Rapid detection of multiple sildenafil and tadalafil adulterants in dietary supplements by dual-labeled probe time-resolved fluorescence immunochromatography assay

In recent years, phosphodiesterase type 5 enzyme inhibitors, including tadalafil, sildenafil, and their analogues have emerged as illegal ingredients in dietary supplements. It can cause serious clinical side effects in consumers, resulting in diverse symptoms. To rapidly screen illegal drugs in dietary supplements, a dual-labeled probe time-resolved fluorescence immunochromatography assay (DL-TRFICA) based on two broad-spectrum antibodies labeled with time-resolved fluorescent microspheres was established for the simultaneous qualitative and quantitative detection of nine sildenafil-like and three tadalafil-like adulterants. The half-maximal inhibitory concentration (IC50) of sildenafil-like and tadalafil-like adulterants were 2.49–5.88 and 2.15–2.78 ng mL−1, the limit of detection were 0.08–1.66 and 0.59–1.85 ng mL−1, and the visualization value (cut-off value) were 31.25–250 and 50–62.50 ng mL−1, respectively. Notably, the potential practical applications of DL-TRFICA evaluated by conducting a quantitative evaluation of sildenafil and tadalafil adulterants in dietary supplement samples (herbal spirit drinks, healthcare oral liquids, and herbal medicine pills) demonstrated a recovery rate ranging from 80.0% to 125.8% with a coefficient of variation of less than 15%, which concluded that the DL-TRFICA approach could be used in real sample detection.