A porphyrin/β-cyclodextrin conjugated nano-system having a Pan-Lid molecular structure for smart drug carrier applications

In this study, 5,10,15-tri[p(9-methoxy-triethyleneoxy)phenyl]-20-[p-phenylisophthalate-β-cyclodextrin] porphyrin, a compound containing a porphyrin and a β-cyclodextrin unit covalently linked by means of an isophthalic bridge, was synthesized and characterized by NMR, MALDI-TOF mass spectrometry and UVvis and circular dichroism spectroscopies. This porphyrin/β-cyclodextrin system, with the porphyrin unit connected to the lower rim (OH-2) of the cyclodextrin structure, is water-soluble and no evidence of a self-assembly arrangement between the porphyrin and cyclodextrin units appears. In this way, the β-cyclodextrin cavities remain free, retaining their potential ability of drug-delivery, with the spectroscopic advantage induced by the high absorbance of the porphyrin unit. Furthermore, the porphyrin unit, interacting with the guest and acting as a lid, could have a role in the controlled release process of the drug.