Turning on fluorescent probe for sensitive detection of streptomycin in pure, pharmaceutical formulations and human plasma

Streptomycin is a clinically important aminoglycoside antibiotic widely used for treating tuberculosis and other bacterial infections. Accurate determination of its concentration is essential for quality control, therapeutic drug monitoring, and preventing toxic effects associated with overdosing or accumulation in the environment. In this work, a simple, rapid, and highly sensitive spectrofluorimetric method was developed for quantifying streptomycin in pure form, pharmaceutical vials, and human plasma using fluorescamine as a fluorogenic probe. The method is based on the reaction of fluorescamine with the primary amine group of streptomycin under mild alkaline conditions to yield a fluorescent product emitting at 482 nm (excitation 390 nm). The calibration curve was linear over the range 100-600 ng/mL, with a correlation coefficient of 0.9999, a detection limit of 8.3 ng/mL, and a quantitation limit of 25.2 ng/mL, ensuring sensitive and accurate determination across the studied range. The procedure demonstrated high precision (RSD < 2%) and accuracy (recoveries 98.1-101.3%). The method was successfully applied to commercial streptomycin vials (% recovery = 99.7 ± 0.8) and to spiked human plasma samples with negligible matrix interference. Owing to its simplicity, short analysis time (3 min), and excellent reproducibility, the proposed assay offers a cost-effective alternative to chromatographic methods for routine quality control and bioanalytical applications.