Aminolaevulinic acid diffusion characteristics in 'in vitro' normal human skin and actinic keratosis: implications for topical photodynamic therapy

Photodermatology, Photoimmunology & Photomedicine
Nabla McLoonePaul A McCarron

Abstract

The response rate of aminolaevulinic acid (ALA)-based photodynamic therapy (PDT) in certain subtypes of actinic keratosis (AK), such as hypertrophic and hyperkeratotic lesions, is variable, an effect attributable to a supposed lack of ALA penetration. A detailed and depth-related profile of spatial ALA permeation in AK following drug administration would lead to a greater understanding of concentrations achievable before protoporphyrin IX biosynthesis and subsequent PDT. ALA penetration through excised normal human skin (NS) and AK lesions was evaluated using a cryostatic sectioning technique and radio-isotope counting following drug delivery using a novel, bioadhesive patch, loaded with 19, 38 or 50 mg/cm(2) ALA. Distinct differences in ALA concentration with respect to depth between AK and NS samples were shown, particularly within the superficial layers of the tissue structure, down to a depth of 1.0 mm. Patch application times were shown to influence ALA concentrations in tissue, but there was no clear correlation between ALA penetration in AK lesions taken from different body locations and from patients of different age. Similarly, the thickness of stratum corneum was not related to the ALA distribution profiles. Sizable v...Continue Reading

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Citations

Nov 29, 2013·Photodiagnosis and Photodynamic Therapy·Asta JuzenieneJohan Moan
Jun 4, 2014·Photodiagnosis and Photodynamic Therapy·C T AndradeC Kurachi
May 13, 2010·Journal of Biomedical Optics·Aneesh AlexWolfgang Drexler
Jul 1, 2010·Journal of Pharmaceutical Sciences·Clara GómezM Dolores Blanco
Jul 14, 2009·Journal of Photochemistry and Photobiology. B, Biology·Tim Smits, Anne C E Moor
Jun 21, 2012·Anais Brasileiros De Dermatologia·Juliano Vilaverde Schmitt, Hélio Amante Miot
Mar 11, 2016·Physics in Medicine and Biology·Brian W PogueTayyaba Hasan
Nov 30, 2019·Facial Plastic Surgery Clinics of North America·Lawrence S MoyStephanie Moy

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