UPR 5301

Crystal and molecular structure of V-amylose complexed with ibuprofen

16 March 2021

We have published an article in Carbohydrate Polymers about the structure of an inclusion compound prepared by crystallizing amylose in the presence of ibuprofen, a well-known anti-inflammatory drug. Using data from solid-state NMR, and electron and X-ray diffraction, we have proposed a molecular model allowing to locate the ibuprofen guest molecules in the lattice of amylose helices. Click on the title for more information.

Abstract:
Rectangular V-amylose single crystals were prepared by adding racemic ibuprofen to hot dilute aqueous solutions of native and enzymatically-synthesized amylose. The lamellar thickness increased with increasing degree of polymerization of amylose and reached a plateau at about 7 nm, consistent with a chain-folding mechanism. The CP/MAS NMR spectrum as well as base‑plane electron and powder X-ray diffraction patterns recorded from hydrated specimens were similar to those of V‑amylose complexed with propan-2-ol. Amylose was crystallized in an orthorhombic unit cell with parameters a = 2.824 ± 0.001 nm, b = 2.966 ± 0.001 nm, and c = 0.800 ± 0.001 nm. A molecular model was proposed based on structural analogies with the V_propan-2-ol complex and on assumptions on the stoichiometry of ibuprofen. The unit cell would contain four antiparallel 7‑fold amylose single helices with ibuprofen molecules distributed inside and between the helices.

The article is available over here.