Pharmaceutical Research

, Volume 21, Issue 10, pp 1871–1879

Phototoxicity of 5-Aminolevulinic Acid in the HeLa Cell Line as an Indicative Measure of Photodynamic Effect After Topical Administration to Gynecological Lesions of Intraepithelial Form

Authors

  • Paul A. McCarron
    • School of PharmacyQueens University Belfast, Medical Biology Centre
  • Ryan F. Donnelly
    • School of PharmacyQueens University Belfast, Medical Biology Centre
  • Brendan F. Gilmore
    • School of PharmacyQueens University Belfast, Medical Biology Centre
  • A. David Woolfson
    • School of PharmacyQueens University Belfast, Medical Biology Centre
  • Raymond McClelland
    • Department of Obstetrics and GynaecologyBelfast City Hospital
  • Agnieszka Zawislak
    • Department of Obstetrics and GynaecologyBelfast City Hospital
  • John H. Price
    • Department of Obstetrics and GynaecologyBelfast City Hospital
Article

DOI: 10.1023/B:PHAM.0000045242.98628.0b

Cite this article as:
McCarron, P.A., Donnelly, R.F., Gilmore, B.F. et al. Pharm Res (2004) 21: 1871. doi:10.1023/B:PHAM.0000045242.98628.0b

Abstract

Purpose. The depth-resolved pattern of aminolevulinic acid (ALA) concentration in excised vaginal tissue was determined after in vitro application of an ALA-loaded bioadhesive patch. From this data, the tissue concentration of ALA achievable at a specified depth from the surface could be related to the concentration needed to elicit a photodynamic effect in a model gynecological tumor cell line (HeLa).

Methods. Excised vaginal tissue was mounted in a modified Franz diffusion cell and exposed to a water-soluble, ALA-loaded, bioadhesive patch. After a period of time, the tissue was cryostatically sectioned and the stratal concentration of radiolabeled ALA determined using scintillation spectroscopy. HeLa cells were cultured in media containing specific concentrations of ALA and exposed to standard photodynamic protocols of light exposure.

Results. An ALA concentration of 65.6 mM was achievable at 2.375 mm from the tissue surface after application of ALA-loaded patch. The photodynamic effectiveness of this concentration was demonstrated in HeLa with exposure to concentrations exceeding 1.0 mM ALA bringing about reductions in viable cell numbers by 90%. An enhancement of PpIX production using adjunctive EDTA over the clinically relevant 4 h application time interval was shown to be minimal in HeLa. Instead, PpIX production was more closely correlated with ALA concentration, with 100 mM ALA producing approximately 3100 ng PpIX mg-1 protein in the same time period.

Conclusions. Given that vaginal intraepithelial neoplasias can extend to 2.0 mm from the lesion surface, the ALA permeability derived from a bioadhesive patch is sufficient to induce photosensitization suitable for light induced destruction at deep sites of this type of lesion.

aminolevulinic acid bioadhesive HeLa intraepithelial photodynamic

Copyright information

© Springer Science+Business Media, Inc. 2004