Brain-to-blood and saliva-to-blood mepivacaine ratios in rats

Mepivacaine hydrochloride, 25 and 50 mg/kg sc (with sacrifice at 15 min) produced higher (p less than 0.005) drug levels in neonate (24--36-hr-old) rat brain and blood than in adult rat brain and blood; however, there was no significant difference in the brain-to-blood ratio of the drug between neonates and adults at either dose level. Intraarterial infusion of mepivacaine hydrochloride (20 micrograms/min) in adult rats resulted in measurable (GLC) mepivacaine base levels in pilocarpine-induced parotid salivary secretions collected throughout 30- and 45-min infusion periods. The saliva-to-blood ratios (+/- SEM) of mepivacaine base were 0.64 +/- 0.13 after a 30-min infusion and 2.13 +/- 0.48 after a 45-min infusion.