USE OF DERIVATIVE UV-SPECTROPHOTOMETRY FOR STABILITY STUDIES OF (DIMETHYLAMINO)ETHYL O-CHLORO, P-DIMETHYLAMINO(SULPHAMOXYLPHENOXY)-ACETATE HYDROCHLORIDE IN AQUEOUS-SOLUTION

The third derivative UV-spectrophotometric method, the ''zero-crossing '' technique, was used for the simultaneous determination of (dimethyl amino)ethyl o-chloro, p-dimethylamino(sulphamoxylphenoxy) acetate hydr ochloride [I] and its major decomposition product by hydrolysis, (o-ch loro, p-dimethylamino(sulphamoxylphenoxy) acetic acid) [II] The method was applied for the kinetic investigation of 0.01% aqueous solution o f [I] in four acetate buffer solutions in the pH range of 4 to 6. It w as calculated the activation energy, (E(a)), and the time at which the compound [I] maintains 90% of its initial activity at 20 degrees C (t (90)).