Drug – bio-affecting and body treating compositions – Anesthetic – topical
Reexamination Certificate
1998-09-04
2001-10-02
Fay, Zohreh (Department: 1614)
Drug, bio-affecting and body treating compositions
Anesthetic, topical
C514S818000, C514S626000, C514S277000, C514S315000, C514S532000, C514S544000
Reexamination Certificate
active
06297290
ABSTRACT:
The present invention relates to a novel aqueous composition based on a compound modulating the reactivity of nerve fibers. It relates more particularly to a pharmaceutical composition for topical use on a human or animal body and intended to anesthetize the skin or the mucous membranes or to treat pruritus.
For many years, it has been attempted to make active compounds, such as local anesthetics or antipruritic agents, penetrate into the epidermis or to the dermo-epidermal junction. Thus, on the one hand, methods using the iontophoresis technique which, however, turns out to be relatively complex, and on the other hand special formulations, were proposed.
Among these special formulations, there have been proposed, for example, compositions in the form of cream, based on a eutectic mixture of local anesthetics. However, these compositions, although efficacious, have the disadvantages of being complicated to prepare and of having to use a combination of local anesthetics and thus of having to make a compromise between the toxicity and the efficacy of the local anesthetics available to date. In addition, these compositions demand, to obtain an anesthetics effect which is satisfactory in terms of time and/or in quality, a relatively long occlusion time (at least 1 hour), which can turn out to be not very practical for the user (patient) and/or for the physician who has prescribed this anesthesia.
Thus, the aim of the present invention is to propose a composition for topical use which is easy to apply on a human or animal body and in particular a composition which does not necessarily demand a long occlusion time.
The aim of the present invention is likewise to propose a composition allowing local anesthesia or a pruritus treatment which is efficacious in terms of duration and/or in quality to be obtained by topical application of this composition.
The aim of the present invention is finally to propose a composition having low, or even zero, toxicity.
These aims and others are thus achieved by the present invention which relates to an aqueous composition, characterized in that it comprises at least one compound (1) modulating the reactivity of nerve fibers, at least one compound (2) which is water-miscible, solubilize the compound (1) and is volatile, the weight ratio water/volatile compounds being greater than or equal to 0.8, the composition being devoid of any compound, other than water, which does not solubilize the compound (1) and is capable of retarding the evaporation of the volatile compounds present in the composition and devoid of compound which solubilizes the compound (1) and is non-volatile.
This composition has the advantages of being easy to prepare and of a low production cost while retaining a satisfactory anesthetic efficacy.
Compound (1) modulating the reactivity of nerve fibers is understood according to the invention as meaning any compound modulating, locally, nerve conduction. More particularly, these compounds inhibit nervous conduction. Among these compounds, it is possible to mention the local anesthetics and the antipruritic agents.
Among the antipruritic agents, it is possible especially to mention crotamiton.
Local anesthetics are compounds which produce a reversible loss of sensation by inhibiting nerve conduction or by decreasing the excitability of the nerve at the level of their site of application. They can also be described as local analgesics because they are often used to cause a decrease in pain without loss of nerve control.
It is possible especially to mention local anesthetics of the amide type, such as lidocaine, bupivacaine, etidocaine, prilocaine and cinchocaine, ester local anesthetics of benzoic acid, such as amylocaine and propanocaine, ester local anesthetics of para-aminobenzoic acid, such as tetracaine, benzocaine, butacaine, oxybuprocaine, parethoxycaine and procaine, or alternatively other anesthetics, such as diperodon, ketocaine, pramoxine, dimethisoquine and myrtecaine.
Among the local anesthetics mentioned above, it is preferred to use lidocaine.
Advantageously, the local anesthetics are used in their non-ionized form.
They can be used on their own or as a mixture.
The compound (1) in the composition is advantageously present in a concentration of between 0.5 and 30%, and preferably between 3 and 10%, by weight in relation to the total weight of the composition.
Volatile compound is understood according to the invention as meaning any compound, other than water, which volatilizes at a temperature which is lower than or equal to that of the skin (which is generally at approximately 32° C.).
Preferably, the weight ratio water/volatile compounds is greater than or equal to 1.
Generally speaking, the composition according to the invention comprises at least one compound solubilizing the compound (1) in a sufficient quantity such that the compound (1) present does not recrystallize when the composition is applied to the skin. Preferably, this quantity is sufficient such that the compound (1) present in the composition does not recrystallize on storage.
The person skilled in the art knows how to adjust this quantity of solubilizing compound(s) in the composition, knowing that, of course, it varies according to the nature and the quantity of the compound (1) present.
The composition according to the invention does not comprise a compound which solubilizes the compound (1) and is non-volatile, such as dimethyl sulphoxide (DMSO), dimethylacetamide (DMAC), dimethylformamide (DMF), dimethyllactamide, propylene glycol (PG), polyethylene glycol (PEG), dimethylisosorbide (DMIS) and ethoxydiglycol (Transcutol® sold by Gattefossé). These compounds, if they are present in the composition, cause a decrease in the efficacy of the composition.
The composition according to the invention thus comprises, as compound solubilizing the compound (1), only compounds (2).
Among the compounds (2) which are water-miscible, solubilize the compound (1) and are volatile, it is possible especially to mention the C
1
-C
6
alcohols and acetone, which can be used on their own or as a mixture.
Preferably, C
1
-C
4
alcohols are used.
Among C
1
-C
4
alcohols, it is possible to mention ethanol and isopropanol. Ethanol is particularly preferred.
The compound (2) in the composition is advantageously present in a concentration of between 10 and 50%, preferably 10 to 40%, by weight in relation to the total weight of the composition.
The composition according to the invention is devoid of any compound, other than water, which does not solubilize the compound (1) and is capable of retarding the evaporation of the volatile compounds present in the composition; thus, it is devoid of compounds such as certain polyols which do not solubilize the compound (1), such as glycerol and sorbitol. These compounds are excluded because they can decrease the efficacy of the composition.
The composition according to the invention can additionally comprise at least one thickener of natural or synthetic origin. As thickeners, it is possible to mention carboxyvinyl polymers (carbomer), acrylic copolymers such as copolymers of acrylates/alkylacrylates, poly(meth)acrylates of glycerol such as the product sold under the name Norgel by Guardian, polyacrylamides and especially the mixture of polyacrylamide, C13-C14 isoparaffin and Laureth-7, sold under the name Sepigel 305 by Seppic, polysaccharides such as alkylcelluloses and hydroxyalkylcelluloses, natural rubbers (xanthan), clays and anhydrous colloidal silicas, such as Aerosil® sold by Degussa.
Certain of these thickeners can necessitate the addition of a neutralizing agent to favour the thickening of the gel, such as amines or sodium hydroxide.
Thus, the composition according to the invention can be present in liquid, semi-solid or gel form.
The composition according to the invention can moreover comprise all the ingredients conventionally used in the cosmetic or dermatological field, in customary concentrations. These ingredients are in particular chosen from preservatives, perfumes, surfactants, antioxidants, fillers, filters, humecta
Allec Josiane
Ctorza Karen
Guise Anne-Emmanuelle
Burns Doane Swecker & Mathis L.L.P.
Centre International de Recherches Dermatoloques Galderma (C.I.R
Delacroix-Muirheid C.
Fay Zohreh
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