Pharmacokinetic and local toxicity studies of liposome-encapsulated and plain mepivacaine solutions in rats

The pharmacokinetics and the local toxicity of commercial and liposome-encapsulated mepivacaine formulations injected intra-orally in rats were studied. Animals were divided in groups (n = 4-6) and treated with 0.1 mL of the formulations: 2% mepivacaine with 1:100,000 epinephrine (MVC2%EPI), 3% mepivacaine (MVC3%), and 2% liposome-encapsulated mepivacaine (MVCLUV). The results showed that the 2% liposome-encapsulated mepivacaine reduced Cmax, prolonged AUC0-∞ and t1/2 compared with 3% plain and 2% vasoconstritor-associated mepivacaine, after intraoral injection. In addition, it was also observed that liposomal mepivacaine might protect the tissue against local inflammation evoked by plain or vasoconstrictors-associated mepivacaine, giving supporting evidence for its safety and possible clinical use in dentistry.