Kinetic Spectrophotometric Determination of Memantine Hydrochloride Based on the Formation of Its Dinitrochlorobenzene Adduct

A facile kinetic spectroscopic technique was devised and validated for the precise estimation of memantine hydrochloride. This method depends upon the measurement of various kinetic characteristics of the reaction between the drug and 1-chloro-2,4-dinitrobenzene in an alkaline medium at 70°C. The resultant memantine-dinitrobenzene complex exhibits a distinctive absorbance maximum at 290.5 nm. Spectroscopic analysis was conducted by scanning the complex within the 200 to 800 nm range using a Shimadzu UV-1900 spectrophotometer. Experimental conditions, including reagent concentration, base quantity, order of addition, and reaction temperature, were optimized. The reaction mechanism and stoichiometric ratio of the drug with the reagent were elucidated. Employing various kinetic methodologies such as initial rate, fixed time, and fixed absorbance under optimal conditions enabled the construction of calibration curves and accurate estimation of memantine hydrochloride. The method demonstrated linearity within the concentration range of 3.0 to 7.0 μg/mL. Precision assessment yielded satisfactory relative standard deviations of 2.05 for intra-day and 1.96 for inter-day precision studies. Accuracy studies revealed mean recoveries ranging between 98.55–102.34%. Moreover, the proposed method effectively determined memantine hydrochloride in a commercial formulation.