INTRODUCTIONProcaine, 4-aminobenzoic acid 2-(diethyl amino) ethyl ester, is a local anesthetic 1 used alone or with penicillin as an antibacterial drug which is marketed as its hydrochloride salt, with molecular weight of 272.8 and the structure is 2 :
• HClProcaine and the other local anesthetic drugs prevent the generation and the conduction of the nerve impulses. Their main site of action is the cell membrane, since conduction block can be demonstrated in giant axons from which the axoplasm has been removed. It is used in obstetrics and sometimes for relief pain in the lower back and tooth extraction 3 .Currently, several analytical methods for the quantitation of procaine in pharmaceutical formulations have been reported. Examples of these methods are high performance liquid chromatography 4,5 , gas chromatography 6 , electrophoresis 7,8 , differentialplus voltammetry and electrochemical analysis [9][10][11][12] , chemiluminsense 13 , atomic absorption 14 , ion association titration 15 , flow injection analysis 16,17 , fluorimetry [18][19][20] , sequential injection analysis 21,22 ,liquid chromatography 23 , colorimetry and spectrophotometric methods [24][25][26][27][28][29][30] . However, some of these methods