To assess the quality of amoxicillin products in Indonesia’s private market by surveying the range of products available across different areas, followed by product sampling and laboratory testing.

A cross-sectional survey employing mystery shoppers to purposively sample the widest possible range of amoxicillin products available to patients across different areas in Indonesia.

Licensed and unlicensed medicine outlets in remote, rural and urban areas and online.

Amoxicillin products that are sold to patients as oral solid and dry liquid formulations.

Quality of amoxicillin products, assessed using compendial testing of active pharmaceutical ingredient content and dissolution. Samples that failed any quality test were classified as substandard or out-of-specification (OOS). The raw prevalence of substandard amoxicillin was adjusted based on the national market volume of each product variant.

We surveyed 476 outlets, mostly pharmacies (68.5%), websites (19.7%) and drug stores (10.9%). Among the 120 collected samples, there were 59 distinct products, collectively representing 95% of the estimated market volume for oral solid products and 65% for dry syrups. 12 out of 110 oral solid samples tested OOS (10.9%), as did 3 out of 10 dry syrups (30%). The samples that failed originated from various areas and types of outlets. We found no relation between the price and quality of amoxicillin.

The oral solid amoxicillin products that tested OOS represent an estimated 12.7% of the national market volume. We found no relation between the price and quality of amoxicillin. Combining product-variety sampling with data on market volume presents a promising approach to gain insight into the prevalence of poor-quality medical products using a relatively small sample size.