Analysis of structural variability in pharmaceutical excipients using solid-state NMR spectroscopy

Area of Science:

• Analytical Chemistry
• Materials Science
• Pharmaceutical Sciences

Background:

• Polysaccharide-based excipients are vital in solid dosage forms, exhibiting diverse structural and functional properties.
• Accurate characterization of these excipients is essential for formulation development and drug delivery.
• Existing analytical methods may not fully capture the nuances of these complex materials.

Purpose of the Study:

• To identify specific solid-state Nuclear Magnetic Resonance (SSNMR) parameters for differentiating polysaccharide excipients.
• To demonstrate the utility of SSNMR in assessing key quality attributes of pharmaceutical excipients.

Main Methods:

• Acquisition of carbon-13 (13C) SSNMR spectra for various excipients using a Chemagnetics CMX-300 spectrometer.
• Analysis of spectral resolution, peak positions, relative intensities, and relaxation parameters.
• Comparison of obtained spectra with known standards and reference materials.

Main Results:

• SSNMR enables positive identification of major excipient forms based on signal resolution.
• Specific parameters like carbonyl peak position differentiate alginic acid from sodium alginate.
• SSNMR quantifies amorphous/crystalline content in starch, assesses carrageenan purity, and correlates starch derivative relaxation with hydrolysis degree.

Conclusions:

• Solid-state NMR spectroscopy is a powerful, non-destructive technique for characterizing polysaccharide excipients.
• SSNMR detects critical attributes including form identification, structural differences, purity, and water content variations.
• This method provides valuable analytical data for ensuring the quality and performance of pharmaceutical formulations.