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The aims of the present study were to develop olive oil microemulsions and characterize their antioxidant and skin moisturizing properties. The acid, iodine, and saponification values of olive oil were 0.38 ± 0.01 mg potassium hydroxide/g, 88.2 ± 5.9 mg iodine/g, and 192.2 ± 1.4 mg potassium hydroxide/g, respectively. Pseudoternary phase diagrams, constructed using the water titration method, produced suitable microemulsions: microemulsion 1 (10% olive oil, 64% Tween 85, 16% propylene glycol, and 10% water) and microemulsion 2 (10% olive oil, 64% Tween 85, 16% ethanol, and 10% water). Microemulsions 1 and 2 exhibited Newtonian flow behavior with internal droplet sizes of 443.60 ± 27.66 nm and 139.37 ± 12.15 nm, respectively. Their in vitro antioxidant and skin moisturizing properties were investigated in comparison with native olive oil. Microemulsion 2 possessed the highest significant antioxidant effect (p < 0.05) giving half maximal inhibitory concentration values in radical-scavenging activity against 1,1-diphenyl-2-picrylhydrazyl and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) of 4.78 ± 1.25 mg/mL and 14.85 ± 11.18 mg/mL, respectively. The lipid peroxidation inhibition of microemulsion 2 was comparable to native olive oil, whereas the skin moisturizing effect of microemulsion 1 was comparable to the well-known skin moisturizer, hyaluronic acid. In conclusion, microemulsions enhanced both antioxidant and skin moisturizing effects and were attractive formulations for using as a cosmetic or drug delivery system.
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Research Article
Enhancement of antioxidant and skin
moisturizing effects of olive oil by
incorporation into microemulsions
Wantida Chaiyana, Pimporn Leelapornpisid,
Rungsinee Phongpradist, and Kanokwan Kiattisin
The aims of the present study were to develop olive oil microemulsions and characterize their antioxidant and skin
moisturizing properties. The acid, iodine, and saponification values of olive oil were 0.38 +0.01 mg potassium hydroxide/g,
88.2 +5.9 mg iodine/g, and 192.2 +1.4 mg potassium hydroxide/g, respectively. Pseudoternary phase diagrams, con-
structed using the water titration method, produced suitable microemulsions: microemulsion 1 (10% olive oil, 64% Tween
85, 16% propylene glycol, and 10% water) and microemulsion 2 (10% olive oil, 64% Tween 85, 16% ethanol, and 10% water).
Microemulsions 1 and 2 exhibited Newtonian flow behavior with internal droplet sizes of 443.60 +27.66 nm and 139.37 +
12.15 nm, respectively. Their in vitro antioxidant and skin moisturizing properties were investigated in comparison with
native olive oil. Microemulsion 2 possessed the highest significant antioxidant effect (p< 0.05) giving half maximal inhibitory
concentration values in radical-scavenging activity against 1,1-diphenyl-2-picrylhydrazyl and 2,20-azino-bis(3-
ethylbenzothiazoline-6-sulphonic acid) of 4.78 +1.25 mg/mL and 14.85 +11.18 mg/mL, respectively. The lipid peroxidation
inhibition of microemulsion 2 was comparable to native olive oil, whereas the skin moisturizing effect of microemulsion 1
was comparable to the well-known skin moisturizer, hyaluronic acid. In conclusion, microemulsions enhanced both anti-
oxidant and skin moisturizing effects and were attractive formulations for using as a cosmetic or drug delivery system.
Antioxidant, moisturizing, microemulsion, olive oil, Olea europaea, cosmetics, drug delivery system
Date received: 20 April 2016; accepted: 22 August 2016
Topic: Synthesis of Nanostructured and Nanoscale Materials
Topic Editor: Di Gao
Topic: Nanoparticles
Topic Editor: Raphael Schneider
Microemulsions (MEs) represent a promising delivery
system for pharmaceuticals and cosmeceuticals due to its
numerous advantages over the existing conventional formu-
There is a growing recognition of their potential
benefits in the field of cosmetic sciences in addition to the
drug delivery abilities. MEs are widely investigated for pre-
paring personal care products with superior features such as
high efficiency, good stability, and improved aesthetic
The key difference between MEs and conven-
tional emulsions is that MEs exhibit excellent thermodynamic
stablility, therefore, phase separation is not likely to occur,
whereas conventional emulsions exhibit fundamentally ther-
modynamic unstablility and phase separation could eventu-
ally take place. The internal droplet size of MEs is below the
Department of Pharmaceutical Science, Chiang Mai University, Chiang
Mai, Thailand
Corresponding Author:
Wantida Chaiyana, Department of Pharmaceutical Science, Faculty of
Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand.
Nanomaterials and Nanotechnology
Volume 6: 1–8
ªThe Author(s) 2016
DOI: 10.1177/1847980416669488
Creative Commons CC-BY: This article is distributed under the terms of the Creative Commons Attribution 3.0 License
( which permits any use, reproduction and distribution of the work without
further permission provided the original work is attributed as specified on the SAGE and Open Access pages (
wavelength of visible light, leading to an optically transparent
The smaller size of MEs results in a deeper
skin penetration compared to conventional emulsions.
Moreover, MEs can increase the dermal delivery of active
compounds by enhancing their solubility, leading to a
greater degree of encapsulation compared to other conven-
tional topical formulations such as ointments, creams, gels,
and lotions.
Normally, MEs are quaternary systems com-
posed of oil, water, and surfactant/cosurfactant mixtures.
They are spontaneously formed isotropic colloidal system-
Therefore, the methods of preparation are distinctly dif-
ferent, since emulsions require a large input of energy,
whereas MEs do not require any input energy, leading to
reductions of the relative cost of commercial production.
Olive oil is the oil extracted from the fruit of olive tree
(Olea europaea). There are several methods to produce olive
oil, however, a mechanical process without the use of exces-
sive heat gives the highest quality olive oil which is classified
as virgin olive oil.
cosmetic products, such as skin and hair care formulations.
There are several studies reporting the potent antioxidant
activity of olive oil.
The active compounds responsible
for the antioxidant activity, belong to three different classes,
including simple phenols, secoiridoids, and lignans.
over, olive oil may be used to protect the skin from ultravio-
let B in the sunlight based on a study reporting that mice
receiving olive oil after UVB exposure showed a signifi-
cantly lower number of developing tumors per mouse than
those in the control group receiving nothing.
Therefore, the
aims of the present study were to develop MEs from olive oil
and characterize their antioxidant activity and skin moistur-
izing properties for further applications in cosmetics.
Materials and methods
Extra virgin olive (Olea europaea) oil was purchased
from the local market in Chiang Mai, Thailand. Hyarulo-
nic acid, quercetin, gallic acid, trolox (6-hydroxy-2,5,7,8-
tetramethylchroman-2-carboxylic acid), 2,20-Azino-bis
(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 1,1-
diphenyl-2-picrylhydrazyl radical (DPPH), linoleic acid,
phenolphthalein test solution (TS), triethanolamine, and
carbopol 940 were purchased from Sigma-Aldrich
(St Louis, Missouri, USA). Disodium hydrogen phosphate,
dipotassium hydrogen phosphate, sodium hydroxide, potas-
sium hydroxide (KOH), potassium iodide (KI), iodobromide,
and sodiumthiosulfate, ammonium thiocyanate, and ferrous
chloride were purchased from Fisher Chemicals (Loughbor-
ough, UK). Hydrochloric acid was analytical reagent (AR)
grade and purchased from Merck (Darmstadt, Germany).
Ethanol, propan-2-ol, dimethyl sulfoxide, hexane, ethyl acet-
ate, and ether (all AR grade) were purchased from Labscan
(Dublin, Ireland). Propylene glycol (PG), polyethylene gly-
col (PEG) sorbitan monolaurate (Tween 20), PEG sorbitan
monopalmitate (Tween 40), PEG sorbitan monostearate
(Tween 60), PEG sorbitan monooleate (Tween 80), PEG
sorbitan trioleate (Tween 85), and sorbitan monooleate
(Span 80) purchased from Acros Organics (Morris Plains,
New Jersey, USA). PEG 400, us pharmacopeia (USP), and
mineral oil were purchased from Wilhelmshaven, Germany.
Characterization of olive oil
Acid value determination. Acid value of olive oil was deter-
mined by the indirect titration method with slight modifi-
Briefly, 10 g of olive oil was mixed with 50 mL of
an ethanol/ether mixture (1:1). The mixture was then sha-
ken until homogeneous. Phenolphthalein TS was added as
an indicator in the titration with 0.1 N sodium hydroxide
(NaOH). The end point of the titration was indicated at the
first permanent pink color which was persisted for at least
10 s. The acid value, which was expressed as the amount of
NaOH (in milligrams) necessary to neutralize free fatty
measurements were done in triplicate.
Iodine value determination. Determination of the iodine value
was conducted according to the American Oil Chemists’
Society (AOCS) official method with slight modification.
Briefly, 0.2 g of olive oil was dissolved in 10 mL of chloro-
form and the mixture was shaken until homogenous. Then
25 mL of iodobromide was added, and the reaction was
carried out in the dark for 30 min. KI solution (30 ml of
KI in 100 mL of water) was then added to stop the reaction.
The remaining iodine was titrated using 0.1 N sodium thio-
sulfate solution. The iodine value which is expressed as
grams of halogen (calculated as iodine) absorbed by 100 g
of olive oil. The measurements were done in triplicate.
Saponification value determination. The saponification value
of olive oil was determined according to the AOCS official
method with slight modification.
Briefly, 2 g of olive oil
was dissolved in 25 mL of alcoholic KOH. After 30 min of
reflux with heating from a water bath, the sample was
titrated with 0.5 N hydrochloric acid (HCl) using 1 mL of
phenolphthalein as an indicator. The end point was indicated
at the appearance of an amber yellow color. The saponifica-
tion value was expressed as milligrams of KOH necessary to
neutralize the free acids and saponify the esters present in 1 g
of substance. The experiments were done in triplicate.
ME development
Pseudoternary phase diagram construction. Pseudoternary
phase diagrams of olive oil were constructed using a
slightly modified water titration method.
Various nonio-
nic surfactants (Tween 20, Tween 40, Tween 60, Tween 80,
Tween 85, or Span 80) were mixed with a cosurfactant
(ethanol, propan-2-ol, PG, or PEG-400) at a weight ratio
of 1:2, 1:1, 2:1, or 4:1 to obtain surfactant mixture (Smix).
The oil and Smix were then mixed at various weight ratios
2Nanomaterials and Nanotechnology
(0:1, 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1, and 1:0) and
the resulting mixtures were subsequently titrated with
water under moderate agitation at room temperature. The
samples were classified as MEs when they appeared
visually as clear liquids. The different formulations were
made in triplicate. The pseudoternary phase diagrams were
drawn using OriginPro 8 software. The areas of the ME
regions were measured by ImageJ 1.47v software.
Characterization of ME
Photon correlation spectroscopy. Particle size analysis was
carried out using photon correlation spectroscopy (Zetasizer
version 5.00, Malvern Instruments Ltd, Malvern, UK). The
sizing measurements were carriedout at a fixed angle of 173.
The reported results are the mean and standard deviation (SD)
of at least 10 measurements on each sample.
Rheology study. Viscosity of the MEs was measured using
a Brookfield DVIII rheometer (Brookfield Engineering
Laboratories, Stoughton, Massachusetts, USA) fitted
with a bob spindle. Brookfield Rheocalc operating
software [version 2.8] was used to control the measure-
ment. A sample volume of 70 mL was used. The measure-
ments were performed in triplicate at 25C.
Antioxidant activity of olive oil and ME
ABTS assay. Olive oil and MEs were tested for ABTS radical
cation scavenging activity using the method reported by
Fellegrin et al.
with slight modification. Briefly, ABTS
solution (7 mM) was reacted with potassium persulfate
(140 mM) solution and kept in the dark overnight (16 h) to yield
a dark colored solution containing radical cation (ABTS
Prior to use, ABTS
was diluted with ethanol for an initial
absorbance of about 0.500 at 734 nm. After the addition of
1.0 mL of diluted ABTS
to 10 mL of sample, the absorbance
was measured after 6 min of initial mixing. The percentage
inhibition was calculated using the following equation:
% Scavenging effect ¼1S
where Sis the absorbance of ABTS
with sample and Cis the
absorbance of ABTS
without sample. The experiment was
done in triplicate. Half maximal inhibitory concentration (IC
was calculated using GraphPad Prism version 2.01 software.
DPPH assay. Olive oil and MEs were tested for radical
scavenging activity against stable DPPH using the method
reported by Blois
with slight modification. Briefly, 20 mL
of test sample was mixed with 180 mL of 167 mM DPPH
solution. The reaction was carried out in the dark for 30 min
at room temperature. Then the absorbance was measured at
520 nm using a DTX-880 multimode detector. %Inhibition
was calculated using the following equation:
% Inhibition ¼ f½ð PC NCÞðSBÞ =ðPC NCÞg
where PC is the absorbance of 20 mL of acetone and 180 mL
of 167 mM DPPH mixture, NC is the absorbance of 200 mL
of acetone, Sis the absorbance of 20 mL of test sample and
180 mL of 167 mM DPPH mixture, and Bis the absorbance
of 20 mL of test sample and 180 mL of acetone mixture. The
experiment was done in triplicate. IC
was calculated
using GraphPad Prism version 2.01 software.
Inhibition of lipid peroxidation by ferric thiocyanate. Olive oil
and MEs were tested for lipid peroxidation inhibition by the
ferric thiocyanate using the method reported by Niehius
and Samuelson
with slight modification. Briefly, 100
mL of test sample was mixed with 1 mL of 25 mM linoeic
acid in acetone and 1 mL of 0.1 M phosphate buffer pH 7.0
in the test tube with a cork lid stock. The reaction was
allowed to carry out in the dark for 6 h at 60C. Then a
50 mL aliquot of the mixture was mixed with 3 mL of 75%
ethanol, 20 mLof35%ammonium thiocyanate, and 20 mL
of 20 mM ferrous chloride in 3.5%HCl. After vortexing the
mixture for 1 min, the absorbance was measured at 500 nm
using an ultraviolet–visible spectrophotometer (Shimadzu,
japan). %Inhibition was calculated using the following
% Inhibition ¼BS
where Bis the absorbance of the combined mixture of
100 mL of acetone, 1 mL of 25 mM linoleic acid in acetone,
and 1 mL of 0.1 M phosphate buffer pH 7.0 and Sis the
absorbance of the combined mixture of 1 mL of 25 mM
linoleic acid in acetone, and 1 mL of 0.1 M phosphate
buffer pH 7.0 and 100 mL of test sample. The experiment
was done in triplicate.
In vitro skin moisturizing test of olive oil and ME
Skin preparation. Full-thickness skin from the flank area of
stillborn piglets was used for skin moisturizing studies.
Stillborn piglets were obtained fresh from a local farm. The
hair was trimmed off with electrical clippers and the skin
pieces from the flank area were carefully dissected with a
surgical blade. After washing in phosphate buffer solution
(PBS; pH 7.4), the skin was wrapped in tin foil and stored at
20C for up to 1 month.
Prior to use in studies, skin was
defrosted and hydrated in PBS overnight at room tempera-
ture. Before experimentation, the subcutaneous fat layer
was carefully trimmed off and the skin was cut into a square
shape (2 2cm
) using surgical scissors.
In vitro skin moisturizing test. The skin hydration was mea-
sured using a Corneometer#CM 825 (Courage-Khazaka
Electronic, Cologne, Germany). A baseline measurement
was performed before applying 100 mL of olive oil or MEs
followed by three additional measurements at 30, 60, and
120 min after application. Three pieces of skin were used
for each measurement. DI water was used as a negative
Chaiyana et al. 3
control and 1%hyaluronic acid solution was used as a
positive control. Skin moisturizing efficacy (%) was calcu-
lated using the formula:
Relative skin hydration ð%Þ¼ ðAtA0Þ
where A
is skin capacitance at a specified time and A
skin capacitance at the baseline. This method was modified
from O’Goshi et al.
Statistical analysis
All data were presented as the mean +SD. Individual
differences were evaluated by one-way analysis of var-
iance: post hoc test. In all cases, p< 0.05 indicated
Results and discussion
Olive oil characteristics
The characteristic of olive oil as the function of acid
value, iodine value, and saponification value are shown
in Table 1.
The acid value can be used to indicate the oil quality and
a low acid value indicates the oxidative stability of the oil.
However, the acid value also depends on the type of oil and
the storage conditions as the acid value will increase over
longer times of storage.
Since the acid value is twice that
of the free fatty acid, it could be used to determine trigly-
ceride hydrolysis, which is often related to the quality of oil
against oxidative reaction.
Therefore, olive oil with a low
acid value and a low free fatty acid value would be stable
against oxidation and not easily become rancid.
The iodine value represents the number of reactive
double bonds in the oil. The iodine value of oleic acid,
an unsaturated free fatty acid containing one double bond,
is 90 while that of linoleic, an unsaturated free fatty acid
containing two double bonds, is 282. The low iodine value
of olive oil places it in the nondrying oil group which is oil
that does not solidify when exposed as a thin film to air.
Normally, nondrying oils contain only small amount of
either linoleic acid that possess three double bonds in one
molecule or linoleic acid that possess two double bonds.
Therefore, the oxidative cleavage of unsaturated bond
decrease and the oxidation slows down. The results
related well with the previous study reported that olive
oil contained 64.4–81.0%unsaturated free fatty acid con-
taining one double bond, 12.6–19.7%unsaturated free
fatty acid containing two double bonds, and 6.0–15.9%
unsaturated free fatty acid containing several double
Oleic acid was the major component (62.0–
80.0%) found in the oil.
High saponification value represents high ester con-
tent or a high number of carboxylic functional groups
per unit mass of olive oil. The results suggested that
olive was suitable for self-emulsification process and
ME formation.
ME development
The effect of surfactant type was studied using various
surfactants, including Tween 20, Tween 40, Tween 60,
Tween 80, Tween 85, and Span 80. When the cosurfactant
was PG and the Smix ratio was 2:1, only Tween 85 could
produce an ME region in the pseudoternary phase diagram
(Figure 1(a)). These results were in a good agreement with
a previous study reporting that Tween 85 showed an excel-
lent ability to produce ME among several surfactants.
However, the type of oil phase affected the ability of
Tween 85 to produce the ME. A previous study reported
that Tween 85 could produce a small ME region in the
psuedoternary phase diagram of ME containing an essential
The likely explanation was that there was no univer-
sal good surfactant that is suitable for all types of oil in ME
development. For olive oil, Tween 85 was a suitable sur-
factant since it could produce the largest ME region in the
pseudoternary phase diagram. The effect of cosurfactant
type was also studied. Ethanol produced the highest ME
region followed by PG and isopropanol, whereas PEG-400
could not produce any ME (Figure 1). PG and ethanol gave
a good promising ME region. Therefore, the effect of Smix
ratio was studied in the system containing these two cosur-
factants. When the Smix ratio increased from 1:2 to 4:1, the
ME region was significantly increased (Figures 2 and 3).
The results related well with the previous study of Gao
et al.
who reported that the polyoxyethylated castor oil
ME region respectively increased when the ratio of poly-
ethylene glycol (35) castor oil to transcutol increased
from 0.5:1 to 4:1. Similarly, Chaiyana et al.
reported that
the ME region increased when the ratio of Tween 20 to
PEG-400 increased from 1:2 to 4:1. Additionally, Kale and
reported that an increase in the Smix ratio could
increase ME formation of mineral oil using a surfactant of
Brij 96 and a cosurfactant ofglycerin, ethylene glycol, or PG.
Two MEs from the systems in Figures 2(d) and 3(d)
were formulated and named as ME1 and ME2, respec-
tively. ME1 contained 10%olive oil, 64%Tween 85,
16%PG, and 10%water, whereas ME2 contained 10%
olive oil, 64%Tween 85, 16%ethanol, and 10%water.
Both MEs were transparent isotropic yellow liquids. The
internal droplet size of ME1 was larger than that of ME2
and both of them showed moderate polydisperse index as
Table 1. Characteristics of olive oil (mean +SD, n¼3).
Characteristic Results Standard
Acid value 0.38 +0.01 mg KOH/g <0.5 mg KOH/g
value 88.2 +5.9 mg I
/g 75–94 mg I
192.2 +1.4 mg KOH/g 190–195 mg KOH/g
KOH: potassium hydroxide; I
: iodine.
4Nanomaterials and Nanotechnology
shown in Table 2. Furthermore, ME1 and ME2 both
showed Newtonian flow behavior with low viscosity
(Table 1) confirming the formation of MEs.
The likely
explanation of the elevated viscosity of ME1 was from the
larger internal droplet size.
Antioxidant activity
The antioxidant activity of olive oil, ME1, and ME2 was
analyzed by means of the DPPH, ABTS, and lipid perox-
idation assays. Several methods were used since it is rec-
ommended to base the conclusions of antioxidant activity
on at least two different test methods and the antioxidant
activity is dependent on the method used.
DPPH and
ABTS assay are test systems using a stable free radical to
give information on the radical scavenging or antiradical
whereas the lipid peroxidation assay is the most
studied biologically relevant free radical chain reaction that
gives information on antioxidant activity.
The IC
culated from the concentration curve versus free radical
scavenging activity against DPPH and ABTS radicals of
Figure 1. Pseudoternary phase diagram of olive oil/Tween 85 and cosurfactant (2:1)/water, when the cosurfactant was (a) PG, (b)
ethanol, (c) isopropanol, and (d) PEG-400. The dark area represents the ME region. PG: propylene glycol; PEG: polyethylene glycol; ME:
Figure 2. Pseudoternary phase diagram of olive oil/Tween 85/PG/water when the Smix ratios were (a) 1:2, (b) 1:1, (c) 2:1, and (d) 4:1.
The dark area represents the ME region. PG: propylene glycol; ME: microemulsion.
Figure 3. Pseudoternary phase diagram of olive oil/Tween 85/ethanol/water when the Smix ratios were (a) 1:2, (b) 1:1, (c) 2:1, and
(d) 4:1. The dark area represents the ME region. ME: microemulsion.
Table 2. Characterization of MEs (mean +SD, n¼3).
droplet size (nm)
ME1 443.60 +27.66 0.30 +0.10 1.95 +0.03
ME2 139.37 +12.15 0.33 +0.02 0.11 +0.00
ME: microemulsion.
Chaiyana et al. 5
olive oil, ME1, and ME2 is presented in Table 3. Both ME1
and ME2 increase the antioxidant activities of the native oil
because of the higher solubilizing power and the larger
surface area of the ME droplets. It is noted that ME2 exhib-
ited the highest radical scavenging activity as it showed the
significantly lowest IC
value against DPPH and ABTS
radicals (p< 0.05). However, the lipid peroxidation inhibi-
tion of ME2 was not different from the native olive oil. The
likely explanation of the distinctly superior antioxidant
activities of ME2 was its lower viscosity and smaller inter-
nal droplet size led to an increase in surface area and sub-
sequently an increase in intimate contact between ME
droplet and the target site. These factors promoted better
efficacy in antioxidant activity.
Skin moisturizing property
The relative skin hydration at 30, 60, and 120 min after
applying 1%hyaluronic acid solution, olive oil, ME1, and
ME2 is shown in Figure 4. ME1 possessed a significantly
higher skin moisturizing effect comparing to a native
olive oil (p< 0.05), whereas ME2 showed almost the
same results as the olive oil. Interestingly, the skin moist-
urizing effect of ME1 was comparable to the hyaluronic
acid. The likely explanation was that the ME1 contain PG
which acts as a humectant. However, the ME of olive oil
was less expensive than the hyaluronic acid solutions,
therefore, it could be used as an alternative choice in
cosmetic preparation.
Tween 85, a major component of the formulation, is not
thought to produce adverse health effects or skin irritation.
Bicontinuous MEs containing Tween 85 were reported as a
safe vehicle for topical drug delivery.
However, it may
cause skin irritation after prolonged or repeated exposure.
Therefore, the skin irritation tests in human subjects are
necessary and need further study.
Olive oil used in the present study met the standard criteria
of acid, iodine, and saponification values which were 0.38
+0.01 mg KOH/g, 88.2 +5.9 mg iodine/g, and 192.2 +
1.4 mg KOH/g, respectively. Two MEs including ME1
(10%olive oil, 64%Tween 85, 16%PG, and 10%water)
and ME2 (10%olive oil, 64%Tween 85, 16%ethanol, and
10%water) were developed and characterized. The larger
internal droplet size of ME1 was correlated well with its
higher viscosity. The internal droplet size of ME1 and ME2
was 443.60 +27.66 and 139.37 +12.15 nm, respectively.
Besides, the viscosity of ME1 and ME2 was 1.95 +0.03
and 0.11 +0.00 mPas, respectively. Comparing to the
native olive oil, ME2 possessed the significant highest anti-
oxidant activity (p< 0.05) with IC
of radical scavenging
activity against DPPH and ABTS radicals of 4.78 +
1.25 mg/mL and 14.85 +11.18 mg/mL, respectively.
Therefore, the olive oil ME significantly possessed higher
antioxidant and skin moisturizing effect than the native
olive oil. However, an effect on their biological activities
depended on the composition of MEs. The lipid peroxida-
tion inhibition of ME2 was comparable to that of native
olive oil. On the other hand, ME1 possessed high skin
moisturizing effect which was comparable to the hyaluro-
nic acid. Therefore, it could be concluded that olive oil ME
is an attractive formulation in the cosmetic development
studies and could be used as a delivery system for cos-
metics ingredients or biological active compouds. The skin
irritation and moisturizing test in human subjects are sug-
gested for further study. Moreover, permeability evaluation
of the olive oil MEs which is a major consideration in drug
delivery system is also recommended for further work.
We thank Dr Karl Bailey, Scientific Officer, Department of
Human Nutrition, University of Otago for improving the use of
English in the manuscript.
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with
respect to the research, authorship, and/or publication of this
Table 3. Antioxidant activity of olive oil and MEs (mean +SD,
DPPH assay ABTS assay
peroxidation assay
Olive oil 11.67 +1.44 112.30 +31.05 16.27 +5.51
ME1 12.70 +3.62 25.22 +3.95* 10.03 +0.43
ME2 4.78 +1.25* 14.85 +11.18* 15.61 +1.08
: half maximal inhibitory concentration; DPPH: 1,1-diphenyl-2-
picrylhydrazyl radical; ABTS: 2,20-azino-bis(3-ethylbenzothiazoline-6-
sulfonic acid); ME: microemulsion.
% Inhibition at the concentration of 5 mg/mL.
*p< 0.05: compared to olive oil.
0 30 60 90 120
Relative skin hydration (%)
Time (min)
Figure 4. Relative skin hydration after applying with 1% hya-
luronic acid solution (~), olive oil (), ME1 (), and ME2 (&)for
30, 60, and 120 min. *p< 0.05: compared to 1% hyaluronic acid
6Nanomaterials and Nanotechnology
The author(s) disclosed receipt of the following financial support
for the research, authorship, and/or publication of this article: The
financial support was received from Chiang Mai University grant
for new researchers.
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8Nanomaterials and Nanotechnology
... Although olive oil has been extensively used as water in oil microemulsion (W/O) for various applications, there are few reports of its utility as oil in water (O/W) micro/ nanoemulsion [50][51][52][53][54] . These microemulsion were prepared using either co-surfactants or a number of chemical stabilizers using highly energy intensive procedures like ultrasonication and temperature induced phase inversion etc. ...
... However, our procedure of olive oil in water nanoemulsion preparation is highly energy efficient wherein nanoemulsion is prepared just by 15 min. of rotation without any cosurfactant. Moreover, unlike the previously published reports [50][51][52][53][54] . we have also presented first visual evidence (TEM image) of olive oil sitting in the micellar cavity of the surfactant, PF 127 (Fig. 3c-e). ...
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The sustainable cellular delivery of the pleiotropic drug curcumin encounters drawbacks related to its fast autoxidation at the physiological pH, cytotoxicity of delivery vehicles and poor cellular uptake. A biomaterial compatible with curcumin and with the appropriate structure to allow the correct curcumin encapsulation considering its poor solubility in water, while maintaining its stability for a safe release was developed. In this work, the biomaterial developed started by the preparation of an oil-in-water nanoemulsion using with a cytocompatible copolymer (Pluronic F 127) coated with a positively charged protein (gelatin), designed as G-Cur-NE, to mitigate the cytotoxicity issue of curcumin. These G-Cur-NE showed excellent capacity to stabilize curcumin, to increase its bio-accessibility, while allowing to arrest its autoxidation during its successful application as an anticancer agent proved by the disintegration of MDA-MB-231 breast cancer cells as a proof of concept.
... However, basic DAP used for microsphere modification attenuated paraffin-stimulated cytotoxicity. In addition, the alkaline environment provided by DPA induced Span 80 to undergo saponification with paraffin oil to achieve the washing effect in the oil phase [27][28][29]. The resulting DAP-modified microspheres possess good compatibility without adverse effects on cells. ...
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Hydrogel-based microspheres prepared by emulsification have been widely used as drug carriers, but biocompatibility remains a challenging issue. In this study, gelatin was used as the water phase, paraffin oil was used as the oil phase, and Span 80 was used as the surfactant. Microspheres were prepared using a water-in-oil (W/O) emulsification. Diammonium phosphate (DAP) or phosphatidylcholine (PC) were further used to improve the biocompatibility of post-crosslinked gelatin microspheres. The biocompatibility of DAP-modified microspheres (0.5–10 wt.%) was better than that of PC (5 wt.%). The microspheres soaked in phosphate-buffered saline (PBS) lasted up to 26 days before fully degrading. Based on microscopic observation, the microspheres were all spherical and hollow inside. The particle size distribution ranged from 19 μm to 22 μm in diameter. The drug release analysis showed that the antibiotic gentamicin loaded on the microspheres was released in a large amount within 2 h of soaking in PBS. It was stabilized until the amount of microspheres integrated was significantly reduced after soaking for 16 days and then released again to form a two-stage drug release curve. In vitro experiments showed that DAP-modified microspheres at concentrations less than 5 wt.% had no cytotoxicity. Antibiotic-impregnated and DAP-modified microspheres had good antibacterial effects against Staphylococcus aureus and Escherichia coli, but these drug-impregnated groups hinder the biocompatibility of hydrogel microspheres. The developed drug carrier can be combined with other biomaterial matrices to form a composite for delivering drugs directly to the affected area in the future to achieve local therapeutic effects and improve the bioavailability of drugs.
... To obtain a concentration range of components for the existing microemulsion boundary, pseudoternary phase diagrams were constructed using a water titration method [14]. Various nonionic surfactants (polysorbate 20, sorbitan laurate, polysorbate 80, and sorbitan oleate) were mixed at room temperature with ethanol (cosurfactant) at a ratio of 1:2, 1:1, or 2:1 to obtain a surfactant mixture (Smix). ...
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Momordica charantia (M. charantia) is rich in flavonoids, which possess a strong antioxidant capacity andmay help prevent hair loss. This study aims to develop the microemulsion of M. charantia with antioxidant activity and 5 alpha-reductase (5aR) inhibitory activity. The total phenolic content (TPC), antioxidant activity, and 5aR inhibitory activity of ethanolic and aqueous extracts of the fruit were investigated. The preparation of M. charantia extract-loaded microemulsion (MELM) was optimized and characterized the MELM. The aqueous extract of M. charantia fruit flesh displayed a TPC of 780.75 � 24.82 mg Gallic acid equivalence/g of extract. ABTS (2,20-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid), DPPH (2,2-diphenyl-1-picrylhydrazyl), and nitric oxide (NO) radical scavenging activities were observed in all the extracts. About 0.461 � 0.003 mg finasteride equivalence/g of extract of 5aR inhibitory activity was detected in the aqueous extract of the inner tissue of M. charantia fruit. Based on NO radical scavenging and 5aR inhibitory activity, an aqueous extract of the inner tissue (pericarp with seed) of M. charantia fruit was used to prepare the MELM. The MELM was prepared using a different ratio of tween 80 and ethanol as Smix. The results showed that the 1:1 ratio of tween 80: ethanol produced microemulsion of an optimum size, zeta potential, and polydispersity index. The MELM samples were stored at 5, 30, and 40 �C for 12 weeks, and the stability was assessed. The results revealed that the size, zeta potential, and polydispersity index of the formulated MELM remained unchanged during the investigated time. This study primarily reports the 5aR inhibitory activity of M. charantia extract and the development of microemulsion. The prepared MELM could be further developed into cosmetic or pharmacological preparations to manage hair loss.
... Therefore SLNs and NLCs containing vegetable oils and fats can be used to increase skin smoothness and moisture or even for the manufacturing of hair-care formulations. Vegetable oils can also be used for the preparation of microemulsions and nanoemulsions, as the main or partial component of the oily phase [48]; however, the use of fats for the preparation of those systems is not as well explored. ...
... Olea europaea, Oleaceae: Ancient use for nourishment of skin and hair, as cleanser and makeup removal, skin moisturizer, as bath oil. It posses skin moisturizing activity [39]. ...
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Beauty is a prime concern of life. The standards of beauty varies from place to place but healthy skin and lustrous hair are focused point of concern in poetries and also applicable in daily life. So this review is based on various disorders of skin such as hyperpigmentation, wrinkle, leucoderma, dark circles, acne etc. and various disorders of hair such as alopecia, dandruff, seborrhea which give rise to ugly and aged appearance and the natural remedies for these disorders as they do not have side effects and are economic, biocompatible and ecofriendly.
Peony (Paeonia suffruticosa Andr.) originated in China and has long been popular worldwide as an ornamental crop. In recent years, peony seed oil (PSO) as edible oil has received extensive attention due to its richness in unsaturated fatty acids, especially α-linolenic acid (ALA). In this work, fatty acid mixture-1 (FAM-1) and fatty acid mixture-2 (FAM-2) with different ALA concentrations were prepared from PSO by saponification and freezing crystallization. Pseudo-ternary phase diagrams were constructed to determine the composition and proportions of microemulsions (MEs), which were used to embed PSO and FAM. Based on pseudo-ternary phase diagrams, PSO ME prepared possessed a droplet size of 54.6 nm using a mixture of Tween 80 and Span 80 as the surfactant, while FAM-1 ME and FAM-2 ME owned droplet sizes of 30.1 and 29.7 nm using Tween 20 as the surfactant, respectively. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) analysis confirmed that the MEs had good dispersibility, and rheological analysis demonstrated excellent resistance to shearing rate changes. Besides, three MEs all exhibited good stability at 4 °C by microemulsification during the 60-day storage period in terms of droplet size, pH, and electrical conductivity. The water solubility and viscosity exhibited by the three synthetic MEs showed large potential to expand the application in cosmetics, medicine, and food industry.
Injectable ibuprofen has been formulated as nanoemulsion, prodrug microemulsion, and freeze-dried. However, its application is limited because of solubility, high dosing, and complex formulation. Microemulsion ibuprofen injection is an alternative dosage form that increases solubility and bioavailability. The study aimed to formulate an ibuprofen microemulsion injection that can fulfill the prerequisites for injection preparations with a simple method and simple reconstitution before use. All combinations of the oil and aqueous phases were formed using the self-emulsification technique. The optimum stability was estimated on particle size, polydispersity index (PDI), and zeta potential at 5°C, 25°C, and 40°C for 120 days. Based on the minimum amount of Tween 80, drug loading, and the highest transmittance value, the optimal microemulsion formula was obtained at a concentration of 2.8% (1:1 combination of olive oil and medium-chain triglyceride oil), 11.2% Tween 80, 2.8% propylene glycol, and 83.2% water for injection. The optimal formula has a droplet size of 16.7 ± 11.2 nm, a zeta potential of 0.8 mV, and a PDI of 0.196. The formula was stable at 45°C storage for up to 14 days, at 25°C, and at 5°C, steady at 120 days based on droplet size diameter of 21.27 ± 0.00 nm, zeta potential -1.3 ± 0.10 mV, and PDI 0.38 ± 0.02. The optimum formula by simple reconstitution without additional isotonization has fulfilled the requirements for injection preparation. It was concluded that the ibuprofen microemulsion with a combination of medium-chain triglyceride oil and olive oil could form a stable microemulsion and has the potential to be developed as a pharmaceutical preparation in the form of injectable ibuprofen.
Background: This study reports the formation of sacha inchi oil (SIO) microemulsions for food and cosmetic applications. Effects of non-ionic surfactants, short-chain alcohols, essential oil and straight-chain esters on the phase behavior and formulation of U-type microemulsion were investigated. Pseudo ternary phase diagrams were constructed to assess the influence of these factors using water titration method. Structural transitions were measured along several water dilution lines using conductivity and viscosity tools. Results: Among four different surfactants, Tween 80 solubilized the maximum oil and induced the formation of a U-type microemulsion system. Oil solubilization was decreased in the presence of short-chain alcohols. In addition, system containing straight-chain esters as the cosolvent showed a higher expansion effect in the U-type areas than that containing essential oils. Finally, upon water dilution of three systems with SIO/ethyl acetate (EA) of 1:1, 1:2 and 1:3, microstructural transition from W/O to bicontinuous occurred at 200 g kg-1 (w/w) water content, and then to O/W structure at 650 g kg-1 (w/w) water content. Conclusion: Straight-chain esters as cosolvent is a potential strategy to extend the dilutability of SIO microemulsions. This article is protected by copyright. All rights reserved.
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Reactive oxygen species have been shown to play a role in ultraviolet light (UV)-induced skin carcinogenesis. Vitamin E and green tea polyphenols reduce experimental skin cancers in mice mainly because of their antioxidant properties. Since olive oil has also been reported to be a potent antioxidant, we examined its effect on UVB-induced skin carcinogenesis in hairless mice. Extra-virgin olive oil was applied topically before or after repeated exposure of mice to UVB. The onset of UVB-induced skin tumors was delayed in mice painted with olive oil compared with UVB control mice. However, with increasing numbers of UVB exposures, differences in the mean number of tumors between UVB control mice and mice pretreated with olive oil before UVB exposure (pre-UVB group) were lost. In contrast, mice that received olive oil after UVB exposure (post-UVB group) showed significantly lower numbers of tumors per mouse than those in the UVB control group throughout the experimental period. The mean number of tumors per mouse in the UVB control, pre-UVB and postUVB groups was 7.33, 6.69 and 2.64, respectively, in the first experiment, and 8.53, 9.53 and 3.36 in the second experiment. Camellia oil was also applied, using the same experimental protocol, but did not have a suppressive effect. Immunohistochemical analysis of DNA damage in the form of cyclobutane pyrimidine dimers (CPD), (6‐4) photoproducts and 8-hydroxy-2-deoxyguanosine (8OHdG) in samples taken 30 min after a single exposure of UVB showed no significant difference between UVBirradiated control mice and the pre-UVB group. In the post-UVB group, there were lower levels of 8-OHdG in epidermal nuclei, but the formation of CPD and (6‐4) photoproducts did not differ. Exposure of olive oil to UVB before application abrogated the protective effect on 8OHdG formation. These results indicate that olive oil topically applied after UVB exposure can effectively reduce UVB-induced murine skin tumors, possibly via its antioxidant effects in reducing DNA damage by reactive oxygen species, and that the effective component may be labile to UVB.
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Key Words: Coconut oil; extraction method; phenolic compounds; fatty acidsDOI: 10.4038/josuk.v2i0.2746J Sci.Univ.Kelaniya 2 (2005): 63-72
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Oil extracted from the ripe ackee (Blighia sapida L) aril was characterized by the classical titrimetric and gravimetric analyses following the British Pharmacopoeia (BP) procedures. Dynamic and kinematic viscosities as well as the true density of the lipid were determined. The sample was subjected to instrumental polarimetric and gas chromatographic analyses. In each test, arachis oil (BP) and/or oleic acid was used as reference. The extraction and purification method produced 37.0 ± 4.9%, on dry weight basis, of bright-yellow oil with characteristic roasted ackee scent. Acid, ester, hydroxyl and saponification values were 1.83 (±0.01), 64.52 (±0.18), 28.01 (±0.04) and 743 (±0.19) respectively. Its specific gravity was 0.905 (±0.008) while the optical rotation was 1.453. The gas chromatography showed several well-defined peaks with two peaks at elution times of 15.41min (n-hexane) and 17.44 min (oleics acid). The sample has comparable specific gravity, viscosities and true density values as arachis oil BP. On the other hand, it contains higher levels of saponifiable matters, free acid and hydrolysable matters than arachis oil. The characteristic properties of ackee oil suggest potential for its application as pharmaceutical base and may satisfy some of the deficiencies of arachis and, possibly, some other vegetable oils.
A new method of acid value determination in vegetable oils has been developed. The method is based on (a) simple, rapid and complete extraction of acids from an oil test portion into reagent (0.05 mol dm-3 triethanolamine (B) in the mixture of 50 % H2O + 50 % 2-PrOH) and (b) indirect titration of acids in BH+ form against aqueous alkali in the presence of a phenolphthalein indicator. Suitable metrological parameters of acid value determination have been obtained. The advantages of the method are (i) absence of a toxic solvent, (ii) extraction and titration of acids at room temperature, and (iii) no need for preliminary neutralization of acid admixtures in a solvent.
Sodium ascorbyl phosphate is a hydrophilic derivative of ascorbic acid, which has improved stability arising from its chemical structure. It is used in cosmetic and pharmaceutical preparations since it has many favorable effects in the skin, the most important being antioxidant action. In order to achieve this, it has to be converted into free ascorbic acid by enzymatic degradation in the skin. In the present work, o/w and w/o microemulsions composed of the same ingredients, were selected as carrier systems for topical delivery of sodium ascorbyl phosphate. We showed that sodium ascorbyl phosphate was stable in both types of microemulsion with no significant influence of its location in the carrier system. To obtain liquid microemulsions appropriate for topical application, their viscosity was increased by adding thickening agents. On the basis of rheological characterization, 4.00% (m/m) colloidal silica was chosen as a suitable thickening agent for w/o microemulsions and 0.50% (m/m) xanthan gum for the o/w type. The presence of thickening agent and the location of sodium ascorbyl phosphate in the microemulsion influenced the in vitro drug release profiles. When incorporated in the internal aqueous phase, sustained release profiles were observed. This study confirmed microemulsions as suitable carrier systems for topical application of sodium ascorbyl phosphate.
The role of surfactants in the formation of nanoparticles is due to the compartmentalization offered by host surfactant assemblies. They affect the growth and particle characteristics significantly. The preparation of Cu2S nanoparticles in reverse micelle and CuS in aqueous micellar hosts has been described. It indicates that different surfactant systems can mediate to give different products even though the basic chemistry is the same.
It was proposed that negative interfacial tension due to high film pressure is responsible for the formation of micro emulsions. It now appears that the initial, negative interfacial tension γφ in mixed films of soap and long-chain alcohols is the result not so much of a high initial film pressure as of a large depression of the interfacial tension (γo/w)a between the water and the oil phase with its adsorbed alcohol monolayer in accordance with the equation γφ  (γo/w)a  π. This depression is brought about by the spontaneous distribution of alcohol between the interface and the oil phase. It is pointed out that this distribution is dependent upon the initial chemical potential of the particular alcohol in the given oil and that it may vary within wide limits. The fraction of the alcohol that remains in the oil phase is available to depress the oil/water interfacial tension while the remainder of it forms a mixed film with emulsifier adsorbed from the water phase. It is submitted that the interaction of coulombic, hydrogen bonding and van der Waals forces among the heads and tails of the tenants of this film develops an initial pressure gradient across the flat interface which generates the initial film pressure . Three stages of pressure development are postulated, the maximum pressure corresponding to an intermediate concentration of alcohol. Hypothetical plots of (γo/w)a and as ordinates versus concentration of alcohol as abscissa provide a graphical characterization of the process of microemulsification.
This volume covers raw materials for coatings (e.g. resins, solvents, pigments) and compares their relative merits and limitations. It deals with the chemistry of polymers, polymerization reactions, rheology of coatings, rheology, surface tension, colloids, film formation, solution and dispersed thermoplastic polymers, latexes, amino resins, acrylic resins, drying oils, alkyd resins, epoxy and phenolic resins etc. Color and gloss of coatings are very important properties of coatings which are discussed in two chapters. Characteristics of pigments are presented in depth in the final chapter. Chapter XV (Solvent Properties) should be of special interest to the readership of this journal. During application and film formation the solvents from coatings must evaporate. The rate of evaporation affects the appearance as well as properties of the fired film. Evaporation of single as well as mixtures of solvents is discussed in thermodynamic terms. Effects of viscosity and flammability are also discussed.