HIGH CONCENTRATION LOCAL ANESTHETIC FORMULATIONS
A transdermal topical anesthetic formulation, which can be used to ameliorate or inhibit pain, has been developed. In the preferred embodiment, the topical anesthetic is a local anesthetic such as lidocaine, most preferably lidocaine free-base in a gel, and the dosage of the local anesthetic is effective in the painful area or immediately adjacent areas, to ameliorate or eliminate the pain. High concentration of local anesthetic in solution in the carrier is used to drive rapid release and uptake of the drug. Relief is typically obtained for a period of several hours.
1 - 19 . (canceled)
20 . A topical anesthetic formulation in the form of a non-aqueous gel, comprising
(a) about 40% by weight of a free base caine alkaloid local anesthetic, wherein the free base caine alkaloid local anesthetic is lidocaine free base; and
(b) a pharmaceutically acceptable carrier for topical application, wherein the carrier comprises an alkylene glycol and an alcohol;
wherein the formulation is a non-aqueous gel, and the formulation can provide pain relief for 3 hours when applied topically to a site at or adjacent a painful region without systemic toxicity.
21 . The formulation of claim 20 , wherein the alkylene glycol is propylene glycol.
22 . The formulation of claim 20 , further comprising diglycol monoethyl ether.
23 . The formulation of claim 21 , further comprising diglycol monoethyl ether.
24 . The formulation of claim 20 , further comprising hydroxypropyl cellulose.
25 . The formulation of claim 21 , further comprising hydroxypropyl cellulose.
26 . The formulation of claim 22 , further comprising hydroxypropyl cellulose.
27 . The formulation of claim 23 , further comprising hydroxypropyl cellulose.
28 . The formulation of claim 21 , wherein the alcohol is ethanol.
29 . The formulation of claim 22 , wherein the alcohol is ethanol.
30 . The formulation of claim 23 , wherein the alcohol is ethanol.
31 . The formulation of claim 25 , wherein the alcohol is ethanol.
32 . The formulation of claim 27 , wherein the alcohol is ethanol.
33 . The formulation of claim 20 , further comprising isopropyl myristate.
34 . The formulation of claim 21 , further comprising isopropyl myristate.
35 . The formulation of claim 23 , further comprising isopropyl myristate.
36 . The formulation of claim 27 , further comprising isopropyl myristate.
37 . The formulation of claim 32 , further comprising isopropyl myristate.
38 . The formulation of claim 20 , further comprising dimethyl isosorbide.
39 . The formulation of claim 21 , further comprising dimethyl isosorbide.
40 . The formulation of claim 23 , further comprising dimethyl isosorbide.
41 . The formulation of claim 27 , further comprising dimethyl isosorbide.
42 . The formulation of claim 32 , further comprising dimethyl isosorbide.
43 . The formulation of claim 23 , wherein the formulation contains 40% by weight lidocaine free base.
44 . The formulation of claim 27 , wherein the formulation contains 40% by weight lidocaine free base.
45 . The formulation of claim 37 , wherein the formulation contains 40% by weight lidocaine free base.
46 . The formulation of claim 42 , wherein the formulation contains 40% by weight lidocaine free base.
47 . The formulation of claim 20 , wherein the formulation contains 40% w/w lidocaine free base, 20% w/w diglycol monoethyl ether, 10% w/w propylene glycol, 10% w/w dimethyl isosorbide, 18.80% w/w ethanol, and 1.2% w/w hydroxypropyl cellulose.
48 . The formulation of claim 20 , wherein the formulation contains 40% w/w lidocaine free base, 10% w/w isopropyl myristate, 10% w/w diglycol monoethyl ether, 20% w/w propylene glycol, 18.80% w/w ethanol, and 1.2% w/w hydroxypropyl cellulose.
49 . The formulation of claim 20 providing an initial burst release within four hours after topical administration.