Determination of vidarabine using fluorescein sodium probe-based resonance Rayleigh scattering

The establishment of novel methods for drug content determination provides additional options for pharmaceutical quality control. A new method for detecting vidarabine (Ara-A) has been developed, utilizing the acidic anionic dye Fluorescein Sodium (FLS) as a resonance Rayleigh scattering (RRS) probe. Within a Clark-Lubs buffer system at pH 6.2, supramolecular aggregates were formed by the self-assembly of FLS molecules which is driven by intermolecular hydrogen bonding. Ara-A molecules bind to these aggregates also through intermolecular hydrogen bonding, forming larger supramolecular aggregates that enhance the resonance Rayleigh scattering signal. The results demonstrate a significant enhancement of the RRS signal at 508 nm. A clear proportionality of the signal to Ara-A levels was evident over the 0.5-5 mg L^-1 range, with the method achieving a sensitivity down to 0.088 mg L^-1 and an average recovery of 100.04-102.31%, offering an innovative, cost-effective, and highly sensitive approach for quantifying vidarabine in injectable formulations.