Comparison of 5-aminolevulinic acid-encapsulated liposome versus ethosome for skin delivery for photodynamic therapy

Int J Pharm. 2008 May 22;356(1-2):144-52. doi: 10.1016/j.ijpharm.2008.01.020. Epub 2008 Jan 19.

Abstract

Topical photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA) is an alternative therapy for many non-melanoma skin cancers. The major limitation of this therapy, however, is the low permeability of ALA through the stratum corneum (SC) of the skin. The objective of the present work was to characterize ethosomes containing ALA and to enhance the skin production of protoporphyrin IX (PpIX), compared to traditional liposomes. Results showed that the average particle sizes of the ethosomes were less than those of liposomes. Moreover, the entrapment efficiency of ALA in the ethosome formulations was 8-66% depending on the surfactant added. The particle size of the ethosomes was still approximately <200 nm after 32 days of storage. An in vivo animal study observed the presence of PpIX in the skin by confocal laser scanning microscopy (CLSM). The results indicated that the penetration ability of ethosomes was greater than that of liposomes. The enhancements of all the formulations were ranging from 11- to 15-fold in contrast to that of control (ALA in an aqueous solution) in terms of PpIX intensity. In addition, colorimetry detected no erythema in the irradiated skin. The results demonstrated that the enhancement ratio of ethosome formulations did not significantly differ between the non-irradiated and irradiated groups except for PE/CH/SS, which may have been due to a photobleaching effect of the PDT-irradiation process.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aminolevulinic Acid / administration & dosage*
  • Aminolevulinic Acid / adverse effects
  • Aminolevulinic Acid / pharmacokinetics
  • Animals
  • Chemistry, Pharmaceutical
  • Drug Stability
  • Drug Storage
  • Ethanol / chemistry*
  • Female
  • Liposomes
  • Mice
  • Mice, Inbred ICR
  • Mice, Nude
  • Particle Size
  • Permeability
  • Photochemotherapy
  • Photosensitizing Agents / administration & dosage*
  • Photosensitizing Agents / adverse effects
  • Photosensitizing Agents / pharmacokinetics
  • Protoporphyrins / metabolism
  • Skin Absorption
  • Skin Neoplasms / drug therapy
  • Surface-Active Agents / chemistry

Substances

  • Liposomes
  • Photosensitizing Agents
  • Protoporphyrins
  • Surface-Active Agents
  • Ethanol
  • Aminolevulinic Acid
  • protoporphyrin IX