Impact of Curcumin Supersaturation in Antibacterial Photodynamic Therapy—Effect of Cyclodextrin Type and Amount: Studies on Curcumin and Curcuminoides XLV

• Published in: Journal of pharmaceutical sciences 2012-04, Vol.101 (4), p.1524-1537
• Main Authors: Hegge, Anne Bee, Nielsen, Thorbjørn T., Larsen, Kim L., Bruzell, Ellen, Tønnesen, Hanne H.
• Format: Article
• Language: English
• Subjects: bioavailability; Biological and medical sciences; Chemistry, Pharmaceutical; Curcumin - administration & dosage; Curcumin - chemistry; Curcumin - pharmacology; cyclodextrins; Cyclodextrins - administration & dosage; drug delivery systems; Drug Storage; Enterococcus faecalis; Enterococcus faecalis - drug effects; Escherichia coli; Escherichia coli - drug effects; excipients; General pharmacology; Medical sciences; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Photochemotherapy; Solubility; UV-VIS absorption spectroscopy
• ISSN: 0022-3549; 1520-6017
• DOI: 10.1002/jps.23046

Curcumin has been investigated as a potential photosensitizer (PS) in antimicrobial photodynamic therapy (aPDT). The phototoxic effect of curcumin is dependent on proper formulations of the compound because of the lipophilic nature of the molecule and the extremely low water solubility at physiological conditions. In the present study, the combination of curcumin with either a methylated β-cyclodextrin (CD) or polyethylene glycol-based β-CD or γ-CD polymers was investigated in aPDT using Escherichia coli (E. coli) and Enterococcus faecalis as model bacteria. Solutions with various supersaturation ratios of curcumin were prepared with the selected CD or CD polymers. The concept of supersaturation was then investigated as a mean to enhance the phototoxic effect of curcumin, especially toward the gram-negative bacteria E. coli. A high supersaturation ratio corresponded with high phototoxicity of E. coli. Depending on the curcumin preparation, the bacterial survival ranged from 0.01% to no significant effect after irradiation with blue light (29 J/cm2). Temporal stabilization of the supersaturated state is necessary in order to retain high and predictable photoreactivity of the PS. Further studies will be needed in order to formulate curcumin preparations with acceptable hydrolytic and photolytic stability and a temporal stabilization of a supersaturated state.