Solution-state polymer assemblies influence BCS class II drug dissolution and supersaturation maintenance.

Area of Science:

• Pharmaceutical Sciences
• Materials Science
• Polymer Chemistry

Background:

• Spray-dried dispersions (SDDs) are crucial for enhancing oral drug delivery of poorly soluble drugs.
• Understanding the role of polymer solution-state assemblies is key to optimizing SDD performance.

Purpose of the Study:

• To investigate how pre-spray drying polymer solution assemblies influence the performance of amorphous SDDs.
• To explore the impact of polymer structure and drug-excipient interactions on drug dissolution and stability.

Main Methods:

• Spray drying of model drugs (phenytoin, probucol) with various polymers (PEP, DMA, MAG based copolymers).
• Induction or repression of polymer solution-state assemblies using selective solvents.
• Characterization using dynamic light scattering (DLS), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM).
• In vitro dissolution testing and analysis of dissolution structures.

Main Results:

• Solution-state polymer assemblies (micelles, aggregates) were successfully formed and characterized.
• SDDs exhibited homogeneous drug/polymer mixtures with drug interactions primarily with DMA-containing polymer segments.
• Spray-dried micelles of PEP-PDMA with probucol showed excellent in vitro dissolution performance.
• Forced aggregation into micelle structures was critical for enhanced dissolution and supersaturation.

Conclusions:

• Pre-forming polymer micelles is a critical factor for improving dissolution rates and supersaturation maintenance in SDDs.
• This strategy offers a promising platform for designing advanced excipients for oral drug delivery.
• The study highlights the importance of controlling polymer solution-state behavior for optimizing solid dispersion performance.