Abstract: A new simple, rapid and sensitive spectrophotometric method for the determination of chlordiazepoxide is described, based on the reaction with 2,4-dinitrophenol in water medium, apparently by a charge-transfer mechanism, to yield 1:1 complex with maximum absorption at 444 nm. Optimum experimental conditions for the determination have been studied. The linear calibration range, apparent molar absorptivity and relative standard deviation are 2.8~96.0 mg·mL^-1, 1.48103 and 0.32%, respectively. The method is accurate and has been successfully applied to the determination of chlordiazpoxide in tablets. The results are in good agreement with those obtained with the official method.

Key words: Chlordiazepoxide, Chlordiazepoxide, 2,4-Dinitrophenol, 2,4-Dinitrophenol, Charge-trandfer reaction, Charge-trandfer reaction, Spectrophotometry, Spectrophotometry