Enhanced sonophoretic delivery of 5-aminolevulinic acid: preliminary human ex vivo permeation data.

Background/aims: 5-Aminolevulinate (ALA) is an important photodynamic therapy drug for the treatment of actinic keratoses and other non-melanoma skin cancers in cosmetically sensitive areas. One limitation of this drug is a relatively high recurrence rate. Our aim was to evaluate the feasibility of ultrasound augmented ALA delivery in excised human skin.

Materials And Methods: An ultrasonic delivery device was used to enhance radiolabelled ALA into excised skin. Quantification of ALA was performed after passive and ultrasonic ALA delivery. Transepidermal water loss was used as a measure of barrier function before and after ultrasonic treatment.

Results: We found that ultrasonic treatment dramatically increased the mean cumulative amount of ALA to P< 0.0001 from 4 to 8 h when compared to passive ALA treatment. The flux was calculated to be 54.8 ± 8.0 μg/cm(2) h with ultrasound treatment. TEWL increased nearly two-fold, from 12.3 to 21.0, after ultrasound treatment.

Conclusion: Our study supports the use of ultrasound for improved ALA delivery by showing significant improvements in the cumulative drug load and flux via combined ultrasound and ALA treatment.