Nanostructures formed by cyclodextrin covered procainamide through supramolecular self assembly – Spectral and molecular modeling study

• PCA forms 1:2 inclusion complex with CDs.
• Phenyl ring of the PCA drug is entrapped in the CD cavity.
• PCA/α-CD complex self-assembled to form nano particles.
• PCA/β-CD complex self-assembled to form micro tubular structure.
• Shape-shifting of 2D nanosheets into 1D microtube by simple rolling mechanism.

Inclusion complexation behavior of procainamide (PCA) with two cyclodextrins (α-CD and β-CD) were analyzed by absorption, fluorescence, scanning electron microscope (SEM), transmission electron microscope (TEM), Raman image, FT-IR, differential scanning colorimeter (DSC), Powder X ray diffraction (XRD) and 1H NMR. Blue shift was observed in β-CD whereas no significant spectral shift observed in α-CD. The inclusion complex formation results suggest that water molecules also present in the inside of the CD cavity. The present study revealed that the phenyl ring of the PCA drug is entrapped in the CD cavity. Cyclodextrin studies show that PCA forms 1:2 inclusion complex with α-CD and β-CD. PCA:α-CD complex form nano-sized particles (46 nm) and PCA:β-CD complex form self-assembled to micro-sized tubular structures. The shape-shifting of 2D nanosheets into 1D microtubes by simple rolling mechanism were analysed by micro-Raman and TEM images. Thermodynamic parameters (ΔH, ΔG and ΔS) of inclusion process were determined from semiempirical PM3 calculations.

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