Solid state NMR perspective of drug-polymer solid solutions: a model system based on poly(ethylene oxide).

Area of Science:

• Materials Science
• Pharmaceutical Science
• Polymer Chemistry

Background:

• Enhancing the bioavailability of poorly water-soluble drugs is a significant challenge in pharmaceutical development.
• Solid dispersions are a promising strategy to improve drug solubility and dissolution rates.

Purpose of the Study:

• To investigate the potential of Poly(ethylene oxide) (PEO) as a polymer matrix for creating solid dispersions of ketoprofen.
• To characterize the miscibility and molecular interactions between PEO and ketoprofen.

Main Methods:

• Solid-state Nuclear Magnetic Resonance (NMR) spectroscopy.
• X-ray Diffraction (XRD) analysis.
• Transmission Electron Microscopy (TEM) imaging.

Main Results:

• High miscibility between PEO and ketoprofen was confirmed, leading to a complete molecular dispersion of ketoprofen within the amorphous PEO matrix.
• Solid-state NMR detected hydrogen bonds between ketoprofen and PEO, explaining the enhanced miscibility.
• Melt-processed blends exhibited increased ketoprofen molecular mobility and enhanced dissolution rates in aqueous media.

Conclusions:

• PEO effectively forms molecular solid dispersions with ketoprofen, significantly improving its dissolution characteristics.
• The observed drug-polymer interactions enable reduced melt-processing temperatures, avoiding thermal degradation and offering processing flexibility.
• The stabilized blend morphology ensures consistent physico-chemical properties during storage, crucial for pharmaceutical applications.