Evaluating Chromatographic and Spectroscopic Techniques in Counterfeit Drug Identification

Abstract

Counterfeit pharmaceuticals present a serious global health risk, with sildenafil being among the most frequently falsified drugs. Rapid and accurate detection methods are essential to ensure patient safety, maintain public trust, and support regulatory enforcement. This study evaluates and compares the performance of five analytical techniques-UV-Vis spectrophotometry, GC-MS/MS, HPLC-PDA, LC-MS/MS, and UPLC-QTOF-in the detection and authentication of sildenafil in genuine, generic, and potentially counterfeit samples.

UV-Vis provided a cost-effective preliminary screening tool, showing consistent λ max values (~290 nm) but limited quantitative accuracy. GC-MS/MS offered strong selectivity but was restricted by volatility and thermal stability requirements. HPLC-PDA balanced speed and robustness for routine quality control, while LC-MS/MS achieved the highest sensitivity and specificity, allowing accurate detection and quantification with short retention times. UPLCQTOF delivered high-resolution mass measurements and precise fragmentation patterns, enabling confident molecular identification.

The results highlight LC-MS/MS and UPLC-QTOF as the most effective confirmatory techniques, with UV-Vis and HPLC-PDA serving as valuable tools for initial screening and routine analysis. Integrating multiple analytical methods provides a comprehensive approach to combating counterfeit pharmaceuticals, enhancing regulatory capacity, and safeguarding public health.