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Hi Helmut,
I may add some background information.
China's regulatory agency (NMPA/CDE) refused to approve multiple highly-variable products which conducted their bioequivalence study in a four-period crossover design. The reason for this acion was based on "The similarity of plasma-concentration curves of the same subject between TEST and REFERENCE is larger than the similarity between two repeated REFERENCE".
I tried to calculate the f2 factor using the Cmax value of the reference product as a correction factor, and I found many different products had a similar pattern that "The similarity of plasma-concentration curves of the same subject between TEST and REFERENCE is larger than the similarity between two repeated REFERENCE".
I believe this is due to the nature of highly-variable products and randomness, but I am not sure if this is correct. Does FDA or EMA have similar statments?
Thanks
I may add some background information.
China's regulatory agency (NMPA/CDE) refused to approve multiple highly-variable products which conducted their bioequivalence study in a four-period crossover design. The reason for this acion was based on "The similarity of plasma-concentration curves of the same subject between TEST and REFERENCE is larger than the similarity between two repeated REFERENCE".
I tried to calculate the f2 factor using the Cmax value of the reference product as a correction factor, and I found many different products had a similar pattern that "The similarity of plasma-concentration curves of the same subject between TEST and REFERENCE is larger than the similarity between two repeated REFERENCE".
I believe this is due to the nature of highly-variable products and randomness, but I am not sure if this is correct. Does FDA or EMA have similar statments?
Thanks
Complete thread:
- Comparing two plasma concentration profiles Darborn 2025-10-17 05:40
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- Comparing two plasma concentration profiles Helmut 2025-10-17 12:51
- Comparing two plasma concentration profilesDarborn 2025-10-21 01:02
- Comparing two plasma concentration profiles ElMaestro 2025-10-21 12:39
- Comparing two plasma concentration profiles Shuanghe 2025-10-29 16:27
- Comparing two plasma concentration profilesDarborn 2025-10-21 01:02
- Negative ƒ2 is possible Helmut 2025-10-30 15:40
- Interesting, however... ElMaestro 2025-11-03 14:15
- Negative ƒ2 is possible Darborn 2025-11-07 06:04
- Comparing two plasma concentration profiles Helmut 2025-10-17 12:51
Ing. Helmut Schütz