Cyclodextrin-based low molecular weight polymers as encapsulates for nonpolar drug molecules

Abstract

Low molecular weight water-soluble polymers containing maltose and cyclodextrin (CD) in the main chain were synthesized and used for slow release of a water-soluble drug. These low molecular weight polymers were synthesized from CDs (β-, γ-, and HP-β-CD) and maltose using the differential reactivity of a triazine linker through a single pot polycondensation reaction under controlled conditions. The low molecular weight polymers were characterized by 1H-NMR, FT-IR spectroscopy, XRD analysis, TGA, ESI-mass, and aqueous solubility determination; and were confirmed to be linear. In addition, the inclusion complex formation of Efavirenz (an anti-HIV drug) with the CD–maltose polymer was confirmed from FT-IR and UV–Vis spectroscopy. Comparison of the stability of drug-inclusion complexes of different CD–maltose polymers with that of the parent CDs using the phase solubility studies indicated that the polymers were better at inclusion of the drug. The release performances of Efavirenz with the polymers were investigated through conventional dissolution studies with similar results. The results are explained based on the expansion of the nonpolar cavity due to functionalization of the parent CD.