betadex and hypericin

Hypericin (HY) is a lipophilic photosensitizer (PS) extensively employed for photodynamic therapy (PDT), presenting high absorption in the visible region, chemical and photostability, as well as a good triplet quantum yield. Supramolecular complexation of photosensitizers into cyclodextrins (CD) is promising to improve their poor solubility, compromising their bioavailability and upcoming applications in PDT. This research produced an inclusion complex between HY and β-CD through the co-solvent method. HY became soluble after inclusion into β-CD cavities, besides retaining its fluorescent and singlet oxygen quantum yields (ϕ

Topics: beta-Cyclodextrins; Models, Theoretical; Perylene; Photochemotherapy; Photosensitizing Agents; Solubility

The naturally occurring anthraquinone derivative hypericin is a highly potent photosensitiser. Several in vitro studies show high phototoxicity of the pigment towards gram-positive bacteria. Nevertheless, the highly lipophilic nature and poor bioavailability prevent its application in daily clinical practice thus leading to a limited therapeutic value of hypericin. Liposomal encapsulation could help overcome these limitations and would make hypericin available for daily clinical practice. The use of liposomes as carriers for hypericin in antimicrobial photodynamic therapy (aPDT) is quite new. The aim of this work was to improve the photodynamic efficiency of the previously mentioned carriers by entrapping hypericin in the aqueous compartment of the liposomes. Therefore, a water-soluble inclusion complex of hypericin and (2-hydroxypropyl)-beta-cyclodextrin (Hyp-HPβCD) was prepared. After encapsulation of the inclusion complex into DSPC and DSPC/DPPC/DSPE-PEG liposomes with the dehydration-rehydration vesicle (DRV) method, the formulations were physicochemical characterised. The photodynamic efficiency towards the gram-positive model strain Staphylococcus saprophyticus subsp. bovis. was tested on planktonic cells as well as on biofilms. DSPC liposomes achieved a 4.1log reduction and the DSPC/DPPC/DSPE-PEG liposomes a 2.6log reduction in growth of planktonic bacteria, while Hyp-HPβCD showed total eradication. Even bacterial cells growing in a biofilm could be treated effectively in vitro.

Topics: Anthracenes; Anti-Bacterial Agents; beta-Cyclodextrins; Biofilms; Drug Compounding; Liposomes; Perylene; Phosphatidylethanolamines; Photochemotherapy; Photosensitizing Agents; Polyethylene Glycols; Staphylococcus saprophyticus

A water-soluble inclusion complex of hypericin (HY) with β-cyclodextrin polymer (CDP) was achieved by supramolecular interactions between HY and CDP. The inclusion complex (HY-CDP) was characterized by (1)H NMR, FTIR, and UV-vis spectroscopies. Compared with HY, the water-solubility of HY-CDP was greatly enhanced because of the water-soluble CDP host. The mole ratio of β-cyclodextrin (β-CD) unit in CDP to HY was determined as 2:1. At 25 °C, the dissociated constant of HY-CDP was measured as 1.47×10(-7) mol L(-1) by UV-vis spectroscopy. In the formation of inclusion complexes, CDP could overcome the β-CD drawbacks - such as the poor water-solubility and the restriction of single cavity size, indicating it was able to use as a universal solubilizer for pharmaceutical application.

Topics: Anthracenes; beta-Cyclodextrins; Cellulose; Cyclodextrins; Magnetic Resonance Spectroscopy; Perylene; Solubility; Spectrophotometry, Ultraviolet; Spectroscopy, Fourier Transform Infrared; Water