# PharmPK Discussion - Unequal washouts during BE studies

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• On 20 Sep 2005 at 22:52:18, "Rhishikesh Mandke" (mandke.rhishikesh.aaa.gmail.com) sent the message
`Dear Group,Recently during one of our 3-way BE studies, 2 volunteers from agroup of 18 were absent for second period. However, these volunteersagreed to participate in the study further and the study wascontinued. Now the problem is as follows.16 Volunteers: Washout between period 1 and 2: (x) days.                         Washout between period 2 and 3: (x) daysRest 2 Volunteers: Washout between period 1 and 2: (x + 7) days                         Washout between period 2 and 3: (x) daysMy first question is that, will this kind of unequal washout affectthe PK parameters measured during the study?My second question is that how this kind of situations treatedstatistically? (What I wanted to know is whether any specialstatistical treatment has to be given during such situations)Thanks and best regards,Rhishikesh MANDKE`
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• On 21 Sep 2005 at 04:40:34, Priti Pandey (priti_pandey.-a-.yahoo.com) sent the message
`Hello Rhishikesh,There are two methods to do statistical analysis in this case. Eitheryou eliminate those two subjects who were absent during period II oranalyse all the 18 subject subjects. In the first case, you arereducing power of your study. In second case your power will be morebut you are using missing value for two subjects in statisticalanalysis. It is upto you how you want to go ahead.Statistial purpose to give equal wash out period between each periodis to test: "Is there significant difference between carry over ornot if it exist?"So unequal wash-out period won't affect much if you have given enoughwashout period between each period in case of bioequivalence. ifthere is any carry over then you will come to know in pre dosesampling time point. if this situation is out of question then youcan go ahead with unequal wash-out period for statistical analysis.All the bestPriti PandeyRanbaxy, India`
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• On 21 Sep 2005 at 07:18:39, manish issar (issarmanish.aaa.yahoo.com) sent the message
`HiI would like to add in addition to what preeti just mentioned.Before the study is initiated there has to be a mention in theprotocol how incomplete data (like missing samples or subjects notcompleting the perioid) is going to be handled in the PK statistics.One cannot make decisions after the study has been executed. Alsorejection of data cannot be according to ones wish.hope this helpsManish Issar, Ph.DSandoz4700 Eon DriveWilson, NC-27893`
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• On 21 Sep 2005 at 13:37:05, Prah.James.at.epamail.epa.gov sent the message
`The following message was posted to: PharmPKDear Manish,In addition one would want to define in the protocol how an outlier isdefined rather than doing it post hoc.JimJames D. Prah, PhDUS EPAHuman Studies Division MD (58B)Research Triangle Park, NC, 27711919 966 6244919 966 6367 FAX`
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