External skin treatment composition

An external skin treatment composition comprising (i) vitamin A and (ii) at least one skin roughening improvement aid selected from the group consisting of (a) polyoxyalkylene modified organopolysiloxanes, (b) sugars, and (c) anti-inflammatory agents.

TECHNICAL FIELD 
The present invention relates to an external skin treatment composition 
and, more specifically, it relates to an external skin treatment 
composition having a synergistically improved skin roughening improvement 
effect by incorporating thereinto vitamin A and a polyoxyalkylene modified 
organopolysiloxane, a sugar or an anti-inflammatory agent, with taking 
safety into consideration. 
BACKGROUND ART 
Various pharmaceutically effective components are formulated into external 
skin treatment compositions. Among these pharmaceutical effects, an 
effect, by which the changes in the skin due to aged skin or sunlight 
exposure etc. are prevented or improved, is one of such effects, and 
therefore, an external skin treatment compositions such as cosmetic 
compositions having such purposes have been desired. 
Under such circumstances, various raw materials extracted from natural 
products, such as proteins, polysaccharides, extracted extracts, natural 
polymers etc. have been heretofore formulated in external skin treatment 
compositions due to their characteristics application effects. 
Recently, Japanese Unexamined Patent Publication (Kokai) No. 64-500355 
discloses a method for preventing or improving the changes or disabilities 
caused due to aged skins or sunlight exposure by formulating thereinto at 
least one component selected from vitamin A and the derivatives thereof. 
However, the effects thereof are not sufficient and it has been strongly 
desired to develop a pharmaceutically effective agent having much more 
excellent effects. 
DISCLOSURE OF THE INVENTION 
Accordingly, the objects of the present invention are to obviate the 
above-mentioned problems in the prior art and to provide an external skin 
treatment composition having sufficient skin roughening improvement 
effects, i.e., prevention effects, improvement effects, etc. against the 
changes or disabilities due to aged skin or sunlight exposure. 
In accordance with the present invention, there is provided an external 
skin treatment composition comprising (i) vitamin A and (ii) at least one 
skin roughening improvement aid selected from the group consisting of (a) 
polyoxyalkylene modified organopolysiloxanes, (b) sugars, and (c) 
anti-inflammatory agents. 
BEST MODE FOR CARRYING OUT THE INVENTION 
In order to achieve the above-mentioned objects, the present inventors have 
been extensibly studied to obtain a substance or substances capable of 
effecting sufficient skin roughening improvement effects, especially, 
among substances having excellent safety and, as a result, found that the 
above-mentioned problems can be solved by formulating, together with 
vitamin A, polyoxyalkylene modified organopolysiloxanes, sugars or 
anti-inflammatory agents. 
The constitution of the present invention will now be explained in detail. 
Vitamin A used in the present invention is also called retinol and is 
usually used in the treatment of infant or childhood diseases or 
nyctalopia (i.e., night blindness) or in the recovery agent after 
pregnancy in the pharmaceutical fields etc. Among these, all-trans 
products or 13-cis products can be preferably used, but the mixture 
thereof can also be used. 
There are no limitations to the amounts of vitamin A formulated into the 
external skin treatment agent according to the present invention, but the 
preferable amount is 0.00001 to 5% by weight, more preferably 0.0001 to 
0.5% by weight, in view of the effect of vitamin A to the skin. 
The polyoxyalkylene modified organopolysiloxanes usable as a skin 
toughening improvement aid, in the present invention are the following 
compounds (A), (B), (C) and (D). 
##STR1## 
wherein R represents an alkyl group having 1 to 3 carbon atoms, or a 
phenyl group, R' represents hydrogen or an alkyl group having 1 to 12 
carbon atoms, p is an integer of 1 to 5, m is an integer of 5 to 100, n 
and x are an integer of 1 to 50 and t and y are an integer of 0 to 50. 
There are no specific limitations to the average molecular weight of the 
polyoxyalkylene modified organopolysiloxane usable in the present 
invention, but the preferable molecular weight is 3,000 or more, further 
preferably 5,000 to 10,000. Furthermore, the preferable polyoxyalkylene 
modified organopolysiloxanes are those having 2-80% by weight, more 
preferable, 11-50% by weight in view of the generation of the effects, of 
polyoxyalkylene group in the molecule thereof. 
The amount of the polyoxyalkylene modified organopolysiloxane formulated is 
preferably 0.1 to 20% by weight, more preferably 0.2 to 10% by weight, in 
the total amount of the external skin treatment composition. When the 
amount is less than 0.1% by weight, there are fears that the skin 
irritation is not sufficiently lowered. Contrary to this, when the amount 
is more than 20% by weight, there are fears that the qualities necessary 
as the skin treatment composition cannot be held. 
In the present invention, as the sugars usable as a skin roughening 
improvement aid, mention may be made of monosaccharides, oligosaccharides, 
sugar alcohols, etc. 
As the monosaccharides, mention may be made of trioses such as 
D-glycerylaldehyde, dihydroxyaceton, etc., tetroses such as D-erythrose, 
D-erythrolose, D-threose, etc., pentoses such as L-arabinose, D-xylose, 
L-lyxose, D-arabinose, D-ribose, D-ribulose, D-xylulose, L-xylulose, etc., 
hexoses such as D-glucose, D-talose, D-psicose, D-galactose, D-fructose, 
L-galactose, L-sorbose, D-mannose, D-tagalose etc., heptoses such as 
aldoheptose, heptalose etc., octoses such as octose etc., deoxy sugars 
such as 2-deoxy-D-ribose, 6-deoxy-L-galactose, 6-deoxy-L-mannose, etc., 
amino sugars such as D-glucosamine, D-galactosamine, sialic acid, 
aminouronic acid, muramic acid, etc., uronic acids such as D-glucuronic 
acid, D-mannuronic acid, L-gluconic acid, D-galacturonic acid, L-iduronic 
acid etc. 
As the oligo sugars, mention may be made of sucrose, gentianose, 
umbelliferose, lactose, planteose, .alpha.,.alpha.-trehalose, raffinose, 
umbilicin, stachyose, verbascoses. 
Furthermore, as the sugar alcohols, mention may be made of sorbitol, 
maltitol, maltriose, mannitol, starch decomposed sugar, erythritol, 
xylitose, starch decomposing sugar reduced alcohols. Of these sugar 
alcohols, mannitol, erythritol and sugar alcohols of disaccharides or 
more. 
There are no specific limitations to the amount of the sugars formulated, 
the preferable amount is at least 0.1% by weight, more preferably 0.5 to 
50% by weight, based on the total amount of the external skin treatment 
agent. When the amount is less than 0.1% by weight, it is not preferable 
because it is difficult to obtain the synergistical skin roughening 
improvement effects according to the present invention. 
Examples of anti-inflammatory agents usable as the skin roughening 
improvement aid according to the present invention are hydrocortisone, 
hydrocortisone acetate, prednisolone, methyl prednisolone, prednisolone 
acetate, prednisolone acetate propionate, dexamethasone, betamethasone, 
triamcinolone, dexamethasone acetate, betamethasone valerate, 
triamcinolone acetnide, aspirin, salicylic acid, acetaminophen, methyl 
salicylate, glycol salicylate, mefenamic acid, flufenamic acid, 
indometacin, diclofenac, ketoprofen, ibuprofen, flurbiprofen, fenbufen, 
lufexamac, piroxicam, oxyphenbutazone, mepirizole, ibuprofen piconol, 
clidanac, phenylbutazone, naproxen, glycyrrhetin, glycyrrhizin, 
glycyrrhetic acid and the salts and esters thereof, glycyrrhizic acid and 
the salts and esters thereof, azulene, camphor, thymol, allantoin, etc. 
Among these agents, one or more agents may be freely selected. Although 
the amount of the anti-inflammatory agents formulated in the present 
invention is not specifically limited, the preferable amount is 0.0001 to 
5.0% by weight, more preferably 0.001 to 2% by weight, based upon the 
total amount of the external skin treatment composition. When the amount 
is less than 0.0001% by weight, there are fears that the reduction of the 
skin irritation, which is the effect of the present external skin 
treatment composition, cannot be achieved. Contrary to this, even when the 
anti-inflammatory agent is formulated in an amount of more than 5.0% by 
weight, further improvement is not expected. 
In addition to the above-mentioned essential components, the external skin 
treatment composition according to the present invention may contain 
various components conventionally formulated into cosmetics, quasi-drugs, 
drugs such as aqueous components, humectants, thickeners, UV absorbers, 
antiseptics, antioxidants, flavours, colorants, medicines, crude drugs, in 
an amount such that the desired effects of the present invention are not 
impaired. It should be, of course, noted that these additives are used in 
such quantitative, qualitative conditions that the objects of the present 
invention are not impaired. 
The external skin treatment composition according to the present invention 
can be in any form, for example, in the form of a solubilized type such as 
cosmetic lotions, an emulsified type such as Emulsions, creams, ointments, 
powder dispersion type, water-oil two layer type, water-oil-powder three 
layer type, etc.