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Anomalous properties of spray dried solid dispersions
Hisham Al-Obaidi1, Steve Brocchini, Graham Buckton
1Department of Pharmaceutics, The School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX, UK. hisham.al-obaidi@pharmacy.ac.uk
Journal of Pharmaceutical Sciences
|May 21, 2009
Summary
Preparing solid dispersions using spray drying with different solvents significantly impacts drug dissolution. Changing solvents altered polymer conformation, affecting the final solid dispersion properties and drug release.
Area of Science:
- Pharmaceutical Technology
- Materials Science
- Physical Chemistry
Background:
- Solid dispersions enhance oral drug dissolution for poorly soluble compounds.
- Spray drying is a key technique for manufacturing solid dispersions.
Purpose of the Study:
- To investigate the effect of solvent composition on spray-dried solid dispersions.
- To understand how polymer conformation in solution influences solid dispersion properties.
Main Methods:
- Preparation of griseofulvin, poly[N-(2-hydroxypropyl)methacrylate] (PHPMA), and polyvinylpyrrolidone (PVP) solid dispersions via spray drying.
- Utilized acetone/water and acetone/methanol solvent systems.
- Analyzed changes in morphology, stability, and dissolution.
Main Results:
- Solvent substitution (water vs. methanol) dramatically altered solid dispersion characteristics.
- Glass transition temperature increased from 83°C to 103°C with the acetone/methanol system.
- Lower drug and polymer concentrations resulted in particles with lower relaxation rates, supporting polymer conformation influence.
Conclusions:
- Polymer conformation in solution prior to spray drying significantly impacts solid dispersion properties.
- Solvent choice is critical for controlling the morphology, stability, and dissolution of spray-dried solid dispersions.
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