## Numerical Deconvolution [Dissolution / BCS / IVIVC]

Dear Daniel!

» So, if possible, I would like to know how apply deconvolution approach to obtain fraction absorbed using excel. This method is known as model-independent approach. Could you help me with details about calculations and articles about this topic?

First I would recommend two other ‘classical’ papers:

Main problems with numerical deconvolution are:

Sampling points of the response function (

Numerical deconvolution is subject to instability such as sudden oscillations in the input function. Errors in early time points have a cumulative effect upon subsequent estimates.

You may use my speadsheet as some kind of a sandbox: alter values, and watch…

But please don’t use it for your actual problems!

For the application of M$-Excel in IVIVC have a look at

Software packages having a deconvolution module onboard (WinNonlin 5.2+, Kinetica, PDx-IVIVC)

Good look!

» So, if possible, I would like to know how apply deconvolution approach to obtain fraction absorbed using excel. This method is known as model-independent approach. Could you help me with details about calculations and articles about this topic?

First I would recommend two other ‘classical’ papers:

- Vaughan DP, Dennis M.
*Mathematical Basis of Point-Area Deconvolution Method for Determining In Vivo Input Functions.*J Pharm Sci. 1978; 67: 663–5.

- Langenbucher F.
*Numerical Convolution/Deconvolution as a Tool for Correlating in Vitro with in Vivo Drug Availability.*Pharm Ind. 1982; 44(11): 1166–72.

- A model-dependent version, where models are defined for the functions, and the convolution integral solved for the unknown function by means of
*Laplace Transformations*. Unfortunatelly the integral may be impossible to solve…

- A model-independent version, where the data are deconvoluted numerically,
*i.e.*differentials are replaced by differences.

Langenbucher F. *In vitro Prüfung und Korrelation mit in vivo Daten.* In: Meier J, Rettig H, Hess H. *Biopharmazie – Theorie und Praxis der Pharmakokinetik.* Stuttgart 1981; Georg Thieme: pp 300–3.

Main problems with numerical deconvolution are:

Sampling points of the response function (

*e.g.*, an oral formulation), and the weighting function (*i.e.*, an i.v. dose or an oral solution)**must**be equidistant, which they almost never are. Therefore you must interpolate ‘missing’ data points by a suitable algorithm (first approximation would be linear interpolation until T_{max}, and linear/log afterwards, better options are splines or Lagrange-polynoms).Numerical deconvolution is subject to instability such as sudden oscillations in the input function. Errors in early time points have a cumulative effect upon subsequent estimates.

You may use my speadsheet as some kind of a sandbox: alter values, and watch…

But please don’t use it for your actual problems!

For the application of M$-Excel in IVIVC have a look at

Langenbucher F. *Handling of computational in vitro/in vivo correlation problems by Microsoft Excel: III. Convolution and deconvolution.* Eur J Pharm Biopharm. 2003; 56(3): 429–37. doi:10.1016/s0939-6411(03)00140-1.

Software packages having a deconvolution module onboard (WinNonlin 5.2+, Kinetica, PDx-IVIVC)

**rely heavily on smoothing of data**– but manufacturers rarely document the actual method in the manual.Good look!

—

Helmut Schütz

The quality of responses received is directly proportional to the quality of the question asked. 🚮

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*Dif-tor heh smusma*🖖_{}Helmut Schütz

The quality of responses received is directly proportional to the quality of the question asked. 🚮

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### Complete thread:

- IVIVC Studies MGR 2007-02-02 10:10 [Dissolution / BCS / IVIVC]
- IVIVC Studies Helmut 2007-02-07 19:56
- IVIVC Studies venu 2007-02-23 06:58
- IVIVC Studies Dipesh Jayswal 2007-03-16 07:53
- Wagner-Nelson, Loo-Riegelman Helmut 2007-03-16 15:39
- Wagner-Nelson, Loo-Riegelman Dipesh Jayswal 2007-03-19 10:04
- Deconvolution drcampos 2007-03-19 15:26
- Numerical DeconvolutionHelmut 2007-03-19 16:20
- Numerical Deconvolution drcampos 2007-03-19 21:17
- Numerical Deconvolution Rayhope 2021-10-07 14:25
- Daniel still active in the Forum? Helmut 2021-10-07 16:38
- Daniel still active in the Forum? Rayhope 2021-10-08 09:07
- Daniel still active in the Forum? Rayhope 2021-11-11 08:35

- Daniel still active in the Forum? Rayhope 2021-10-08 09:07

- Daniel still active in the Forum? Helmut 2021-10-07 16:38

- Numerical DeconvolutionHelmut 2007-03-19 16:20
- Wagner-Nelson Dipesh Jayswal 2007-03-21 08:21
- Wagner-Nelson Helmut 2007-03-21 12:13
- IVIVC jesse08 2007-09-01 01:38
- IVIVC / Mapping Helmut 2007-09-01 14:49
- IVIVC / Mapping jesse08 2007-09-02 00:32
- IVIVC / Software Helmut 2007-09-02 12:03
- IVIVC / Software jesse08 2007-10-03 02:13
- IVIVC / Software Nirali 2007-11-21 12:38
- at least 3 formulations for IVIVC Helmut 2007-11-21 15:25
- at least 3 formulations for IVIVC Nirali 2007-11-22 07:53
- at least 1 formulation for Level A Helmut 2007-11-22 09:53
- at least 1 formulation for Level A Nirali 2007-11-27 06:05

- at least 1 formulation for Level A Helmut 2007-11-22 09:53

- at least 3 formulations for IVIVC Nirali 2007-11-22 07:53
- IVIVC / Software SDavis 2009-09-25 09:11

- at least 3 formulations for IVIVC Helmut 2007-11-21 15:25

- IVIVC / Software Nirali 2007-11-21 12:38

- IVIVC / Software jesse08 2007-10-03 02:13

- IVIVC / Software Helmut 2007-09-02 12:03

- IVIVC / Mapping jesse08 2007-09-02 00:32

- IVIVC / Mapping Helmut 2007-09-01 14:49

- IVIVC jesse08 2007-09-01 01:38
- IVIVC set up/ requirements sonu 2009-09-23 08:47

- Wagner-Nelson Helmut 2007-03-21 12:13

- Wagner-Nelson, Loo-Riegelman Helmut 2007-03-16 15:39

- IVIVC Studies Dipesh Jayswal 2007-03-16 07:53

- IVIVC Studies venu 2007-02-23 06:58

- IVIVC Studies Helmut 2007-02-07 19:56