AI ‐assisted identification of a novel vardenafil analog ( KD ‐027) adulterated in capsules

Sexual dysfunction is a health issue that significantly affects adults. However, the increased demand for pharmacological treatments, such as sildenafil, tadalafil, and vardenafil has led to the emergence of counterfeit drugs, posing a serious public health concern. These counterfeit drugs and their analogs often lack clinical validation, leaving their effects on the human body largely unknown. In this case study, a suspected novel vardenafil analogue adulterated in sexual enhancement capsules was identified using gas chromatography–mass spectrometry (GC–MS). High‐resolution mass spectrometry (LC‐HRMS) was employed to determine the protonated molecular ion at m / z 562.2438 for the compound, and its possible elemental compositions were predicted. Based on AI‐assisted analysis using ChatGPT–4o, the compound was inferred to be KD‐027 (SLx‐2101), a potential phosphodiesterase type 5 (PDE5) inhibitor. Following purification by column chromatography, nuclear magnetic resonance (NMR) spectroscopy confirmed this structure. In addition, evidence of coexisting E/Z tautomerism of KD‐027 was observed in the NMR data. To the best of our knowledge, this is the first report to identify KD‐027 in sexual enhancement products, providing its characteristic mass spectral fragments and NMR data, and demonstrating the utility of ChatGPT–4o in forensic investigations.