Skin treatment composition

1. An external composition for skin, comprising:

an alkylene oxide derivative expressed by Formula (I):

R 1 O—[(AO) m (EO) n ]—R 2   (I)

wherein AO is an oxyalkylene group having a carbon number of 3 or 4;

EO is an oxyethylene group; m and n are average addition numbers of said AO and EO respectively, which are 1≦m≦70 and 1≦n≦70,

wherein said EO is 20-80% by weight with respect to a total of said AO and EO;

wherein AO and EO are added to each other in random form;

wherein R 1 and R 2 are either identical to or different from each other, and

wherein said R 1 and said R 2 are alkyl groups having a carbon number of 1-4; and

a water-soluble medicament,

wherein said skin of said external composition is human skin or hair, wherein said external composition is applied to said human skin or hair, and wherein said alkylene oxide derivative is a transdermal absorption improving agent for said water-soluble medicament.

2. The composition according to claim 1 , wherein said water-soluble medicament is a humectant.

3. The external composition according to claim 2 , wherein said humectant is glycerin.

4. The composition according to claim 2 , wherein said humectant is xylitol.

5. The composition according to claim 1 , wherein said water-soluble medicament is at least one selected from the group consisting of arbutin, ascorbyl glucoside, magnesium ascorbyl phosphate, and ethyl ascorbic acid.

6. The external composition for skin according to claim 1 , wherein said R 1 is methyl or ethyl and said R 2 is methyl.

7. The external composition for skin according to claim 1 , wherein said alkylene oxide derivative (I) is 0.01-70% by weight.

8. An external composition for skin, comprising:

an alkylene oxide derivative expressed by Formula (I):

R 1 O—[(AO) m (EO) n ]—R 2   (I)

wherein AO is an oxyalkylene group having a carbon number of 3 or 4;

EO is an oxyethylene group; m and n are average addition numbers of said AO and EO respectively, which are 1≦m≦70 and 1≦n≦70,

wherein said EO is 20-80% by weight with respect to a total of said AO and EO;

wherein AO and EO are added to each other in random form;

wherein R 1 and R 2 are either identical to or different from each other, and

wherein said R 1 and said R 2 are alkyl groups having a carbon number of 1-4; and

a refreshing agent,

wherein said skin of said external composition is human skin or hair, and wherein said external composition is applied to said human skin or hair.

9. The composition according to claim 8 , wherein said alkylene oxide derivative is 0.1-80% by weight.

10. The composition according to claim 8 , wherein said refreshing agent is menthol or camphor.

11. The composition according to claim 8 , wherein said refreshing agent is 0.001-20% by weight.

12. The external composition for skin according to claim 8 , wherein said R 1 is methyl or ethyl and said R 2 is methyl.

13. An external composition for skin, comprising:

5-40% by weight an alkylene oxide derivative expressed by Formula (I):

R 1 O—[(AO) m (EO) n ]—R 2   (I)

wherein AO is an oxyalkylene group having a carbon number of 3 or 4;

EO is an oxyethylene group; m and n are average addition numbers of said AO and EO respectively, which are 1≦m≦70 and 1≦n≦70;

wherein said EO is 20-80% by weight with respect to a total of said AO and EO;

wherein AO and EO are added to each other in random form;

wherein R 1 and R 2 are either identical to or different from each other;

wherein said R 1 and said R 2 are alkyl groups having a carbon number of 1-4; and

a refreshing agent, which is menthol or camphor,

wherein said composition is applied to skin or hair.

14. The external composition for skin according to claim 13 , wherein R 1 is methyl or ethyl and R 2 is methyl.

15. An external composition for skin, comprising:

5-40% by weight an alkylene oxide derivative expressed by Formula (I):

R 1 O—[(AO) m (EO) n ]—R 2   (I)

wherein AO is an oxyalkylene group having a carbon number of 3 or 4;

EO is an oxyethylene group; m and n are average addition numbers of said AO and EO respective, which are 1≦m≦70 and 1≦n≦70;

wherein said EO is 20-80% by weight with respect to a total of said AO and EO;

wherein AO and EO are added to each other in random form;

wherein R 1 and R 2 are either identical to or different from each other;

wherein said R 1 and said R 2 are alkyl groups having a carbon number of 1 -4; and

a humectant, which is xylitol or glycerin,

wherein said composition is applied to skin or hair.

16. The external composition for skin according to claim 15 , wherein R 1 is methyl or ethyl and R 2 is methyl.

17. An external composition for skin, comprising:

an alkylene oxide derivative expressed by Formula (I):

R 1 O—[(AO) m (EO) n ]—R 2   (I)

wherein AO is an oxyalkylene group having a carbon number of 3 or 4;

EO is an oxyethylene group; m and n are average addition numbers of said AO and EO respectively, which are 1≦m≦70 and 1≦n≦70,

wherein said EO is 20-80% by weight with respect to a total of said AO and EO;

wherein AO and EO are added to each other in random form;

wherein R 1 and R 2 are either identical to or different from each other, and

wherein said R1 and said R 2 are alkyl groups having a carbon number of 1-4; and

wherein said skin of said external composition is human skin or hair, wherein said external composition is applied to said human skin or hair, and wherein said external composition is a cream, a lotion, a foundation, a lipstick, a gel, a deodorant stick, or a hair tonic.

18. The external composition for skin according to claim 17 , wherein R 1 is methyl or ethyl and R 2 is methyl.

19. The external composition for skin according to claim 17 , wherein said alkylene oxide derivative (I) is 0.01-70% by weight.