Development of a pH Gradient Dissolution Condition to Predict the Behavior of Delayed Release Formulations under Fed...

Area of Science:

• Pharmaceutical Sciences
• Drug Delivery Systems
• Gastroenterology

Background:

• Modified-release Mesalamine (MSA) formulations for Ulcerative Colitis (UC) often use pH-dependent polymers for colon-specific drug release.
• Existing in vitro dissolution methods lack predictability due to overlooking physiological variations like intraluminal pH, ionic strength, and postprandial effects.
• These limitations hinder accurate prediction of in vivo drug release and formulation performance.

Purpose of the Study:

• To develop a discriminatory and bio-predictive dissolution (DBD) method for Mesalamine (MSA) delayed-release (DR) formulations.
• To establish a robust in vitro-in vivo correlation (IVIVIC) for predicting the in vivo performance of MSA formulations.
• To overcome the unpredictability of current pH-dependent drug release systems.

Main Methods:

• Developed a novel DBD method incorporating postprandial gastrointestinal (GI) pH gradients, ionic strength, and surfactant concentrations.
• Optimized the DBD method by adjusting pH gradients, treatment duration, osmotic agents, and bio-relevant surfactants based on in vivo data.
• Utilized comparative in vivo observations of reference and test formulations to guide method development.

Main Results:

• Achieved a linear relationship (R² > 0.99) between formulation variables (release-controlling polymer) and in vitro drug release under optimized DBD conditions.
• Established a Level A in vitro-in vivo correlation (IVIVIC) using pharmacokinetic (PK) data from a bioequivalence (BE) study.
• Demonstrated an average prediction error of less than 10% for predicting test formulation behavior.

Conclusions:

• The developed DBD method is discriminatory and bio-predictive for Mesalamine (MSA) delayed-release (UC) formulations.
• The DBD method accurately predicts in vivo performance, overcoming limitations of conventional in vitro tests.
• This advancement enables more reliable assessment of modified-release drug delivery systems.