Analysis of Counterfeit Antimicrobial Tablets Intercepted at Lagos Port Using Fourier Transform Infrared Spectroscopy

Counterfeit pharmaceuticals represent a major public health challenge in Nigeria, with antimicrobial agents among the most frequently falsified drug classes. The Lagos seaport complex serves as a critical entry point for both genuine and falsified medicinal products. This study analysed fifteen batches of antimicrobial tablets intercepted by regulatory officers at Lagos Port using Fourier Transform Infrared Spectroscopy combined with UV-Visible spectrophotometry. Products included tablets labelled as amoxicillin, ciprofloxacin, and metronidazole. The FTIR spectra of each sample were compared with reference spectra of authentic pharmaceutical standards. Quantitative determination of active pharmaceutical ingredient content was performed by UV spectrophotometry against externally validated calibration curves. FTIR analysis confirmed substandard or falsified composition in nine of the fifteen batches, with three samples showing no detectable API by either method. Ciprofloxacin tablets showed the highest rate of falsification, with four of five batches containing less than 50% of the declared content. Metronidazole samples had the lowest falsification rate but showed significant impurity peaks inconsistent with genuine products. The study demonstrates the effectiveness of FTIR as a rapid screening tool for counterfeit detection at Nigerian ports. Expanded deployment of portable FTIR instruments at entry points is recommended. Keywords: counterfeit drugs, FTIR spectroscopy, antimicrobials, Lagos Port, quality control.