Spectrophotometric Determination of Doxycycline Hyclate in Pure and Capsule using Diazotization Reaction


A sensitive spectrophotometric method has been developed for the determination of Doxycycline hyclate (DCH) as pure and capsule forms. This method is based on diazotization of primary amine group of benzocaine with sodium nitrite in hydrochloric acid medium; the formed diazonium salt is then reacted with DCH in sodium hydroxide medium, to form yellow – orange Azo dye. Beer's law is obeyed in the concentration rang 16-34mg. ml-1 at 480 nm with detection limit LOD and molar absorptivity Є were found to be 0.418 mg.ml-1 and 2.214× 10+4 L.mol-1.cm-1, respectively.