Bioequivalence and Bioavailability Forum • Tscale parameter calculation in winnonlin

vjkumar
☆

India,
2012-08-23 12:47
(5046 d 12:09 ago)

Posting: # 9095
Views: 6,812

Tscale parameter calculation in winnonlin [Software]

Dear all,
I am using winnonlin v. 6.2 with ivivc toolkit for ivivc,
I want to know how Time scalling parameter calculated in this software also i didn't understand the correlation parameter estimation specified in the manual for eg. Abscale and Tscale etc..initial value or bound should be provided for them..

Why there is need to give the upper bound and lower bound to be given
for Tscale parameter or Tlag?when it can be calculated only from Tvitro vs Tvivo Levy plot BY LINEAR REGRESSION or is it nonlinear regression :confused:

,

also can anyone elaborate the correlation model which are provided in
manual some of them as per i understood

(1) Fabs = Diss(Tvivo)

means :- regression between Fabs (amount absorbed at time invivo for given formulations) vs Diss (Tvivo) (amount dissolved at the corresponding invivo time for given formulations)
y=x;
y=amount absorbed at time invivo
x=amount dissolved at the corresponding invivo time(which can be
calculated easily from any dissolution fitted function which already
i have done in invitro tab)

(2) Fabs = AbsScale * Diss(Tscale * Tvivo)

means :- regression between Fabs (amount absorbed at time vivo for given formulations) vs Diss (Tvivo*Tscale) (amount dissolved at the (corresponding invivo time*Tscale) for given formulations)
here what is the need of intial value or bound to be given for Tscale which can be measured from Tvitro vs Tvivo Levy plot.

y=mx

y= Fabs(amount absorbed at time invivo)
m= Absscale parameter

x=amount dissolved at the (at time invivo*Tscale)
this amount(X) can be calulated from any dissolution data fitted model eg. hill, weibull which already i have done in invitro tab if i have Tscale
parameter obtained from Tvitro vs Tvivo Levy plot

Also when performing regression (most probably linear or is it NONLINEAR :confused:

if it is in nonlinear regression i think Absscale parameter's initial value or bound should be provided) between Fabs(amount absorbed at time invivo) vs amount dissolved at the (at time invivo*Tscale) Absscale parameter which can be calculated by simple regression-analysis equation THAN WHY BOUNDS OR INITIAL VALUE
SHOULD BE GIVEN
y=mx

y= Fabs(amount absorbed at time invivo)
x=amount dissolved at the (at time invivo*Tscale)
m= Absscale parameter

Please correct me if i am wrong..i will highly appreciate your response

Vijay

Helmut
★★★

Vienna, Austria,
2012-08-23 18:55
(5046 d 06:01 ago)

@ vjkumar
Posting: # 9098
Views: 5,673

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Dear Vijay,

although Simon Davis is a member of the forum there’s no guarantee that he will notice your post in due time. Consider registering at Pharsight’s Extranet and post your question there.

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Dif-tor heh smusma 🖖🏼 Довге життя Україна!
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Science Quotes

vjkumar
☆

India,
2012-08-24 11:26
(5045 d 13:30 ago)

@ Helmut
Posting: # 9101
Views: 5,644

⇒ Pharsight’s Extranet

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Dear Helmut,

I appriciate your response :-)

and i did the same, i am waiting for answer
but can anybody here put a light on Tscale parameter calculation and its use. because as far as i know about Tscale and Tlag should be calculated from levy plot by linear regression (right ?? :confused:

)...

what i understood (please correct me if i am wrong..i am novice here) for making a regression line in ivivc we proceed as:-

At any IN-VIVOtime we have fraction absorbed amount (Fabs) now we are correlating with fraction amount dissolved(Fdiss), this fraction dissolved (Fdiss) we calculate at a time(IN-VIVOtime*Tscale-Tlag) by using appropriate model like hill, weibull etc and parameter for those models (MDT,SHAPE PARAMETER) already have have been calculated by fitting given fraction dissolved and time in appropriate equation (hill or weibull)
now we will perform linear regression here for taking one or multiple formulatios and obtain a regression equation

y=mx+c

y= Fabs
x= Fdiss
m= slpoe
c= intercept
..right?

moreover i didn't see any intercept(c) in winnonlin ivivc..

Thanks,
waiting for your response
Vijay

Edit: Full quote removed. Please delete anything from the text of the original poster which is not necessary in understanding your answer; see also this post! [Ohlbe]

SDavis
★★

UK,
2012-08-25 10:49
(5044 d 14:07 ago)

@ Helmut
Posting: # 9106
Views: 5,676

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Thanks Helmut for the 'plug'. Anyone who wants to follow this conversation, please follow this link to the Pharsight forum;

http://www.pharsight.com/extranet/index.php?option=com_kunena&Itemid=55&func=view&catid=44&id=1200

thanks,
Simon.

Edit: Note that the link only works if you are registered and logged in to the Extranet. [Helmut]

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