Spectrofluorimetric Determination of Alendronate by Conjugation with the Rhodamine B Sulfonyl Group

摘要

Alendronate, one of the bisphosphonate group of drugs, is used in the treatment of bone metastasis and several bone disorders, such as Paget's disease and osteoporosis, in postmenopausal women and older people. Generally, because the concentrations of alendronate in the therapeutic range are very low for intravenous and transdermal administration, its quantitative estimation is quite difficult. Therefore, a sensitive and simple method for determining alendronate concentration in patients' blood is required for medical and clinical purposes; to this end, a number of researchers have attempted to develop various sensitive analytical methods. NadDPA-2Zn~(2+), a fluorescent chemosensor (FCS), which is used for the recognition of certain molecules or ions, was identified as a new analytical tool for the determination of alendronate in our previous study. However, analysis using NadDPA-2Zn~(2+) is not very effective as a method because of its low sensitivity(limit of quantitation (LOQ) = 0.104 μg/mL),due to the fact that fluorescent activity of the naphth-alzene group, which act as a chromophore in NadDPA-2Zn~(2+),is not high; the molar extinction coefficient (ε) is 6,000 M~(-1) cm~(-1) at 275 nm.