Spectrophotometric method for the determination of ritodrine hydrochloride and amoxicillin

A rapid and sensitive spectrophotometric method is described for the determination of ritodrine hydrochloride (RTH) and amoxicillin (AMX) in both pure and dosage forms. The proposed method uses 3-methyl benzothiazolin-2-one hydrazone as a chromogenic reagent. A mixture of aqueous solutions of the drug and reagent is treated with ammonium cerium(IV) sulfate in an acidic medium to yield pink-colored species. These species exhibit maximum absorption at 520 nm for RTH and at 490 nm for AMX with a molar absorptivity of 2.35x10(4) and 1.27x10(4) l mol(-1) cm(-1) for Pim and AMX, respectively. The optimum reaction conditions and other analytical parameters are evaluated. The influence of the substrates commonly employed as excipients with these drugs have been studied. The proposed method was applied to the determination of these drugs in pharmaceutical formulations. The results have demonstrated that the method is equally accurate and reproducible as the official methods.