Methods for photodynamic therapy

1. A method of enhancing penetration of a topical composition of 5-aminolevulinic acid (ALA) into tissue for photodynamic therapy, the method comprising:

topically applying ALA to a treatment area to be treated with photodynamic therapy;

after the ALA is applied to the treatment area, covering the treatment area with a low density polyethylene barrier prior to light treatment to minimize transepidermal water loss from the treatment area; and

removing the low density polyethylene barrier within 3 hours and then applying light to the treatment area.

2. A method as set forth in claim 1 , wherein the low density polyethylene barrier is removed from the treatment area within 3 hours and then blue light is applied to the treatment area for a 10 J/cm 2 light dose.

3. The method of claim 1 , wherein a maximum plasma concentration of ALA following application of the ALA is less than about 110 ng/mL.

4. A method of enhancing penetration of a topical composition of 5-aminolevulinic acid (ALA) into tissue for photodynamic therapy, the method comprising:

topically applying ALA to a treatment area to be treated with photodynamic therapy; and

after the ALA is applied to the treatment area, covering the treatment area with a low density polyethylene barrier prior to light treatment to minimize transepidermal water loss from the treatment area,

wherein the treatment area is located on a hand or a forearm.

5. A method as set forth in claim 4 , wherein the low density polyethylene barrier is removed from the treatment area and then red light is applied to the treatment area for a 10 to 75 J/cm 2 light dose.

6. The method as set forth in claim 4 , wherein the treatment area is a dorsal surface of the hand.

7. The method as set forth in claim 4 , wherein the treatment area is a dorsal surface of the forearm.

8. A method of using 5-aminolevulinic acid (ALA) and a low density polyethylene barrier, comprising:

contacting a treatment site with a composition comprising the ALA so as to wet the treatment site;

following wetting of the treatment site, covering the wetted treatment site with the low density polyethylene barrier;

removing the low density polyethylene barrier so as to expose the treatment site; and

illuminating the exposed treatment site with an illuminator so as to deliver a 10 J/cm 2 dose of blue light.

9. The method of claim 8 , wherein the low density polyethylene barrier is removed no later than three hours after the treatment site is covered.

10. The method of claim 8 , further comprising:

positioning the treatment site between two inches and four inches from a surface of the illuminator.