Physical confinement of drug molecules

Storage and release systems of active ingredients where drug molecules are trapped within mesoporous matrices are promising systems for the controlled release of active principle ingredients (API). These systems exhibit release profiles much faster than conventional formulations formed of microcrystals. This property considerably increases the bioavailability of APIs and would help to reduce the dispensed daily doses and therefore minimize side effects. We were able to demonstrate by 1H and 13C NMR (D- and J-based) experiments at variable temperature coupled with molecular dynamics studies that an anti-inflammatory drug such as ibuprofen adopted the behavior of a liquid once encapsulated in MCM-41 silica. Hence, the strong physical confinement effect (green arrows) undergone by the drug explains the fast release profiles observed in vitro. Moreover, the action of water molecules at interfaces has also been highlighted. The resulting proton exchange further weakens molecule-molecule and molecule-silica interaction (blue arrows).

Funding: ANR Biodynamics (2005–2008), Emergence UPMC (2010-2011)
PhD Students: D. Aeillo (2008), C. Sanfeliu Cano (2011)
Post-doc: Kuldeep Panesar (2010-2011)
Main Collaborations: J-M. Devoisselle, C. Tourné-Petheil & S. Bégu (ICG Montpellier), F. Tielens (Vrije Universiteit Brussel Belgique)
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