In vitro--in vivo correlation, a time scaling problem? Basic considerations on in vitro dissolution testing.

Area of Science:

• Pharmaceutical Sciences
• Drug Delivery Systems
• Physical Pharmacy

Background:

• Drug release profiles are crucial for understanding drug performance.
• Dissolution curves are influenced by formulation type and experimental conditions.
• Comparing release profiles across different settings can be challenging.

Purpose of the Study:

• To demonstrate that differing drug dissolution profiles can be superimposed through time base transformation.
• To define and discuss the concept of 'equivalence' for dissolution profiles.
• To show the applicability of the method to various formulations and dissolution apparatus.

Main Methods:

• Calculating statistical moments from cumulative frequency functions of drug residence times.
• Applying a linear transformation to the time base of dissolution curves.
• Testing film-coated pellets and erosible matrix tablets in Sartorius and USP-Paddle dissolution models.

Main Results:

• Differing dissolution profiles from distinct formulations and apparatus were successfully superimposed.
• Parameters for time base transformation were derived from statistical moments of residence times.
• The concept of dissolution profile equivalence was clearly defined and illustrated.

Conclusions:

• A linear time transformation method can achieve profile superimposability, simplifying dissolution profile comparison.
• This approach is robust across different drug formulations and dissolution testing equipment.
• The methodology is directly applicable to comparing in vitro and in vivo drug release data.