Solid-forming topical formulations for pain control

Abstract

Solid-forming topical formulations can include a local anesthetic, an emulsifying agent, polymer, and water. The formulation can include from 0.1 wt % to 5 wt % more of the emulsifying agent, from 0.1 wt % to 20 wt % more of the polymer, and from 0.1 wt % to 30 wt % more water than a comparative formulation, and drying time is faster than the comparative formulation when applied to a skin surface and dried under the same ambient conditions.

What is claimed is: 
     
         1 . A solid-forming topical formulation, comprising:
 a local anesthetic,   an emulsifying agent,   a polymer, and   water,   wherein the topical formulation comprises from 0.1 wt % to 5 wt % more of the emulsifying agent, from 0.1 wt % to 20 wt % more of the polymer, and from 0.1 wt % to 30 wt % more water than a comparative formulation, and drying time is faster than the comparative formulation when applied to a skin surface and dried under the same ambient conditions.   
     
     
         2 . The formulation of  claim 1 , wherein a drying time is based on an average drying time applying and spreading 6.5 grams of the topical formulation or the comparative formulation over a 50 cm 2  skin surface of human subjects and allowing the topical formulation or the comparative formulation to dry at ambient conditions. 
     
     
         3 . The formulation of  claim 2 , wherein the topical formulation dries at least 1.15 times faster than the comparative formulation dries. 
     
     
         4 . The formulation of  claim 1 , wherein the topical formulation comprises about 6 wt % more water than the comparative formulation. 
     
     
         5 . The formulation of  claim 1 , wherein the local anesthetic is present in the topical formulation from about 4 wt % to about 30 wt %. 
     
     
         6 . The formulation of  claim 1 , wherein the local anesthetic in the topical formulation comprises lidocaine and tetracaine. 
     
     
         7 . The formulation of  claim 1 , wherein the polymer in the topical formulation comprises polyvinyl alcohol. 
     
     
         8 . The formulation of  claim 1 , wherein the polymer comprises from about 13 wt % to about 25 wt % of the topical formulation. 
     
     
         9 . The formulation of  claim 1 , wherein the water comprises from about 30 wt % to about 55 wt % of the topical formulation. 
     
     
         10 . The formulation of  claim 1 , wherein a water to polymer weight ratio of the topical formulation is greater than 2.4. 
     
     
         11 . The formulation of  claim 1 , wherein the emulsifying agent comprises from about 3 wt % to about 7 wt % of the topical formulation. 
     
     
         12 . The formulation of  claim 1 , further comprising an emollient, wherein the emollient includes white petrolatum. 
     
     
         13 . A method of preventing pain, comprising:
 applying a layer of the solid-forming formulation of  claim 1  to the skin surface of a subject, and   maintaining said layer on said skin surface for a period of time sufficient to allow said formulation to deliver said local anesthetic to the subject, thereby numbing the skin surface.   
     
     
         14 . A method of treating existing pain, comprising:
 applying a layer of the solid-forming topical formulation of  claim 1  to a skin surface of a subject, and   maintaining said layer on said skin surface for a period of time sufficient to allow said formulation to deliver said local anesthetic to the subject, thereby reducing the pain.   
     
     
         15 . A method of preventing pain in a subject prior to a dermatological procedure, comprising:
 applying a layer of a solid-forming topical formulation comprising from 4 wt % to 30 wt % of a local anesthetic to a treatment site of a subject;   maintaining the layer of the formulation on the treatment site for a period of time sufficient to allow the layer of the formulation to transition from a semi-solid to a cohesive film and to topically deliver the local anesthetic to the treatment site of the subject; and   removing the layer of the formulation from the treatment site of the subject by peeling the layer of the formulation off the treatment site, wherein the layer of the formulation is operable to be removed as a single piece or two to three large pieces and does not leave a residue on a surface of the treatment site,   wherein the formulation dries at least 1.10 times faster than a comparative formulation.   
     
     
         16 . The method of  claim 15 , wherein the layer of the formulation is applied at a thickness ranging from about 1 mm to 2 mm to the treatment site of the subject of about 50 cm 2  and 2.5 grams of the formulation dries to touch at ambient conditions, in less than 23 minutes on average. 
     
     
         17 . The method of  claim 15 , wherein the layer of the formulation is applied at a thickness ranging from about 1 mm to 2 mm to the treatment site of the subject of about 50 cm 2  and 6.5 grams of the formulation dries to touch at ambient conditions, in less than 43 minutes on average. 
     
     
         18 . A method of treating existing pain in a subject, comprising:
 applying a layer of a solid-forming topical formulation comprising from 4 wt % to 30 wt % of a local anesthetic to a skin surface of a subject;   maintaining the layer of the formulation on the skin surface for a period of time sufficient to allow the layer of the formulation to transition from a semi-solid to a cohesive film and to topically and/or transdermally deliver the local anesthetic to the subject; and   removing the layer of the formulation from the skin surface of the subject by peeling the layer of the formulation off the skin surface, wherein the layer of the formulation is operable to be removed as a single piece or two to three large pieces,   wherein the layer of the solid-forming topical formulation excludes a backing layer, a backing film, or other support substrates,   wherein the transition from the semi-solid to the cohesive film does not require further treatment, and   wherein the formulation dries at least 1.10 times faster than a comparative formulation having less water.   
     
     
         19 . A solid-forming topical formulation comprising:
 local anesthetic; and   polyvinyl alcohol in an amount of more than 12% w/w based on total weight of the topical formulation,   wherein the formulation has a drying time less than about 43 minutes on average when the topical formulation is applied as a 6.5 gram sample at a thickness of less than 2 mm at ambient conditions on human subjects.   
     
     
         20 . The formulation of  claim 19 , wherein the formulation can be easily removed and has a viscosity less than 1,500,000 cps at a temperature of about 25° C. and relative humidity of about 38-45° C.