Bioequivalence and Bioavailability Forum

Dear All,

We have done a pilot 3 way crossover study(3trt 3prd 3seq) compairing two test and one reference using a MIXED model with SUB(SEQ) as random.

The cov parms estimates for SUB(SEQ) and Residual are used for the inter and intra CV calculation using the formula given below

Inter CV = sqrt(exp(sub(seq))-1)
intra CV = sqrt(exp(Residual)-1)

where sub(seq) and residual estimates are obtained from the covariance parameter estimates table from the SAS output given below

Covariance Parameter
Estimates
Cov Parm Estimate
Subject(Seq) 0.01100
Residual 0.03186

and which also same as that of the estimates from the 'Final Variance Parameters' sheet of WinNonlin.

but when calculating the inter and intra CV's using the above formulas, the intra CV (18%) is larger than inter CV (11%) for Cmax and AUC.

Is it possible?...Whether the formula is correct? If not please give me correct formula for the inter and intra calculation.

Regards

Matz

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Edit: Category changed. [Helmut]