Bioequivalence and Bioavailability Forum

Hi Anu,

please don’t fork; sounds like your previous thread.

❝ A crossover study with 21 subjects. It was Average daily Urinary analysis study with phosphorus as a component.

❝ Bioequivalence assessment using pharmacodynamics:

❝ 1. Test-Reference= -0.69

❝ 2. 90 % CI = -1.07 to -0.30 which is in the limit of ( -20 to 20) %

Are you sure you know what you are doing? I would not call P-excretion a PD measurement (though it might be an effect, you have still to deal with concentrations/amounts). Whether amount excreted follows a normal distribution or lognormal is subject of heated debates. Personally I tend towards the former.
You didn’t give units. Normal ranges of P in 24 h-urine are 0.8–1.6 mmol/L (2.5–4.9 mg/dL). If you assume a normal distribution, you should apply an additive model (untransformed data) and (!) state the acceptance range in absolute values – not percent (I have no idea, maybe –0.75 mg/dL, +0.75 mg/dL). So what was stated in the protocol? If you want to deal with percentages and still assume normal distri­buted data, you have to go with Fieller’s confidence interval (then the acceptance range would be 80–125%). For some references see this thread.