The improved photostability of naproxen in the inclusion complex with 2-hydroxypropyl-β-cyclodextrin

The aim of this work was the preparation of the inclusion complex of naproxen with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) in order to improve the physical and chemical properties of naproxen. The molecular inclusion complexes of naproxen with HP-β-CD were prepared by using the co-precipitation method in the solid state with the molar ratio of 1:1. The structure of the obtained complex was characterized by using FTIR, 1H NMR, UV-Vis and XRD methods. The testing of naproxen photostability by the UV-Vis method indicated the degradation to aromatic ketone, 2-acetyl-6-methoxynaphthalene. FTIR analysis showed that the degradation has started 15 days after the exposure of naproxen to daylight while the inclusion complex of naproxen:2-hydroxypropyl-β-cyclodextrin was photostable for a period of 30 days