Title: O/W emulsion composition and method of preparing the same
Abstract: The present invention provides an O/W emulsion composition containing an electrolyte. More particularly, the invention provides an O/W emulsion composition excellent in emulsion stability despite its electrolyte content. The O/W emulsion composition of the invention can be prepared using an electrolyte, a polyglycerin fatty acid ester, an alkanoyl lactylic acid or the salt thereof, an acrylic acid-alkyl methacrylate copolymer, water, an oil, and preferably a polyhydric alcohol.
Patent Number: 6,946,436 Issued on 09/20/2005 to Wakamatsu, et al.
| Inventors:
|
Wakamatsu; Kosaburo (Kyoto, JP);
Tanaka; Masahiko (Otsu, JP);
Yoshino; Noboru (Kyoto, JP)
|
| Assignee:
|
Otsuka Pharmaceutical Co., Ltd. (Tokyo, JP)
|
| Appl. No.:
|
432400 |
| Filed:
|
November 22, 2001 |
| PCT Filed:
|
November 22, 2001
|
| PCT NO:
|
PCT/JP01/10230
|
| 371 Date:
|
May 21, 2003
|
| 102(e) Date:
|
May 21, 2003
|
| PCT PUB.NO.:
|
WO02/41853 |
| PCT PUB. Date:
|
May 30, 2002 |
Foreign Application Priority Data
| Nov 22, 2000[JP] | 2000-355997 |
| Current U.S. Class: |
510/417; 424/59; 424/400; 424/401; 510/475 |
| Intern'l Class: |
C11D 017/00; C11D 003/37 |
| Field of Search: |
510/417,475
424/401,59,400
|
References Cited [Referenced By]
U.S. Patent Documents
| 4606913 | Aug., 1986 | Aronson et al.
| |
| 5250290 | Oct., 1993 | Giacomoni et al.
| |
| 5911981 | Jun., 1999 | Dahms et al.
| |
| 5977037 | Nov., 1999 | Giret et al.
| |
| 6316030 | Nov., 2001 | Kropf et al.
| |
| 6783766 | Nov., 2001 | Kropf et al.
| |
| 6716419 | Apr., 2004 | Zoltowski et al.
| |
| Foreign Patent Documents |
| 195 45 107 | Jun., 1997 | DE.
| |
| 0 484 199 | May., 1992 | EP.
| |
| 0 815 838 | Jan., 1998 | EP.
| |
| 47-26687 | Jul., 1972 | JP.
| |
| 8-99860 | Apr., 1996 | JP.
| |
| 9-295915 | Nov., 1997 | JP.
| |
| 11-269049 | May., 1999 | JP.
| |
| 11-276881 | Oct., 1999 | JP.
| |
| 2000/-256188 | Sep., 2000 | JP.
| |
| 2001/-199872 | Jul., 2001 | JP.
| |
Primary Examiner: Webb; Gregory E.
Attorney, Agent or Firm: Finnegan, Henderson, Farabow, Garrett & Dunner, L.L.P.
Claims
1. An O/W emulsion composition comprising a purine nucleic acid-related substance,
a polyglycerin fatty acid ester, an alkanoyl lactylic acid or the salt thereof,
an acrylic acid-alkyl methacrylate copolymer, water, and an oil.
2. An O/W emulsion composition according to claim 1, further comprising a polyhydric alcohol.
3. An O/W emulsion composition according to claim 1, wherein the purine nucleic
acid-related substance is at least one member selected from the group consisting
of adenosine 3′,5′-cyclic monophosphate, adenosine monophosphate,
adenosine diphosphate, adenosine triphosphate, and the salts thereof.
4. An O/W emulsion composition according to claim 2, wherein the purine nucleic
acid-related substance is adenosine monophosphate or the salt thereof.
5. An O/W emulsion composition according to claim 2, wherein the polyglycerin
fatty acid ester is an ester of a C
12-36 fatty acid and a polyglycerin
having a polymerization degree of 6 or more.
6. An O/W emulsion composition according to claim 2, wherein the polyglycerin
fatty acid ester is an ester of a C
12-36 fatty acid and a polyglycerin
having a polymerization degree of 6 to 10.
7. An O/W emulsion composition according to claim 2, wherein the alkanoyl lactylic
acid contains an alkanoyl group having 8 or more carbons.
8. An O/W emulsion composition according to claim 2, wherein the alkanoyl lactylic
acid contains a C
8-18 alkanoyl group.
9. An O/W emulsion composition according to claim 2, wherein the acrylic acid-alkyl
methacrylate copolymer contains a C
5-40 alkyl group.
10. An O/W emulsion composition according to claim 2, wherein the acrylic acid-alkyl
methacrylate copolymer contains a C
10-30 alkyl group.
11. An O/W emulsion composition according to claim 2, wherein the oil is a hydrocarbon
liquid oil.
12. An O/W emulsion composition according to claim 2, wherein the purine nucleic
acid-related substance is contained in a proportion of at least 0.1 wt. % based
on 100 wt. % of the emulsion composition.
13. An O/W emulsion composition according to claim 2, wherein the purine nucleic
acid-related substance is contained in a proportion of 0.5 to 7 wt. % based on
100 wt. % of the emulsion composition.
14. An O/W emulsion composition according to claim 2, wherein the purine nucleic
acid-related substance is contained in a proportion of 1 to 6 wt. % based on 100
wt. % of the emulsion composition.
15. An O/W emulsion composition according to claim 2, wherein the polyglycerin
fatty acid ester is contained in a proportion of 0.05 to 6 wt. %, the alkanoyl
lactylic acid or the salt thereof is contained in a proportion of 0.01 to 1 wt.
%, the acrylic acid-alkyl methacrylate copolymer is contained in a proportion of
0.01 to 0.8 wt. %, the oil is contained in a proportion of 0.3 to 20 wt. %, and
the polyhydric alcohol is contained in a proportion of 0.05 to 15 wt. %, based
on 100 wt. % of the emulsion composition.
16. An O/W emulsion composition according to claim 2, wherein the polyglycerin
fatty acid ester and the alkanoyl lactylic acid or the salt thereof are contained
in a weight ratio of 95:5 to 60:40.
17. An O/W emulsion composition according to claim 2, the polyglycerin fatty
acid ester and the alkanoyl lactylic acid or the salt thereof are contained in
a weight ratio of 90:10 to 70:30.
18. An O/W emulsion composition according to claim 2, further comprising a lower alcohol.
19. An O/W emulsion composition according to claim 2 used for a skin cosmetic
or an externally-applied medical or quasi-medical drug for the skin.
20. A method for preparing an O/W emulsion composition comprising the steps:
1) preparing a nonaqueous emulsion using a composition comprising a polyglycerin
fatty acid ester, an alkanoyl lactylic acid or salt thereof, an oil, and, as required,
a polyhydric alcohol;
2) preparing an aqueous solution using a composition comprising a purine nucleic
acid-related substance, water, and an acrylic acid-alkyl methacrylate copolymer;
and
3) bending the nonaqueous emulsion with the aqueous solution to give the emulsion
composition.
21. A method for preparing an O/W emulsion composition according to claim 20,
wherein Step 2) is for preparing the aqueous solution using the composition further
comprising at least one member selected from lower alcohols and polyhydric alcohols.
22. A method for preparing an O/W emulsion composition according to claim 20,
wherein the method comprising incorporating the nonaqueous emulsion in a proportion
of 1 to 40 wt. % based on 100 wt. % of the final emulsion composition.
23. A method for stabilizing the emulsion of an O/W emulsion composition containing
a purine nucleic acid-related substance, water, and an oil, the method comprising
incorporating a polyglycerin fatty acid ester, an alkanoyl lactylic acid or the
salt thereof, an acrylic acid-alkyl methacrylate copolymer, and, as required, a
polyhydric alcohol into the emulsion composition.
24. A method for stabilizing the emulsion of an O/W emulsion composition according
to claim 23, wherein the method comprising incorporating the polyglycerin fatty
acid ester in a proportion of 0.05 to 6 wt. %, the alkanoyl lactylic acid or the
salt thereof in a proportion of 0.01 to 1 wt. %, the acrylic acid-alkyl methacrylate
copolymer in a proportion of 0.01 to 0.8 wt. %, and, as required, the polyhydric
alcohol in a proportion of 0.05 to 15 wt. % based on 100 wt. % of the emulsion
composition containing the oil in a proportion of 0.3 to 20 wt. %.
25. A method for stabilizing the emulsion of an O/W emulsion composition, the
method comprising blending a nonaqueous emulsion containing a polyglycerin fatty
acid ester, an alkanoyl lactylic acid or the salt thereof, an oil, and, as required,
a polyhydric alcohol with an aqueous solution containing a purine nucleic acid-related
substance, water, and an acrylic acid-alkyl methacrylate copolymer, to give the
emulsion composition.
Description
TECHNICAL FIELD
The present invention relates to an O/W emulsion composition containing an electrolyte.
More particularly, the present invention relates to an O/W emulsion composition
excellent in emulsion stability despite its electrolyte content. The invention
further relates to a method for preparing an O/W emulsion composition excellent
in emulsion stability. Moreover, the invention relates to a method for stabilizing
the emulsion of an O/W emulsion composition containing an electrolyte.
BACKGROUND OF THE INVENTION
Various physiological functions of electrolytes are widely known. It is necessary,
however, to incorporate at least a specific concentration of an electrolyte in
order to prepare pharmaceutical compositions that are capable of effectively exhibiting
the functions provided by electrolytes. Since electrolytes have a characteristic
of decreasing the strength of membranes formed at oil/water interfaces, it is known
that when an emulsion composition, particularly an O/W emulsion composition, containing
an electrolyte is prepared, emulsion particles agglomerate and are likely to cause
a separation of water and oil phases, oil floating, etc. Moreover, the emulsion
itself sometimes degenerates over time due to the influence of the electrolyte,
resulting changes in color and smell.
When preparing emulsion compositions containing an electrolyte, therefore, various
pharmaceutical techniques are employed to improve the stability of the emulsion.
Although polyglycerin fatty acid esters are emulsifiers heretofore known
to be highly safe and excellent in usability and functionality, the emulsifying
ability thereof is relatively low. Therefore, when a large number of electrolytes
are used, it is difficult to prepare a stable emulsion composition from the polyglycerin
fatty acid ester. Recently, a nonaqueous emulsion method was proposed as a method
for preparing a stable emulsion using a polyglycerin fatty acid ester (Japanese
Unexamined Patent Application No. 37040/1981). Even when this method is employed,
phenomena such as oil floating and the like sometimes occur as the concentration
of the electrolyte increases and the emulsifying ability decreases. Further, an
acrylic acid-alkyl methacrylate copolymer has recently drawn attention as an excellent
high-molecular emulsifier for an O/W emulsion due to properties such as the ability
to provide a stable emulsion by a small amount; the ability to be used regardless
of the type of oil, thereby making it versatile; gentleness to humans and the environment;
an excellent feel when applied to the skin and hair related to a lack of tackiness;
etc. However, it is also reported that the viscosity and the emulsion stability
are decreased when the acrylic acid-alkyl methacrylate copolymer is used with ionic
components. ("Function and Application of High-Molecular Emulsifier for O/W Emulsion"
FRAGRANCE JOURNAL 1998-8 pp. 79-83)
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide an O/W emulsion composition
that
is excellent in emulsion stability despite having an electrolyte contained as an
ingredient and that stably maintains its emulsified state over a long period of
time. Another object of the invention is to provide various external preparations
that exhibit, in addition to good emulsion stability, desired functions derived
from the electrolyte contained as an ingredient therein, and that can be used in
the field of medical or quasi-medical drugs and in the field of fragrances and cosmetics.
Still another object of the invention is to provide a method for preparing
an O/W emulsion composition excellent in emulsion stability despite its electrolyte
content, and a method for stabilizing the emulsion of the O/W emulsion composition
containing an electrolyte.
The inventors conducted research for the purpose of stably emulsifying a composition
containing an electrolyte and found that it is possible to emulsify electrolytes
by the combined use of an acrylic acid-alkyl methacrylate copolymer and a known
emulsifier, i.e., a polyglycerin fatty acid ester, even though the polyglycerin
fatty acid ester alone could not heretofore emulsify. However, the inventors also
found that the emulsion particles of the polyglycerin fatty acid ester and those
of the acrylic acid-alkyl methacrylate copolymer agglomerate due to long term storage
or temperature change, and they gelate on the inner wall of a container and in
the upper layer of the emulsion. The inventors conducted further research in view
of the above findings and discovered that the further addition of an alkanoyl lactylic
acid or the salt thereof prevents the gelation caused by temperature change and
disadvantages such as oil floating and separation caused by long-term storage,
thus enabling an emulsion composition excellent in emulsion stability to be prepared.
The present invention has been accomplished based on these findings.
Specifically, the present invention provides the O/W emulsion compositions
described in the following Items 1 to 21:
Item 1. An O/W emulsion composition comprising an electrolyte, a polyglycerin
fatty acid ester, an alkanoyl lactylic acid or the salt thereof, an acrylic acid-alkyl
methacrylate copolymer, water, and an oil.
Item 2. An O/W emulsion composition according to Item 1, further comprising
a polyhydric alcohol.
Item 3. An O/W emulsion composition according to Item 2, wherein the electrolyte
is a purine nucleic acid-related substance.
Item 4. An O/W emulsion composition according to Item 3, wherein the electrolyte
is at least one member selected from the group consisting of adenosine 3′,5′-cyclic
monophosphate, adenosine monophosphate, adenosine diphosphate, adenosine triphosphate,
and the salts thereof.
Item 5. An O/W emulsion composition according to Item 3, wherein the electrolyte
is adenosine monophosphate or the salt thereof.
Item 6. An O/W emulsion composition according to Item 2, wherein the polyglycerin
fatty acid ester is an ester of a C12-36 fatty acid and a polyglycerin
having a polymerization degree of 6 or more.
Item 7. An O/W emulsion composition according to Item 2, wherein the polyglycerin
fatty acid ester is an ester of a C12-36 fatty acid and a polyglycerin
having a polymerization degree of 6 to 10.
Item 8. An O/W emulsion composition according to Item 2, wherein the alkanoyl
lactylic acid contains an alkanoyl group having 8 or more carbons.
Item 9. An O/W emulsion composition according to Item 2, wherein the alkanoyl
lactylic acid contains a C8-18 alkanoyl group.
Item 10. An O/W emulsion composition according to Item 2, wherein the acrylic
acid-alkyl methacrylate copolymer contains a C5-40 alkyl group.
Item 11. An O/W emulsion composition according to Item 2, wherein the acrylic
acid-alkyl methacrylate copolymer contains a C10-30 alkyl group.
Item 12. An O/W emulsion composition according to Item 2, wherein the oil
is a hydrocarbon liquid oil.
Item 13. An O/W emulsion composition according to Item 2, wherein the electrolyte
is contained in a proportion of at least 0.1 wt. % based on 100 wt. % of the emulsion composition.
Item 14. An O/W emulsion composition according to Item 2, wherein the electrolyte
is contained in a proportion of 0.5 to 7 wt. % based on 100 wt. % of the emulsion composition.
Item 15. An O/W emulsion composition according to Item 2, wherein the electrolyte
is contained in a proportion of 1 to 6 wt. % based on 100 wt. % of the emulsion composition.
Item 16. An O/W emulsion composition according to Item 2, wherein the polyglycerin
fatty acid ester is contained in a proportion of 0.05 to 6 wt. %, the alkanoyl
lactylic acid or the salt thereof is contained in a proportion of 0.01 to 1 wt.
%, the acrylic acid-alkyl methacrylate copolymer is contained in a proportion of
0.01 to 0.8 wt. %, the oil is contained in a proportion of 0.3 to 20 wt. %, and
the polyhydric alcohol is contained in a proportion of 0.05 to 15 wt. %, based
on 100 wt. % of the emulsion composition.
Item 17. An O/W emulsion composition according to Item 2, wherein the polyglycerin
fatty acid ester is contained in a proportion of 0.1 to 5.5 wt. %, the alkanoyl
lactylic acid or the salt thereof is contained in a proportion of 0.1 to 0.5 wt.
%, the acrylic acid-alkyl methacrylate copolymer is contained in a proportion of
0.3 to 0.6 wt. %, the oil is contained in a proportion of 0.5 to 15 wt. %, and
the polyhydric alcohol is contained in a proportion of 3 to 10 wt. %, based on
100 wt. % of the emulsion composition.
Item 18. An O/W emulsion composition according to Item 2, wherein the polyglycerin
fatty acid ester and the alkanoyl lactylic acid or the salt thereof are contained
in a weight ratio of 95:5 to 60:40.
Item 19. An O/W emulsion composition according to Item 2, wherein the polyglycerin
fatty acid ester and the alkanoyl lactylic acid or the salt thereof are contained
in a weight ratio of 90:10 to 70:30.
Item 20. An O/W emulsion composition according to Item 2, further comprising
a lower alcohol.
Item 21. An O/W emulsion composition according to Item 2 used for a skin
cosmetic or an externally-applied medical or quasi-medical drug for the skin.
Further, the present invention provides the methods for preparing an O/W
emulsion composition as defined in Items 22 to 24 below:
Item 22. A method for preparing an O/W emulsion composition comprising the steps:
- 1) preparing a nonaqueous emulsion using a compound comprising a polyglycerin
fatty acid ester, an alkanoyl lactylic acid or the salt thereof, an oil, and, as
required, a polyhydric alcohol;
- 2) preparing an aqueous solution using a composition comprising an electrolyte,
water, and an acrylic acid-alkyl methacrylate copolymer; and
- 3) blending the nonaqueous emulsion with the aqueous solution to give
the emulsion composition.
Item 23. A method for preparing an O/W emulsion composition according to
Item 22, wherein Step 2) is for preparing the aqueous solution using the composition
further comprising at least one member selected from lower alcohols and polyhydric alcohols.
Item 24. A method for preparing an O/W emulsion composition according to
Item 22, wherein the method comprising incorporating the nonaqueous emulsion in
a proportion of 1 to 40 wt. % based on 100 wt. % of the final emulsion composition.
The methods described above include the following embodiments:
(1) A method for preparing an O/W emulsion composition using a purine nucleic
acid-related substance as an electrolyte.
(2) A method for preparing an O/W emulsion composition using, as an electrolyte,
at least one member selected from the group consisting of adenosine 3′,5′-cyclic
monophosphate, adenosine monophosphate, adenosine diphosphate, adenosine triphosphate,
and the salts thereof.
(3) A method for preparing an O/W emulsion composition using an adenosine
monophosphate or the salt thereof as an electrolyte.
(4) A method for preparing an O/W emulsion composition using, as a polyglycerin
fatty acid ester, an ester of a C12-36 fatty acid and a polyglycerin
having a polymerization degree of 6 or more.
(5) A method for preparing an O/W emulsion composition using, as a polyglycerin
fatty acid ester, an ester of a C12-36 fatty acid and a polyglycerin
having a polymerization degree of 6 to 10.
(6) A method for preparing an O/W emulsion composition using, as an alkanoyl
lactylic acid, an alkanoyl lactylic acid containing an alkanoyl group having 8
or more carbons.
(7) A method for preparing an O/W emulsion composition using, as an alkanoyl
lactylic acid, an alkanoyl lactylic acid containing a C8-18 alkanoyl group.
(8) A method for preparing an O/W emulsion composition using an acrylic
acid-alkyl methacrylate copolymer containing an alkyl chain with 5 to 40 carbons
as an acrylic acid-alkyl methacrylate copolymer.
(9) A method for preparing an O/W emulsion composition using an acrylic
acid-alkyl methacrylate copolymer containing an alkyl chain with 10 to 30 carbons
as an acrylic acid-alkyl methacrylate copolymer.
(10) A method for preparing an O/W emulsion composition using a hydrocarbon
liquid oil.
(11) A method for preparing an O/W emulsion composition, wherein the method
comprising incorporating an electrolyte in a proportion of at least 0.1 wt. % based
on 100 wt. % of the emulsion composition.
(12) A method for preparing an O/W emulsion composition, wherein the method
comprising incorporating an electrolyte in a proportion of 0.5 to 7 wt. % based
on 100 wt. % of the emulsion composition.
(13) A method for preparing an O/W emulsion composition, wherein the method
comprising incorporating an electrolyte in a proportion of 1 to 6 wt. % based on
100 wt. % of the emulsion composition.
(14) A method for preparing an O/W emulsion composition, wherein the method
comprising incorporating a polyglycerin fatty acid ester in a proportion of 0.05
to 6 wt. %, an alkanoyl lactylic acid or the salt thereof is contained in a proportion
of 0.01 to 1 wt. %, an acrylic acid-alkyl methacrylate copolymer is contained in
a proportion of 0.01 to 0.8 wt. %, an oil is contained in a proportion of 0.3 to
20 wt. %, and a polyhydric alcohol is contained in a proportion of 0.05 to 15 wt.
%, based on 100 wt. % of the emulsion composition.
(15) A method for preparing an O/W emulsion composition, wherein the method
comprising incorporating a polyglycerin fatty acid ester in a proportion of 0.1
to 5.5 wt. %, an alkanoyl lactylic acid or the salt thereof is contained in a proportion
of 0.1 to 0.5 wt. %, an acrylic acid-alkyl methacrylate copolymer is contained
in a proportion of 0.3 to 0.6 wt. %, an oil is contained in a proportion of 0.5
to 15 wt. %, and a polyhydric alcohol is contained in a proportion of 3 to 10 wt.
%, based on 100 wt. % of the emulsion composition.
(16) A method for preparing an O/W emulsion composition, wherein the method
comprising employing a polyglycerin fatty acid ester and an alkanoyl lactylic acid
or the salt thereof contained in the emulsion composition in a weight ratio of
95:5 to 60:40.
(17) A method for preparing an O/W emulsion composition, wherein the method
comprising employing a polyglycerin fatty acid ester and an alkanoyl lactylic acid
or the salt thereof contained in the emulsion composition in a weight ratio of
90:10 to 70:30.
(18) A method for preparing an O/W emulsion composition, wherein the O/W
emulsion composition is used for a skin cosmetic or an externally-applied medical
or quasi-medical drug for the skin.
Moreover, the present invention provides methods for stabilizing the emulsion
of the O/W emulsion composition as defined in the following Items 25 and 27:
Item 25. A method for stabilizing the emulsion of an O/W emulsion composition
containing an electrolyte, water, and an oil, the method comprising incorporating
a polyglycerin fatty acid ester, an alkanoyl lactylic acid or the salt thereof,
an acrylic acid-alkyl methacrylate copolymer, and, as required, a polyhydric alcohol
into the emulsion composition.
Item 26. A method for stabilizing the emulsion of an O/W emulsion composition
according to Item 25, wherein the method comprising incorporating the polyglycerin
fatty acid ester in a proportion of 0.05 to 6 wt. %, the alkanoyl lactylic acid
or the salt thereof in a proportion of 0.01 to 1 wt. %, the acrylic acid-alkyl
methacrylate copolymer in a proportion of 0.01 to 0.8 wt. %, and, as required,
the polyhydric alcohol in a proportion of 0.05 to 15 wt. %, based on 100 wt. %
of the emulsion composition containing the oil in a proportion of 0.3 to 20 wt. %.
Item 27. A method for stabilizing the emulsion of an O/W emulsion composition,
the method comprising blending a nonaqueous emulsion containing a polyglycerin
fatty acid ester, an alkanoyl lactylic acid or the salt thereof, an oil, and, as
required, a polyhydric alcohol with an aqueous solution containing an electrolyte,
water, and an acrylic acid-alkyl methacrylate copolymer, to give the emulsion composition.
The methods described above for stabilizing the emulsion of an O/W emulsion composition
include the following embodiments:
(1) A method for stabilizing the emulsion of an O/W emulsion composition,
wherein the O/W emulsion composition contains a purine nucleic acid-related substance
as an electrolyte.
(2) A method for stabilizing the emulsion of an O/W emulsion composition,
wherein the O/W emulsion composition contains, as an electrolyte, one member selected
from the group consisting of adenosine 3′,5′-cyclic monophosphate,
adenosine monophosphate, adenosine diphosphate, adenosine triphosphate, and the
salts thereof.
(3) A method for stabilizing the emulsion of an O/W emulsion composition,
wherein the O/W emulsion composition contains adenosine monophosphate or the salt
thereof as an electrolyte.
(4) A method for stabilizing the emulsion of an O/W emulsion composition,
wherein the O/W emulsion composition contains an electrolyte in a proportion of
at least 0.1 wt. % based on 100 wt. % of the composition.
(5) A method for stabilizing the emulsion of an O/W emulsion composition,
wherein the O/W emulsion composition contains an electrolyte in a proportion of
0.5 to 7 wt. % based on 100 wt. % of the composition.
(6) A method for stabilizing the emulsion of an O/W emulsion composition,
wherein the O/W emulsion composition contains an electrolyte in a proportion of
1 to 6 wt. % based on 100 wt. % of the composition.
(7) A method for stabilizing the emulsion of an O/W emulsion composition,
wherein the O/W emulsion composition contains a hydrocarbon liquid oil as an oil.
(8) A method for stabilizing the emulsion of an O/W emulsion composition,
wherein the O/W emulsion composition contains an oil in a proportion of 0.3 to
20 wt. % based on 100 wt. % of the composition.
(9) A method for stabilizing the emulsion of an O/W emulsion composition,
wherein the O/W emulsion composition contains an oil in a proportion of 0.5 to
15 wt. % based on 100 wt. % of the composition.
(10) A method for stabilizing the emulsion of an O/W emulsion composition,
wherein an ester of a C12-36 fatty acid and a polyglycerin having a
polymerization degree of 6 or more is used as a polyglycerin fatty acid ester.
(11) A method for stabilizing the emulsion of an O/W emulsion composition,
wherein an ester of a C12-36 fatty acid and a polyglycerin having a
polymerization degree of 6 to 10 is used as a polyglycerin fatty acid ester.
(12) A method for stabilizing the emulsion of an O/W emulsion composition,
wherein an alkanoyl lactylic acid containing an alkanoyl group having 8 or more
carbons is used as an alkanoyl lactylic acid.
(13) A method for stabilizing the emulsion of an O/W emulsion composition,
wherein an alkanoyl lactylic acid containing a C8-18 alkanoyl group
is used as an alkanoyl lactylic acid.
(14) A method for stabilizing the emulsion of an O/W emulsion composition,
wherein an acrylic acid-alkyl methacrylate copolymer containing an alkyl chain
with 5 to 40 carbons is used as an acrylic acid-alkyl methacrylate copolymer.
(15) A method for stabilizing the emulsion of an O/W emulsion composition,
wherein an acrylic acid-alkyl methacrylate copolymer containing a C10-30
alkyl group is used as an acrylic acid-alkyl methacrylate copolymer.
(16) A method for stabilizing the emulsion of an O/W emulsion composition,
wherein the method comprising incorporating a polyglycerin fatty acid ester in
a proportion of 0.1 to 5.5 wt. %, an alkanoyl lactylic acid or the salt thereof
in a proportion of 0.1 to 0.5 wt. %, an acrylic acid-alkyl methacrylate copolymer
in a proportion of 0.3 to 0.6 wt. %, and, as required, a polyhydric alcohol in
a proportion of 3 to 10 wt. %, based on 100 wt. % of the emulsion composition containing
an oil in a proportion of 0.5 to 15 wt. %.
(17) A method for stabilizing the emulsion of an O/W emulsion composition,
wherein the method comprising employing a polyglycerin fatty acid ester and an
alkanoyl lactylic acid or the salt thereof contained in the emulsion composition
in a weight ratio of 95:5 to 60:40.
(18) A method for stabilizing the emulsion of an O/W emulsion composition,
wherein the method comprising employing a polyglycerin fatty acid ester and an
alkanoyl lactylic acid or the salt thereof contained in the emulsion composition
in a weight ratio of 90:10 to 70:30.
(19) A method for stabilizing the emulsion of an O/W emulsion composition,
wherein the O/W emulsion composition is used for a skin cosmetic or an externally-applied
medical or quasi-medical drug for the skin.
BEST MODE FOR CARRYING OUT THE INVENTION
(1) O/W Emulsion Composition and Method for Preparation thereof
The O/W emulsion composition of the present invention essentially contains an
electrolyte, water, a polyglycerin fatty (aliphatic) acid ester, an alkanoyl lactylic
acid or the salt thereof, an acrylic acid-alkyl methacrylate copolymer, and an oil.
Electrolytes usable in the invention are not limited. Preferable are
those that exhibit physiological functions when applied to the skin. Examples include
a wide variety of electrolytes that can be incorporated into external preparations,
particularly cosmetics, and externally-applied medical and quasi-medical drugs.
Preferable are those that are water soluble or hydrophilic. Specific examples of
usable electrolytes are adenine, adenosine monophosphate, adenosine diphosphate,
adenosine triphosphate, cyclic adenosine monophosphate, and like adenylic acid
derivatives, and the salts thereof; guanine, guanosine monophosphate, guanosine
diphosphate, guanosine triphosphate, and like guanylic acid derivatives, and the
salts thereof; xanthine, xanthylic acid, inosinic acid, and the salts thereof,
and like purine nucleic acid-related substances; uracil, cytosine, thymine, and
the derivatives thereof, and like pyrimidine nucleic acid-related substances; deoxyribonucleic
acid and the salt thereof, ribonucleic acid and the salt thereof, nucleoside, nucleotide,
and like nucleic acid-related substances; vitamin B1, vitamin B2, vitamin B6, vitamin
B12, niacin, pantothenic acid, biotin, folic acid, lipoic acid, inositol, ascorbic
acid, and like water-soluble vitamins, and the derivatives thereof; serine, glycin,
asparagine, aspartic acid, lysine, arginine, threonine, cysteine, glutamic acid,
pyrrolidone carboxylic acid, and like amino acids, and the derivatives thereof.
These electrolytes may be used alone or in combination of two or more species.
Examples of the variety of salts described above include sodium salt, potassium
salt, and like alkali metal salts; arginine, lysine, and like basic amino acid
salts; ammonium salt, triethanolamine salt, and the like.
Preferable electrolytes are nucleic acid-related substances, especially
purine nucleic acid-related substances. Among them, adenylic acid derivatives and
the salts thereof such as adenosine phosphate and the like are known to exhibit,
when applied to the skin, a moisturizing effect by increasing the number of free
amino acids in the horny cell layer, and, in addition, function to stimulate the
turn over thereby preventing drying and aging of the skin and improving the condition
of rough skin. Therefore, they are electrolytes that can be suitably used in the
present invention.
Specific examples of adenosine phosphates and the salts thereof include
adenosine 3′,5′-cyclic monophosphate, adenosine monophosphate, adenosine
monophosphate monosodium, adenosine monophosphate disodium, adenosine diphosphate,
adenosine diphosphate monosodium, adenosine diphosphate disodium, adenosine triphosphate,
adenosine triphosphate monosodium, adenosine triphosphate disodium, adenosine triphosphate
trisodium, and the like. Preferable among these are adenosine monophosphate and
the salts thereof (adenosine monophosphate monosodium and adenosine monophosphate disodium).
The proportion of the electrolyte contained in the emulsion composition is not
limited insofar as each electrolyte can exhibit the desired effects. Particularly,
although it varies depending on the kind of electrolyte used, it is in a range
of at least 0.1 wt. %, preferably 0.5 to 7 wt. %, more preferably 1 to 6 wt. %
per 100 wt. % of the final emulsion composition.
The O/W emulsion composition of the present invention contains water as an essential
ingredient. Distilled water, ion-exchanged water, sterilized water, or electrolyte-containing
water can be used as the water ingredient. Examples of electrolyte-containing water
include sea water, hot-spring water, mineral water, and the like. The term "sea
water" herein refers to surface sea water, intermediate sea water, deep sea water,
and ultra deep sea water.
The proportion of the water contained in 100 wt. % of the final emulsion composition
is not limited. Usually, it is suitably selected from a range of 50 to 90 wt. %.
Preferably, it is selected from a range of 60 to 80 wt. %.
Polyglycerin fatty acid esters usable in the present invention are not
limited. Examples include esters of a C
12-36 fatty acid and a polyglycerin
having a polymerization degree of 6 or more, especially 6 to 10. Fatty acids that
form esters with polyglycerins include saturated, unsaturated, linear or branched
fatty acids. Specific examples are capric acid, lauric acid, isotridecanoic acid,
myristic acid, palmitic acid, palmitoleic acid, stearic acid, isostearic acid,
oleic acid, linoleic acid, behenic acid, ricinoleic acid, and the like.
Specific examples of polyglycerin fatty acid esters are hexaglyceryl monolaurate,
hexaglyceryl monoisostearate, hexaglyceryl monomyristate, hexaglyceryl dioleate,
hexaglyceryl dimyristate, hexaglyceryl dipalmitate, hexaglyceryl distearate, hexaglyceryl
dibehenylate, hexaglyceryl trilaurate, hexaglyceryl trimyristate, hexaglyceryl
tripalmitate, hexaglyceryl tristearate, hexaglyceryl tribehenylate, hexaglyceryl
tetralaurate, hexaglyceryl tetramyristate, hexaglyceryl tetrapalmitate, hexaglyceryl
tetrastearate, hexaglyceryl tetrabehenylate, hexaglyceryl pentalaurate, hexaglyceryl
pentamyristate, hexaglyceryl pentapalmitate, hexaglyceryl pentastearate, hexaglyceryl
pentabehenylate, decaglyceryl monocaprate, decaglyceryl monolaurate, decaglyceryl
monomyristate, decaglyceryl monopalmitate, decaglyceryl monostearate, decaglyceryl
monooleate, decaglyceryl monolinoleate, decaglyceryl monoisostearate, decaglyceryl
dicaprate, decaglyceryl dilaurate, decaglyceryl dimyristate, decaglyceryl dipalmitate,
decaglyceryl distearate, decaglyceryl diisostearate, decaglyceryl trilaurate, decaglyceryl
trimyristate, decaglyceryl tripalmitate, decaglyceryl tristearate, decaglyceryl
trioleate, decaglyceryl tribehenylate, decaglyceryl pentastearate, decaglyceryl
pentaoleate, decaglyceryl pentaisostearate, decaglyceryl heptastearate, decaglyceryl
decastearate, decaglyceryl decaoleate, decaglyceryl decaisostearate, and the like.
However, the polyglycerin fatty acid esters are not limited thereto.
The polyglycerin fatty acid esters may be used alone or in combination of two
or more species. Polyglycerin fatty acid esters having an HLB value of 10 or more,
especially 10 to 15, can be suitably used. It is preferable to use the polyglycerin
fatty acid ester in a proportion of 0.05 to 6 wt. % per 100 wt. % of the final
emulsion composition, more preferably in a proportion of 0.1 to 5.5 wt. %.
Alkanoyl lactylic acids usable in the invention are not limited. Examples
include alkanoyl lactylic acids having an alkanoyl group with 8 or more carbons,
preferably alkanoyl lactylic acids having a C
8-18 alkanoyl group. Specific
examples include octanoyl lactylic acid, caproyl lactylic acid, 2-ethyl hexanoyl
lactylic acid, lauroyl lactylic acid, myristoyl lactylic acid, palmitoyl lactylic
acid, stearoyl lactylic acid, isostearoyl lactylic acid, oleoyl lactylic acid,
12-hydroxystearoyl lactylic acid, linoleyl lactylic acid, and hebenoyl lactylic
acid. Preferable are stearoyl lactylic acid and isostearoyl lactylic acid. The
alkanoyl lactylic acids can be used in the form of a salt. Examples of such salts
include sodium salts, potassium salts, and like alkali metal salts; ammonium salts,
triethanolamine salts, and the like. Preferred are sodium salts, more specifically,
sodium stearoyl lactylate and sodium isostearoyl lactylate.
The alkanoyl lactylic acids and the salts thereof may be used alone or in combination
of two or more species. It is preferable to use the alkanoyl lactylic acid or the
salt thereof in a proportion of 0.01 to 1 wt. % in 100 wt. % of the final emulsion
composition, more preferably in a proportion of 0.1 to 0.5 wt. %.
The polyglycerin fatty acid esters and alkanoyl lactylic acids and the salts
thereof are used as an emulsifier for the nonaqueous emulsion prepared in the production
process of the emulsion composition of the invention. The proportion for blending
a polyglycerin fatty acid ester with an alkanoyl lactylic acid or the salt thereof
is desirably such that the HLB value of the mixture be 10 or more, preferably 10
to 13. Specific examples of the proportion for blending a polyglycerin fatty acid
ester with an alkanoyl lactylic acid or the salt thereof are weight ratios of 95:5
to 60:40, preferably 90:10 to 70:30.
Acrylic acid-alkyl methacrylate copolymers usable in the invention are not
limited. Examples usually include those having an alkyl chain with 5 to 40 carbons.
Preferred are those having an alkyl chain with 10 to 30 carbons. Although not limited
thereto, such polymers are commercially available, for example, from Goodrich Corporation
under the trademarks of Carbopol and Pemulen, such as Carbopol 1342, Pemulen TR-1,
and Pemulen TR-2.
The acrylic acid-alkyl methacrylate copolymers may be used alone or in combination
of two or more species. It is preferable to use the acrylic acid-alkyl methacrylate
copolymer in a proportion of 0.01 to 0.8 wt. % per 100 wt. % of the final emulsion
composition, more preferably in a proportion of 0.3 to 0.6 wt. %, still more preferably
in a proportion of 0.4 to 0.6 wt. %.
Oils usable in the invention are not limited. Specific examples include peanut
oil, sesame oil, soybean oil, safflower oil, avocado oil, sunflower oil, corn oil,
rapeseed oil, cottonseed oil, castor oil, camellia oil, coconut oil, olive oil,
poppy oil, cacao oil, jojoba oil, and like vegetable oils; beef tallow, lard, wool
oil, and like animal oils and fats; petrolatum, liquid paraffin, squalane, α-olefin
oligomer, and like hydrocarbon liquid oils; isopropyl myristate, isopropyl isostearate,
myristyl myristate, cetyl palmitate, cetyl isooctate, isocetyl myristate, n-butyl
myristate, octyldodecyl myristate, isopropyl linolenate, propyl ricinoleate, isopropyl
ricinoleate, isobutyl ricinoleate, heptyl ricinoleate, diethyl sebacate, diisopropyl
adipate, and like higher fatty acid esters; white beeswax, whale wax, Japan wax,
and like waxes; cetyl alcohol, stearyl alcohol, behenyl alcohol, batyl alcohol,
chimyl alcohol, and like higher aliphatic alcohols; waxes; stearic acids, oleic
acids, palmitic acids, and like higher fatty acids; mono-, di-, or triglyceride
mixtures of C
12-18 saturated or unsaturated fatty acids; methyl polysiloxane,
dimethyl polysiloxane, methylphenyl polysiloxane, methyl hydrogen polysiloxane,
and like linear silicones; decamethylcyclopentasiloxane, octamethylcyclotetrasiloxane,
methylcyclosiloxane, and like cyclic silicones; crosslinked methyl polysiloxane,
crosslinked methylphenyl polysiloxane, and like crosslinked silicones; and, for
example, silicone oils such as silicones modified by polyoxyethylene, polyoxypropylene
or the like; in addition to others. Preferable are hydrocarbon liquid oils such
as vaseline, liquid paraffin, squalane, α-olefin oligomer, and the like.
The oils may be used alone or in combination of two or more species. When oils
are solid, it is preferable to liquefy them by means of an auxiliary resolvent
before using.
It is preferable to use the oil in a proportion of 0.3 to 20 wt. % per 100 wt.
% of the final emulsion composition, more preferably in a proportion of 0.5 to
15 wt. %.
Although the preparation method for the O/W emulsion composition is not
limited, it is preferable to prepare it according to the method described below:
(1) The polyglycerin fatty acid ester and the alkanoyl lactylic acid or
the salt thereof are mixed with the oil and preferably with the polyhydric alcohol.
The mixture is stirred while being heated. After the mixture is uniformly dissolved,
it is cooled to give a nonaqueous emulsion.
(2) The nonaqueous emulsion thus obtained is blended with an aqueous solution
(aqueous composition) that is separately prepared and contains the electrolyte,
the water, and the acrylic acid-alkyl methacrylate copolymer. The O/W emulsion
composition is then prepared according to a conventional method.
It is preferable to use the polyhydric alcohol in Process (1) for preparing the
nonaqueous emulsion in order to further improve the development of the emulsifying
ability of the polyglycerin fatty acid ester, the alkanoyl lactylic acid, etc.
Polyhydric alcohols usable herein are not limited. Specific examples include
polyglycerins having a polymerization degree of 2 to 10 (for example, diglycerin,
triglycerin, tetraglycerin, etc.), ethylene glycol, diethylene glycol, polyethylene
glycol, 1,3-buthylene glycol, propylene glycol, dipropylene glycol, isoprene glycol,
pentadiol, sorbitol, maltitol, fructose, and the like. The use of glycerin is preferable.
These polyhydric alcohols may be used alone or in combination of two or more species.
In this case, the polyhydric alcohol is used in a proportion of 0.05 to 15 wt.
% per 100 wt. % of the final emulsion composition, preferably in a proportion of
3 to 10 wt. %.
In Process (2), which is for emulsification, a lower alcohol can be incorporated
in addition to the electrolyte, the water, and the acrylic acid-alkyl methacrylate
copolymer in the aqueous solution (aqueous composition) that is blended with the
nonaqueous emulsion. This enhances the percutaneous absorption of the electrolyte.
Lower alcohols usable in the invention are not limited, but are usually suitably
selected from alcohols having 1 to 6 carbons. Preferable examples are ethanol,
propanol, isopropanol, and like C
1-4 alcohols. These lower alcohols
may be used alone or in combination of two or more species. The use of ethanol
is preferable. In this case, the lower alcohol is used in a proportion of 0.5 to
15 wt. % per 100 wt. % of the final emulsion composition, preferably in a proportion
of 3 to 10 wt. %.
Moreover, a polyhydric alcohol can be used in the aqueous solution described
above (aqueous composition). The use thereby makes it possible to control the moisturizing
ability and sensory characteristics of the final emulsion composition to the desired
degree. Polyhydric alcohols usable in the aqueous solution include those described
above. When a polyhydric alcohol is used in the preparation of the nonaqueous emulsion,
it is preferable to use polyhydric alcohols that are identical or highly compatible therewith.
Examples of the method for emulsifying the mixture of the nonaqueous emulsion
and the aqueous solution (aqueous composition) include stirring the mixture under
atmospheric pressure or high pressure using a homomixer. The particles of the resulting
emulsion can be further refined by a homogenizer as required.
The proportion of the nonaqueous emulsion to the aqueous solution (aqueous composition)
is not limited. It is usually desirable to control the proportion of the nonaqueous
emulsion to 1 to 40 wt. %, preferably 1 to 30 wt. %, based on 100 wt. % of the
final emulsion composition, thereby giving a more stable O/W emulsion composition.
The O/W emulsion composition of the invention, insofar as the effects of the
invention are not impaired, may contain, as required, a wide range of known substances,
such as humectants, UV absorbers, UV dispersants, vitamins, plant extracts, astringents,
anti-inflammatory agents, whiteners, antioxidants, cell activators, and especially
those known substances used in externally-applied compositions suitable for the
skin, such as cosmetics and externally-applied medical/quasi-medical drugs in addition
to surfactants, coloring matter (dyes, pigments), aromatics, antiseptic agents,
bactericides, thickeners, antioxidants, sequestering agents, pH adjusters, deodorizers,
and a wide variety of additives.
The viscosity of the O/W emulsion composition of the invention is not limited.
When the O/W emulsion composition is employed as a cosmetic suitable for the skin
or as an externally-applied medical or quasi-medical drug, it is usually desirable
to prepare the O/W emulsion composition to have a viscosity of 30,000 cps or less,
preferably 500 to 20,000 cps, at a temperature of 20° C.
The O/W emulsion composition of the invention stably maintains its emulsified
state by inhibiting the oil separation that is typically caused by long-term storage
under a condition in which the O/W emulsion composition is likely to be affected
by temperature change, even when an electrolyte is contained therein in any amount
desired in accordance with the use and the effect intended, especially in any amount
desired from the range of 0.1 wt. % or more, preferably 0.1 to 6 wt. %. The O/W
emulsion composition of the invention can be prepared, according to the intended
use, to provide an excellent, non-tacky feel when used to the skin. The O/W emulsion
composition of the invention is therefore especially useful for external preparations,
such as cosmetics suitable for the skin (including the scalp), and externally-applied
medical and quasi-medical drugs for the skin (including the scalp). Particularly,
when adenosine monophosphate (AMP) or the salt thereof is used as an electrolyte,
the invention can be prepared as a cosmetic and external preparation for the skin
(medical or quasi-medical drug) that is excellent in its moisturizing effect, prevention
of dryness and aging, and ability to cure rough skin due to the action of the AMP
or the salt thereof.
When the O/W emulsion composition of the invention is prepared as an external
preparation such as a cosmetic or an external preparation for skin (medical or
quasi-medical drug), the form thereof is not limited. Examples include emulsions,
suspensions, creams, and the like.
Examples of cosmetics include emollient emulsions, milky lotions, nourishing
emulsions, cleansing emulsions, and like emulsions; emollient creams, massage creams,
cleansing creams, makeup creams, and like creams; and the like. These cosmetics
are applied to the skin in a suitable amount per application or with a suitable
frequency per day, according to the age of the user, the gender, the intended use,
the condition of the affected part of the skin, etc.
(2) Method for Stabilizing the Emulsion of an O/W Emulsion Composition Containing
an Electrolyte
The present invention also provides a method for stabilizing the emulsion of
an O/W emulsion composition containing an electrolyte. This method can be demonstrated
by preparing an O/W emulsion composition using an acrylic acid-alkyl methacrylate
copolymer, a polyglycerin fatty acid ester, and an alkanoyl lactylic acid or the
salt thereof, in addition to an electrolyte, water, and an oil, all of which are
as described above. To give higher emulsion stability to the emulsion composition,
a polyhydric alcohol may be further added in addition to the ingredients mentioned above.
Specifically, the method can be demonstrated by incorporating the polyglycerin
fatty acid ester in a proportion of 0.05 to 6 wt. %, preferably 0.1 to 5.5 wt.
%; the alkanoyl lactylic acid or the salt thereof in a proportion of 0.01 to 1
wt. %, preferably 0.1 to 0.5 wt. %; and the acrylic acid-alkyl methacrylate copolymer
in a proportion of 0.01 to 0.8 wt. %, preferably 0.3 to 0.6 wt. %, more preferably
0.4 to 0.6 wt. % into 100 wt. % of the final O/W emulsion composition containing
the electrolyte in a proportion of 0.1 wt. % or more, preferably 0.5 to 7 wt. %,
more preferably 1 to 6 wt. %. In this case, the proportion of the oil contained
in the final O/W emulsion composition is not limited, but is preferably 0.3 to
20 wt. %, more preferably 0.5 to 15 wt. %. The water accounts for the portion of
the O/W emulsion composition other than that constituted by the oil and other ingredients.
The proportion of the water is not limited, but is usually suitably selected from
the range of 50 to 90 wt. %, preferably 60 to 80 wt. %.
It is preferable to use the polyglycerin fatty acid ester and the alkanoyl lactylic
acid or the salt thereof in such a proportion that the HLB value of the mixture
will be 10 or more, preferably 10 to 13. Specifically, it is preferable to use
the polyglycerin fatty acid ester and the alkanoyl lactylic acid or the salt thereof
in such a proportion that the weight ratio thereof will be 95:5 to 60:40, preferably
90:10 to 70:30.
When a polyhydric alcohol is incorporated, the proportion thereof is, for example,
in a range of 0.05 to 15 wt. %, preferably 2 to 10 wt. %.
More specifically, the method of the invention can be demonstrated by using
each ingredient in the proportion specified above and then preparing an O/W emulsion
composition as described below:
1) The polyglycerin fatty acid ester and the alkanoyl lactylic acid or the
salt thereof are mixed with the oil and preferably with the polyhydric alcohol.
The mixture is stirred while being heated. After the mixture is uniformly dissolved,
it is cooled to give a nonaqueous emulsion.
2) The nonaqueous emulsion thus obtained is blended with an aqueous solution
(aqueous composition) that is separately prepared and contains the electrolyte,
the water, and the acrylic acid-alkyl methacrylate copolymer. The O/W emulsion
composition is then prepared according to a conventional emulsifying method.
By preparing an O/W emulsion composition as described above, emulsion stability
can be given to the O/W emulsion composition, and the oil separation that is typically
caused by long-term storage under conditions in which the O/W emulsion composition
is likely to be affected by temperature change can be significantly inhibited,
thereby providing an emulsion composition that stably maintains its emulsified state.
EXAMPLES
The present invention is described in more detail with reference to the following
examples, but the scope of the present invention is not limited by these examples.
Examples 1 to 8
A polyglycerin fatty acid ester, an alkanoyl lactylate, an oil, and a polyhydric
alcohol were blended, dissolved while being heated, and cooled, to prepare a uniform
nonaqueous emulsion. Mixed therewith was an aqueous composition (aqueous solution)
that was separately prepared by dissolving in distilled water (pure water) an electrolyte,
an acrylic acid-alkyl methacrylate copolymer, a polyhydric alcohol, and a lower
alcohol. The mixture was stirred by a homomixer to give the emulsion composition
of the present invention (Examples 1 to 8). Table 1 shows the ingredients for the
final emulsion compositions.
Each of the eight emulsion compositions thus prepared was placed in two transparent
glass bottles. One bottle was left to stand for 2 weeks at a temperature of 60°
C., and the other bottle was subjected to a 15-cycle test at temperatures ranging
from -5° C. to 40° C. (1 cycle: 24 hours). The appearance (separation,
oil floating, presence/absence of gel formation) of each emulsion composition after
the test was visually observed and evaluated according to the following criteria.
<Evaluation Criteria>
◯: Neither separation, oil floating, nor gel formation was observed.
X: Separation, oil floating, or gel formation was observed.
For comparison, an emulsion composition (Comparative Example 1) containing no
alkanoyl lactylate, and an emulsion composition (Comparative Example 2) containing
no acrylic acid-alkyl methacrylate copolymer were prepared in the same manner as
in Examples 1 to 8 (Table 2 shows the ingredients for these emulsion compositions),
and were subjected to the emulsion stability test as described above.
Tables 1 and 2 show the results of the emulsion stability test for the emulsion
compositions of Examples 1 to 8 and Comparative Examples 1 to 2.
| |
TABLE 1 |
| |
| |
Ex. 1 |
Ex. 2 |
Ex.3 |
Ex. 4 |
Ex. 5 |
Ex. 6 |
Ex. 7 |
Ex. 8 |
| |
| |
| 1 |
Decaglyceryl |
— |
1.6 |
0.16 |
4.8 |
— |
4.8 |
— |
1.6 |
| |
monoisostearate |
| 2 |
Decaglyceryl diisostearate |
1.2 |
— |
— |
— |
1.2 |
— |
1.2 |
— |
| 3 |
Decaglyceryl monostearate |
— |
— |
0.02 |
0.5 |
— |
0.5 |
— |
0.2 |
| 4 |
Decaglyceryl monomyristate |
0.6 |
0.2 |
— |
— |
0.6 |
— |
0.6 |
— |
| 5 |
Sodium stearoyl lactate |
— |
— |
0.02 |
— |
— |
— |
— |
0.2 |
| 6 |
Sodium isostearoyl lactate |
0.2 |
0.2 |
— |
0.5 |
0.2 |
0.5 |
0.2 |
— |
| 7 |
Squalane |
5.0 |
8.0 |
— |
15.0 |
3.0 |
15.0 |
— |
5.0 |
| 8 |
α-Olefln oligomer |
— |
— |
5.0 |
— |
2.0 |
— |
5.0 |
— |
| 9 |
Purified glycerin |
6.0 |
6.0 |
2.0 |
9.0 |
4.0 |
10.0 |
8.0 |
9.0 |
| 10 |
Dipropylene glycol |
— |
— |
5.0 |
— |
2.0 |
— |
— |
— |
| 11 |
Adenosine monophosphate |
1.5 |
1.5 |
3.0 |
6.0 |
—<
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