“…A UV spectrophotometric procedure has been used for the determination of CPT in bulk drug and tablets in the presence of iodine, where the indirect quantization of the product was carried at 351 nm [34] This method present low selectivity, as all unsaturated compounds display one or more bands in that region of the spectrum. The CPT has been determined in the area of the visible after the reaction with iodine [34], ferric chloride in presence of 2,2'-bipirydil [34] and potassium ferricyanide [35], Pd(II) [27,36,37], Co(II) in presence of 2,2'-dipyridil-2-pyridylhydrazone [38], N-(1-naphtyl) ethylenediamine in acid media (nitrous acid) [39], Folin-Ciocalteu reagent [40,41] and molybdophosphoric acid [42]. This last procedure can only be used for the determination of CPT in pure forms, because the presence of the most common excipients in pharmaceutical formulations (glucose, fructose, lactose, sucrose, starch) they interfere seriously in this method.…”