Implementation of dose superimposition to introduce multiple doses for a mathematical absorption model (transit...

Area of Science:

• Pharmacokinetics and mathematical modeling.
• Computational drug development.

Background:

• Complex absorption processes often require mathematical models, like transit compartment models.
• Existing models necessitate assumptions about complete prior dose absorption before administering subsequent doses, limiting accuracy.

Purpose of the Study:

• To propose and implement a novel dose superimposition method for accurately modeling multiple drug administrations.
• To eliminate the restrictive assumption of complete prior dose absorption in pharmacokinetic models.

Main Methods:

• Developed a dose superimposition technique to handle multiple drug doses without prior absorption assumptions.
• Provided implementation code for WinNonlin and NONMEM software.
• Discussed special (SC) and general (GC) cases for NONMEM implementation, including NM-TRAN and FORTRAN-based solutions.

Main Results:

• The dose superimposition method successfully eliminates the assumption of complete prior dose absorption.
• Implementation in NONMEM offers flexibility through NM-TRAN (SC) and user-defined FORTRAN functions (GC).
• The general case (GC) removes the pre-defined limit on the maximum number of doses per subject.

Conclusions:

• Dose superimposition is an effective method for improving the accuracy of mathematical absorption models with multiple doses.
• The provided implementations facilitate advanced pharmacokinetic modeling in WinNonlin and NONMEM.
• This approach enhances the precision of drug absorption analysis in complex dosing scenarios.