HPLC-fluorescent analysis of memantine: An investigation on fluorescent derivative formation

Memantine is an n-methyl-d-aspartate receptor antagonist recommended for treatment of alzheimer's disease. due to the lack of chromophores/fluorophores in memantine molecule,this work focuses on a novel procedure for memantine-fluorescent derivative formation enabling it to be monitored by a fluorescence detector. 4-(n-chloroformylmethyl-n-methyl)amino-7-n,n-dimethylaminosulphonyl 2,1,3-benzoxadiazole (dbd-cocl) was chosen as a fluorescent probe since the carbonyl chloride of dbd-cocl could easily react with the amine on memantine to form the fluorescent derivative. the derivatization was achieved at 5: 1 of dbd-cocl and memantine,at 60°c for 50 min. structure elucidation from mass spectrometry and infrared spectroscopy spectra confirmed the amide bond of memantine-dbd-cocl. the derivative was stable up to 24 h and could be monitored by high performance liquid chromatography (hplc) coupled with a fluorescence detector using a vertisep ges c18 column,acetonitrile and water (80: 20) as the mobile phase with a flow rate of 1 ml/min using the excitation and emission wavelengths at 430 and 520 nm,respectively. the derivative was eluted at 4.50 min and was separated from the dbd-cocl. preliminary validation data reveals good linearity (r2≥0.99),repeatability (%rsd < 0.54) and accuracy (%r between 94 and 119%) with a limit of detection of 0.79 g/ml. © 2015 pornpan prapatpong et al.