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RegisterCVintra ≤ CVwr [Power / Sample Size]
posted by Helmut 
– Vienna, Austria, 2012-09-13 16:45 (5025 d 10:57 ago) – Posting: # 9201
Views: 3,597
Hi Nee!
In a 2×2 crossover the CVintra is actually a pooled estimate from σ²WR and σ²WT. If you assume that these variances are equal you can apply CVintra directly. Since pharmaceutical technology improves, quite often σ²WR > σ²WT. CVintra from the 2×2 crossover will be < CVWR (‘dampening effect’ of σ²WT).
Now you have two options:
Yes, this is the right reference.
❝ We have the CV% of a 2x2 crossover study. Based on this CV can we calculate the sample size for SABE?
In a 2×2 crossover the CVintra is actually a pooled estimate from σ²WR and σ²WT. If you assume that these variances are equal you can apply CVintra directly. Since pharmaceutical technology improves, quite often σ²WR > σ²WT. CVintra from the 2×2 crossover will be < CVWR (‘dampening effect’ of σ²WT).
Now you have two options:
- Allow for a safety margin (e.g., use a higher CV).
- Perform a pilot study in a replicate design.
❝ […] find the sample size from this article "Sample Sizes for Designing Bioequivalence Studies for Highly Variable Drugs"?
Yes, this is the right reference.
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Complete thread:
- Sample size calculation for SABE aquapurple 2012-09-13 07:14
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- CVintra ≤ CVwrHelmut 2012-09-13 14:45
Ing. Helmut Schütz