Levofloxacin Quantification in Pharmaceutical Tablets Using Highly Sensitive Spectrofluorometric Analysis with Benzidine as a Fluorescent Reagent

Abstract
To ensure correct dosage, therapeutic effectiveness, patient safety, and quality control during manufacturing and storage, it is essential to determine the concentration of pharmaceutical products. This study presents the development of a straightforward, precise, and sensitive spectrofluorometric method for the quantitative analysis of levofloxacin in various pharmaceutical products, utilizing benzidine as a fluorescence reagent. The approach utilizes the quenching effect of levofloxacin on the intrinsic fluorescence signal of benzidine when combined with a Britton-Robinson buffer solution (pH 9.0), resulting in the formation of a stable ion-associated complex. The measurement of benzidine fluorescence intensity reduction occurred at 407 nm after excitation at 285 nm. A strong linear relationship (R² = 0.9995) was observed between the quenching fluorescence intensity (ΔF) and the concentration of levofloxacin, which ranged from 0.10 to 10 μg ml-1, with a detection limit of 0.08 μg ml-1. The method demonstrated minimal interference from frequently present substances in pharmaceutical formulations. The results were confirmed by comparing them to a standard high-performance liquid chromatography (HPLC) method. The suggested spectrofluorometric method is a reliable way to check the amount of levofloxacin in medicine tablets regularly.

Author
Aryan Fathulla Qader

DOI
https://doi.org/10.22036/abcr.2025.515869.2320

ISSN
2383-093X

Publish Date: 8-Sep-2025