A simple, sensitive, accurate and low cost effective spectrophotometric method has been developed for the determination of Tetracycline, Doxycycline and methyldopa in pure and pharmaceutical formulations. The method is based on the reaction of methyldopa with 4-aminoantipyren (4-AAP) in presence of potassium ferriecyanide (PFC) in an alkaline medium. Two optimization methods were applied to determine the optimum conditions of oxidizing coupling reaction...