COMPARISON OF ABSORPTION OF AQUEOUS LIDOCAINE AND LIPOSOME LIDOCAINE FOLLOWING TOPICAL APPLICATION ON RABBIT VESSELS

Liposomes are small particles that encapsulate lidocaine to form topic al drug carriers. Forty rabbits were used to compare the absorption of aqueous lidocaine with that of liposome lidocaine after application o f each on femoral and iliac vessels. Both agents entered the circulati on rapidly. The serum levels of lidocaine were significantly lower and the peaks in concentration appeared later after the use of liposome l idocaine than after the use of aqueous lidocaine. This phenomenon was due to local accumulation of liposome lidocaine and slow release of li docaine from the liposome. As a topical spasmolytic agent, liposome li docaine may be superior to the aqueous form due to a lower serum conce ntration and less total absorption.