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07- LALY


									                  Qomariah, The comparison of hydration effect of 1% Aloe Vera extract cream and 10% urea cream
Berkala Ilmu Kedokteran
Vol. 41, No. 2, Juni 2009: 101-107

The comparison of hydration effect of 1%
Aloe Vera extract cream and 10% urea
cream as moisturizer for non dermatotic skin
        Laily Noor Qomariah, Sunardi Radiono, Fajar Waskito
        Department of Dermatovenereology
        Faculty of Medicine, Gadjah Mada University/Dr. Sardjito Hospital Yogyakarta

        Laily Noor Qomariah, Sunardi Radiono, Fajar Waskito- The comparison of hydration effect of 1% Aloe
        Vera extract cream and 10% urea cream as moisturizer for non dermatotic skin

        Background: Xerotic or dry skin is a condition with manifestation of scaly, coarse skin with itchy sensation.
        Moisturizers have been used as treatment to alleviate xerotic skin. Aloe vera is a traditional medicinal
        plant which has been used as skin moisturizer for a long time, however, the hydration effect of this
        material had not been studied. Urea is a humectant material that has been widely used as moisturizer.
        Objective: This study was aimed to compare the hydration effects of 1% Aloe vera extract cream with
        10% urea cream as moisturizer for non-dermatotic dry skin.
        Methods: This research was a single-blinded randomized controlled trial. Thirty research subjects who met
        inclusion criteria were given 2 types of interventions (1% Aloe vera extract cream or 10% urea cream).
        Randomization was conducted to determine which cream was applied on the subject’s lower arm. Cream
        was given as a single application. Evaluation of stratum corneum hydration level was conducted objectively
        using corneometer instrument : before application, 30 minutes, 1 hour, 2 hours, 3 hours and 4 hours after
        single application. Data of the two groups were analyzed with paired t-test.
        Results: There was no significant difference of stratum corneum hydration level between 1% Aloe
        vera extract cream treatment and 10% urea cream at each time of measurement (p > 0.05).
        Conclusion: 1% Aloe vera extract cream showed similar or equivalent hydration effect with 10% urea
        cream as moisturizer for non-dermatotic dry skin.

        Key words: aloe vera - urea - skin moisturizer - skin hydration.

        Laily Noor Qomariah, Sunardi Radiono, Fajar Waskito - Perbandingan efek hidrasi dari krim ekstrak Aloe
        Vera 1% dengan krim urea 10% sebagai pelembab pada kulit kering non-dermatotik

        Latar belakang: Kulit kering adalah keadaan kulit dengan manifestasi berupa kulit bersisik, teraba kasar
        serta rasa gatal. Penggunaan pelembab merupakan salah satu cara untuk mengatasi gejala tersebut. Aloe
        vera adalah salah satu tanaman obat tradisional yang telah lama digunakan sebagai pelembab kulit, namun
        belum pernah diteliti efek hidrasi bahan tersebut. Urea adalah bahan humektan yang digunakan sebagai
        Tujuan: Penelitian ini bertujuan untuk membandingkan efek hidrasi krim ekstrak Aloe vera 1% dengan krim
        urea 10% sebagai pelembab pada kulit kering non-dermatotik
        Metode: Tiga puluh subyek penelitian yang memenuhi kriteria mendapat 2 macam intervensi (krim ekstrak
        Aloe vera 1% atau krim urea 10%). Randomisasi dilakukan untuk menentukan pemakaian krim pada salah
        satu bagian lengan bawah subyek. Pemakaian krim dilakukan sebanyak satu kali (single application).
        Evaluasi dilakukan secara obyektif terhadap hidrasi stratum korneum pada jam ke-0 (sebelum perlakuan),
        30 menit, 1 jam, 2 jam, 3 jam dan 4 jam setelah pemakaian tunggal dengan menggunakan alat korneometer.
        Data hasil pengukuran obyektif antara kedua kelompok dianalisis dengan menggunakan uji paired t-test.
        Hasil: Tidak terdapat perbedaan bermakna antara hidrasi stratum korneum krim ekstrak Aloe vera 1%
        dibanding krim urea 10% pada tiap waktu pengukuran (p > 0,05).
        Simpulan: Krim ekstrak Aloe vera 1% mempunyai efek hidrasi sama atau setara dengan krim urea 10%
        sebagai pelembab pada kulit kering non-dermatotik.

Laily Noor Qomariah, Department of Dermatovenereology, Faculty of Medicine,
Gadjah Mada University/Dr. Sardjito Hospital Yogyakarta

Berkala Ilmu Kedokteran, Volume 41, No. 2, Juni 2009: 101-107

INTRODUCTION                                               were from plants.17 One of the traditional remedy
                                                           plants which had been examined clinically is Aloe
     Skin is the outer layer of the body that serves
                                                           vera. Aloe vera is used traditionally as hair fertilizer,
as a barrier against all forms of trauma, and it also
                                                           wound healing remedy, and skin treatment. 17
covers the body with an aesthetic value, as the skin
looks smooth, soft and shiny.1 However, in certain         Various studies in dermatology had shown its
circumstances, the skin looks dry, coarse and scaly        potential in wound healing, psoriasis, radiation and
that makes it looks dull and uninteresting.2               seborrhoic dermatitis.18,19,20 Aloe vera contains
     Dry skin is a problem that has become a               mono- and polysaccharides, amino acids (histidin,
common complaint of many people, especially                arginin, treonin, serin, glisin and alanin) and vitamins
women. Several factors considered to have                  that act as moisturizer.21 Some side effects had been
influence on dry skin condition including disease,         reported, such as eczema and allergic dermatitis.20, 22
age, gender, and environment.3                                  The skin humidity is determined by the amount
     Clinically, xerotic or dry skin is defined as scaly   of water contained in stratum corneum and
and coarse skin, with itching that disturbs daily          hydrolipid layer, and the loss of fluid through the
activities.4 Dry skin is caused by the decrease in         skin (TEWL). 23 It can be measured with a
skin barrier function, so that water evaporation is        corneometer and tewameter.24 In some studies,
easily happened on the epidermis, known as                 various methods were used for the evaluation and
transepidermal water loss (TEWL), and the                  the measurement of TEWL on stratum corneum
decrease in skin hydration.5 One of the efforts to         hydration after moisturizer usage. Short-term effect
prevent dry skin is using a moisturizer.6                  can be measured at 1 hour, 2 hours, 3 hours and 6
     Moisturizer is used as a therapy to improve           hours after a single application, whereas the long-
dry skin condition by increasing stratum corneum           term effect can be measured on the last 10-15 hours
hydration level. Substances that contained in              after 2 times a day usage in the first week until the
moisturizer are able to prevent water evaporation          fourth week.21,25 Moisturizer evaluation is also
(occlusive) or increase water absorption                   influenced by the skin locations.26 So far there are
(humectant).5,7,8 Moisturizer is a substance applied       no reports that compare the hydration effects of
to increase and/or maintain water in the stratum           1% Aloe vera extract cream with 10% urea cream
corneum.7,9 Almost all people use moisturizer every        as moisturizer on xerotic non-dermatotic skin.
day, and it is one of the most popular products                 The aim of this satudy was to compare the
available in the market.10 There are various form          hydration effect of 1% Aloe vera extract cream
of moisturizers marketed as cosmetics or as                with 10% urea cream as moisturizer for xerotic
remedies with the goal to overcome skin                    non-dermatotic skin. Hopefully this research could
dryness.4,11,12 The most popular form of moisturizer
                                                           help community in obtaining alternative material to
is in the form of cream and lotion. To achieve
                                                           be used as skin moisturizer, if proven that 1% Aloe
maximum efficacy, moisturizer should be used right
                                                           vera extract cream gives better hydration
after taking a bath, and can be added as needed,
                                                           compared to 10% urea cream.
especially in the area of the body that is often dry.13
     Urea is an organic chemical compound that
has been long and widely used as a moisturizer and         METHODS
its nature is universal.3,14 Urea has humectant
nature, so its effect depends on skin hydration.13,15           The study comprised thirty subjects (18 women
Application of 10% urea cream for 3 weeks can              and 12 men) with the age of 20-50 years old. This
improve the function of the skin barrier, and it is        research was a single-blinded randomized controlled
not toxic to the skin.16 There are some reports of         clinical trial, with xerotic non-dermatotic skin
local unpleasant skin sensation such as redness,           population as subjects (based on corneometer
irritation and pain at the place of urea cream             measurement with < 45 value). Subject recruitment
application.3                                              was conducted in Dr. Sardjito Hospital Yogyakarta
     History has proven that many drugs have been          in November 2008. The inclusion criteria included:
derived from traditional remedies, and most of them        (1) male/female with xerotic skin based on dry skin

                 Qomariah, The comparison of hydration effect of 1% Aloe Vera extract cream and 10% urea cream

measurement using corneometer with < 45                   measurement (baseline data) was conducted to
capacitance value, (2) willing to stop any cream,         obtain the initial level of skin dryness objectively.
lotion, moisturizer or other skin product application     Objective measurements of the stratum corneum
on the lower arm during the research, (3) filling         humidity or skin hydration were performed by
and signing and the research consent form.                researchers. Measurements were conducted on the
Exclusion criteria included: (1) pregnant,                volar side of the lower arm and the application site
breastfeeding or using hormonal contraceptive             was marked using marker pen. Each measurement
method, (2) allergic history to any of the cream          was performed 3 times.
components; (3) having acute skin disease or visible           During the research period, both lower arms
skin disease on the area of research; (4) atopic          of the subject were drenched using aquadest and
history; (5) having other chronic diseases, such as       then dried. 1% Aloe vera extract cream and 10%
diabetes mellitus and chronic renal failure; (6) still    urea cream were applied on one of the lower arms
included in other clinical research.
                                                          that had been divided into 5 boxes with the size of
     Two types of moisturizers were used in this
                                                          3 x 3 cm2 each. Cream was applied once within
research, they were, 1% Aloe vera extract cream
                                                          each box, in the amount of 0.09 grams cream A
and 10% urea cream. Aloe vera extract cream
                                                          (1% Aloe vera extract cream) or cream B (10%
was made by adding Aloe vera extract (TerrapureTM
organic non-preserved, decolorized, freeze-dried          urea cream). Cream was applied on the lower arm
Aloe vera powder, Terry Laboratories Inc) into            randomly and balanced. Both creams were stored
vehiculum. Meanwhile, 10% urea cream medium               in the container with the same shape, color and
was made by adding urea crystal into vehiculum.           weight, so subjects could not distinguished them.
Biocream® is used as the vehiculum. The cream                  Variables measured objectively at 0 hour
was made at the Faculty of Pharmacy GMU                   (before treatment), 30 minutes, 1 hour, 2 hours, 3
Yogyakarta. Corneometer CM 820 from Courage               hours and 4 hours after single application.
& Khazaka, Kohn, Germany was used as the                  Measurements were conducted in the same room
measuring tool.                                           at the same time, with the optimal conditions at 20ºC
     Subjects who met the inclusion and exclusion         and 40-60% relative humidity. Acclimatization was
criteria and signed research consent forms were           conducted before measurements carried out.
asked to fill the data subject questionnaire. During      Subjects took rest approximately 10-20 minutes, and
the research, and 2 weeks before the research,            air conditioning (AC) was turn on 2 hours before
subjects were not permitted to use any moisturizer        the measurement. During research, subject did
or other products on both lower arms. First               normal activities.

Berkala Ilmu Kedokteran, Volume 41, No. 2, Juni 2009: 101-107

      Statistical analysis of the subjects characte-          and cream B. The data indicated that there was a
ristic data and average stratum corneum hydration             higher increase in stratum corneum hydration value
value was conducted. Descriptive analysis was                 in group given cream A than that in group given
conducted on the subject characteristic data, as both         cream B at 30 minutes up to 2 hours after single
types of intervention was conducted in the same               application, and then the values were decreased.
individual. The average stratum corneum hydration             After the data was analyzed, there was no significant
values was generated as numerical data. Hydration             difference between average stratum corneum
value data analysis was performed using paired t-             hydration values at each measurement time (p >
test. Level of significance was p < 0.05 (95% CI =            0.05).
95% confidence interval).                                          The result indicated that 30 minutes after single
                                                              application, both creams showed hydration effect.
RESULTS                                                       Maximum hydration effect of cream A and cream
    TABLE 1 shows statistical analysis on average             B could be seen in 2 hours, and decreased in 3 and
hydration values on both lower arms of the subjects           4 hours after single application. The side effects of
before and after the single application of cream A            both creams could not be assessed.

        TABLE 1. Comparison of average stratum corneum hydration values of groups given cream A and cream B

    TABLE 2 and TABLE 3 indicated that there                  after single application, and then the values were
was an increase in average stratum corneum                    decreased. The increased average hydration value
hydration values of groups given both creams                  was significant at each measurement time (p <0.05).
compared to baseline at 30 minutes until 2 hours

                TABLE 2. Average stratum corneum hydration value of groups given cream A and baseline

                TABLE 3. Average stratum corneum hydration value of groups given cream B and baseline

                  Qomariah, The comparison of hydration effect of 1% Aloe Vera extract cream and 10% urea cream

DISCUSSION                                                 vera is also a humectant material with hygroscopic
                                                           nature which increases water retention on stratum
     Stratum corneum contains 10-20% water in
                                                           corneum.21 In this study, cream A (1% Aloe vera
the optimal environmental conditions, but moisturizer
                                                           extract cream) gave similar hydration effect with
usage every day will increase it. If the stratum
                                                           cream B (10% urea cream) (p > 0.05). This may
corneum hydration level is more than the normal
                                                           be due to the mono- and polysaccharide and also
level, its function as skin barrier will be decreased.10
                                                           the amino acids (histidin, arginin, treonin, serine,
     Moisturizer is often used to alleviate dry skin
and irritated skin. Skin barrier function repair using     glisin and alanin) contained by Aloe vera were
moisturizer is one of the basic therapies for dry          hygroscopic, so they could increase water retention
skin.10,13 Skin dryness could cause the increase in        in the stratum corneum. Aloe vera also contains
skin vulnerability together with the increase in           several vitamins such as vitamin A, C and E, which
exposure to water, detergent or other irritative           is an additional component in the moisturizer.21
materials. Moisturizer is also a common product                  Amino acid is one of natural moisturizer factor
used in normal skin with cosmetic reasons, or in           (NMF) components. There is a group of components
subjective dry skin condition.8                            that is reported controlling stratum corneum hydration,
     There are various ways to examine dry skin,           known as NMF. NMF contains a mixture of amino
among them is clinical examination with a visual analog    acids, amino acid derivatives, and salt. Ten percent of
scale/VAS, surface microscopy, skin surface                stratum corneum dry weight consists of NMF. Skin
photography, scanning electron microscopy, skin            that can not produce NMF will be dry and easily
surface biopsy, profilometry, the actual hydration         broken so that NMF plays an important role in the
measurement using corneometer and TEWL using               skin hydration.29
evaporimeter or tewameter. Assessment on                         Vitamins A, C and E contained in Aloe vera can
moisturizer materials can be conducted with those          act as antioxidants, bind oxygen radicals that can
manners.24 This research assessed the comparative          damage the dermis structure. Vitamin C is a hydrophilic
hydration effects of 1% Aloe vera extract cream and        compound that can act as antioxidants, or as oxidant
10% urea cream by measuring the skin humidity or           if combined with iron. The topical use of vitamin C
skin hydration using corneometer. Corneometer was          can protect the skin from UVA- and UVB-induced
used to determine the stratum corneum capacitance          phototoxic reaction. Therefore, Aloe vera might be
value and suggest the stratum corneum relative             able to act as a broad spectrum photoprotectant by
hydration value.27                                         increasing vitamin C level on the skin. This material
     Skin hydration and TEWL are measured to find          can also prevent cell damage, thus it may prevent
out the effect of a moisturizer. If we want to             dehydration. Vitamin C prevents early aging process,
investigate the hydration effect of a moisturizer,         so it also can be used indirectly for skin hydration.29
measurement is based on the electrical conductance               The hydration effect of moisturizer can be
on the skin. Increased skin hydration may occur            evaluated by observing through the short-term effects
due to hydrating properties such as natural                of single application or long-term effects with repeated
moisturizing factors (NMF) or humectant that can           usage. On single application, most moisturizers produce
bind water, and because of the lipid components            improvement in skin hydration immediately after the
occlusive nature. Meanwhile, the value of TEWL             application with the maximum level of hydration
emphasizes whether a product has a protective              between the first 30-90 minutes, and then
function on stratum corneum, thus evaporation is           decreasing.26 Studies conducted to know the effect
reduced. Therefore, TEWL values better reflect             of single moisturizer application on the skin indicated
the damage on stratum corneum that play role as            that there was an evaporating phase (less than 15
skin barrier or skin protection.28                         minutes), and then continued with lipidization phase
     Urea is an active moisturizer material that has       when the lipid in the moisturizer penetrated the
humectant nature. Its hygroscopic nature and ability       epidermis and increased skin hydration.30 This research
on denaturing protein played as the underlying             proved that hydration effect was showed 30 minutes
mechanisms for urea moisturizing property.3 Aloe           after the second single cream application. Maximum

Berkala Ilmu Kedokteran, Volume 41, No. 2, Juni 2009: 101-107

hydration effect was found at 2 hours after single           to do for the researchers or the subjects, because the
application, and then decreased until 4 hours after          areas in this study was very small, each box sized
single application.                                          only 3x3 cm2, so it was impossible to evaluate clinically
      Dal Belo research (2006) compared 0.10%,               using VAS measurement. TEWL measurement using
0.25% and 0.5% Aloe vera extract cream in single             tewameter in this research could not be used, either,
application to give hydration effect, and after 1 hour,      due to damage of the device.
only 0.25% and 0.5% concentration produced
significant hydration effect, so this research used 1%       CONCLUSION AND SUGGESTION
Aloe vera extract to assess the hydration effect of
single application. While 10% urea concentration was              Based on the results of this research, it can be
normally used as moisturizer. 31 This was the                concluded that 1% Aloe vera extract cream had
benchmark for 10% urea concentration used in this            similar or equivalent hydration effect with 10% urea
research.                                                    cream as moisturizer for non-dermatotic skin.
      Research by Serup et al. (1998) showed that the        Further research is needed on the 1% Aloe vera
repeated use of moisturizer would increase the               extract cream as moisturizer with different research
hydration effect after 2 day therapy, and then the           design, repetitive application frequency, longer
hydration was decreased 7 days after termination of          duration of therapy and subjective (using VAS) and
therapy. Previous research by Agner and Held (2001)          objective (using tewameter and corneo-meter)
showed that the hydration level increased after 3-5          moisturizer effect evaluation.
days of usage. These different results were possibly
because of the difference in frequency and duration
of therapy.
      Urea side effects, such as irritation and burning      1.  Johnson AW. Overview : Fundamental skin care-protecting
                                                                 the barrier. Dermatol Ther 2004; vol 17: 1-5
sensation on the skin, will increase along with the          2. Harding CR. The stratum corneum: structure and function
increasing concentration.3, 16, 31 Meanwhile, the side           in health and disease. Dermatol Ther 2004;31:1015-21
effects of Aloe vera are very rarely found, although         3. Loden M. Moisturizer. In: Elsner P, Maibach HI,
there were some researches reporting the incidence               Cosmeceuticals, Drugs vs. Cosmetics. New York : Marcel
                                                                 Dekker, Inc., 2000; chap. 7:73-96
of eczema in hypersensitive patients after using Aloe
                                                             4. Centurion SA. Moisturizer. 2002. http//www.eMedicine.
vera cream.20,22 In this study, side effects of both cream       com. Diakses 7/09/2006.
could not be assessed, due to the concentrations used        5. Shai A, Maibach HI, Baran R. Skin moisturizer and
in this study were in the normal limit and the duration          moisturizer. Handbook of Cosmetic Skin Care. London:
was only for 4 hours, so that the side effects of both           Martin Dunitz, 2001.
                                                             6. Giacomoni PU, Muizzuddin N, Sparacio RM, Pelle E,
creams were not observed.                                        Mammone T, Marenus K, Maes D. Sensitive skin and
      Limitations of this research was that it did not           moisturization. J Toxicol-Cut & Ocular Toxicol
measure the vehiculum, so that the effects of                    2002;21;(3):245-54.
vehiculum itself, without the addition of Aloe vera          7. Engasser PG, Maibach HI. Cosmetics and skin care in
                                                                 dermatologic practice. In: Freedberg IM, Eisen AZ, Wolff
extract nor urea, on skin hydration could not be
                                                                 K, et al. Fitzpatrick‘s Dermatology in General Medicine.
elucidated. Vehiculum used in this research was                  6th edition, vol.1.Berlin : McGraw Hill, 2003;2369-79.
Biocream®, an ambiphillic cream that could be mixed          8. Zhai H, Maibach HI. Moisturizer in preventing irritant
with water, other components that dissolves in water,            contact dermatitis: an overview. Contact Dermatitis
fat, and other components that dissolve in fat without           1998;38:241-44.
                                                             9. Madison KC. Barrier function of the skin. “La raison d`ntre”
disrupting its stability. It could be assumed that there         of epidermis. J Invest Dermatol 2003;121:231-41.
was no meaningful differences in the result of this          10. Held E. So moisturizer may cause trouble. Int J Dermatol
research between 1% Aloe vera extract cream and                  2001;40:12-13.
10% urea cream, because the vehiculum added was              11. Idson B. Moisturizer, emollient and bath oils. Principles of
                                                                 Cosmetics for the Dermatologist. St Louis: The CV Morsby
similar in both creams.
                                                                 Co., 1982.
      This research also did not measure the value of        12. Loden M. The clinical benefit of moisturizers. JEADV
VAS and TEWL. Clinical evaluation was very difficult             2005;19:672-88.

                     Qomariah, The comparison of hydration effect of 1% Aloe Vera extract cream and 10% urea cream

13. Barel AO, Clarys P, Gabard B. In vivo evaluation of the                vivo pharmachokinetics using microdialysis and noninvasive
    hydration state of the skin: Measurements and methods                  quantification of barrier function. Br J Dermatol
    for claim support. In : Elsner P, Merk HF, Maibach HI,                 1999;140:739-48.
    Cosmetic Controlled Efficacy Studies & Regulation. Berlin:       24.   Boyce JM, Kelliher S, Vallande N. Skin Irritation and
    Springer-Verlag, 1999;chap.5:57-77.                                    Dryness Assosiated With Two Hand-Hygiene Regimen:
14. Koestriana H, Handoko RP. Penggunaan urea dalam                        Soap-and-Water Hand Washing Versus Hands Antisepsis
    dermatologi. Media Dermato Venereologi Indonesia                       With and Alcoholic Hand Gel. Infect Control Hosp
    1992;XIX/52:30-33                                                      Epidemiol 2000;21:442-48.
15. Kuzmina N, Hagströmer L, Emtestam L. Urea and sodium             25.   Hagstromer L, Kuzmina N, Lapins J, Talme T, Emtestam.
    chloride in moisturizer for skin of the elderly-a comparative,         Biophysical assessment of atopic dermatitis skin and effects
    double-blind, randomized study. Skin Pharmacol App Skin                of a moisturizer. Clin Exp Dermatol 2006;31:271-77.
    Physiol 2002;15:166-74.                                          26.   Wilhelm KP. Possible pitfalls in hydration measurement.
16. Serup J. A three-hour test for rapid comparison of effects             In: Elsner P, Barel AO, Berardesca E, Gabard B, Serup J,
    of moisturizers and active constituents (urea). Acta Derm              editors. Skin Bioengineering techniques and apllications in
    Venereol Suppl (Stockh) 1992;suppl. 177:29-33.                         dermatology and cosmetology. Karger, 1998;vol 26, p 235-
17. Furnawanthi I. Khasiat dan manfaat lidah buaya si tanaman              43.
    ajaib. Jakarta: Penerbit PT AgroMedia Pustaka, 2002.             27.   Rudolph R, Kownatzki E. Corneometric, sebumetric and
18. Eshun K, He Q. Aloe vera: a valuable ingredient for the                TEWL measurement following the cleaning of atipoc skin
    food, pharmaceutical and cosmetic industries – a review.               with a urea emultion versus a detergent cleanser. Contact
    Crit Rev Food Sci Nutrition 2004;44(2):91-96.                          Dermatitis 2004;50;354-58.
19. Laksmintari P. Efikasi terapi herbal krim ekstrak gel aloe       28.   Derde K, Paule M, Diane R, Verra R. Claim substantination
    vera lokal 0,5% pada penderita psoriasis vulgaris di RS Dr             and efficacy of hydrating body lotion and protective agent.
    Sardjito Yogyakarta, Tesis. Yogyakarta: Universitas Gadjah             Contact Dermatitis 2000;42:227-34.
    Mada, 2002.                                                      29.   Draelos ZD. Moisturizer. Dalam : Cosmetics in Dermato-
20. Reynolds T, Dweek AC. Aloe vera leaf gel: a review update.             logy, 2nd edition, Churchill Livingstone, 1995:p 83-93.
    J Ethnopharmacol 1999;68:3-37.                                   30.   Hildebrandt D, Ziegler K, Wollina U. Electrical impedance
21. Dal'Belo SE, Gaspar LR, Maia Campos PM. Moisturizing                   and transepidermal water loss of healty human skin under
    effect of cosmetic formulations containing Aloe vera extract           different conditions. Skin Research and Technology 1998,
    in different concentrations assessed by skin bioengineering            130-34.
    techniques. Skin Res Technol 2002;12:241-46.                     31.   Couteau C, Colffard LJM, Sebile R. Influence of excipients
22. Hogan DJ. Widespread dermatitis after topikal treatment                on moisturizing effect of urea. Drug development and
    of chronic leg ulcer and stasis dermatitis. Can Med Assoc J            Industrial Pharmacy 2006;32:239-42.
    1988;138;336-38 (abs).                                           32.   Serup J, Winther A, Blichmann CW, cit Held E, Agner T.
23. Benfeldt E, Serup J, Menne T. Effect of barrier pertubation            Effect of moisturizers on suseptibility to irritants. Acta
    on cutaneous salicyclic acid penetration in human skin: in             Derm Venereol 2001;81:104-07.


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