COMPARISON OF SYSTEMIC ABSORPTION OF AQUEOUS AND LIPOSOMAL, LIDOCAINEFOLLOWING INTRAARTICULAR INJECTION IN RABBITS

Aqueous lidocaine is a local anesthetic that is frequently used in int raarticular injection. However, aqueous lidocaine may be less than ide al because of its rapid absorption. Liposomes call serve as drug carri ers for encapsulating lidocaine. Both aqueous lidocaine and liposomal lidocaine were injected into knee joints of adult rabbits and the phar macokinetic changes were studied. The peak serum level of lidocaine fr om the liposomal preparation was significantly lower than that from th e aqueous preparation. The amount of lidocaine absorbed in 4 hours was also significantly lower in the liposomal group. This phenomenon may have been due to local accumulation of liposomal lidocaine and the slo w release of lidocaine from liposomes. Intra-articular use of liposoma l lidocaine may have advantages over the aqueous form because of its l ower systemic serum concentration.