15165 IUPAC Gold Book - crossover study 10.1351/goldbook.15165 15165 current 1 Type of comparative bioavailability study designed in such a way as to take into account differences in bioavailability arising from differences between patients suffering from disease, participating in the study. The differences between the subjects may be in age, stage or severity of the disease, and prior drug treatment that some may have received. In such a crossover study, the patients are divided into two equal size groups, uniform with respect to age, body weight, sex, etc. The first group is given a specific dose of the product studied, while the second group is given a second product of proven clinical efficacy, containing the same active ingredient. After taking an appropriate number of blood samples from each individual and a washout period, the groups are reversed and the first group is given the product of proven clinical efficacy and the second is given the product being studied. This way each patient serves as his or her own control. PAC, 2009, 81, 971. 'Glossary of terms related to pharmaceutics (IUPAC Recommendations 2009)' on page 980 (https://doi.org/10.1351/PAC-REC-04-10-14) https://goldbook.iupac.org/terms/view/15165/html https://goldbook.iupac.org/terms/view/15165/json https://goldbook.iupac.org/terms/view/15165/plain Citation: 'crossover study' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.15165 The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using. 2026-06-28T15:43:50+00:00