Water Solubilization of Phthalocyanine Derivatives via Interactions of Long Alkyl Chains and Cyclodextrins: Potential Complexes for Photodynamic Therapy

Abstract

AbstractFive types of cyclodextrins, based on α‐cyclodextrin (α‐CDx) and β‐cyclodextrin (β‐CDx), were used to make hydrophobic phthalocyanine (Pc) derivatives with long alkyl chains soluble in water via a high‐speed vibration milling method. Aqueous solutions of DMe‐β‐CDx‐based complexes were found to be the most stable, for at least 1 week over those containing α‐CDx. Although DMe‐β‐CDx complexes containing a free‐base Pc and Zn−Pc with eight dodecyl chains showed greater solubility than their α‐CDx‐base counterparts, α‐CDx complexes containing a free‐base Pc and Zn−Pc with eight dodecyl chains show no self‐aggregation of the Pcs and, as a result, exhibit fluorescence signals. Overall, it was found that the α‐CDx−Zn−Pc complex exhibits higher photodynamic activity than that of the commercially available and widely used photosensitizer Photofrin.