INTERFACE MEDIUM FOR DERMATOLOGICAL LASER TREATMENTS
Exemplary compositions and methods can be used for dermatological laser treatments, by providing suitable interface media between the skin and a source of electromagnetic radiation. The interface medium should act as a refractive index matching agent between the applicator window and the skin, and also reduce the friction between the applicator window and the skin so that the applicator can glide easily on the skin. The optical interface medium exhibits photostability such that optical clarity of the medium is maintained upon exposure to electromagnetic radiation without plasma formation, cavitation, or burning.
1 . An optical interface medium for dermatological phototherapy, comprising a single-phase, transparent, aqueous gel that is optically clear such that across a wavelength range of about 380 nm to about 1900 nm: absorbance is below 15 cm −1 ; and optical scattering is below 1 cm −1 ,
wherein the optical interface medium has a refractive index in the range of about 1.33 to about 1.5 with a viscosity in the range of about 5,000 to about 100,000 cP, and
wherein the optical interface medium exhibits photostability such that optical clarity is maintained upon exposure to electromagnetic radiation up to about 10 8 W/cm 2 without plasma formation, cavitation, or burning.
2 . The optical interface medium of claim 1 , comprising 1,3-propanediol present at a range of about 5 to about 70 weight percent.
3 . The optical interface medium of claim 1 , further comprising:
water, present at a range of about 28.5 to about 93.5 weight percent;
a water-soluble refractive index adjusting agent, present at a range of about 5 to about 70 weight percent; and
a gelling agent, present at a range of about 0.05 to about 3 weight percent.
4 . The optical interface medium of claim 1 , wherein the viscosity of the optical interface medium is in the range of about 6,000 to about 8,000 cP as measured by the Brookfield method: RV, spindle 27 and speed 30 rpm.
5 . The optical interface medium of claim 1 , wherein the pH of the optical interface medium is in the range of about 5 to about 6.
6 . The optical interface medium of claim 1 , further comprising a numbing agent.
7 . An optical interface medium for dermatological phototherapy, comprising:
water;
1,3-propanediol as a water-soluble refractive index adjusting agent; and
a gelling agent, configured to form a single-phase transparent gel with water and the refractive index adjusting agent;
wherein the optical interface medium is optically clear, has a refractive index in the range of about 1.33 to about 1.43, and exhibits photostability upon exposure to electromagnetic radiation up to about 10 8 W/cm 2 without plasma formation, cavitation, or burning.
8 . The optical interface medium of claim 7 , wherein the gelling agent is a hydroxyethyl acrylate/sodium acryloyldimethyl taurate copolymer, a polyacrylate crosspolymer-6, an acrylic acid copolymer, an acrylates/C10-30 alkyl acrylate crosspolymer, a carbomer, or a sodium polyacrylate.
9 . The optical interface medium of claim 7 , further comprising one or more antioxidants, antimicrobials, soothing agents, fragrance masking agents, or preservatives.
10 . The optical interface medium of claim 7 , comprising about 28.5 to about 50 percent water by weight.
11 . The optical interface medium of claim 7 , comprising about 37 to about 70 percent refractive index adjusting agent by weight.
12 . The optical interface medium of claim 7 , comprising about 0.7 to about 1.1 percent gelling agent by weight.
13 . A method of applying electromagnetic radiation (EMR) to skin tissue, comprising:
applying a coupling medium to a target region of the skin, the coupling medium being optically clear with a refractive index in the range of about 1.33 to about 1.43, and having a viscosity in the range of about 5,000 to about 8,000 cP as measured by the Brookfield method: RV, spindle 27 and speed 30 rpm;
positioning an EMR delivery device in contact with the coupling medium overlaying the target region while moving the device over the skin without bubble formation within the coupling medium; and
applying EMR through the device as it is moved over the target region while the coupling medium maintains photostability without exhibiting plasma formation, cavitation, or burning.
14 . The method of claim 13 , wherein the coupling medium exhibits photostability upon exposure to electromagnetic radiation up to about 10 8 W/cm 2 without plasma formation, cavitation, or burning.
15 . The method of claim 13 , wherein the coupling medium maintains photostability to retain optical clarity such that across a wavelength range of about 380 to about 1600 nm: absorbance is below 15 cm −1 ; and optical scattering is below 1 cm −1 .