fatmaelzahraa
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2007-11-06 16:19
(5986 d 22:07 ago)

Posting: # 1289
Views: 14,064
 

 new trainer in bioequivalence study [Tips / Tricks]

I am a research chemist.....
really we have a drug to do bioequivalence study....
I am new in this field.... as I a experienced in dissolution testing, HPLC, but I am so bad in stastical calculations and also the main idea of this study, and its results indication...
Please can u help me to be a good one.....?
what should I know?
what should I read?
Helmut
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Vienna, Austria,
2007-11-08 14:47
(5984 d 23:40 ago)

@ fatmaelzahraa
Posting: # 1291
Views: 11,804
 

 BE basics

Dear fatmaelzahraa!

❝ ... I am so bad in stastical calculations and also the main idea of this study, and its results indication...


For a summary of basic designs see this thread.

❝ Please can u help me to be a good one.....?

Hhm,... :ponder:

❝ what should I know?


I would start with:
  • read all the threads of this Forum, ;-)
  • browse through the archives (look for 'Summaries of PharmPK discussions') of David Bourne's PK/PD-List,
  • a basic course in pharmacokinetics (otherwise you will never understand the important points),
  • a basic course in statistics for nonstatisticians (optional, but highly recommended),
  • a basic course in BA/BE.
Not participating in some courses and only reading textbooks and articles (i.e., starting from scratch) is close to reinvent the wheel and very time consuming; you should avoid attending conferences on BA/BE in such an early stage, because they generally are too technical and not suitable for beginners.

❝ what should I read?


For a collection of textbooks see this post. National and international guidelines are given here.

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drrammohanj
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2007-12-20 09:32
(5943 d 04:55 ago)

@ Helmut
Posting: # 1401
Views: 11,288
 

 BE basics

Dear Helmut,

I am not a Bio-statistician, I know that all biological samples follow normal distribution before or after log transformation of data, in present context PK data. when I see a statistical report, I won't understand the statistical report after log tranformation of Pk data, like point estimate, CV, ANOVA, p-value, t-test, least square mean (LSM) etc.

can you give me algorithm of calculation of data.

I think it is very difficult question for you to answer


with best regards
Ram Mohan
Helmut
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Vienna, Austria,
2007-12-20 14:15
(5943 d 00:12 ago)

@ drrammohanj
Posting: # 1404
Views: 12,470
 

 BE basics

Dear Ram!

❝ … that all biological samples follow normal distribution before or after log transformation of data, in present context PK data.


It’s a common consensus that some metrics follow a normal distribution (untransformed data, additive model), e.g., Ae (amount excreted), whilst others follow a log-normal distribution (multiplicative model), e.g., AUC, Cmax,…
Due to the sampling schedule the theoretical continous metric tmax has to be assessed by nonparametric methods (valid for discrete data).

Rationale behind assuming a multiplicative model (i.e., performing the analysis on log-transformed data):Since parametric statistical methods (ANOVA, GLM, t-test, F-test,…) call for normally distributed data, additivity of effects, etc. and some metrics follow a log-distribution, data have to be transformed before analysis.

❝ when I see a statistical report, I won't understand the statistical report after log tranformation of Pk data, like point estimate, CV, ANOVA, p-value, t-test, least square mean (LSM) etc.


What are you problems in particular? Maybe the report is not clearly written. Generally PE and the confidence interval should be back-transformed into the linear domain. Example:
Acceptance range [0.80, 1.25] (Napierian log: [-0.2231, +0.2231])
Unity 1.0 (log: 0)
PE [CI] from study's ANOVA on log-data: -0.02314 [-0.1231, +0.07686] Back-transformation:
PE: ℯ–0.02314 = 0.9771 (or 97.7%)
CI: ℯ–0.1231 = 0.8841 (88.4%), ℯ+0.07686 = 1.080 (108%)

❝ can you give me algorithm of calculation of data.


Please refer to this post. As a starter I would recommend Hauschke et al. (2007), Patterson & Jones (2006), and Chow & Liu (2000).

❝ I think it is very difficult question for you to answer


No, not at all… :wink:
… but not within even a couple of posts!

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