Nanostructures formed by cyclodextrin covered procainamide through supramolecular self assembly--spectral and...

Area of Science:

• Pharmaceutical Sciences
• Materials Science
• Physical Chemistry

Background:

• Procainamide (PCA) is an antiarrhythmic drug.
• Cyclodextrins (CDs) are widely used to improve drug properties.
• Understanding drug-cyclodextrin interactions is crucial for drug delivery.

Purpose of the Study:

• To investigate the inclusion complexation behavior of procainamide (PCA) with alpha-cyclodextrin (α-CD) and beta-cyclodextrin (β-CD).
• To characterize the structural and morphological changes upon complex formation.
• To determine the stoichiometry and thermodynamic parameters of the inclusion complexes.

Main Methods:

• Spectroscopic techniques (absorption, fluorescence, FT-IR, Raman)
• Microscopy (SEM, TEM)
• Thermal analysis (DSC)
• X-ray diffraction (XRD)
• (1)H NMR spectroscopy
• Semiempirical PM3 calculations

Main Results:

• PCA forms 1:2 inclusion complexes with both α-CD and β-CD.
• A blue shift in spectra indicates complex formation, with water molecules likely present in the cavity.
• The phenyl ring of PCA is entrapped within the CD cavity.
• PCA:α-CD complexes form nano-sized particles (46 nm).
• PCA:β-CD complexes self-assemble into micro-sized tubular structures.
• Shape-shifting from 2D nanosheets to 1D microtubes was observed.

Conclusions:

• PCA forms stable inclusion complexes with α-CD and β-CD.
• The complexation influences the morphology of the resulting materials, leading to nano- and micro-structures.
• Thermodynamic parameters indicate the spontaneity and nature of the inclusion process.