Bioequivalence and Bioavailability Forum

Dear all,

how can we calculate the sample size for the bioequivalence studies which require clinical endpoints especially Gel & cream formulations.

where do we get the information on the variability and other parameters like mean difference values of test and reference etc. required to calculate sample size.

what are the formulas & softwares usually used?

Do we have to do a pilot study to estimate the parameters, if so how may subjects should be considered in pilot study?

please enlighten me on this.

Thanks in advance