Background: Antibiotics remain the cornerstone of modern medicine, preventing deaths from bacterial infections that
would otherwise have been fatal. However, the widespread circulation of counterfeit and substandard medicines,
especially in developing countries, has emerged as a critical challenge for public health. Amoxicillin, a broad-spectrum
beta-lactam antibiotic, is among the most prescribed drugs in Zambia, yet little evidence exists on the quality of brands
circulating in the local market. This study assessed the quality standards of amoxicillin capsules sold in Lusaka, Zambia,
with a focus on active pharmaceutical ingredient (API) content, stability, labelling, and compliance with international
standards.
Methods: A descriptive cross-sectional study was conducted between August and September 2023 in the Lusaka district.
Twelve brands of amoxicillin capsules were randomly collected from pharmacies, hospitals, and informal retail outlets,
yielding 384 capsule samples. Analytical testing was performed using High-Performance Liquid Chromatography (HPLC)
according to United States Pharmacopoeia (USP) standards. Data on labelling and packaging were also collected. Results
were analysed using SPSS version 21.0.
Results: Out of the twelve brands tested, only three (25%) complied with USP specifications for API content (90–120%
of the labelled claim). Nine brands (75%) contained insufficient API, ranging from 52% to 88%. Stability tests over 14 days
revealed a significant decline in API content, raising concerns about degradation during storage. Labelling analysis
showed that 25% of brands lacked manufacturer license numbers and 50% failed to indicate the date of manufacture. All
samples contained amoxicillin as indicated, but varied greatly in concentration.
Conclusion: The study demonstrates a high prevalence of substandard amoxicillin capsules in Zambia, with major
implications for antimicrobial resistance (AMR), treatment failure, and public health. Strengthening local manufacturing,
enforcing Good Manufacturing Practices (GMP), and enhancing pharmacovigilance systems are crucial steps forward.
This study provides baseline data for policymakers, regulators, and healthcare practitioners.

Keywords: Amoxicillin, substandard drugs, antibiotic resistance, Zambia, pharmaceutical quality, HPLC, USP
compliance.