An In Vitro Model for Cocrystal Dissolution with Simultaneous Surface and Bulk Precipitation

Area of Science:

• Pharmaceutical Sciences
• Physical Chemistry
• Chemical Engineering

Background:

• Cocrystals can improve drug solubility but often lead to precipitation during dissolution.
• This precipitation limits drug concentration and bioavailability.
• Existing models lack explicit consideration of surface precipitation effects.

Purpose of the Study:

• To develop a predictive in vitro model for cocrystal dissolution-supersaturation-precipitation (DSP) behavior.
• To explicitly account for surface precipitation in cocrystal dissolution modeling.
• To aid in drug development and formulation design by understanding DSP processes.

Main Methods:

• A population balance-based model was developed to describe cocrystal dissolution, surface precipitation, and bulk precipitation.
• Dissolution experiments using carbamazepine-succinic acid cocrystals were performed for model development and validation.
• The model was integrated with numerical optimization for parameter identification.

Main Results:

• The developed model successfully captured key experimental trends in cocrystal dissolution-supersaturation-precipitation (DSP).
• It accurately predicted dose-dependent DSP behavior beyond the initial regression dataset.
• Surface precipitation was identified as a critical factor in the model's accuracy.

Conclusions:

• The population balance model provides an accurate description of in vitro cocrystal DSP behavior.
• Accounting for surface precipitation is essential for realistic modeling of cocrystal dissolution.
• The model can guide the optimization of cocrystal formulations for improved drug delivery.