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neethu ☆ 2008-07-31 13:44 (6127 d 01:34 ago) Posting: # 2116 Views: 10,678 |
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hello, I want to know the resons for the period effect and subject nested in sequence in a BA/BE study? Thanks®ards Neethu Research Assistant-Biostatistics -- Edit: Category and unspecific subject line changed. Please see here. [Helmut] — Thanks & Regards Nees |
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ElMaestro ★★★ Denmark, 2008-07-31 14:15 (6127 d 01:03 ago) @ neethu Posting: # 2117 Views: 9,290 |
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Dear Neethu, a period effect could arise when the washout period was too short. In that case you might see positive (non-zero) pre-dose levels period 2. Subject effect is a little different. Generally, not two people on this planet are identical (neither in looks, nor in PK, nor in ...) etc. But we need to bear in mind that the subj effect is evaluted by F being the between-MS divided by within-MS. When F is significant (large) then the between-MS is larger than the within-MS. This gives you joy and happiness in your evaluation of the 90% Conf. interval. EM. |
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neethu ☆ 2008-07-31 15:12 (6127 d 00:06 ago) (edited on 2008-08-01 09:06) @ ElMaestro Posting: # 2118 Views: 9,245 |
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Dear Em, Thanks for ur reply. If the wash out period is for 10 days for the test drug. then how the period effect is occuring? -- Edit: Full quote removed. Please see this post! [Jaime] — Thanks & Regards Nees |
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ElMaestro ★★★ Denmark, 2008-07-31 15:58 (6126 d 23:20 ago) @ neethu Posting: # 2120 Views: 9,294 |
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Dear Neethu, no one knows what the chance is of getting a period effect even if there is none. It happens and one must be aware of this. Is it significant for both AUCt, Aucinf and Cmax? Second, try and look at the LSMeans for period1 and period2: how different are they? Which one is higher? What type of API are you working with? BREM. |
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neethu ☆ 2008-08-01 08:16 (6126 d 07:02 ago) (edited on 2008-08-01 09:10) @ ElMaestro Posting: # 2123 Views: 9,222 |
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Dear EM, The period effect is significant for the AUCt,AUCinf and Cmax for the test drug.bt for the refernce drug AUCt,AUCinf and Cmax the period effect is not significant. -- Edit: Full quote removed. Please see this post! ...and this one also. [Jaime] — Thanks & Regards Nees |
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ElMaestro ★★★ Denmark, 2008-08-01 10:45 (6126 d 04:33 ago) @ neethu Posting: # 2124 Views: 9,241 |
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Hi Neethu, You wrote: ❝ The period effect is significant for the AUCt,AUCinf and Cmax for the test drug.bt for the refernce drug AUCt,AUCinf and Cmax the period effect is not significant. This sounds confusing to me; what design has been used, and are you sure you are not confusing unequal carry-over with period effect? Could you paste the ANOVA table here, along with the period means? And please provide info on the api. BR EM. |
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neethu ☆ 2008-08-01 14:04 (6126 d 01:14 ago) @ ElMaestro Posting: # 2126 Views: 9,209 |
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The design used is a 2x2 cross over design. In the ANOVA table the P-value of period for the test drug for AUCt is 0.0492.for AUCinf is0.0304 nad for Cmax is 0.0020. The P-value for the refernce drug for AUCt is 0.1577,AUCinf is 0.1018 and for Cmax is 0.3919. -- Edit: Full quote removed. Please see this post! ...and this one also. [Jaime] — Thanks & Regards Nees |
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Jaime_R ★★ Barcelona, 2008-08-01 14:55 (6126 d 00:22 ago) @ neethu Posting: # 2129 Views: 9,174 |
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Dear Neehtu! ❝ The design used is a 2x2 cross over design. ❝ [...] P-value of period for the test drug for AUCt is 0.0492 [...] ❝ for the refernce drug for AUCt is 0.1577. I'm as confused as ElMastro. In a 2x2 cross-over it's simply not possible to distinguish between treatment-/period-/sequence-effects separated for treatment (there's just one period effect in ANOVA; not 'PE for test' and 'PE for reference'). Where do you get this numbers from? Can you please come up with a table here (columns: subject, period, sequence, AUCt - one row per subject), or provide a link to a text-file for download. If you decide posting it here, please don't use tabulators to separate columns (see here how to format tables). — Regards, Jaime |
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shankar ★ India, 2008-07-31 16:01 (6126 d 23:17 ago) @ neethu Posting: # 2121 Views: 9,250 |
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Dear Neethu, Please note that as per FDA recommendation "more than 5 half lives of the moieties to be measured" for washout period. Period effect may due to posture, conditions, formulation effect and gastric empting time of individuals. Thanks, — Shankaranarayanan |
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neethu ☆ 2008-08-01 14:07 (6126 d 01:10 ago) @ shankar Posting: # 2128 Views: 9,211 |
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Hai, The period effect for the test drug for AUCt,AUCinf and Cmax are significant.But the period effect for the reference drug is not significant for any of these parameters... -- Edit: Full quote removed. Please see this post! [Jaime] — Thanks & Regards Nees |
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ElMaestro ★★★ Denmark, 2008-08-01 15:21 (6125 d 23:56 ago) @ neethu Posting: # 2130 Views: 9,143 |
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Dear Neethu, Think of your design: 2 treaments, two periods, two sequences. Each subject is assigned to either sequence TR (P1: test; P2: ref) or RT (p1: Ref; P2:test). Not TT and/or RR. Therefore, you are not able to acquire any data that indicate that there is a period effect for the test but not for the ref etc. Best regards EM. |
Ing. Helmut Schütz