacodynamic effects and the pharmacokinetics of bupivacaine from the spray-dried emulsion were evaluated and compared to a bupivacaine hydrochloride solution, following a two-period cross-over epidural administration in rabbits. ⋯ The onset time of epidural anesthesia was similar for both formulations of bupivacaine used, while a significant blockade prolongation (360%) was observed with the emulsion compared to the solution, suggesting a controlled release of bupivacaine. Dry emulsions could be promising dosage forms to optimize the disposition of epidurally administered LAs.