CA2431745A1 - External preparation for treating dermatosis and pruritus due to hemodialysis - Google Patents

Abstract

Method for treating dermatosis and pruritus due to hemodialysis by applying to a patient suffering from said diseases due to hemodialysis the external preparation containing Aspirin as an active ingredient.

Description

DESCRIPTION
EXTERNAL PREPARATION FOR TREATING DERM.?~TOSIS AND PRURITUS
DUE TO HE1'~IODIALYSIS
BACKGROUND OF THE INVENTION
FIELD OF THE TNVENTION
The present invention relates t~~ therapeutic agents for xerosis cutis (skin-dry) dermatos~.s such as exanthema, or pruritus which becomes problem to patients receiving hemodialysis treatment.
In more detail the present irmention relates to external preparations for treating dermatosis and/or pruritus due to hemodialyss.s, which contains acetylsalicylic acid as an active ingr_edient~ and a. method for treating said diseases by administering transdermally said external preparations ir. ar~ amount of an effective dose to patients sufferi:n~ from said diseasesa DESCRIPTION OF THE RELATED ART
Recently, with increase of patients suffering from endocrinism such as diabetes, and dysmetabolism such as nephropathy, patients who receive hemodialysis treatment are increasing. In the patients receiving hemodialysis treatment, turning for the deterioration of the skin condition and strong itching on body have become severe problem.
In regard to itching or pain on the patient receiving hemodialysis treatment, many studies have been doize, but the mechanism thereof has not dissolved anct that said patients are hardly cured comparing with the patients receiving no hemodialysis treatment. In addition there is none of agents effective to ~ruritus dL:ring hemodialysis treatment.

Nowadays many antipruritic agents for oral administration such as anti~~istamines etc. are sold. In case of such an agent being takenp it is anxious for its side effects, such as sleepiness, worthlessness feeling, etc. It is more difficult to use an antipruritic agent for oral administration to tre patier~~ receiving hemodialysis treatment, because frequencies of the side effects to the patients are higher comparing ~.~aith ones to healthy persons.
On the other hand, an activity to dermatosis and an antipruritic activity of an external preparation containing an antihistamine or a nonsteroidal ant_inflammatory agent are not satisfactory. Especia l=y the preparation containing an antihistamine is also anxious for its side effects such as dermal anaphylaxis, and the preparation containing a nonsteroidal ar~tiinfl_ammatory agent is also anxious for its side effects, such as dermal irritation, contact dermatitis, etc.
Furthermore, although steroids for an external application are very useful for treatment of eczema, skin pruritus, etc., these steroids are not cnly anxious for their side effects, such as atrophia cubs, steroid flush, angiotelectasis, etc., when repeatedly taken, but also these steroids are transo:ermally absorbed to migrate to blood and have a possibility to gizre :>ystE:mically bad effects.
Acetylsalicylic acid (Hereinafter it may be wr~_tten as Aspirin. ) has a strong analgesic actl_-Ui.ty, an ant~~febrile activity and an antirheuma-tic activity being less in its side effects and being su~cerior in. its safetyo Therefore, acetylsalicylic acid has been w7dely used from of old.
Recently studies for new uses of external preparations containing acetylsalicylic acid have been done. For example, ointments for treating neuralgia (Japanese Patent Pub. A3-72426), external preparations for treating skin injury (Japanese Patent Pub,. A9-235232), a transdermal administration system for treatment of thrombosis and for prophylactic treatment of cancer (Japanese Patent Pub.
Tokuhyo 8-50198) are illustrated.
However, any external preparation containing acetylsalicylic acid for treating deterioration of skin condition and pruritus on body for_ tr_e patieni~s receiving hemodialysis treatment, and therapeutic effects thereof have not been reported.
SUMMARY OF THE II~IVENTIOhT
An object of the present invention is to provide external preparations v,Thich have an activity for improvement of skin condition and an excellent antipruritic activity on the patients receiving hemodialysis treatment and are less in their side effects.
The present invention relates to external preparations for treating dermatosis and/or pruritus due to hemodialysis, which contains acetylsalicylic acid as an active ingredient and a method for treating said diseases by a.dminrsterir~g transdermally said exterv~al preparations in an amount of an effective dose to patients suffering from said diseases.
Further scope of app=~_icability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention wil_L become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF TEE DRA~~1INGS
Fig. 1 is a photo of a knee of a patient receiving hemodialysis treatment before administration of the external preparation of -the present invention.
5 Fig. 2 is a photo of 'the same lesion of the patient after administration of the external preparation of 'the present invention.
DETAILED DESCRIPTION
The present inventors have earnestly studied and as a result, have found that peahen an external preparation containing acetylsalicylic acid as an active ingredient is administered to a patient receiving hemodialysis treatment, the preparation is less in its side effects and shaves an excellent antipruritic activity and an excellent activity to dermatosis. Thus t;he present invention has been completed.
Namely, the present inventors have prepared the external preparation containing acetylsalicylic acid and ~.lhen the preparation has been applied to, for e~:ample a lesion with itching and dermat~osis, such as injured skin, eczema, tuber, ulticaria, prutitus, bulla, edema, et c., the excellent therapeutic activities thereto have been found.
Acetylsalicylic acid contained ir~ the external preparation of the present invention is described in the Pharmacopoeia of Japan XIII and USP 26.
The dosage of Aspirin transdermally administered to a patient depends on the condition of the patient, but it is usually 0.01-200mg/day/body weight (60kg}.
The external preparation of the present invention is applied to in the usual manner, such as, applied directly to the affected legion or is once painted or immersed an the cloth and then applied to the affected legion.
The diseases which the external preparation of the i0 present invention is applied to are xerosis cutis, with itching and dermatosis, such as injured skin, eczema, rubor, ulticaria, pruritus, bulla, edema, etc. in patients receiving hemodialysis treatment.
The amount of acetylsalicylic acid contained in the external preparation of the present invention depends on form of the preparation but .is 005-800~~ preferably 0.05-700, more preferably 0.1-50o per total amount by weight.
When the amount of acetylsalicylic acid is more than 80o by weight, it is impossible to maintain the physical property as an external preparation. Wizen the amount of acetylsalicylic acid is less than Or05o by weight, the antipruritic activity by acetylsalicylic acid does not show enough. The amount as more than 80o cr less than 0.050 by weight, therefore is not preferable.

The external preparation of the present _invention is not limit ed as far as ~t is the p.r_eparation in which acetylsalicylic acid can. be directly applied on the local surface of skin, such. as ointments, solutions (e. g.
suspensions, emulsions, lotions), cataplasm;~, patches, plasters, tapes, aerosols and external. powders (powders for external use).
As other ingredients except acety?_salicylic acid of the external preparation of the present lnver~tion can be used any ;ingredient used a_n the ordinarily external preparations.
In case of ointments, creams, gels and lotions, bases, such as white vaseline (petrolatum), yellow vaseline, lanolin, purified bee wax, cetanol, stearyl alcohol, stearic acid, hydrogenated oil, hydrocarbon gel, polyethylene glyco-~, liquid par_af_fin a:rld squalanea solvents or solubilizing agents, such as o~_elc acid, isopropyl myristate, glycerol tri.isooctanoate, crot amii~ons diethyl sebacate, diisopra-,oyl sebacate, diiso,propyl ac'~ipate, hexyl laulate, a fatty acid., a fatty acid ester, an aliphatic alcohol, and a plant oil; antioxidants, such as a tocopherol derivative' L-ascorbic acid, dibutylhydroxytoluene and butylhydroxyanisoleo antiseptics such as p-hydroxybenzoate; humectants, such as glycerin, propylene glycol and sodium hyaluronatea surfactants, such as a polyoxyethylene derivative, a glycerol fati~y acid ester, a sucrose fatty acid ester, a sorbitar~ fatty acid ester, a propylene glycol fatty acid ester and lecithin;
thickening agents, such as carboxyvinyl polymer, xanthan gum, carboxymethyl cellulose, sodium carboxymeth_yl cellulose, hydroxypropyl cellulose and hydroxypropylmethyl cellulose; stabilize_rs9 preserva.-t~_vesa absorption enhancerso and other suitable fillers niay be added.
In case of tapes, tacking agents, such as a stylene isoprene-stylene block copolymer and. an acrylate resinP
tackifier resins, such as an alicyclic saturated hydrocarbon resin, a hydrogenated rosin. resin a.nd a. terpene resins softeners, such as liquid gum anal liquid paraffin antioxidants such as dibutylhydroxytolueneo polyhydric alcohols such as polyethylene glycol; absorption enhancers such as oleic acids surfactants such as a pol_yoxyethylene derivatives and other suitable fillers may be added. In addition a water-absorbable polymer, sur_h as sodium polyacrylate and polyvinyl alcohol, and a small amount of purified water may be added to prepare tape preparations containing water.
In case of aerosols; bases, such as white vaseline (petrolatum!, yellow vaseline, lanolin, purified bee wax, cetanol, stearyl alcohol, stearic acid, hydrogenated oil, hydrocarbon gel, polyethylene glycol, liquid paraffin and squalane; solvents or solubilizing agents, such as oleic acid, isopropyl myristate, isopropyl adipate, diisopropyl sebacate, glycerol triisooctanoate, crotamiton, diethyl sebacate, hexyl laurate, a fatty acid, a fatty acid ester, an aliphatic alcohol and a plant oil; antioxidants, such as a tocopherol derivative, L-ascorbic acid, dibutylhydroxytoluene and butVlhydrox_yanisolee antiseptics such as p-hydroxybenzoate; humectants, such as glycerin, propylene glycol and sodium hyaluronate; surfactart:s, such as a polyoxyethylene derivative, a glycerol tatty acid ester, a sucrose fatty acid ester, a sorbitan fatty acid ester, a propylene glycol_ fatty acid ester and lecithin;
thickening agents, such as carboxyvinyl polymer, xanthan gum, carboxymethyl cellulose,, sodium c:arboxymethyl cellulose, hydroxyp.ropyl cellulose and hydrox~rpropylmethyl cellulose, as used in the ointments, the creanus, the gels, the suspensions, the emulsifying agents or the lotions;
stabilizers; buffering agents; sweetening agents;
suspending agents; emulsifying agents,P flavors;
preservatives; solubili.zing agents; and other suitable fillers, may be added.
In case of external powders, fillers, sL.ch as potato starch, rice starch, corn starch, talc and zinc oxide, and other suitable additi~re;~ may be added.

The external preparation of the present i:nvent.ion can be prepared, for example by well kneading each ingredient, if necessary with a suitable base, in accordance with a usual manner.
5 In case of preparing ointments, using fat, fatty oil, lanolin, wax, resin, plastic, glyccls, highe r molecular weight alcohols, glycerin, water, emulsifier, suspending agent, or other suitable ingredients as a starting material, or these ingredients as a base and adding a medicament 10 thereto the resulting mixture are kneaded to become homogeneity. Namely, tre ingredients for the base are dissolved under heating and mixed to beccme homogeneity and if necessary, absorption enhancer, antioxidant, preservative, purified waver, etc., is added Teen 25 acetylsalicylic acid in powders is added under stirring and kneaded to prepare ointments or creams.
For example, in case of preparing oleaginous ointments, a base is melted under warming and mixed and after the mixture is semi-cooled, a medicament ir= powde r or solution is mixed with a part of the base. Then the mixture is mixed with the rest of the base to become homogeneity.
For example, in case of preparing emulsified or water-soluble ointments, after the solid base is melted on a water bath and to the melted base keeping at about: 75°C is added the water-soluble base which is d.isso7_ved in water kept at the same temperature or a little higher. The mixture is kneaded to become homogeneity. In case of adding another medicament to this mixture, according t0 the property of the base, a water-soluble or oil-soluble medicament is first mixed with a part of the base and then homogeneously with the rest of the base.
In case of preparing tapes, to a tacking agent such as an acrylate resin or a stylene-isoprene-stylene block copolymer are added tacl~ifier resins, such as an alicyclic saturated hydrocarbon resin, a hydrogenated rosin resin and a terpene resin, softeners, such as -Liquid gum and liquid paraffin, absorption. enhancers and antioxidants. The mixture is dissolved i.n an organic solvent such as toluene, or is melted under heating and the zraixtur a is well mixed.
To the mixture is mixed a medicament in powder or in solution. The m~zxture is spread on a release paper. In case of a soluble type, after spreading and dry, the paper is laminated on a flexible support such as with polyurethane film, polyethylene fil_ma poly chlorinated vinyl film, woven cloth or unwoven cloth and then cut in a desired size.
In case of preparing lotions, a medicament, a solvent, an emulsifier, a suspending agent, etc., are added to an aqueous solution and the mixture is homogenized. In case of preparing suspending lotions, after pulverizing -the medicament and making it wettab 1e with. glyceri.:n or ethanol etc., then thereto is gradually added a solution of a suspending agent or a base of the lotion and the mixture is homogenized. In case of preparing emulsifying lotions, an oil-soluble medicament and an oil layer are put in one vessel, and an aquecus layer -_s put i:n other vessels Each vessel is warmed, and in case of preparing 0/T~7 type emulsion, the oil layer is gradually added to the aqueous layer, and in case of preparing W%O type emulsion, in contrast, the aqueous layer is gradually added to the oil layer. mach mixture ccntirlues to be mixed until the emulsifying is completed.
In case of preparing the aerosols, an ointment, a cream, a gel, a suspension, an emulsion, a solution or a lotion, etc. is p-~epared lay the method as mentioned above and then, it is poured with a liquid gas or a compressed gas in a sealed vessel to prepare the aerosols.
The diseases which the external preparation of the present invention is applied to are, as mera fined above, xerosis cutis, with itching and dermatosis, such as injured skin, eczema, rubor, ulticaria, pruritus, bulla~ edema, etc.
in patients receiving hemodialysis treatment.
MODE FOR CARRYING OUT THE INVENTION
The external preparations containing acetylsalicylic acid of the present invention are explained by examples and experimental examples, but the present invention is not limited by these examples.
Examples 1-6 ~j0intmentsl According to ingredients indicated in Table 1, an ointment base (vaseline or 'hydrocarbon gel), a solvent (Tween 80, crotamiton, an a_lcohcl, diisopropyl ads_pate or isopropyl myristate} anal Aspirin were dissolved or dispersed under well stirring on a water bath. Then the mixture was cooled under stirring to prepare ointments.
Table 1: Ingredients of ointments containing Aspirin Examples ~ .1 ~ 2~~ ~ - ~ 5 6 4 -'- _,_ ingredients ~ Ingredie:~~t I
ratio(wt o }

Aspirin ' 0.1 1.0 10.01 0.5 5.0 2.0 Ethanol ~ 1.0 2.0 10.0 - - -8 G.- ~~ - - - ; - _ Tween - 5 Crotamiton j - - _ - 5.0 Diisopropyl adipate - - - - - 5.0 Vaseline , 98.9 - 80.0 94.5 - -~

Hydrocarbon gel - 97.0- 90.0 97.0 Examples 7-9 (Lotion s According to ingredients indicated in Table 2, Aspirin was added to a warmed oil.. layer to be dissolved or dispersed. Separately otter ingredients were dissolved in i4 previously ~,aarmed purified . ~.aai~er ~ and the oil layer was added thereto under vigorously stirring. The mixture was mixed to homogeneity under gradually cooling to prepare lotions.
Table 2o Ingredients of lotions containing Aspirin E x amp l a s ~' 7 ~~_ 8 ~~
g Ingredients ~ Ing ent ratio (wto) Aspirin ~ 0.05 0.5 5.0 Crotamiton ~ 1.0 2.0 5.0 Isopropanol - -~ 2.0 Diisopropyl sebac~~.te 1.0 - -E~

Squalane 3.0 3.0 3.0 ~ 3v0 3.0 3.0 Cetanol -- 0.5 0.5 0.5 Solbitan sesquioleate Polyoxy(20)cetyl ether 1a5 1.5 1.5 Propylene glycol 5.0 ~ 5.0 5.0 Triethanolamine 0.4 ' 0.4 Oa4 Purified water ( 84.55 ?7.0 74,.~
L

Examples 10-12 (Ge,~. s~
According to ingredients indicated in Table 3~ after a water soluble polymer was melted on a relater bath Pspirin wa.s dissolved or dispersed in a solvent(s:) and these ingredients with other bases were homogeneously mixed to prepare gels.

Table 3: Ingredienv~.s of gels containing Aspirz_n Examples ~~ 10 C 11~ 12 Ingredients Tr~.gredieni= ratio ('at o;

Aspirin Om2 2~0 20.0 Crotamiton ~ 1.0 5~0 2.0 Isopropanol i~ 1.0 ~ - 2.0 ~

Propylene glycol ~5m0 '1 5x0 36.0 Polyacrylic acid ~ 25m0 2 50 25.0 Triethanolamine ~ 0.7 0.7 0.7 Purif i ed wa ~~ ~'.7 . 1 2 . 3 ~ l4 ter_~ ~-- 2 0 3 Examples 13-15 (Creams) According to ingredients indicated in Table 4, after a solid base was melted on a water bath Aspirin dissolved or~
dispersed in a solvent U~as added thereto. A water--soluble base was dissolved in ara.ter and its warmed ;sol,ation Haas added to the mixturem The mixture was }cneaded until it became homogenous to prepare creams.

Table 4: Ingredients of ointments containing Aspirin Examples ' 1~ 14 15 Ingredients Ingredient (wto) ratio Aspirin 4.0 4.0 4.0 ~ Crotamiton 1. 0 1. 0 1_ .

Sesame oil 2.0 - 1.0 a i ~Diisopropyl sebacate ~ 2.0 1.0 i Cetanol 9.0 9~0 9.0 l White vaseline 8.0 8.0 8.0 F

Hexyldecanoi 1.0 1D0 1.0 Polyethylene glycol monostea_rate 2.0 2.0 I
2.0 Polyoxy(9)lauryl_ ether 2.8 E 2.8 ~ 2.8 !Polyoxy(23)cetyl ether 2,00 2.0 2.0 Propylene glycol 12.0 I2.0 i2.~
~

Methylparaben 0.1 I 0.1 0.1 i ~Propylparaben 0.1 0.1 0.1 iPurified water 4 0 54.0 54.0 Examples 16-18 (1'a~es) According to ingredients indicated in Table 5~ to a tacking agent consisting of an acrylate resin or a stylene-isoprene-stylene block copolymer were added <~n alicyclic saturated hydrocarbon resinY liquid paraffiny polybutene9 an antioxidant, etc. and the mixture was dissolved in an organic solvent such as toluene etc. ura.der stirring,, or the mixture was melted by heating under stirring. Thereto was added Aspirin and the resulting mixture was spread on release paper and then in case of a soluble type~ was spread on release paper and dwried. T:iZe relea:~e paper was laminated on a flexible support to be cut into a desired size to prepare tapes.
Table 5o Ingredients of tapes coru~aining ~sspirin Examples l~ 17~~ 1 Ir~gredier.ts Ingredient ratio (wt o ) Aspi rin - 5. 0 7_0 0. 0 ~ 30 . 0 Isopropyl myristate ~ 5.0 - ~ -'Diisopropyl adipate - - 5.0 !
~Crotamiton 500 5a.0 ; 1 0 !
Acrylate-vinyl acetate copolymer - 85..0 -Stylene-isoprene-stylene E'-20.0 - i! 13.4 block copolymer _- ~ __;
Alicyclic saturated 4200 - 23.5 hydrocarbon resin _~ t Polybutene _- 15.0 - ~~ 11.6 ~ Liquid paraffin ~ ;1.0 - ~) 14~5~
Dibutyl hydroxytoluene 1.0 - ~I 1.0 iL_-Examples 7_9-21 (PowdersZ
According to ingredients indicated in Tab_Le 6~ potato starch~ zinc oxide anal Aspirin were well mixed to prepare powders.
Table 6e Ingredients of powders containing Aspirin E mplas-Ingredients Ingredient ratio (wt'o ) Aspirin 20.0 40.0 80.0 ..
Potato starch 76.0 56.0 16.0 Zinc oxide 4.0 4.0 4.0 !

Comparative examples 1-3 According to the method of preparing ointments, ointments having an ingredients} of Table 7 (comparative examples 1-3) were prepa.redo Table 7 o Ingredients of oirltrrients (Cornparat~_VE~ examples Comparative examples ~~~C- 2~C 3 Ingredients Ingredient ratio (wt a ) Diphenhydramine 1~0 Dexamethasone 0.1 Propylene glycol ~ ._0 0 0 10 ~ 0 Isopropyl myr=estate j 5e0 5v0 Hydrocarbon gel ~8~e0 84.9 C100.0~
Clinical Testsa An antipruritic activity was tesf~ed dy administering the external preparations of the present invention and control-preparations to patients receiving hemodialysis (volunteers)a The degree of improvre_nenL of skin condition or itching was evaluated based on tze following five steps stand.arda A: Remarkably effective, Bm Effective, C~ Slightly effective, Da No change, Ee Worse.

Being slightly effective (C) or more than slightly effective (A, B), degree was judged too be effective, and its effective rate was calcula-~ed.
Experiment l: Improvement of s:'~in conditvons The external preparation of the present invention containing Aspirin was administered to affected lesions of patients having dermatosis (bad skin conditions) and skin itching among patients receiving hemodialysis 10 treatment. Degree of improvement of the skin conditions was evaluated.
As controls, the preparations of comparative examples 1 to 3 were ad.minist.ered to the '7 patients raving dermatosis and skin itching in the same manner as above.
The result was shown in Table 8.
Table 8o Degree of impvyovement of skin conditions due to hemodialvsis Drugs ~I~lo. of E~Talu~~tion yffective Group i_ o ~ o (w~ o ) patient A B ~ C D ~ E race ( ~ ) Example 2 Aspirin ( 1. 0 ) 2 1 0 1 0 ~ 0 100 . 0 Example 4 Aspirin (0.5) 3 2 1 0 0~0 100.0 Example 6 Aspirin (2.0) ~ 3 0 0 0~0 100.0 Example 13 Aspiri n ( 4 . 0 ) v2~ 0 1 0 l i 0 ~ 50 . 0 Comp . Diphen- ~ 3 0 0 0 3 ~ 0 0 Ex.1 hydramine(1.0) Comp. Dexamethasone 3 0 0 1 2 0 33.0 Ex.2 (0.1 ) Comp . _ _-~ -~ 0 0 ' 0 0 1 0 E x . 3 ~ ~ ~ ~-_ As is clear from the result in Cable 8~ preparations of examples 2~ 4~ 6 and i3 containing A.spirir~ (the preparations of the present in~entio:r~) showed improvement of the skin condition due to hemodialysis and the effects 5 were strong comparing with. controls (preparations cf comparative examples 1 to 3)a Experiment 2a Improvement of itc'_~ing The external preparation containing Aspirin was 10 administered to affected lesions of 12 patients having itching among patients receiving hemod_ialysis treatmentm Degree of improvement of the itching was evaluatedo As controls, the preparations of comparative example 1 to 3 were administered to the 7 patients having itching in 15 the same manner as above The result was shown in Table 9e Table 9: Degree of improvement of itching due to hPm~c~ialvSiS
Evaluation n Drags I No. of affective Groins (wt o) ~ patient A g C D E rate ( ) r -~
Example 2 Aspi rin ( 1. ~2 1 1 0 0 100 . 0 0 ) ~ I

Example 4 Aspirin (0.5) 3 2 1 0 0 ~0 100.0 r Example 6 Aspirin (2.0) ~ 3 2 0 1 0 ; 100.0 ~ 0 Example 13Aspirin ( 4 s 2 1 1 0 0 ' 100 . 0 . 0 ) 0 E~ xample17Aspirin ( 1 _2 0 1 1 0 0 1000 0 . 0 ) Comp. Diphen- (~ -Ex . 1 hydramine ( I 1. 0 ) Comp. Dexamethasone 3 0 0 1 2 ~ 33.0 Ex.2 (0.1) -~

-- ~1 0 (0 0 0 ~1 0 As is clear from tze result in 'fable 9, preparations of examples 2, 4, 6, 1.3 arid 17 containing Aspirin (the preparations of the :~resent invention) inhibited the itching due to hemod:iall~sis ar:d showed very strong antipruritic activity, comparing with controls (the preparations of corrparat_we examples 1 to 3).
POSSIEILITY OF INDUSTRIAL APPLICABILIT'~
The external prepara.tiorl of the present invention containing Aspirin as an active ingredient has an excellent therapeutic effect to itching due to hemod_alysis.
furthermore, the external preparation of the present invention shows im~rovem.ent for skin conditions as well as sedative for itch-ng. The external_ preparation of the present invention does not affect any value of clinical assay (pathology) and belongs to the drug ~>howi-ng very little side effects and therefore, is cons__dered as a safety medicamentm The present inven~~ion can provide -the external preparation being nov only excellently effective to various itching due to hemodialysis, but also shows improvement for skin conditions and being ver_~y little in its side effects.

Claims (6)

1. A method for treating dermotosis or pruritus due to hemodialysis which comprises applying to an affected lesion of a patient an external preparation containing acetylsalicylic acid as an active ingredient.

2. The method according to claim 1 wherein the disease treated is xerosis cutis or itching.

3. Use of acetylsalicylic acid for the external preparation for treating dermotosis or pruritus due to hemodialysis.

4. The use according to claim 3 wherein the disease treated is xerosis cutis or itching.

5. An external composition containing acetylsalicylic acid as an active ingredient for treating dermotosis or pruritus due to hemodialysis.

6. The composition according to claim 5 wherein the disease treated is xerosis cutis or itching.