# PharmPK Discussion - Tablet content uniformity

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• On 29 Mar 2013 at 22:36:11, sent the message
`Dear All,Here is a statistical question I need help to respond:  Five batches oftablets have been produced and the average drug content (10 tabletsassayed per batch) is 99.2 mg with a standard deviation of 2.4. How manytablets should be assayed (sample size?) in order to statistically showthat there is zero or near zero possibility that an individual tabletproduced will have a drug content higher than 110 mg? Thank you.Konstantinos Avgoustakis`
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• On 1 Apr 2013 at 12:49:50, "Lavigne, Jean" (jean.lavigne.-at-.celerion.com) sent the message
`The following message was posted to: PharmPKDear Konstantinos,You have 4.5 standard deviation [=(110-99.2)/2.4].Assuming a normality distribution, the probability of being lower or equal to110 is 0.999996602.You may want to do an ANOVA to include the variability between batch to be moreprecise.You already have a sample size of 50 (10 tablet per batch), increasing thesample size will just increase the power (more precise mean and variability ofthe "true" distribution), it will not change the probability of having anindividual tablet above 110 mg.Other non-parametric estimation is to calculate the proportion of individualtablet that are above 110 mg in a very large sample size.Jean`
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• On 1 Apr 2013 at 08:41:53, David Bourne (david.aaa.boomer.org) sent the message
`Dear Avgoustakis,Please check you want to study according USP or B.P. and the follow that book details.Dr Zafar`
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