METHODS OF INCREASING SKIN PERMEABILITY BY TREATMENT WITH ELECTROMAGNETIC RADIATION
Methods of treating tissue with fractional laser radiation are disclosed. The fractional laser treatment methods reversibly increase skin permeability while maintaining a substantially intact stratum corneum and producing alterations within the epidermis and dermis. The alterations in the epidermis and dermis can include necrosis and/or coagulation. The alterations in the epidermis can include the creation of a plurality of pores in the stratum corneum and/or the creation of vacuoles in the layers of the epidermis below the stratum corneum. The fractional laser treatment methods disclosed herein can be used to provide treatments to the skin, to increase permeation of active substances into or through tissue, to deliver active substances locally or systemically, and to control the delivery of active substances.
1 . A method of increasing the permeability of skin, the method comprising:
selecting a region of skin in need an increase in permeability to an active substance and treating the region of skin with fractional laser radiation, wherein said treating produces the increase in the permeability of the skin to the active substance and maintains a substantially intact stratum corneum.
2 . The method of claim 1 wherein the increase in the permeability of the skin to the active substance is reversible.
3 . The method of claim 2 wherein the increase in the permeability of the skin is for a duration of about 1 hour, about 2 hours, about 6 hours, about 12 hours, about 1 day, about 2 days, or about 5 days.
4 . The method of claim 1 , wherein the treating produces alterations in the epidermis and dermis of the skin.
5 . The method of claim 4 , wherein the alterations in the epidermis and dermis consist of coagulated tissue.
6 . The method of claim 4 , wherein the alterations in the epidermis and dermis consist of necrosed tissue.
7 . The method of claim 1 , wherein the treating produces pores in the stratum corneum.
8 . The method of claim 1 , wherein the treating produces vacuoles in the epidermis below the stratum corneum.
9 . The method of claim 1 wherein the fractional laser radiation has an absorption coefficient between about 4 cm −1 and about 150 cm −1 , or between about 15 cm −1 and about 120 cm −1 .
10 . The method of claim 1 wherein the fractional laser radiation has a wavelength selected from the group consisting of between about 1100 nm and about 2500 nm, between about 1280 nm and about 1350 nm, between about 1400 nm and about 1500 nm, between about 1500 nm and about 1620 nm, between about 1780 nm and 2000 nm, and combinations thereof.
11 . The method of claim 1 wherein the fractional laser radiation has a wavelength of 1550 nm.
12 . The method of claim 1 wherein the fractional laser radiation has a local irradiance selected from the group consisting of between about 25 kW/cm 2 and about 4 MW/cm 2 , between about 0.1 MW/cm 2 and about 4 MW/cm 2 , between about 0.05 MW/cm 2 and about 2 MW/cm 2 , and between about 10 kW/cm 2 and about 800 kW/cm 2 .
13 . The method of claim 1 wherein the fractional laser radiation has a local fluence selected from the group consisting of between about 10 J/cm 2 and about 320 kJ/cm 2 , between about 4 kJ/cm 2 and about 160 kJ/cm 2 , between about 1 kJ/cm 2 and about 40 kJ/cm 2 , and between about 10 J/cm 2 and about 1600 J/cm 2 .
14 . The method of claim 1 wherein the fractional laser radiation has a pulse energy selected from the group consisting of between about 2 mJ and about 1 J, between about 1 mJ and about 500 mJ, and between about 0.1 mJ and about 50 mJ.
15 . The method of claim 1 wherein the fractional laser radiation has a treatment zone size selected from the group consisting of between about 0.5 μm and about 500 μm, between about 1 μm and about 360 μm, between about 1 μm and about 250 μm, between about 1 μm and about 180 μm, about 60 μm, and about 140 μm.
16 . The method of claim 1 wherein the fractional laser radiation has a treatment zone density selected from the group consisting of between about 100 and 10,000 TZ/cm 2 , between about 100 and about 2000 TZ/cm 2 , between about 100 and about 1000 TZ/cm 2 , and between about 100 and about 500 TZ/cm 2 .
17 . The method of claim 1 wherein the fractional laser radiation is delivered using a contact window.
18 . The method of claim 1 wherein the fractional laser radiation is delivered using a non-contact window.
19 . The method of claim 1 wherein the region of skin is cooled during the treating.
20 . The method of claim 1 wherein positive pressure is applied to the region of skin during the treating.
21 . The method of claim 1 wherein a vacuum is applied to the region of skin during the treating.
22 . The method of claim 1 wherein the increase in the permeability of the skin to the active substance is used to deliver the active substance.
23 . The method of claim 1 wherein the increase in the permeability of the skin to the active substance is used to deliver a photodynamic active substance into the skin.
24 . The method of claim 1 wherein the treating is used to restore, remodel or rejuvenate skin; to treat aging of the skin; to reduce the appearance of wrinkles in the skin; and combinations thereof.
25 . The method of claim 1 the treating is used to treat a pigmentary disorder, post-inflammatory hyperpigmentation, melasma, striae, scar tissue, and combinations thereof.
26 . The method of claim 1 wherein the treating is used to treat acne, rosacea, alopecia, neoplasia of the skin, and combinations thereof.
27 . The method of claim 1 wherein the active substance is applied in conjunction with the fractional laser treatment.
28 . The method of claim 27 wherein the active substance is applied before treatment, during treatment, after treatment, or combinations thereof.
29 . The method of claim 27 wherein the active substance is applied once, repeatedly, or continuously.
30 . The method of claim 27 wherein the active substance comprises a pharmaceutical composition or a cosmetic composition.
31 . The method of claim 27 wherein the active substance is a local anesthetic, a drug for treatment of acne, a drug for treatment of rosacea, a drug for treatment of alopecia, a drug for treatment of neoplasia of the skin, a photodynamic substance, an antibiotic or combinations thereof.
32 . The method of claim 27 wherein the active substance is a retinoid.
33 . The method of claim 27 wherein the active substance is a neurotoxin.
34 . The method of claim 27 wherein the active substance is selected from the group consisting of a vitamin, a mineral, an anti-oxidant, an agent that promotes skin recovery or combinations thereof.
35 . The method of claim 27 wherein the active substance is vitamin C.
36 . A method of increasing the permeability of skin, the method comprising:
treating a region of skin with laser radiation, wherein the treating produces a plurality of individual treatment zones,
increases the permeability of the region of skin to at least one active substance, and produces a minimal level of disruption to skin barrier function in the region of skin.
37 . A method of increasing the permeability of skin, the method comprising:
treating a region of skin with laser radiation in a manner so as to produce a plurality of individual treatment zones within the region of skin, wherein said treating reversibly increases permeability of the region of skin to at least one active substance by producing alterations in the epidermis and dermis including a coagulation zone and a vacuole in the layers of the epidermis and dermis below the stratum corneum, and wherein said treating maintains a substantially intact stratum corneum in the region of skin such that the region of skin maintains a level of barrier function immediately after the treating equivalent to at least 60% of a level of barrier function present in normal untreated skin based on an indicator of skin barrier function.
38 . The method of claim 37 , wherein the alterations in the epidermis and dermis further comprise a plurality of pores in the stratum corneum which extend to a depth less than the full thickness of the stratum corneum.
39 . The method of claim 37 , wherein the indicator of skin barrier function is measurement of transepidermal water loss.
40 . The method of claim 37 , wherein the indicator of skin barrier function is measurement of skin electrical resistance.
41 . The method of claim 37 , wherein the indicator of skin barrier function is measurement of tritiated water flux.
42 . The method of claim 37 , wherein the indicator of skin barrier function is measurement of skin susceptibility to an irritant.
43 . The method of claim 37 , wherein the indicator of skin barrier function is measurement of skin susceptibility to an infectious agent.
44 . The method of claim 37 , wherein an increase in a level of uptake of the active substance is dependent on the number of independent treatment zones created during the treating.
45 . The method of claim 37 , wherein an increase in a level of uptake of the active substance is dependent on the density of independent treatment zones created during the treating.
46 . A method of delivering an active substance to the skin, the method comprising the steps:
treating a region of skin with laser radiation in a manner so as to produce a plurality of individual treatment zones within the region of skin, wherein said treating increases permeability of the region of skin to at least one active substance for a limited period of time by producing alterations in the epidermis and dermis including a coagulation zone and a vacuole in the layers of the epidermis below the stratum corneum, and wherein said treating maintains a substantially intact stratum corneum in the region of skin such that the region of skin maintains a level of skin barrier function immediately after the treating equivalent to at least 60% of the skin barrier function present in normal untreated skin based on an indicator of skin barrier function; and
applying the at least one active substance to the region of skin immediately before the treating, during the treating, and/or following the treating within the limited period of time over which the treating increases the permeability of the region of skin to the at least one active substance.
47 . The method of claim 46 , wherein the alterations in the epidermis and dermis further comprise a plurality of pores in the stratum corneum which extend to a depth less than the full thickness of the stratum corneum.
48 . The method of claim 46 , wherein the indicator of skin barrier function is measurement of transepidermal water loss.
49 . The method of claim 46 , wherein the indicator of skin barrier function is measurement of skin electrical resistance.
50 . The method of claim 46 , wherein the indicator of skin barrier function is measurement of tritiated water flux.
51 . The method of claim 46 , wherein the indicator of skin barrier function is measurement of skin susceptibility to an irritant.
52 . The method of claim 46 , wherein the indicator of skin barrier function is measurement of skin susceptibility to an infectious agent.
53 . The method of claim 46 , wherein an increase in a level of uptake of the active substance is dependent on the number of independent treatment zones created during the treating.
54 . The method of claim 46 , wherein an increase in a level of uptake of the active substance is dependent on the density of independent treatment zones created during the treating.