“…However, the real great importance of difference spectrophotometry is in quantitative analysis as a consequence of its potential to increase the selectivity of the measurement(16).The aim of this research is to develop a new and simple method for prothipendyl hydrochloride determination. It seems promising to carry out the analysis of prothipendyl hydrochloride in the form of the corresponding stable S-oxide, which is easily obtained in a slightly acidic medium using aliphatic diperoxyacids or inorganic Caro peroxoacid(10,15,17,18).in water and a water-ethanol solution 1:1 (v/v) respectively. All other used chemicals were analytical grade.…”