Background: To investigate the pharmacokinetics of complexation of levobupivacaine with maltosyl-beta-cyclodextrin, the plasma concentrations of levobupivacaine were measured following epidural administration of levobupivacaine conjugated with maltosyl-beta-cyclodextrin or levobupivacaine alone in a rabbit model.
Methods: Rabbits were randomly divided into two groups, levobupivacaine (1%) group (n = 6) and levobupivacaine (1%) conjugated with maltosyl-beta-cyclodextrin (100 mM) group (n = 6). One ml of each solution was randomly injected through an epidural catheter placed at L5-6. The plasma levobupivacaine concentrations were measured before and 5, 10, 15, 30, 60, 120, 240, 360, and 480 min after injection.
Results: The plasma levobupivacaine concentrations were significantly higher in the levobupivacaine conjugated with maltosyl-beta-cyclodextrin group than in levobupivacaine group at 5 min (1,465 +/- 311, 1,033 +/- 347 ng x ml(-1)), 10 min (1,068 +/- 237, 731 +/- 191), and 15 min (958 +/- 311, 605 +/- 118). There were no differences in area under the curve (1,551 +/- 387, 1,176 +/- 154 ng x hr x ml(-1)) and elimination half life (100 +/- 54, 78 +/- 37 min) between the two groups.
Conclusions: The results of this study indicated that the absorption of levobupivacaine conjugated with maltosyl-beta-cyclodextrin from the epidural space and the elimination from the blood were similar to plain levobupivacaine.