A Green GLANCE‐Assisted Spectrofluorimetric Method for the Nanogram‐Level Quantification of Terazosin, Singly and in Combination With Triamterene, With Therapeutic Drug Monitoring Applications: Greenness, Whiteness, and Blueness Assessment

Hypertension (silent killer) is a leading cause of cardiac arrest and has become increasingly prevalent across all age groups. To support therapeutic drug monitoring of an antihypertensive combination, two highly sensitive spectrofluorimetric methods were developed for the analysis of terazosin (TRZ) and triamterene (TRM) as co‐administered drugs. Method I applied first‐derivative synchronous spectrofluorometry to analyze the combination, while Method II is conventional spectrofluorometry to determine TRZ alone. Method I measured the peak and trough intensities of TRZ and TRM at a constant wavelength difference Δλ 20 nm at 355 and 410 nm, respectively. The detection and quantitation limits for TRZ and TRM were 0.58 and 1.76 ng/mL and 0.27 and 0.80 ng/mL, through the entire range of 2.00–100.0 and 5.00–100.0 ng/mL, respectively, while Method II was calibrated at λem 380 nm after λex 330 nm within the 0.25–10.00‐ng/mL range with detection and quantitation limits of 0.07 and 0.21 ng/mL, respectively, and 10.00–100.0 ng/mL. Both approaches were validated and successfully applied in human plasma samples and dosage forms. Statistical analysis showed close agreement between the performance of the proposed and comparison approaches. Greenness, whiteness, and blueness were evaluated for both proposed procedures.