Applicability of multi-walled carbon nanotubes (MWCNTs) in loading dipyridamole (DDM), a poorly soluble drug, was evaluated. Additionally, the effect of drug-loading efficiency on the release behavior of the MWCNT-DDM system was also investigated. DDM as a model drug was incorporated into MWCNTs with different drug-loading rates (10, 25 and 50%) using the solvent deposition method. The MWCNT-DDM system was successfully established and characterized using common solid-state characterization methods. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption analysis and Fourier transform-infrared (FT-IR) spectroscopy were carried out to observe the progress of drug loading. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to systematically assess the crystalline state of the DDM after being loaded into the MWCNTs. Improvements in dissolution rate were evaluated by the dissolution test. The results revealed that with the increase of drug loading, the form of DDM in the MWCNTs changed from amorphous to crystalline state. Also, the release rate of DDM decreased upon increasing the drug-loading rate of carriers. In conclusion, MWCNTs are proven to be promising carriers for loading DDM.
Keywords: dipyridamole; drug delivery system; drug loading; multi-walled carbon nanotube.