• 13C spectra
• API
• Drug
• MAS
• Nuclear Magnetic Resonance
• nuclear relaxation

The exploration of new solid forms of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) with higher performance and reduced side effects maintains a big interest in the pharmaceutical field. The development of drugs in the form of salts and co-crystals usually results in higher solubility in water and more rapid absorption in the body compared to the corresponding acidic forms. Pharmaceutical products in the amorphous state generally show improved release properties and high dissolution rates.
In this work the structural and dynamic properties of Ibuprofen Arginate and Ketoprofen were investigated by means of Solid State NMR. Both low- and high-resolution techniques at room temperature and variable temperature were applied to the crystalline and amorphous forms of the two Active Pharmaceutical Ingredients (APIs).
Information on several structural and dynamic properties was obtained by proton relaxation times (T1 and T2), 1H and 13C static spectra, 1D-2D 1H and 13C CP-MAS spectra.