Spectrophotometric Determination of Alzheimer’s Drug, Memantine Hydrochloride in Biological Samples Using Ninhydrin and Ferric Chloride

Two simple, rapid, accurate and precise spectrophotometric procedures have been developed for the determination of memantine HCl (MEM). The first method (A) is based on the interaction of ninhydrin in N, N′dimethylformamide (DMF) medium, with primary amino group present in MEM. This reaction produced a bluepurple product, which absorbed maximally at 595 nm. Beer's law is obeyed in the concentration range of 0.419.3 μg/mL with RSD of 0.88 % and molar absorptivity of 1.12×10 4 L/mol.cm in addition to limits of detection and quantification. In second method (B) MEM was reacted with ferric chloride solution, yellowish orange colored chromogen showed λmax at 375 nm showing linearity in the concentration range of 0.3-9.7 μg/mL with RSD of 1.03 % and molar absorptivity of 1.73×10 4 L/mol.cm in addition to limits of detection and quantification. The proposed method has been applied successfully to the analysis of the bulk drug and its dosage forms and spiked human plasma. No interference was observed from common pharmaceutical adjuvant. Statistical comparison of the results with the reference method shows excellent agreement and indicates no significant difference in accuracy and precision.