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A semi-mechanistic model to link in vitro and in vivo drug release for modified release formulations
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmaceutical Biosciences. (Pharmacometrics Research Group)
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(English)Article in journal (Other academic) Submitted
Abstract [en]

In vivo prediction of drug release based on in vitro experiments is important for the development of new modified release (MR) formulations. Most efforts to improve such predictions have focused on altering the in vitro experiments to more resemble the in vivo conditions. A novel approach is evaluated in the present article where a computer model is established and used to link results from standard static in vitro experiment to in vivo predictions. A nonlinear mixed-effects model describing the in vitro drug release for 6 closely related hydrophilic matrix based MR formulations across different experimental conditions (pH, rotation speed and ionic strength) was developed. This model was applied to in vivo observations of drug release and tablet gastro intestinal (GI) position assessed with Magnetic Marker Monitoring (MMM). By combining the MMM observations with literature information on pH and ionic strength along the GI tract, the mechanical stress in different parts of the GI tract could be estimated in units equivalent to rotation speed in the in vitro set-up (USP 2 apparatus). The mechanical stress in the upper stomach was estimated to be 94 rpm and 134 rpm in the lower stomach. For the small intestine and colon the estimates of mechanical stress was 93 and 38 rpm respectively. Predictions of in vivo drug release including expected between subject/tablet variability could be made for other newly developed formulations based on the drug release model combined with a model describing tablet GI transit. This exemplifies a modeling approach that can be utilized to predict in vivo behavior from standard in vitro experiments and support formulation development and quality control of MR formulations.

Keyword [en]
modified release, IVIVC, magnetic marker monitoring, mechanistic modeling, NONMEM
National Category
Pharmaceutical Sciences
Research subject
Pharmacokinetics and Drug Therapy
Identifiers
URN: urn:nbn:se:uu:diva-149188OAI: oai:DiVA.org:uu-149188DiVA: diva2:404096
Available from: 2011-03-15 Created: 2011-03-15 Last updated: 2011-05-04Bibliographically approved
In thesis
1. Application of Mixed-Effect Modeling to Improve Mechanistic Understanding and Predictability of Oral Absorption
Open this publication in new window or tab >>Application of Mixed-Effect Modeling to Improve Mechanistic Understanding and Predictability of Oral Absorption
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Several sophisticated techniques to study in vivo GI transit and regional absorption of pharmaceuticals are available and increasingly used. Examples of such methods are Magnetic Marker Monitoring (MMM) and local drug administration with remotely operated capsules. Another approach is the paracetamol and sulfapyridine double marker method which utilizes observed plasma concentrations of the two substances as markers for GI transit. Common for all of these methods is that they generate multiple types of observations e.g. tablet GI position, drug release and plasma concentrations of one or more substances. This thesis is based on the hypothesis that application of mechanistic nonlinear mixed-effect models could facilitate a better understanding of the interrelationship between such variables and result improved predictions of the processes involved in oral absorption.

Mechanistic modeling approaches have been developed for application to data from MMM studies, paracetamol and sulfapyridine double marker studies and for linking in vitro and in vivo drug release. Models for integrating information about tablet GI transit, in vivo drug release and drug plasma concentrations measured in MMM studies was outlined and utilized to describe drug release and absorption properties along the GI tract for felodipine and the investigational drug AZD0837. A mechanistic link between in vitro and in vivo drug release was established by estimation of the mechanical stress in different regions of the GI tract in a unit equivalent to rotation speed in the in vitro experimental setup. The effect of atropine and erythromycin on gastric emptying and small intestinal transit was characterized with a semi-mechanistic model applied to double marker studies in fed and fasting dogs.

The work with modeling of in vivo drug absorption has highlighted the need for, and led to, further development of mixed-effect modeling methodology with respect to model diagnostics and the handling of censored observations.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2011. 89 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Pharmacy, ISSN 1651-6192 ; 142
Keyword
Absorption, magnetic marker monitoring, drug release, IVIVC, pharmacometrics, NONMEM, model diagnostics, pcVPC, pvcVPC, visual predictive check, VPC, BQL, paracetamol, sulfapyridine.
National Category
Pharmaceutical Sciences
Research subject
Pharmacokinetics and Drug Therapy
Identifiers
urn:nbn:se:uu:diva-149314 (URN)978-91-554-8030-1 (ISBN)
Public defence
2011-04-29, B41, Uppsala Biomedicinska Centrum (BMC), Husargatan 3, Uppsala, Sweden, 09:15 (English)
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Supervisors
Available from: 2011-04-07 Created: 2011-03-17 Last updated: 2011-05-04Bibliographically approved

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Bergstrand, Martin

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