Figure 3. Duration of intercostal block for doses from 8 to 80 mg/kg for bupivacaine microspheres and bupivacaine-dexamethasone microspheres (A). Points are mean +/− SD; n = 5 sheep per dose-group. The same data are plotted as total dose of microspheres per animal (mg) to allow comparison of drug efficacy based on absolute dose administered (B). An increase in dose of bupivacaine microspheres did not prolong nerve blockade, whereas an increase in dose of bupivacaine-dexamethasone microspheres significantly prolonged nerve blockade. Bupivacaine-dexamethasone microspheres achieved a significantly longer nerve blockade at all doses (P < 0.05; Student's t test). The 50% recovery time points differ greatly between the bupivacaine microspheres groups and the bupivacaine-dexamethasone microspheres groups (C).