Feasibility of 1H-high resolution-magic angle spinning NMR spectroscopy in the analysis of viscous cosmetic and pharmaceutical formulations.

The feasibility of (1)H-High Resolution-Magic Angle Spinning (HR-MAS) nuclear magnetic resonance (NMR) spectroscopy for the direct analysis of viscous cosmetic and pharmaceutical formulations such as creams, gels, and pastes is presented. Three examples are described: (i) the detection of chitosan in toothpaste, (ii) the analysis of dexamethasone acetate (DMA) in a cream, and (iii) the analysis of the local anesthetics, lidocaine and prilocaine, in a gel and a cream. All active components could be directly detected in their original commercial formulations without the need for laborious sample preparation steps. In addition, the possibility for HR-MAS-based quantifications and the analysis of dynamic properties of active components in different formulations applying HR-MAS diffusion-ordered NMR spectroscopy are shown.