Effect of natural sunflower oil and its components on the skin permeability to water and some drugs

Abstract

Objective: To investigate the effect of natural oils and their components on the water permeability and marker molecules of stratum corneum either when intact or after exposure to mechanical stress. Methods: Full thickness porcine skin was used. The subcutaneous fat was removed with a scalpel. The remaining tissue was dermatomed. A validated tape-stripping procedure was used to induce skin damage. Tritiated water coupled with a scintillation counter was used for measuring the water permeability of skin, caffeine as hydrophilic molecule and testosterone as hydrophobic one. Results: Mean flux values for permeation of tritiated water versus time were monitored for intact and stripped skin treated with the oils and for untreated controls shows reduction of water permeability and retain skin barrier function for stripped skin, on the other hand all tested oils increases the reflux of caffeine and testosterone for both intact and stripped skin. Conclusions: Both sunflower oil and its main components, oleic acid and linoleic acid, significantly decreased the permeability of skin to water. For the damaged skin the oils were effective in reducing the flux to values lower than intact skin. No significant differences between sunflower oil and its components were found to exist, the implication being that either the natural sunflower oil or its components could be employed in skin products.

Full text

Research Article
EFFECT OF NATURAL SUNFLOWER OIL AND ITS COMPONENTS ON THE SKIN PERMEABILITY
TO WATER AND SOME DRUGS
HASSAN M. GHONAIM*1,2, MASSIMO G. NORO3, AND JAMSHED ANWAR1,4
1Computational Chemistry Laboratory, Institute of Life Sciences Research, University of Bradford, Bradford, W. Yorkshire BD7 1DP U.K.,
2Department of Pharmaceutics, Faculty of Pharmacy, Suez Canal University, Ismailia, Egypt, 3Physical and Chemical Insights Group,
Unilever Port Sunlight, U.K., 4Dept of Chemistry, Lancaster University, Bailrigg, Lancaster, LA1 4YB, UK.
Email: hassan_ghonaim@pharm.suez.edu.eg
Received: 16 Dec 2013, Revised and Accepted: 11 Feb 2014
ABSTRACT
Objective: To investigate the effect of natural oils and their components on the water permeability and marker molecules of stratum corneum
either when intact or after exposure to mechanical stress.
Methods: Full thickness porcine skin was used. The subcutaneous fat was removed with a scalpel. The remaining tissue was dermatomed. A
validated tape-stripping procedure was used to induce skin damage. Tritiated water coupled with a scintillation counter was used for measuring the
water permeability of skin, caffeine as hydrophilic molecule and testosterone as hydrophobic one.
Results: Mean flux values for permeation of tritiated water versus time were monitored for intact and stripped skin treated with the oils and for
untreated controls shows reduction of water permeability and retain skin barrier function for stripped skin, on the other hand all tested oils
increases the reflux of caffeine and testosterone for both intact and stripped skin.
Conclusions: Both sunflower oil and its main components, oleic acid and linoleic acid, significantly decreased the permeability of skin to water. For
the damaged skin the oils were effective in reducing the flux to values lower than intact skin. No significant differences be tween sunflower oil and
its components were found to exist, the implication being that either the natural sunflower oil or its components could be employed in skin
products.
Keywords: Stratum corneum, Sunflower oil, Oleic acid, Linoleic acid, Tritiated water
INTRODUCTION
Water permeation is considered to be a good indicator of potential
changes in the barrier integrity of skin. For this reason, and
because tritiated water is one of the most frequently used probes
for permeability experiments in general, we considered it to be
suitable for evaluating the efficacy of the oils [1,2]. The hypothesis
tested being do the oils ‘heal’ the stratum corneum and restore the
water barrier function [3]. To investigate the effect of natural oils
and their components on the water and marker molecules
permeability of stratum corneum either when intact or after
exposure to mechanical stress[4]. Water permeation is considered
to be a good indicator of potential changes in the barrier integrity
of skin. For this reason, and because tritiated water is one of the
most frequently used probes for permeability experiments in
general, we considered it to be suitable for evaluating the efficacy
of oils [5].Marker molecules (hydrophilic and lipophilic) also have
been tested to measure the permeability of intact and injured skin
[6-8].The hypothesis tested being do the oils ‘heal’ the stratum
corneum and restore the water barrier.
METHODS AND MATERIALS
Materials
- Franz cells, permegear (USA) for diffusion through the skin
- Scintillation counter (Perkin Elmer's)and Tritiated water
(Perkin Elmer's)for measuring water permeability of skin
tissues.
- Caffeine, testosterone, oleic, conjugated linoleic and monoolein,
Sigma Aldrich, UK.
- Zimmer air dermatome (USA)
Methods
Methods have been developed for the exsiccated skin to introduce
mechanical stress by the use of tape stripping to view of
investigating the effect of the oils on damaged skin tissues.
Skin Tissue preparation
Full thickness porcine skin was obtained from a local
slaughterhouse. The skin was cleaned carefully under cold running
water. The subcutaneous fat was removed with a scalpel. The
remaining tissue was dermatomed to a thickness of ~750 μm using
Zimmer dermatome then cut into 2 cm ×2 cm pieces. Finally, the skin
samples were washed under cold running water, dried and sealed in
plastic bags at -20°C until used[9].
Application of oils
Skin samples (about 2.7×2.7 cm2) were soaked by sunflower oil,
oleic acid and linoleic acid for 1, 8 or 24 hours then wiped with soft
tissue prior to run the permeation experiment. A control experiment
was also conducted using an untreated skin pieces.
SC tape-stripping
A validated tape-stripping procedure was used to mechanical
damage to the skin by removing top layers.
Pieces of 2.7×2.7 cm square tapes were prepared using transparent
Scotch® No.845 Book Tapes (3M Media, Broken, Germany). To
delimit a fixed area for tape stripping, a 5×5 cm square mask was
prepared with a cut central aperture of 2 cm in diameter. A strip of
adhesive tape was pressed firmly onto the skin surface, and then
removed in a single movement. The direction of stripping was
changed with each tape to ensure a more uniform removal of the SC
with fewer tape-strips. Then, given that the area stripped is kept at
known, constant value[9,10].
Water permeability studies using Tritiated water
By using Franz cells 10 μL of tritiated water was applied to the
epidermal skin surface of the donor compartment to examine the skin
water barrier function and for the next 5 hours. Tritiated water
coupled with a scintillation counter were used for measuring the
water permeability of skin tissues after 1, 8 and 24 hours exposure to
sunflower oil, oleic acid, and linoleic acid by using of Franz cells.
Buffer/tritiated water was collected from the acceptor chambers at 1
International Journal of Pharmacy and Pharmaceutical Sciences
ISSN- 0975-1491 Vol 6, Suppl 1, 2014
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Int J Pharm Pharm Sci, Vol 6, Suppl 2, 630-636
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hour intervals for a total of 5 hours and counted in a liquid scintillation
counter. The data collected and analysed using excels sheets.
Permeation studies for oils:
The permeability studies of the skin to caffeine (hydrophilic drug)
testosterone (hydrophobic drug) were investigated by means of
Franz type diffusion cells (diffusion area of 1.00 cm2, donor
compartment 2 ml and receptor compartment 8 ml. The
dermatomed skin were mounted in the diffusion cells and hydrated
with sodium citrate buffer (pH 5.5) for caffeine and PBS (pH 7.4) for
testosterone for prior to the experiment. The diffusion cells were
placed in a hot plate with the temperature being maintained at 32 C
throughout the experiment.
The donor compartment was filled with 1.5 ml of caffeine solution in
citrate buffer (pH 5.5) at a 25 mg/ml or 1.5 ml of testosterone
solution in PBS (pH 7.4) at a 2.0 mg/ml concentration. The receptor
compartment was completely filled with the respective buffer (8 ml)
and gently stirred using a magnetic stirrer throughout the
experiment. The donor compartment was covered with a paraffin
film to avoid evaporation of the solution. Sample fractions were
collected from the receptor compartment at 1 hour intervals for 5
hours. The total volume of the receptor compartment was
maintained by replenishing with fresh buffer. The amount of drug
permeated through the model membrane was determined by UV
analysis in standard quartz cells after suitable dilution using a
Perkin Elmer UV-Vis spectrometer at 273 nm for caffeine and 250
nm after suitable dilution. A control experiment was also conducted
using an untreated skin.
RESULTS AND DISCUSSION
Water permeability studies
Mean flux values for permeation of tritiated water versus time were
monitored for intact and stripped skin treated with the oils and for
untreated controls (Figures 1-7).
Fig. 1: Standard calibration plot of tritiated water with scentillation counter.
Fig. 2: Effect of oil and oil components on the water permeability through skin after 1hour exposure.

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Fig. 3: Effect of oil and oil components on the water permeability through skin after 8hours exposure.
Fig. 4: Effect of oil and oil components on the water permeability through skin after 24hours exposure.
Fig. 5: Effect of oil and oil components on the water permeability through stripped skin after 1hour exposure.

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Fig. 6: Effect of oil and oil components on the water permeability through stripped skin after 8hours exposure.
Fig. 7: Effect of oil and oil components on the water permeability through stripped skin after 24hours exposure.
The mean steady state fluxes (1–5 h) for tritiated water (average of
three exposure times, 1, 8 and 24 hours ) showed that the oils
significantly reduced the water flux values from 111.65 μl/cm2hr for
the untreated intact skin to 102.99 μL/cm2hr for sunflower oil, 103.38
μL/cm2hr for oleic acid, and 103.54 μL/cm2hr for linoleic acid. For the
stripped skin (Table 2) the water flux was 117.82 μL/cm2hr, which
reduced to 108.70 μL/cm2hr for sunflower oil, 107.36 μL/cm2hr for
oleic acid, and 107.16 μL/cm2hr for linoleic acid.
Measure the permeability of the stratum corneum to marker molecules as a function of addition of applied oil and oil components.
Caffeine permeability
0
500
1000
1500
2000
2500
3000
3500
0123456
Cumulative amount of caffeine (ug/cm2)
Time (hr)
Skin
Sunflower
Oleic a.
Linoleic a.
Fig. 8: Effect of oil and oil components on the Permeation of caffeine through the excicated porcine skin after 1 hour exposure.

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Fig. 9: Effect of oil and oil components on the Permeation of caffeine through the excicated porcine skin after 8 hours exposure.
Fig. 10: Effect of oil and oil components on the Permeation of caffeine through the excicated porcine skin after 24 hours exposure.
Fig. 11: Effect of oil and oil components on the Permeation of testosterone through the excicated porcine skin after 1 hour exposure.

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Fig. 12: Effect of oil and oil components on the Permeation of testosterone through the excicated porcine skin after 8 hours exposure.
Fig. 13: Effect of oil and oil components on the Permeation of testosterone through the excicated porcine skin after 24 hours exposure.
The mean steady state fluxes (1–5 h) for caffeine (figures 8:11)
showed that the oils significantly increase the caffeine flux
values(average of three exposure times, 1, 8 and 24 hours ) from
187.62μg/cm2hr for the untreated intact skin to 270.29μg/cm2hr for
sunflower oil, 403.22μg/cm2hr for oleic acid, and 262.73μg/cm2hr
for linoleic acid after 1 hour exposure, and 359.15μg/cm2hr and
220.53μg/cm2hr for sunflower oil, 387.67μg/cm2hr and
398.58μg/cm2hr for oleic acid, and 299.98μg/cm2hr and
217.70μg/cm2hr for linoleic acid after 8 and 24 hours exposure
respectively. The oleic acid is the most effective in increasing the
caffeine permeability followed by sunflower oil then oleic acid. The
exposure of skin to oils for 8 hours is much more effective in
increasing the permeability than 1 and 24 hour exposure.
Testosterone permeability
The mean steady state fluxes (1–5 h) for testosterone (figures 11:13)
showed that the oils significantly increase the testosterone flux
values (average of three exposure times, 1, 8 and 24 hours ) from
10.98 μg/cm2hr for the untreated intact skin to 12.67 μg/cm2hr for
sunflower oil, 11.06 μg/cm2hr for oleic acid, and 14.80 μg/cm2hr for
linoleic acid after 1 hour exposure, which increases to 17.36
μg/cm2hr and 17.24 μg/cm2hr for sunflower oil, 15.29 μg/cm2hr and
16.14 μg/cm2hr for oleic acid, and 19.22 μg/cm2hr and 22.45
μg/cm2hr for linoleic acid after 8 and 24 hours exposure
respectively. The linoleic acid is the most effective in increasing the
testosterone permeability followed by sunflower oil then oleic acid.
The exposure of skin to oils for 8 hours is much more effective in
increasing the permeability than 1 hour exposure, while no big
difference between 8 and 24 hours exposure.
CONCLUSIONS
We demonstrated that both sunflower oil and its main components,
oleic acid and linoleic acid, significantly decreased the permeability
of skin to water. For the damaged skin the oils were effective in
reducing the flux to values lower than intact skin. No significant
differences between sunflower oil and its components were found to
exist, the implication being that either the natural sunflower oil or
its components could be employed in skin products. Both sunflower
oil and its main components, oleic acid and linoleic acid, significantly
increased the permeability of skin to caffeine as an example of
hydrophilic drug and testosterone as an example of hydrophobic
drug. For caffeine permeability oleic acid was the most effective then
sunflower oil and linoleic acid with no significant differences
between them were found to exist while for testosterone linoleic
acid was the most effective then sunflower oil and oleic acid with no
significant differences between them were found to exist. The
exposure time for 8 hours is the optimum time for the permeability
of both drugs, the implication being that either the natural sunflower

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oil or its components could be employed in skin products to restore
skin barrier functions.
REFERENCES
1. Marta Machado, Teresa M. Salgado, Jonathan Hadgraft, Majella
E. Lane. The relationship between transepidermal water loss
and skin permeability. Int. J. Pharm. 2010;384: 73-77.
2. Pieter van der,BijlArmorel D.,Jacques Cilliers, Ilse A. Standercet.
Diffusion of Water across Human Skin in the Presence of Two
Barrier Creams, Skin PharmacolAppl Skin Physiol2000;13:
104-110.
3. Darmstadt GL; Mao-Qiang M Chi E; E Chi, SK Saha, VA Ziboh, RE
Black,et al. Impact of topical oils on the skin barrier: possible
implications for neonatal health in developing countries.
actapaediatrica. 2002;91.5:546-554.
4. Joke A. Bouwstra, Maria Ponec. The skin barrier in healthy
and diseased state. Biochim. Biophys. Acta 2006; 1758: 2080-
2095.
5. S. Gattu a H.I. Maibach. Enhanced Absorption through Damaged
Skin: An Overview of the in vitro Human Model. Skin
PharmacolAppl Skin Physiol2010;23: 171-176.
6. Shuji Kitagawa and Hui Li. Effects of Removal of Stratum
Corneum, Delipidization and Addition of Enhancers, Ethanol
and l-Menthol, on Skin Permeation of Benzoic Acid and Its 4-n-
Alkyl Substituents in Excised Guinea Pig Dorsal Skin Chem.
Pharm. Bull. 1999;47(1):44-47.
7. SindyTrauer, Alexa Patzelt, Nina Otberg, Fanny Knorr,
ChristelRozycki, Gabor Balizs, Rolf Büttemeyer, Michael
Linscheid, et al. "Permeation of topically applied caffeine
through human skin - a comparison of in vivo and in vitro data.
Br. J. Clin. Pharmacol. 2009; 68:2:181-186.
8. M. Dias, A. Farinha, J. Hadgraft, J. Pais, C. Toscano. Topical
delivery of caffeine from some commercial formulations. Int. J.
Pharm.1999;182: 41-47.
9. Wu Xiao; Griffin Peter;Price Gareth J.; Guy Richard
H.Preparation and in Vitro Evaluation of Topical Formulations
Based on Polystyrene-poly-2-hydroxyl Methacrylate
Nanoparticles. MolPharm.2009;6.5: 1449-1456.
10. Wu Xiao; Biatry Bruno;CazeneuveColett, Guy Richard H. Drug
Delivery to the Skin from Sub-micron Polymeric Particle
Formulations: Influence of Particle Size and Polymer
Hydrophobicity. Pharm Res.2009;26.8:1995-2001.