Assessing the Use of 50% Enantiomeric Excess Bupivacaine-Loaded Microspheres after Sciatic Nerve Block in Rats

Autor: Pedro Paulo Tanaka, Rohnelt Machado de Oliveira, Sérgio Bernardo Tenório
Rok vydání: 2011
Předmět:
Zdroj: Brazilian Journal of Anesthesiology. 61:736-747
ISSN: 0034-7094
DOI: 10.1016/s0034-7094(11)70083-6
Popis: SummaryBackground and objectivesTo achieve better therapeutic benefits of local anesthetics in the control of postoperative pain through controlled-release carrier. The objective of this study was to compare the characteristics of sensory and motor blockade between microspheres without local anesthetic: racemic bupivacaine-loaded microspheres; 50% enantiomeric excess bupivacaine-loaded microspheres; and free 50% enantiomeric excess bupivacaine.MethodsWistar rats were distributed into four groups: A (Microsphere); B (S50–R50 bupivacaine-loaded microsphere); C (50% enantiomeric excess bupivacaine-loaded microsphere); and D (50% enantiomeric excess bupivacaine). Inhalation anesthesia was performed before the sciatic nerve block (2% halothane and 100% O2). Sensorial blockade was measured by the time required for each rat to withdraw its paw from a hot plate at 56°C (positive>4 sec). Motor blockade was measured by the time between drug injection until recovery of a motor score of 2 on the established criterion.ResultsThe sensory response was significantly more frequent in groups B, C, and D than in group A (p0.05). The response to the motor test was also significantly more frequent in groups B, C, and D than in group A (p=0.02). A tendency to greater positivity in the motor test was more frequently found in groups B and D than in group C (p=0.10).ConclusionsControlled-release of 50% enantiomeric excess bupivacaine-loaded microspheres showed similar results regarding analgesia and less motor blockade when compared to other anesthetic formulations.
Databáze: OpenAIRE