Microneedle pre-treatment of human skin improves 5-aminolevulininc acid (ALA)- and 5-aminolevulinic acid methyl ester (MAL)-induced PpIX production for topical photodynamic therapy without increase in pain or erythema.

Abstract

PURPOSE:

To determine the impact of skin pretreatment with microneedles (MNs) on ALA- and MAL-induced protoporphyrin IX (PpIX) production, as well as MN impact on pain sensations during light exposure and erythema after PDT.

METHODS:

The skin of 14 healthy volunteers was preteated with MNs. Equal amounts of creams containing 2%, 8% and 16% (w/w) ALA and MAL were applied on 1 cm(2) areas for 4 h. Additionally, 16% ALA and MAL creams were applied for 24 h. Afterwards, PpIX fluorescence spectra were measured. Sixteen percent ALA and MAL spots were exposed to red light (632 nm, 77 mW/cm(2)). Time for pain to occur was measured in seconds, and erythemal response was monitored up to 6 h after the end of the light exposure.

RESULTS:

Use of MNs increased the PpIX fluorescence after 4 h incubation time with 2% and 8% ALA or MAL, but not with 16% ALA or MAL. Pretreatment with MNs did not increase the pain sensations during light exposure, nor did it influence erythema occurrence.

CONCLUSIONS:

MNs are a promising tool for improving the efficiency of topical PDT by improving the cutaneous delivery of ALA and MAL, without increase in side effects.

• Authors: Patrycja Mikolajewska, Ryan F Donnelly, Martin J Garland, Desmond I J Morrow, Thakur Raghu Raj Singh, Vladimir Iani, Johan Moan, Asta Juzeniene
• Journal: Pharmaceutical research (Pharm Res) Vol. 27 Issue 10 Pg. 2213-20 (Oct 2010) ISSN: 1573-904X [Electronic] United States
• PMID: 20676735 (Publication Type: Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Photosensitizing Agents
• Protoporphyrins
• delta-aminolevulinic acid methyl ester
• Aminolevulinic Acid
• protoporphyrin IX
• Silicon

Topics

• Administration, Cutaneous
• Adult
• Aminolevulinic Acid (administration & dosage, analogs & derivatives, therapeutic use)
• Erythema (prevention & control)
• Female
• Humans
• Light
• Male
• Needles
• Pain (prevention & control)
• Photochemotherapy (adverse effects, instrumentation, methods)
• Photosensitizing Agents (administration & dosage, therapeutic use)
• Protoporphyrins (biosynthesis)
• Punctures (instrumentation)
• Silicon
• Skin (drug effects, metabolism, radiation effects)
• Skin Absorption