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Microstructural Insights into Solid Dispersions: A Combined Small-Angle Neutron Scattering and Molecular Dynamics
Haoshi Gao1,2, Yunsen Zhang2,3, Hanqiu Jiang4,5
1School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, China.
Molecular Pharmaceutics
|February 7, 2026
Summary
Preparation methods significantly impact solid dispersion structure. The melting method enhances amorphous content for better drug solubility, while solvent evaporation yields more ordered structures, advancing formulation development.
Area of Science:
- Pharmaceutical Sciences
- Materials Science
- Physical Chemistry
Background:
- Solid dispersions enhance solubility of poorly soluble drugs.
- Understanding molecular structure is key to stability and dissolution.
- Current knowledge on structural determinants is limited.
Purpose of the Study:
- Investigate preparation method effects (melting vs. solvent evaporation) on PXM-PEG solid dispersion microstructure and crystallinity.
- Determine the influence of drug loading (10%, 15%, 25%) on these properties.
- Elucidate molecular-level structural determinants of stability and dissolution.
Main Methods:
- Small-Angle Neutron Scattering (SANS) with deuterated PEG (d-PEG) for enhanced scattering.
- Coarse-Grained Molecular Dynamics (CGMD) simulations.
- Analysis of lamellar thickness, d-spacing, layer stacking, and amorphous/crystalline content.
Main Results:
- Melting method decreased lamellar thickness and d-spacing, indicating structural disruption and higher amorphous content.
- Solvent evaporation method maintained larger d-spacing and stable layer stacking, showing higher structural order and crystallinity.
- CGMD simulations revealed distinct aggregation dynamics: dense clusters (melting) vs. larger, asymmetrical aggregates (solvent evaporation).
Conclusions:
- Preparation method is a critical factor influencing solid dispersion structural characteristics.
- Melting method favors amorphous content for improved bioavailability, while solvent evaporation yields ordered structures.
- Combined SANS and CGMD elucidate the "sandwich-like" structure, advancing solid dispersion formulation development and industrial production.
Keywords:
PEGcoarse-grained molecular dynamics simulationspiroxicamsmall-angle neutron scatteringsolid dispersionMore Related Videos
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