Bioequivalence and Bioavailability Forum • TTT method

TTT method [NCA / SHAM]

posted by Helmut – Vienna, Austria, 2008-05-10 15:56 (5828 d 09:43 ago) – Posting: # 1844
Views: 26,863

Dear Detlew,

just discovered a recent paper:

Scheerans C, Derendorf H, Kloft C. Proposal for a Standardised Identification of the Mono-Exponential Terminal Phase for Orally Administered Drugs. Biopharm Drug Dispos. 2008; 29(3): 145–57. doi:10.1002/bdd.596

Authors recommend the so-called TTT (two times t_max) method for identifying the mono-exponential terminal phase in the case of oral drug administration. Rules for selecting sample points in the estimation of lambda_z are quite simple:
First point: 2× t_max – or, if no sampling point is available, the subsequent one in the profile
Last point: last measured (C ≥LLOQ)

A large Monte-Carlo-Study was performed to compare the TTT-method to the maximum adjusted R² algorithm (ARS). TTT was found to be superior to ARS, both in terms of bias and precision.

The method is not intended as an automated procedure – and for any ≥1 compartment model, which shows up as a multilinear decline in a lin/log-plot.
Quote:

“It should be emphasised that the TTT method has been introduced in this paper to provide a reasonable tool to support visual curve inspection for reliably identifying the mono-exponential terminal phase. Moreover, the TTT method should not be utilised without visual inspection of the respective concentration-time course. Thus, before using this new approach the monophasic shape post the peak of the curve has to be checked visually by means of a semilogarithmic diagram.”

P.S.: For my example data set five points would be chosen again.

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Helmut Schütz

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Complete thread:

Methods for calculation of half lives d_labes 2008-02-01 14:58 [NCA / SHAM]
- Methods for calculation of half lives Helmut 2008-02-01 16:59
  - Methods for calculation of half lives Ohlbe 2008-02-02 23:00
    - Minimum AIC?! Helmut 2008-02-03 13:49
      - G (Kinetica) = R²adj (WinNonlin) Helmut 2008-02-04 01:12
  - Methods for calculation of half lives d_labes 2008-02-04 16:43
    - MAIC and beyond... Helmut 2008-02-04 17:49
- TTT methodHelmut 2008-05-10 13:56
  - TTT method d_labes 2008-05-16 09:12
    - TTT method Helmut 2008-05-16 17:21
      - TTT method d_labes 2008-05-23 15:43
        
        TTT method hiren379 2012-07-11 11:11
        
        TTT method Ohlbe 2012-07-11 11:37
        
        TTT method hiren379 2012-07-11 11:44
        
        TTT method Ohlbe 2012-07-11 12:16
        
        TTT method hiren379 2012-07-11 12:53
        
        Eyeball-PK Helmut 2012-07-11 14:37
        
        Eyeball-PK hiren379 2012-07-11 15:28
        
        Eyeball-PK Helmut 2012-07-11 15:47
        
        Eyeball-PK hiren379 2012-07-11 16:24