Table 1 Eligibility criteria
Inclusion criteria | Exclusion criteria |
|---|---|
• peer-reviewed original articles with full-text available • no restriction regarding country and date • articles in English language or with English abstracts • articles that present proportions of original and/or counterfeit and/or substandard drugs | • abstract-only papers as preceding papers, conferences, editorials, and author response theses and books • articles without full text available • articles where the exact composition of analyzed IPEDs is not provided by the author • to increase the homogeneity, article with mixed samples (e.g., if the analysis includes different classes of IPED) in which data on AAS are < 75% of the analyzed substances |