J. Cosmet. Sci., 54, 527-535 (November/December 2003)
Evaluation of hair fiber hydration by differential
scanning calorimetry, gas chromatography, and sensory analysis
KLE´ ZIA M. S. BELLETTI, ISRAEL H. FEFERMAN, TAˆ NIA R. O.
MENDES, ANGELA D. PIACESKI, VALE´RIA F. MONTEIRO, NEFTALI L.
V. CARREN˜ O, ANTONINHO VALENTINI, EDSON R. LEITE, and ELSON
LONGO, O Botica´rio, Av. Rui Barbosa 3450, Afonso Pena, Sa˜o
Jose´ dos Pinhais, PR, Brazil 83065-260 (K.M.S.B., I.H.F., T.R.O.M.,
A.D.P.), CMDMC/LIEC/DQ/UFSCar, Universidade Federal de Sa˜o
Carlos, Rod Washington Luis, Km 235, Caixa Postal 676, Sa˜o
Carlos, SP, Brazil 13565-905 (V.F.M., N.L.V.C., E.R.L., E.L.),
and Departamento de Quý´mica, UFSC, CP-476, CEP 88040-900, Floriano´polis,
SC, Brazil (A.V.).
Accepted for publication March 19, 2003.
Hair hydration is one of the effects that consumers most expect
when using a cosmetic hair product. The purpose of this study
was to combine differential scanning calorimetry (DSC) and gas
chromatography (GC) techniques for a precise evaluation of the
water content in hair fiber. DSC allowed determination of the
bonding strength of water to hair fibers by quantifying the
amount of energy required to remove the water. The amount of
water thus removed was determined by GC. Post-treatment sensory
evaluations of hair tresses were conducted to determine whether
the values obtained with these techniques correspond to the
moisturizing sensation perceived by consumers.
J. Cosmet. Sci., 54, 537-550 (November/December 2003)
Improving the aqueous solubility of triclosan
by solubilization, complexation, and in situ salt formation
CHRISTINE GROVE, WILNA LIEBENBERG, JAN L. DU PREEZ, WENZHAN
YANG, and MELGARDT M. DE VILLIERS, School of Pharmacy, Potchefstroom
University for Christian Higher Education, Potchefstroom 2520,
South Africa (C.G., W.L., J.L.d.P.), and Department of Basic
Pharmaceutical Sciences, School of Pharmacy, University of Louisiana
at Monroe, Monroe, LA 71209 (W.Y., M.M.d.V.).
Accepted for publication July 29, 2003.
Triclosan, an antimicrobial, although widely incorporated into
many skin care products, toothpastes, and liquid soaps, presents
formulation difficulties because it is practically insoluble
in water. The objective of this study was to improve the aqueous
solubility of triclosan through solubilization, complexation,
and salt formation. The solubility of triclosan in distilled
water and in phosphate buffers (pH 7.4) was determined at 30°C.
The order of solubilizing performance of the solubilizers was:
N-methylglucamine _ L-arginine > sodium lauryl sulfate > _-cyclodextrin
_ hydroxypropyl-_-cyclodextrin > ethanolamine > sodium benzoate
> sodium methyl 4-hydroxybenzoate > triethanolamine _ diethanolamine.
These solubilizers increased the solubility of triclosan from
80- to 6000-fold. Micellar solubilization and the formation
of either salts or complexes are postulated as possible mechanisms
for the increase in the solubility of triclosan by the surfactant
sodium lauryl sulphate, the cyclic sugar derivatives _-cyclodextrin
and 2-hydropropyl- _-cyclodextrin, the amino acid L-arginine,
and the amino sugar alcohol N-methylglucamine. Furthermore,
although the bacteriostatic efficacy of triclosan was significantly
increased when solubilized with Nmethylglucamine, L-arginine,
and ethanolamine, increased solubilization did not increase
the effectiveness of triclosan for all solubilizers tested.
J. Cosmet. Sci., 54, 551-558 (November/December 2003)
Comparison of antioxidant activity of extract
from roots of licorice (Glycyrrhiza glabra L.) to commercial
antioxidants in 2% hydroquinone cream
KATAYOUN MORTEZA-SEMNANI, MADJID SAEEDI, and BITA SHAHNAVAZ,
Department of Medicinal Chemistry (K.M.-S., B.S.) and Department
of Pharmaceutics (M.S.), Faculty of Pharmacy, Mazandaran University
of Medical Sciences, Sari, Iran.
Accepted for publication May 20, 2003.
Powdered dry roots of licorice (Glycyrrhiza glabra L.) were
extracted with methanol. Licorice extract was tested for antioxidative
activity in comparison with antioxidants (sodium metabisulfite
and BHT) at 0.1%, 0.5%, 1.0%, and 2.0% w/w in 2% w/w hydroquinone
cream. The systems were incubated in a dark room at 25° ± 0.5°C
and 45° ± 0.5°C for three months. The physical stability and
the percentages of hydroquinone remaining after two weeks and
one, two, and three months were determined by UV spectrophotometer
at 294 nm according to official standard procedures. The experiment
revealed that oxidation degradation of hydroquinone was accelerated
by heat even with the existence of antioxidants. The higher
percentages of remaining hydroquinone were observed for higher
antioxidant concentration but showed lower physical stability
in the formulation in the presence of commercial antioxidants,
especially in the cases of 1.0% and 2.0% BHT. In the third month,
at 25° ± 0.5°C and 45° ± 0.5°C, the extract demonstrated more
antioxidant activity from two other commercial antioxidants
at all concentrations, with about 43-53% and 34-46%, respectively,
more hydroquinone remaining than in the control system (p <
0.001). In the third month, the preparation containing 0.1%,
0.5%, 1.0%, and 2.0% extract gave good physical formulation
stability with about 72%, 76%, 78%, and 81% hydroquinone remaining
at 25° ± 0.5°C and 51%, 55%, 60%, and 63% hydroquinone remaining
at 45° ± 0.5°C, respectively. This suggested the possibility
of using a licorice extract at 0.5% and 1.0% as an effective
natural antioxidant for substances that are oxidation-susceptible.
J. Cosmet. Sci., 54, 559-568 (November/December 2003)
Solubilization of sodium cocoyl isethionate
JAMES ZIMING SUN, JAMES W. PARR, and MICHAEL C. E. ERICKSON,
Advanced Research Laboratories, 151 Kalmus Dr. Suite H-3, Costa
Mesa, CA 92626.
Accepted for publication July 15, 2003. Presented at the
Annual Scientific Seminar of the Society of Cosmetic Chemists,
Washington, DC, May 9, 2003.
Sodium cocoyl isethionate (SCI) has been a predominant ingredient
in syndet bar formulation for more than thirty years. Although
cost effective and well recognized for good skin compatibility,
SCI is not regularly found in liquid detergent systems due to
its limited solubility in water. This study focuses on the understanding
of enthalpy of solubilization, equilibrium of solubilization,
and the structures and properties of sodium cocoyl isethionate
and various surfactants. The purpose of this exercise is to
help the formulator to find appropriate surfactant systems to
keep sodium cocoyl isethionate in aqueous solution. The solubility
of SCI in water is unfavorable in terms of enthalpy of solvation.
When setting up equilibrium of solubilization, there are three
possible phases, and three methods have been developed to prevent
SCI from recrystallizing in aqueous solutions. The first focuses
on tying CI- ions within micelles made of secondary surfactants.
The second focuses on the exchange of sodium ions with ammonium
ions (and/or triethanolamonium). The third centers on emulsification
of SCI and the subsequent change of micelles into emulsified
oil drops. A combination of two or three of these methods will
enable the formulator to use SCI as the primary surfactant in
liquid detersive systems.
J. Cosmet. Sci., 54, 569-577 (November/December 2003)
Nano-structured biphasic polymer film on the
hair surface from PEGylated polymer latexes
HEE-KYUNG JU, JIN-WOONG KIM, JI-YOUNG PARK, HAK-HEE KANG, SEONG-GEUN
OH, and KYUNG-DO SUH, Amore-Pacific R&D Center, 314-1, Bora-ri,
Giheung-eup, Yongin-si, Gyeonggi-do 449-726 (H.-K.J., J.-W.K.,
J.-Y.P., H.-H.K.) and Department of Chemical Engineering, College
of Engineering, Hanyang University, Seoul 133-791 (S.-G.O.,
K.-D.S.), South Korea
Accepted for publication July 29, 2003.
In this study, biphasic polymer latexes were synthesized by
surfactant-free-emulsion polymerization of butyl methacrylate,
poly(ethylene glycol) methyl ether methacrylate, and 2-(methacryloyloxy)
ethyl trimethyl ammonium chloride. The latexes synthesized were
composed of hydrophobic core phase and hydrophilic shell phase.
Nano-structured film morphology could be obtained by annealing
the biphasic polymer latexes between the two transition temperatures.
It was found that the unique film morphology gave a viscoelastic
property to the film. Scanning electron microscope and atomic
force microscope images revealed that the biphasic polymer latexes
deposited effectively onto the entire hair surface upon conditioning
with 1 wt% polymer concentration in water. Consequently, they
formed a smooth polymer membrane thereon, showing a high potential
for a new hair cosmetic ingredient.
J. Cosmet. Sci., 54, 579-588 (November/December 2003)
Effects of conditioners on surface hardness
of hair fibers: An investigation using atomic force microscopy
S. B. RUETSCH, Y. K. KAMATH, L. KINTRUP, and H.-J. SCHWARK,
TRI/Princeton, Princeton, NJ 08542 (S.B.R., Y.K.K.), and Henkel
KGaA, Du¨sseldorf, Germany (L.K., H.-J.S.).
Accepted for publication July 29, 2003.
Conditioners are known to have a prophylactic effect on hair
damage caused by cosmetic chemical treatments or mechanical
grooming procedures (1). They are known to impart softness and
smoothness to hair by moisturizing the fiber (2). Since the
amount of conditioners deposited on the fiber is very small
in quantity, it is conceivable that mainly the surface is moisturized.
This is especially true of polymeric conditioners, which deposit
preferentially on the surface of the fiber, rather than penetrate
into the cortex. Therefore, this study strictly investigates
whether cationic polymeric conditioners impart softness to the
surface cuticle cell as a result of their hydrophilicity, with
no regard to its applicability to cosmetic effects. Such softening
can be detected by indentation of the surface and can be quantified
by measuring the depth of the indent in real time. Atomic force
microscopy (AFM), equipped with nano-indentation capability,
is ideally suited for this purpose. In this work it was used
to determine changes in the microhardness (micromechanical properties)
of the hair fiber surface as a result of fiber/conditioner/moisture
interactions. In a preliminary study, we observed that the scale
faces of hair treated with Polyquaternium 10 (PQ-10) conditioner
gave deeper indents, while scale edges yielded shallower ones
in comparison to cuticle cells of untreated hair. This suggests
that the conditioner softens the scale face and hardens the
scale edges. However, because of significant amounts of conditioner
residues left on the scale face, this conclusion was rather
ambiguous. Therefore, the study was repeated in which multiple
indentations were made on the surface cuticle cells of a larger
number of the same hair fibers before and after multiple applications
of the conditioner. This reduces errors due to fiber-to-fiber
variation in pre-existing microhardness differences in surface
cuticle cells. Also, the larger number of fibers investigated
in the current work allowed for a statistical outcome. This
latter study has led to a rather definite conclusion that the
scale face is indeed softened by polymeric conditioners such
as Polyquaternium-10 (PQ-10). These studies will ultimately
help in the development of conditioners with suitable moisturizing
and softening effect on hair.
J. Cosmet. Sci., 54, 589-598 (November/December 2003)
Bioconvertible vitamin antioxidants improve
sunscreen photoprotection against UV-induced reactive oxygen
KERRY M. HANSON and ROBERT M. CLEGG, Laboratory for Fluorescence
Dynamics, Department of Physics, University of Illinois, Urbana-Champaign,
Accepted for publication May 20, 2003.
The ability of sunscreens and antioxidants to deactivate highly
destructive reactive oxygen species in human skin has remained
inconclusive. Two-photon fluorescence imaging microscopy was
used to determine the effect of sunscreen/antioxidant combinations
upon UV-induced ROS generation in ex vivo human skin. A sunscreen
combination containing octylmethoxycinnamate (Parsol_ MCX) and
avobenzone (Parsol_ 1789) at SPF 8 and SPF 15 was tested for
its ability to prevent UV radiation from generating ROS in the
viable epidermal strata of ex vivo human skin. A UV dose equivalent
to two hours of North American solar UV was used to irradiate
the skin. Each sunscreen reduced the amount of ROS induced in
the viable strata by a value consistent with the SPF level.
UV photons that were not absorbed/scattered by the sunscreen
formulations generated ROS within the viable epidermal layers.
The addition of the bioconvertible antioxidants vitamin E acetate
and sodium ascorbyl phosphate (STAY-C_ 50) improves photoprotection
by converting to vitamins E and C, respectively, within the
skin. The bioconversion forms an antioxidant reservoir that
deactivates the ROS generated (within the strata granulosum,
spinosum, and basale) by the UV photons that the sunscreens
do not block in the stratum corneum.