The use of low-quality antibiotics presents a major risk to global health by contributing to the rising tide of antimicrobial resistance while simultaneously jeopardizing the health of patients. This capstone project focuses on the quality evaluation of 500 mg amoxicillin capsule formulations from two commercial brands available in Saudi Arabia. In this study, two brands were included in this study to be investigated, Amoxil and Omacillin to form 50 capsules were collected from registered pharmacies. Active pharmaceutical ingredients content was measured using High-Performance Liquid Chromatography HPLC and was validated as per International Council for Harmonisation (ICH) Q2(R1) guidelines. Important validation criteria were all met, including R2 > 0.99 for linearity, %RSD 1% for precision, 98-102% recovery for accuracy, 0.3% interference for specificity, and established levels of sensitivity for LOD (Limit of Detection) and LOQ (Limit of Quantification) which were LOD ~1,500 ppm and LOQ ~5,000 ppm. The results suggest that the majority of the samples achieved the label claim and were in the range of 90-110% which indicates compliance with the pharmacopeial. In addition, the other observed results justify the need for constant post marketing surveillance. The study concludes that HPLC is a reliable method for assessing the quality of antibiotics and calls for greater collaboration from manufacturers, regulators, and pharmacists to prevent inconsistencies at the batch level and address the issue of increasing antibiotic resistance
Keywords: Amoxicillin, Counterfeit detection, HPLC, Drug quality, Pharmaceutical analysis.
How to cite this article:Alnafisah AH, Almunahi SF, Kalo NA, Idris M, Altowairqi GAA, Alsulami HMM, Kannikanti GH, Identifying Counterfeit Variants in Amoxicillin Formulation Using HPLC. 2026;16(1s): 830-839; DOI: 10.25258/ijddt.16. 830-839