Drug release modeled by dissolution, diffusion, and immobilization

Area of Science:

• Pharmaceutical Sciences
• Chemical Engineering
• Materials Science

Background:

• Drug release from solid dosage forms is complex, influenced by multiple simultaneous processes.
• Existing models often simplify or omit key mechanisms like drug adsorption.
• Understanding these mechanisms is crucial for optimizing drug delivery systems.

Purpose of the Study:

• To develop a comprehensive mathematical model for drug release from disintegrating tablets.
• To integrate drug dissolution, diffusion, and adsorption into a single predictive framework.
• To validate the model against experimental drug release profiles.

Main Methods:

• Developed a novel drug release model combining the Noyes-Whitney equation for dissolution and a Langmuir-Freundlich isotherm for adsorption.
• Incorporated dissolution and adsorption as source and sink terms within the diffusion equation.
• Applied the model to tablets assumed to disintegrate into spherical fragments, with rapid absorption, swelling, and disintegration.

Main Results:

• The integrated model successfully captures the interplay between dissolution, diffusion, and adsorption.
• Model predictions demonstrated good agreement with experimentally observed drug release characteristics.
• The simplified assumptions regarding rapid physical processes were validated by the model's predictive power.

Conclusions:

• The novel model provides a more accurate representation of drug release from disintegrating tablets.
• This approach enhances the understanding and prediction of drug release kinetics.
• The model serves as a valuable tool for the rational design of oral drug delivery systems.