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Ravi ★ India, 2009-01-12 11:57 (6365 d 10:05 ago) Posting: # 3020 Views: 7,762 |
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Dear all, Thanks for ur prompt replies to my quires previously. I have on more problem regarding Calculation of IVIVC using IVIVC toolkit of WinNonlin. I have tried performed Level A Correlation by the toolkit. In IVIVC Wizard under the In-Vitro tab four dissolution models are given. Now my first question is on what basis Model is choosen for a particular case (MR Formulation). My second question is same i.e. under the Correlation tab three models are given and which is to be choosen in which case and why? Third question is, In correlation tab we get Levy plots between Fraction absorved and Fraction Dissloved. This plot have one line known as Line of unity. Now what this line of unity stands for, what can we interpret from this and how? Sorry for so many questions and poor english. — Thanks & Regards Ravi Pandey |
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SDavis ★★  UK, 2009-01-15 01:48 (6362 d 20:14 ago) @ Ravi Posting: # 3031 Views: 7,300 |
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Hi Ravi, ❝ first question is on what basis Model is choosen for a particular case (MR Formulation). 4 built in models are currently supplied you can choose the most appropriate one for your data using normal fitting assessments e.g. AIC ❝ Second question is same i.e. under the Correlation tab three models are given and which is to be choosen in which case and why? the correlation models (3 built-in plus the option for custom models) are trying to account for lag, time shifting, speed and magnitude of response between plasma concentrations and dissolution profiles. You need to choose one that is appropriate for your data. the percentage error seen for Cmax and AUC on this page shows the difference between the observed PK and the PK your correlation model would predict. Try to minimise that, depending on your aims there are boundaries you must meet. ❝ Third question is, In correlation tab we get Levy plots between Fraction absorved and Fraction Dissloved. This plot have one line known as Line of unity. Now what this line of unity stands for, what can we interpret from this and how? if your correlation is 'good' you will be able to make predictions from %dissolution to %absorbed - a line of unity would be a 1 to 1 relation. However be careful with the automatically generated Levy plot as I think you need to make a couple of extra transformations to see the 'classic' graph you might be expecting. this is covered in the manual somewhere - I don't have that to hand but if you need it I can look it up, or you could drop a line to [email protected], (or try one of our courses! ;0) Simon --- _____________________________________ http://www.linkedin.com/in/simondavis Forthcoming meetings and training http://www.pharsight.com/training WinNonlin v5.2 Hands-on: 24-25 Feb 2009 Berlin, Germany WinNonlin v5.2 Hands-on: 9-10 Mar 2009 London, UK, WinNonlin IVIVC toolkit: 11 Mar 2009 London, UK |
Ing. Helmut Schütz