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Article Dans Une Revue Pure and Applied Chemistry Année : 2009

Solid-state NMR characterization of drug-model molecules encapsulated in MCM-41 silica

Résumé

In this contribution, we present a solid-state NMR approach to characterize drugmodel molecules as ibuprofen, benzoic acid, and lauric acid, encapsulated in MCM-41 silica and submitted to strong confinement effects. In particular, we show that by a careful choice of the solid-state NMR sequences, it is possible to efficiently characterize these highly mobile molecules and their interactions with the pore surface. Thus, we demonstrate that 13C NMR spectroscopy is a powerful tool to characterize and even quantify entrapped and non-entrapped species by using either single-pulse excitation (SPE) or cross-polarization (CP). Whereas the standard {1H}-13C CP experiment is of poor efficiency for mobile species, we show that 13C signal-to-noise (S/N) ratio can be significantly improved through 1H-13C cross-relaxation (namely, nuclear Overhauser effect, nOe) by using a 1H power-gated technique. The long transversal relaxation times [T2(1H) up to 22 ms] observed allow the setup of J-coupling-based experiments such as 2D {1H}-13C heteronuclear multiple-quantum coherence (HMQC) in order to fully characterize the encapsulated molecules. Thus, we demonstrate that the use of sequences derived from solution-state NMR such as these two latter experiments is highly efficient to characterize highly mobile organic molecules trapped in mesopores. Finally, we show that 1H spin diffusion-based experiments can give useful information on the proximities between trapped molecules and the silica surface

Domaines

Matériaux

Dates et versions

hal-00414146 , version 1 (08-09-2009)

Identifiants

Citer

Thierry Azais, G. Hartmeyer, S. Quignard, Guillaume Laurent, Corine Tourne-Peteilh, et al.. Solid-state NMR characterization of drug-model molecules encapsulated in MCM-41 silica. Pure and Applied Chemistry, 2009, 81 (8), pp.1345-1355. ⟨10.1351/PAC-CON-08-11-10⟩. ⟨hal-00414146⟩
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