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Pre-clinical pharmacokinetic
and safety assessment of topical rose bengal
Wachter, E1,
Dees, C1, Harkins, J1,
Scott, T1, Fisher, W1,
Petersen, M2 and Bjerring, P3
Photogen, Inc., Knoxville, TN1
The University of Tennessee College of Veterinary Medicine, Knoxville,
TN2
Department of Dermatology, Marseliborg Hospital, University of Aarhus,
Aarhus, Denmark3
Abstract-
Rose bengal (RB) is well known photosensitizer that appears to have
been overlooked as a potential agent for photodynamic therapy (PDT).
As an initial step in assessing the photodynamic potential of RB for
treatment of superficial diseased tissue (such as plaque psoriasis,
Barretts esophagus, and diseases of the urinary tract), feasibility
of selective topical delivery of RB to normal murine, canine, and human
epithelial tissue has been evaluated. Various topical formulations (ranging
from hydrophilic to lipophilic solutions, gels and creams) have been
tested using normal murine skin, human skin and the canine esophagus.
Rapid, selective, uniform delivery of RB to epithelial tissue (with
no significant RB delivery to underlying tissues) has been observed
in all of these models, with no apparent toxicity at concentrations
20% RB. Effects of illumination of RB-treated tissue with green laser
radiation (532 nm) indicated an absence of acute phototoxicity in normal
tissue for light intensities 100 mW/cm2 at light doses 100 J/cm2. Prolonged
illumination at intensities 200 mW/cm2 resulted in superficial thermal
damage to skin. These results suggest that RB may be suitable for new
PDT regimens exhibiting minimal adverse effects in normal tissue while
avoiding the complexities of drug application and light dosimetry inherent
to prior regimens.
Keywords: PDT,
rose bengal, topical, phamacokinetics
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