Exploring UV Spectroscopic Approaches for Alendronate Sodium Quantification in Pharmaceutical and Biological Samples

Alendronate sodium is a nitrogen-containing amino bisphosphonate that is used to treat bone-related disorders such as osteoporosis and periodontitis by inhibiting the activity of osteoclasts and promoting the function of osteoblasts. The detection of alendronate in biological fluids and pharmaceutical products is still challenging with traditional methods such as capillary electrophoresis, chromatography, and ion chromatography, which are expensive, require skilled operators, and have complicated sample preparation. Simplified methods, like UV spectrophotometry, have been developed to overcome these challenges. However, alendronate's molecular structure poses a complication in detection due to the lack of strong chromophores. Multiple methods to improve UV absorption have been implemented by using organic reagents and metal chelation. Derivatization with reagents ortho-phthalaldehyde, sodium-1,2-naphthoquinone-4-sulphonate; 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole; 2,4-dinitrofluorobenzene, and ninhydrin have been used to aid in the detection of alendronate through UV spectrophotometry. Complexation-based methods utilize the metal chelating ability of alendronate. Using metal ions like Fe³⁺, Cu²⁺, and Ce⁴⁺ sensitivity for detection can be enhanced. The newer strategies also involve carbon dots, where the fluorescence intensity gets modulated through interactions of metal ions with alendronate. This fluorescence quenching and restoration system has shown great potential in offering sensitive detection of alendronate. This review article discusses with the specific focus on UV-spectroscopic techniques which are not only economical and easy to operate but also crucial for monitoring the controlled release of the drug.