Claims for Patent: 5,919,479

Summary for Patent: 5,919,479

Title:	Noninvasive dermal anesthetics
Abstract:	An apparatus, product formulation, and method for improved dermal permeation of pharmaceuticals wherein the apparatus includes a thin drug formulation reservoir and a heat-generating chamber separated by a first non-permeable wall, wherein the reservoir and chamber are formed in or supported by a housing. The drug formulation reservoir houses or is capable of housing a predetermined amount of a formulation containing pharmaceutically-active agent(s). The heat-generating/temperature-regulating chamber includes a medium for generating controlled heat, preferably a chemical composition made of carbon, iron, water and/or salt which is activated upon contact with air (oxygen). The function of the heat-generating/temperature-regulating element is to heat the user's skin, rapidly bring the skin temperature to a desired and elevated narrow range and keep it in this range for sufficient time to obtain more rapid, enhanced and less variable dermal absorption of selected pharmaceutically-active agents and to obtain improved clinical effects. Structure for controlling the generation of heat is also disclosed. The apparatus may optionally include a spacing or standoff structure which spans the drug formulation reservoir between the non-permeable wall and the user's skin surface for maintaining a predetermined thickness of the drug formulation on the user's skin surface. Also, a novel product formulation which can be used with the apparatus which uses high percentage of eutectic mixture of local anesthetics to reduce the overall degradation rate of the local anesthetic compound(s) in formulations which are subject to hydrolysis.
Inventor(s):	Zhang; Jie (Salt Lake City, UT), Zhang; Hao (Salt Lake City, UT)
Assignee:	Zars, Inc. (Salt Lake City, UT)
Application Number:	08/819,880
Patent Claims:	1. A formulation with reduced degradation rate of anesthetic(s) and improved noninvasive dermal anesthesia comprising: an emulsion with an oil phase and an aqueous phase; and said oil phase being a eutectic mixture of tetracaine and lidocaine, wherein the weight percentage of said eutectic mixture in said formulation is about 12% or greater. 2. The formulation of claim 1, wherein said emulsion is thickened such that it is substantially non-flowable and cohesive at ambient temperature. 3. The formulation of claim 1, further including pH regulating agent(s), coloring agent(s), permeation enhancing agent(s), or a combination thereof. 4. The formulation of claim 1, wherein the ratio of tetracaine to lidocaine is between 1:0.5 and 1:1.5. 5. The formulation of claim 1, wherein said tetracaine and lidocaine in said eutectic mixture is formulated in a substantially one to one weight ratio. 6. The formulation of claim 1, wherein the weight percentage of said eutectic mixture in said formulation is greater than about 18%. 7. The formulation of claim 1, further including at least one compound that is an emulsifying agent, a gelling agent, or a thickening agent. 8. The formulation of claim 7, wherein said emulsion is gelled. 9. The formulation of claim 8, wherein said gelled emulsion rapidly melts or significantly softens when heated to greater than about 30.degree. C. 10. The formulation of claim 8, wherein said gelled emulsion does not melt or significantly soften when heated to about 30.degree. C. 11. A formulation with reduced degradation rate of anesthetic(s) and improved noninvasive dermal anesthesia comprising: a gelled-emulsion with an oil phase and an aqueous phase which melts or significantly softens when heated to about 30.degree. C.; said oil phase being a eutectic mixture of tetracaine and lidocaine; the weight percentage of said eutectic mixture in said emulsion being about 12% or greater; said formulation having at least one compound that is an emulsifying agent, a gelling agent, or a thickening agent; and said gelled-emulsion optionally including pH regulating agent(s), coloring agent(s), permeation enhancing agent(s), or a combination thereof. 12. A formulation with reduced degradation rate of anesthetic(s) and improved noninvasive dermal anesthesia comprising: a gelled-emulsion with an oil phase and an aqueous phase which does not melt or significantly softens when heated to about 30.degree. C.; said oil phase being a eutectic mixture of tetracaine and lidocaine; the weight percentage of said eutectic mixture in said emulsion being about 12% or greater; said formulation having at least one compound that is an emulsifying agent, a gelling agent, or a thickening agent; and said gelled-emulsion optionally including pH regulating agent(s), coloring agent(s), permeation enhancing agent(s), or a combination thereof.