Spinal disposition and meningeal permeability of local anesthetics.

Purpose: To investigate the spinal disposition, the cerebrospinal fluid (CSF) bioavailability, and the ex vivo meningeal permeability of six homologous pipecoloxylidide local anesthetics and to search for correlations with lipophilicity.

Methods: The ex vivo meningeal permeability was studied on fresh specimen of meninges (dura mater and arachnoid mater) removed from lumbar and cervical level of rabbit spine following laminectomy. Spinal disposition and CSF bioavailability were investigated using microdialysis sampling after simultaneous injection of an equimolar dose of the six homologs in the epidural or in the intrathecal spaces.

Prolongation of epidural bupivacaine effects with hyaluronic acid in rabbits.

To assess the prolongation of epidural bupivacaine by hyaluronic acid viscous formulations we designed a cross-over study in rabbits. Different doses of bupivacaine (3 or 6 mg) either as a solution (bupivacaine hydrochloride), or as viscous formulations with hyaluronic acid (bupivacaine base and bupivacaine hydrochloride) were administered in a rabbit model of epidural anesthesia. In the first part of the study, in vitro release characteristics were determined.

Sciatic nerve block with bupivacaine-loaded microspheres prevents hyperalgesia in an inflammatory animal model.

Purpose: The aim of this study was to evaluate the effect of different durations of local anesthetic neural blockade on hyperalgesia after carrageenan infiltration in a rat model.

Methods: Inflammation was obtained by injection of carrageenan in the righ hind paw. Hyperalgesia was determined by measuring the threshold of response to increasing mechanical stimuli on the contralateral and on the ipsilateral paw.

Spray-dryed bupivacaine-loaded microspheres: in vitro evaluation and biopharmaceutics of bupivacaine following brachial plexus administration in sheep.

Microspheres could be used as a drug delivery system to prolong the duration of action of bupivacaine and to reduce its systemic absorption leading to high plasma concentrations related to central nervous and cardiovascular toxicity. Bupivacaine-loaded microspheres were made by spray-drying using polylactide-co-glycolide polymers from different sources and with different bupivacaine-polymer ratio. The characterization of microspheres concerned the shape and size, the bupivacaine drug-content (DC) and the cumulative release profiles.

Alkalinization of intracuff lidocaine improves endotracheal tube-induced emergence phenomena.

Unlabelled: We sought to evaluate the effect of filling an endotracheal tube cuff with 40 mg lidocaine alone (Group L) or alkalinized lidocaine (Group LB) in comparison to an Air Control group (Group C) on adverse emergence phenomena in a randomized controlled study (n = 25 in each group). The incidence of sore throat was decreased for Group LB in comparison to Group L during the 24 postextubation hours. The difference between Group L and Group C remained significant in the two postextubation hours only.