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Surface area normalized dissolution to study differences in itraconazole-copovidone solid dispersions prepared by
Vivekanand Bhardwaj1, Niraj S Trasi1, Dmitry Y Zemlyanov2
1Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, IN 47907, United States.
International Journal of Pharmaceutics
|February 10, 2018
Summary
Amorphous solid dispersions of itraconazole (ITZ) and copovidone (PVPVA 64) significantly enhance drug dissolution. Formulation and processing methods like spray-drying and hot-melt extrusion influence drug release rates and surface properties.
Area of Science:
- Pharmaceutical Science
- Materials Science
Background:
- Amorphous solid dispersions (ASDs) are crucial for improving the bioavailability of poorly soluble drugs.
- Itraconazole (ITZ) is a widely used antifungal agent whose solubility can be enhanced through ASD formulation.
Purpose of the Study:
- To comparatively evaluate amorphous solid dispersions of itraconazole (ITZ) and copovidone (PVPVA 64) prepared by spray-drying (SD) and hot-melt (HM) extrusion.
- To investigate the influence of drug loading, processing methods, and solvent composition on the dissolution profiles and performance of ITZ ASDs.
Main Methods:
- Preparation of ASDs using spray-drying (SD) and hot-melt (HM) extrusion at various drug-polymer ratios.
- Dissolution studies using a modified intrinsic dissolution rate (IDR) assembly.
- Quantification of drug and polymer release using ultraviolet spectroscopy.
- Characterization using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS).
Main Results:
- Melt-quenched amorphous ITZ showed an 18-fold dissolution advantage over its crystalline form.
- SD and HM extrusion yielded ASDs with similar drug release profiles.
- Dissolution behavior transitioned from drug-controlled to polymer-controlled at approximately 20% drug loading or lower.
- Spray drying solvent composition significantly impacted drug release at 20% drug loading.
- SEM, TEM, and XPS revealed distinct surface morphologies, internal structures, and surface compositions, with drug enrichment in poorly dissolving systems.
Conclusions:
- The amorphous form of ITZ significantly enhances dissolution compared to its crystalline counterpart.
- Both SD and HM extrusion are effective methods for preparing ITZ ASDs with comparable dissolution profiles.
- Drug loading dictates the dissolution mechanism, shifting from drug-controlled to polymer-controlled as loading decreases.
- Processing parameters, particularly solvent choice in SD, critically influence ASD performance.
- Surface characteristics and composition play a key role in the dissolution behavior of ITZ ASDs.
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