Biological and pharmacological activities of squalene and related compounds: potential uses in cosmetic dermatology

Squalene is a triterpene that is an intermediate in the cholesterol biosynthesis pathway. It was so named because of its occurrence in shark liver oil, which contains large quantities and is considered its richest source. However, it is widely distributed in nature, with reasonable amounts found in olive oil, palm oil, wheat-germ oil, amaranth oil, and rice bran oil. Squalene, the main component of skin surface polyunsaturated lipids, shows some advantages for the skin as an emollient and antioxidant, and for hydration and its antitumor activities. It is also used as a material in topically applied vehicles such as lipid emulsions and nanostructured lipid carriers (NLCs). Substances related to squalene, including β-carotene, coenzyme Q10 (ubiquinone) and vitamins A, E, and K, are also included in this review article to introduce their benefits to skin physiology. We summarize investigations performed in previous reports from both in vitro and in vivo models.

Changes in skin barrier function following long-term treatment with moisturizers, a randomized controlled trial

BACKGROUND

Moisturizers are commonly used by patients with dry skin conditions as well as people with healthy skin. Previous studies on short-term treatment have shown that moisturizers can weaken or strengthen skin barrier function and also influence skin barrier recovery. However, knowledge of the effects on skin barrier function of long-term treatment with moisturizers is still scarce.

OBJECTIVES

To investigate the impact of long-term treatment with moisturizers on the barrier function of normal skin, as measured by transepidermal water loss (TEWL) and susceptibility to an irritant, and to relate those effects to the composition of the designed experimental moisturizers.

METHODS

Volunteers (n = 78) were randomized into five groups. Each group treated one volar forearm for 7 weeks with one of the following preparations: (i) one of three simplified creams, containing only a few ingredients in order to minimize the complexity of the system; (ii) a lipid-free gel; (iii) one ordinary cream, containing 5% urea, which has previously been shown to decrease TEWL. The lipids in the simplified creams were either hydrocarbons or vegetable triglyceride oil, and one of them also contained 5% urea. After 7 weeks, treated and control forearms were exposed for 24 h to sodium lauryl sulfate (SLS) using a patch test. TEWL, blood flow and skin capacitance of both SLS-exposed and undamaged skin were evaluated 24 h after removal of patches. Additionally, a 24-h irritancy patch test of all test preparations was performed on 11 volunteers in order to check their possible acute irritancy potential.

RESULTS

Changes were found in the barrier function of normal skin after 7 weeks of treatment with the test preparations. The simplified creams and the lipid-free gel increased TEWL and skin response to SLS, while the ordinary cream had the opposite effect. One of the simplified creams also decreased skin capacitance. All test preparations were shown to be nonirritant, both by short-term irritancy patch test and by measurement of blood flow after long-term treatment.

CONCLUSIONS

Moisturizers influence the skin barrier function of normal skin, as measured by TEWL and susceptibility to SLS. Moreover, the effect on skin barrier function is determined by the composition of the moisturizer. The ingredients which influence the skin barrier function need to be identified, and the mechanism clarified at the molecular level.

Poor correlation between stated and found concentrations of diphenylmethane-4,4'-diisocyanate (4,4'-MDI) in petrolatum patch-test preparations

Diphenylmethane diisocyanate (MDI) is widely used in its polymeric form in the manufacturing of polyurethane products. Previous reports on MDI-related contact allergy have shown a pattern, where patients seem to react to their own MDI-based work material but not to commercial patch-test preparations, which contain 4,4'-MDI. Therefore, we performed chemical analyses of 14 commercial test preparations of 4,4'-MDI obtained from 8 European and 4 American dermatology departments as well as 2 preparations from 2 major European suppliers of patch-test allergens. A new method for monitoring 4,4'-MDI in petrolatum preparations was developed and the determination of 4,4'-MDI as the MDI-dibutylamine derivative using liquid chromatography-mass spectrometry was performed. None of the preparations obtained from the dermatology departments contained more than 12% of the concentration stated on the label. In most cases, 4,4'-MDI content was only a few percentages or less of the concentration stated. 7 of the 14 preparations were analysed before the expiry date. Yet, only 1 of them, a preparation directly obtained from the supplier, came close to the concentration stated on the label. Thus, using these preparations, patients will be tested with a lower concentration than intended, leading to possible false-negative reactions.

Emollients and moisturisers for eczema

BACKGROUND

Eczema is a chronic skin disease characterised by dry skin, intense itching, inflammatory skin lesions, and a considerable impact on quality of life. Moisturisation is an integral part of treatment, but it is unclear if moisturisers are effective.

OBJECTIVES

To assess the effects of moisturisers for eczema.

SEARCH METHODS

We searched the following databases to December 2015: Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase, LILACS, the GREAT database. We searched five trials registers and checked references of included and excluded studies for further relevant trials.

SELECTION CRITERIA

Randomised controlled trials in people with eczema.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures.

MAIN RESULTS

We included 77 studies (6603 participants, mean age: 18.6 years, mean duration: 6.7 weeks). We assessed 36 studies as at a high risk of bias, 34 at unclear risk, and seven at low risk. Twenty-four studies assessed our primary outcome 'participant-assessed disease severity', 13 assessed 'satisfaction', and 41 assessed 'adverse events'. Secondary outcomes included investigator-assessed disease severity (addressed in 65 studies), skin barrier function (29), flare prevention (16), quality of life (10), and corticosteroid use (eight). Adverse events reporting was limited (smarting, stinging, pruritus, erythema, folliculitis).Six studies evaluated moisturiser versus no moisturiser. 'Participant-assessed disease severity' and 'satisfaction' were not assessed. Moisturiser use yielded lower SCORAD than no moisturiser (three studies, 276 participants, mean difference (MD) -2.42, 95% confidence interval (CI) -4.55 to -0.28), but the minimal important difference (MID) (8.7) was unmet. There were fewer flares with moisturisers (two studies, 87 participants, RR 0.40, 95% CI 0.23 to 0.70), time to flare was prolonged (median: 180 versus 30 days), and less topical corticosteroids were needed (two studies, 222 participants, MD -9.30 g, 95% CI -15.3 to -3.27). There was no statistically significant difference in adverse events (one study, 173 participants, risk ratio (RR) 15.34, 95% CI 0.90 to 261.64). Evidence for these outcomes was low quality.With Atopiclair (three studies), 174/232 participants experienced improvement in participant-assessed disease severity versus 27/158 allocated to vehicle (RR 4.51, 95% CI 2.19 to 9.29). Atopiclair decreased itching (four studies, 396 participants, MD -2.65, 95% CI -4.21 to -1.09) and achieved more frequent satisfaction (two studies, 248 participants, RR 2.14, 95% CI 1.58 to 2.89), fewer flares (three studies, 397 participants, RR 0.18, 95% CI 0.11 to 0.31), and lower EASI (four studies, 426 participants, MD -4.0, 95% CI -5.42 to -2.57), but MID (6.6) was unmet. The number of participants reporting adverse events was not statistically different (four studies, 430 participants, RR 1.03, 95% CI 0.79 to 1.33). Evidence for these outcomes was moderate quality.Participants reported skin improvement more frequently with urea-containing cream than placebo (one study, 129 participants, RR 1.28, 95% CI 1.06 to 1.53; low-quality evidence), with equal satisfaction between the two groups (one study, 38 participants, low-quality evidence). Urea-containing cream improved dryness (investigator-assessed) more frequently (one study, 128 participants, RR 1.40, 95% CI 1.14 to 1.71; moderate-quality evidence) with fewer flares (one study, 44 participants, RR 0.47, 95% CI 0.24 to 0.92; low-quality evidence), but more participants in this group reported adverse events (one study, 129 participants, RR 1.65, 95% CI 1.16 to 2.34; moderate-quality evidence).Three studies assessed glycerol-containing moisturiser versus vehicle or placebo. More participants in the glycerol group noticed skin improvement (one study, 134 participants, RR 1.22, 95% CI 1.01 to 1.48; moderate-quality evidence), and this group saw improved investigator-assessed SCORAD (one study, 249 participants, MD -2.20, 95% CI -3.44 to -0.96; high-quality evidence), but MID was unmet. Participant satisfaction was not addressed. The number of participants reporting adverse events was not statistically significant (two studies, 385 participants, RR 0.90, 95% CI 0.68 to 1.19; moderate-quality evidence).Four studies investigated oat-containing moisturisers versus no treatment or vehicle. No significant differences between groups were reported for participant-assessed disease severity (one study, 50 participants, RR 1.11, 95% CI 0.84 to 1.46; low-quality evidence), satisfaction (one study, 50 participants, RR 1.06, 95% CI 0.74 to 1.52; very low-quality evidence), and investigator-assessed disease severity (three studies, 272 participants, standardised mean difference (SMD) -0.23, 95% CI -0.66 to 0.21; low-quality evidence). In the oat group, there were fewer flares (one study, 43 participants, RR 0.31, 95% CI 0.12 to 0.7; low-quality evidence) and less topical corticosteroids needed (two studies, 222 participants, MD -9.30g, 95% CI 15.3 to -3.27; low-quality evidence), but more adverse events were reported (one study, 173 participants; Peto odds ratio (OR) 7.26, 95% CI 1.76 to 29.92; low-quality evidence).All moisturisers above were compared to placebo, vehicle, or no moisturiser. Participants considered moisturisers more effective in reducing eczema (five studies, 572 participants, RR 2.46, 95% CI 1.16 to 5.23; low-quality evidence) and itch (seven studies, 749 participants, SMD -1.10, 95% CI -1.83 to -0.38) than control. Participants in both treatment arms reported comparable satisfaction (three studies, 296 participants, RR 1.35, 95% CI 0.77 to 2.26; low-quality evidence). Moisturisers led to lower investigator-assessed disease severity (12 studies, 1281 participants, SMD -1.04, 95% CI -1.57 to -0.51; high-quality evidence) and fewer flares (six studies, 607 participants, RR 0.33, 95% CI 0.17 to 0.62; moderate-quality evidence), but there was no difference in adverse events (10 studies, 1275 participants, RR 1.03, 95% CI 0.82 to 1.30; moderate-quality evidence).Topical active treatment combined with moisturiser was more effective than active treatment alone in reducing investigator-assessed disease severity (three studies, 192 participants, SMD -0.87, 95% CI -1.17 to -0.57; moderate-quality evidence) and flares (one study, 105 participants, RR 0.43, 95% CI 0.20 to 0.93), and was preferred by participants (both low-quality evidence). There was no statistically significant difference in number of adverse events (one study, 125 participants, RR 0.39, 95% CI 0.13 to 1.19; very low-quality evidence). Participant-assessed disease severity was not addressed.

AUTHORS' CONCLUSIONS

Most moisturisers showed some beneficial effects, producing better results when used with active treatment, prolonging time to flare, and reducing the number of flares and amount of topical corticosteroids needed to achieve similar reductions in eczema severity. We did not find reliable evidence that one moisturiser is better than another.

Simultaneous determination of methylparaben, propylparaben, hydrocortisone acetate and its degradation products in a topical cream by RP-HPLC

A novel reversed-phase high-performance liquid chromatographic method with UV spectrophotometric detection was developed and validated for the determination of compounds in topical cream. The method describes determination of active component hydrocortisone acetate (HCA), its degradation products hydrocortisone (HC) and cortisone acetate (occurring in formulation after long-term stability tests) and two preservatives presented in the cream-methylparaben and propylparaben, using dexamethasone as an internal standard. The chromatographic separation was performed on a 5 microm SUPELCO Discovery C18 125 x 4-mm ID column. The optimised mobile phase for separation of all the compounds consists of methanol, acetonitrile and water (15:27:58, v/v/v), with the analysis time less than 13 min. The method was applicable for routine analysis (assays and stability tests) of active compound HCA, preservatives and degradation products in pharmaceutical product--topical cream Hydrocortizone cream 1%.

Modulated release of triterpenic compounds from a O/W/O multiple emulsion formulated with dimethicones: infrared spectrophotometric and differential calorimetric approaches

From the use of silicones within O/W/O multiple emulsions, we can expect, two principal advantages: (1) the silicones with the lowest molecular weight decrease the oily touch; (2) due to the large range of viscosity, this excipient should influence the skin distribution of actives after topical application. The purpose of our work is to highlight these advantages. Multiple emulsions were formulated with several dimethicones and with drug model. Firstly, the effects of different dimethicones incorporated within multiple emulsions were studied, through in vitro penetration results. Secondly, we investigated the residual film on the skin by Differential Scanning Calorimetry (DSC) and by Fourier Transform Infrared (FTIR) to determine its structure. Correlations were established between the silicone structure and the distribution of drugs in different skin levels or between the silicone structure and the percutaneous penetration. The incorporation of silicones within O/W/O multiple emulsions seems to be an efficient means of modulating the penetration and the distribution of drugs in the skin.

Drug penetration as studied by noninvasive methods: fourier transform infrared-attenuated total reflection, fourier transform infrared, and ultraviolet photoacoustic spectroscopy

The penetration of the drugs dithranol and methoxsalen from semisolid Vaseline formulation into an artificial dodecanol-collodion membrane was followed by three spectroscopic methods; they are, step-scan Fourier transform infrared (FTIR) photoacoustic spectroscopy (PAS) with phase modulation, FTIR-attenuated total reflection (FTIR-ATR), and ultraviolet (UV) PAS. The uptake of the drug in the membrane was quantified by monitoring the dependence of an appropriate drug band on the penetration time. The PAS experiments were carried out with various modulation frequencies for generating various sampling depths. Based on Fick's second law, the diffusion coefficient was derived by numerical fitting of the experimental data. It appears that the diffusion coefficient for the drug in the membrane depends on the distance. The comparative studies demonstrate that FTIR-ATR is favored for permeation studies, whereas the PAS techniques are capable of providing the drug penetration profile in the membrane. Thus, extended experimental data are available for new insight into the penetration process. However, because of the photacoustic cells at hand, PAS is only suitable for in vitro studies.

A method for quantification of formaldehyde in the presence of formaldehyde donors in skin-care products

Reliable and uncomplicated methods for detection of free formaldehyde in products preserved with formaldehyde donors are desirable to decrease the risk of allergic contact dermatitis. The aim of this study was to develop a method that could be used in clinics and workplaces for quantification of free formaldehyde in products preserved with formaldehyde donors. The method developed is named the closed container diffusion (CCD) method. Formaldehyde in a sample is allowed to evaporate in a closed container and react with 2,4-dinitrophenylhydrazine coated on a glass fibre filter. The hydrazone formed is analyzed with HPLC. The method was tested on 3 different formaldehyde donors, imidazolidinyl urea, diazolidinyl urea and 2-bromo-2-nitropropane-1,3-diol, using 4 different cream bases. The results obtained with this method accord, with those obtained with the official method within the European Union (EU). The method is sensitive enough for analysis of patients' products and for control of labelled amounts of formaldehyde in technical products without solvent extraction. As a result of our studies, we observed a risk of exceeding the labelling limit for free formaldehyde in cosmetic products when using the highest amount of diazolidinyl urea allowed within the EU.

Effect of Skin Care With an Emollient Containing a High Water Content on Mild Uremic Pruritus

Skin care is very important for preventing uremic pruritus. However, mild uremic pruritus has usually been treated with antihistamine and urea-containing ointments. We therefore examined the effects of an aqueous gel with higher water content. Twenty hemodialysis patients with mild pruritus who were not being treated with any emollient were divided into two groups of 10 each. Patients in one group were treated with an aqueous gel containing 80% water. This emollient was applied twice daily for 2 weeks. No emollient was applied for the next 2 weeks. The other group of patients were not treated with any emollient for the 4 weeks. Visual analog scale scores for itching in the experimental group at week 2 were significantly decreased compared with that at week 0 (3.5 +/- 0.3 vs 0.6 +/- 0.2, P < 0.01). Skin dryness in the experimental group was significantly improved at week 2 compared with that at week 0. The visual analog scale score for itching increased to 1.2 +/- 0.5 and skin dryness reappeared in 40% of patients by week 4, i.e. after the emollient was stopped. There were no significant changes in the control group during the study. It is concluded that the aqueous gel with high water content reduced itching and improved xerosis in patients with mild uremic pruritus. It is reasonable that skin care with an emollient containing a high water content is first started for hemodialysis patients with xerosis, even if they do not feel itching.

Final report on the safety assessment of acetyl triethyl citrate, acetyl tributyl citrate, acetyl trihexyl citrate, and acetyl trioctyl citrate

Acetyl Triethyl Citrate, Acetyl Tributyl Citrate, Acetyl Trihexyl Citrate, and Acetyl Trioctyl Citrate all function as plasticizers in cosmetics. Additionally, the Trihexyl and Trioctyl forms are described as skin-conditioning agents-emollients, although there are currently no reported uses of Acetyl Trihexyl Citrate or Acetyl Trioctyl Citrate. Acetyl Triethyl Citrate and Acetyl Tributyl Citrate are used in nail products at concentrations up to 7%. Recognizing that there are no reported uses of Acetyl Trihexyl or Trioctyl Citrate, if they were to be used in the future, their concentration of use is expected to be no higher than that reported for Acetyl Triethyl and Tributyl Citrate. These ingredients were sufficiently similar in structure that safety test data on one were considered applicable to all. Approximately 99% of orally administered Acetyl Tributyl Citrate is excreted-intermediate metabolites include acetyl citrate, monobutyl citrate, acetyl monobutyl citrate, dibutyl citrate, and acetyl dibutyl citrate. In acute, short-term, subchronic, and chronic feeding studies, these ingredients were relatively nontoxic. Differences from controls were either not statistically significant or not related to any organ toxicity. Ocular exposures produced moderate reactions that cleared by 48 hours after instillation. Dermal application was not toxic in rabbits. In a guinea pig maximization test, Acetyl Triethyl Citrate was a sensitizer whereas Acetyl Tributyl Citrate was not. Limited clinical testing of Acetyl Triethyl Citrate and Acetyl Tributyl Citrate was negative for both skin irritation and sensitization. These clinical data were considered more relevant than the guinea pig maximization data, suggesting to the Cosmetic Ingredient Review Expert Panel that none of these ingredients would be a sensitizer. Physiologic effects noted with intravenous delivery of Acetyl Triethyl Citrate or Acetyl Tributyl Citrate include dose-related decreases in blood pressure and intestinal muscular spasms. These ingredients were not genotoxic in bacterial or mammalian test systems. No significant differences in tumor induction (lymphomas) were noted in rats fed Acetyl Tributyl Citrate for 2 year. Acetyl Tributyl Citrate was not a developmental or reproductive toxicant in studies in mice and rats. Based on all the available data, these ingredients were considered safe as used in cosmetics.

A case of contact dermatitis due to impurities of cetyl alcohol

A 29-year-old man being treated for itchy lesions on the amputation stump of the thigh became allergic to betamethasone valerate and gentamicin sulfate cream (Rinderon VG). Closed patch tests with all the ingredients of the cream revealed positive reactions to cetyl alcohol 30% to 5% pet. Gas chromatographic analysis of the cetyl alcohol in the cream base detected stearyl alcohol (C18), myristyl alcohol (C14) and lauryl alcohol (C12) in addition to the main component of cetyl alcohol (C16). Patch testing with 99% pure analytical reagent grade saturated alcohols (C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, C20) showed negative reactions. Thus, it is concluded that some minor impurities in cetyl alcohol not detected by gas chromatography might be the cause of this dermatitis.

Photoprotective action of emollients in ultraviolet therapy of psoriasis

An in vitro technique was used to measure the monochromatic protection factors of all emollients available on prescription. The action spectra for ultraviolet erythema and erythema in psoralen-sensitized skin were used to calculate, for each emollient, erythema protection factors relevant to UVB phototherapy and psoralen photochemotherapy, respectively. Of the 40 products tested, 22 (55%) had a UVB erythema protection factor > 1.2 at an application density of 2 microliters/cm2, and 31 (78%) at an application density of 4 microliters/cm2. Fewer products, 25% at 2 microliters/cm2 and 50% at 4 microliters/cm2, had a psoralen erythema protection factor > 1.2. A protection factor of 1.2 is equivalent to a reduction in ultraviolet dose of 17%, and is thus likely to be of clinical importance. These results allow a choice of emollient products which may improve response by increasing transmission of radiation through psoriasis scale without a concomitant decrease in transmission due to a sunscreening action.

Investigation of drug release from suspension using FTIR-ATR technique: part I. Determination of effective diffusion coefficient of drugs

Fourier transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy was used to study directly the release of drug particles (ketoconazole) in a liquid medium (paraffinum liquidum). In the case of the release experiment, the formulation is placed on the ATR crystal and the acceptor membrane on the top of the ointment. The decrease of the drug content in the sediment near the interface ATR crystal-formulation in the course of the release process was quantified by monitoring the changes of the IR spectrum in relevant spectral ranges using multivariate analysis. A mathematical model based on Fick's second law with appropriate initial and boundary conditions was applied in order to determine the diffusion coefficient of the drug in the liquid medium. Knowing this value, it is possible to calculate the effective diffusion coefficient of the drug in heterogeneous semisolid formulation (Vaseline) as a function of the volume fraction of the solid phase.

Does hand care ruin hand disinfection?

Hand washing and hand disinfection put considerable stress on the skin thus requiring specific hand care. It is important however that the care products do not impair the effect of hand disinfectants. We therefore investigated the interaction of two hand care products (oil-in-water and water-in-oil emulsions) on the microbicidal efficacy of different alcoholic hand-rubs, using the contamination model described in EN 1500. The mean log10-reduction factors for three hand-rubs varied between 4.03 and 4.22 compared with 3.76 and 4.43 for six possible combinations of hand-rubs and hand care products applied immediately prior to disinfection. Differences between reduction factors achieved with hand-rubs alone and in combination with hand care were not significant. Repeated application of care products with subsequent hand disinfection also did not result in significantly lower reduction factors than achieved with hand disinfection alone. Our data suggest that administration of selected products for hand care does not necessarily impair hand disinfection and is therefore recommended for occupational health as well as for infection control reasons.

Some pertinent factors in skin care emulsion

Emulsion structures are reviewed with special consideration given to the conditions in emulsions for topical applications with more phases than the traditional two liquids. The fundamentals of emulsions containing liquid crystals and vesicles are described, focussing on the dependence of the volume ratios of liquid crystals and vesicles on the surfactant content.

Interaction of Lipophilic Moisturizers on Stratum Corneum Lipid Domains in vitro and in vivo

Dry skin symptoms such as scaling and itching are often treated with lipophilic moisturizers. The aim of this study was to investigate the effect of lipophilic moisturizers on the stratum corneum (SC) ultra-structure and lipid organization. Lipophilic moisturizers were applied on the forearms of 4 healthy volunteers for 3 h. Subsequently, the application sites were tape stripped, and selected tape strips prepared for Freeze Fracture Electron Microscopy (FFEM), a method to visualize the SC intercellular lipid parallel to the skin surface. To investigate the effect of lipid moisturizers on the lipid lamellae, isolated SC was pretreated with the lipophilic moisturizers for 24 h prior to performing small angle X-ray diffraction (SAXD) measurements. Additionally, the lipid organization of mixtures prepared with ceramides, cholesterol, free fatty acids and lipophilic moisturizer in a 2:1:1:1 molar ratio were studied using SAXD. The FFEM data (in vivo) as well as the SAXD data (in vitro) show that the lipophilic moisturizers do not change the lipid lamellar organization in the SC. Addition of 20% m/m lipophilic moisturizer to the ceramide:cholesterol:free fatty acids mixture did not inhibit the formation of the long periodicity phase, the characteristic lamellar phase in the SC, even though there was clear evidence that two of the three moisturizers were at least partially incorporated in the long periodicity phase. Concluding, all findings suggest that the lipophilic moisturizers investigated in this study do not drastically change the lamellar organization of the SC intracellular lipid matrix, but that the moisturizers form separate domains in the SC, as was visualized by FFEM.

Can glutathione-containing emollients inactivate methylchloroisothiazolinone/methylisothiazolinone?

Many persons are exposed to preservatives/biocides based on methylchloroisothiazolinone/methylisothiazolinone (MCI/MI), since toiletries and cosmetics, as well as products/water-based systems used occupationally, may all contain MCI/MI. In toiletries and cosmetics, the MCI/MI concentration is often below 15 ppm (0.0015%). In some industries, workers handle high concentrations of MCI/MI, which can cause chemical burns and induce sensitization if skin is exposed. Contact allergy to MCI/MI is common and reports on chemical burns have been published. Thus, there is a need for prevention of skin diseases caused by MCI/MI. The inactivation of MCI/MI by glutathione (GSH) in emollients, containing different amounts of lipids, was studied by HPLC. Various amounts of GSH were added to Fenuril, Essex, and Locobase, giving 3 preparations of each emollient containing 0.10%, 0.50% and 2.0% GSH, respectively. The inactivation of 15 ppm MCI/MI and the total inactivating capacity of GSH in these preparations, kept at room temperature and refrigerated, was studied over a period of 6 months. The inactivating capacity of GSH in the emollients was almost equivalent, regardless of the lipid contents of the emollients, type of storage and age. On the other hand, the GSH concentration in the emollients had a crucial importance on the inactivation of MCI/MI. Emollients containing 2% GSH were capable of inactivating up to 2400 ppm MCI/MI.

Evaluation of lotion formulations on irritation using the modified forearm-controlled application test method

BACKGROUND/PURPOSE

Cold and allergy sufferers often develop irritation around the nostrils as a result of repeated and frequent rubbing of the skin site with facial tissues. This irritation is a combination of the inherent irritant properties of the tissue components (chemical irritation), and mechanical irritation from friction. Lotion-coated facial tissues are being developed to provide soothing, skin benefits, and to promote healing of this type of irritation. The objective of these studies was to evaluate the efficacy of different lotion formulations on facial tissues in preventing irritation, or aiding in the healing of irritation.

METHODS

The modified forearm-controlled application test (Modified FCAT) was adapted as a means of quickly evaluating the relative skin benefits of various lotion formulations used to coat facial tissues. The test was conducted on the volar surface of the forearms of volunteer subjects. Test sites were pretreated with 24 h occlusive patches of sodium lauryl sulfate (SLS) to induce mild or moderate skin irritation. This was followed by repeated wiping of the lotion-coated tissues. Irritation was evaluated using visual scoring for erythema and dryness. Lotion formulation options were compared in the model. Comparisons included assessments of the type of fatty alcohol in the formulation (stearyl and cetearyl alcohol), the presence of silicone and the base formulation (mineral oil, petrolatum of a proprietary formula).

RESULTS

Differences in the degree of erythema and dryness were detected among various formulation options. No differences were found between formulations containing stearyl or cetearyl alcohol. Low levels of silicone produced benefits in one of two experiments. The proprietary base formula produced greater reductions in erythema following treatment of SLS-irritated skin compared with mineral oil and petrolatum bases.

CONCLUSIONS

The results indicated that this modification of the FCAT can be used to compare various lotion formulations for skin benefits and healing properties, and to rank qualitatively the benefits of various formulation options.

Efficacy of Nonprescription Moisturizers for Atopic Dermatitis: An Updated Review of Clinical Evidence

Twice-daily moisturization is recommended by international guidelines as the bedrock of the management of atopic dermatitis (AD). Moisturizers should be selected based on proven clinical effectiveness in improving the skin barrier and improving the symptoms of AD. We searched the PubMed database for clinical trials assessing daily moisturization for the treatment of AD published between 2006 and 2019. Studies had to assess the efficacy of commercially available moisturizers using objective measures of corneometry, transepidermal water loss, or incidence of flare as endpoints, and treatments had to be currently available to patients. Clinical studies showed that moisturization (typically twice daily) significantly improved the skin barrier in adults and children with AD. Longer-term flare studies showed that daily moisturization reduced the incidence of flares and extended the time between flares. Proactive moisturization of infants at high risk of developing AD may reduce its manifestation. Therapeutic moisturizers for AD are specifically formulated with ingredients that target symptoms of AD, such as itch, inflammation, or compromised skin barrier. The US FDA requires that any moisturizer available in the USA and claiming to treat AD must contain colloidal oatmeal. Healthcare providers can maximize compliance and outcomes by educating patients on the benefits of liberally applying a therapeutic moisturizer twice daily to support the skin barrier and help reduce the incidence of flares. Specific recommendations should be for clinically tested moisturizers evaluated using objective, validated skin assessments.

Buccal adhesive films with moisturizer- the next level for dry mouth syndrome?

This study was undertaken to prepare films by solvent evaporation method comprising well-known polymers in order to investigate their potential for buccal suitability. Mucoadhesive films were manufactured using different polymers such as ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methylcellulose as well as carboxymethyl cellulose. Buccal films were evaluated in regards of mucoadhesiveness, swelling and physico-chemical properties. Furthermore rheological measurement and adhesion study were carried out on the buccal porcine mucosa. Moreover, allantoin as humectant was incorporated and trans-mucosal water loss was determined. The results showed that physico-chemical, buccal adhesive and swelling properties varied depending on the composition of the polymers. The findings indicated films containing allantoin to be suitable for buccal application. In completion, adhesive films are appropriate and promising formulations in the treatment of various disease in the intraoral cavity.

The effect of bilayer and hexagonal HII phase lipid films on transepidermal water loss

The common membrane phospholipids tend to adopt either the familiar bilayer phase or the less familiar hexagonal H(II) phase when isolated and hydrated in excess water. The objective of this study was to compare the effects of these very different macroscopic lipid structures on transepidermal water loss (TEWL) when they are applied to the surface of pig skin mounted in Franz diffusion cells. First, a novel in vitro method for monitoring TEWL was developed and characterized in which the flux of water from the subphase through skin was measured through the absorption of (3H)-water by lyophilized polyethylene glycol (PEG) mounted above the skin surface. TEWL was varied by disrupting the skin barrier to different degrees by tape stripping or solvent extraction. Bilayer-forming egg phosphatidylcholine (EPC) or hexagonal H(II)-forming dioleoyl phosphatidylethanolamine (DOPE) were applied topically as solutions in ethanol and subsequently dried to films. The molecular configuration adopted by each lipid at the skin surface was confirmed by phosphorus NMR. TEWL for normal skin was approximately 2 g H2O/h/m2, increasing to a maximum of 80 g H2O/h/m2 after the stratum corneum was completely removed by tape stripping. On tape-stripped skin, films of lipid doses as low as 10 mg/cm2 significantly reduced TEWL, and DOPE (hexagonal H(II)) was approximately twofold more effective than EPC (bilayer). Furthermore, the effects of EPC and Vaseline on reducing TEWL from damaged skin were readily reversed by a simple aqueous wash, whereas the DOPE effect was unaltered even by vigorous washing. Similar results were obtained with lipid films applied to solvent-extracted skin. The data are consistent with the formation of extensive hydrophobic interactions between the skin and the outwardly facing acyl chains of the inverted, hexagonal H(II) phase adopted by DOPE. This results in the formation of a durable surface barrier capable of significantly reducing TEWL from damaged skin.

Effects of some emollients on the transmission of ultraviolet

BACKGROUND/PURPOSE

Various topical agents which can be used in combination with phototherapy may have blocking or enhancing effects. In this in vivo study, the effects of topical petrolatum, basis cream, glycerine and olive oil on the transmission of ultraviolet B (UVB) were investigated.

METHODS

A phototest was performed to determine the minimal erythema dose (MED) on 32 volunteers and the test was repeated with white petrolatum, basis cream, glycerine, olive oil and sunscreen (0.3 cm3/25 cm2). The effects of each agent on MED was determined after 24 h.

RESULTS

MEDs were increased with the application of white petrolatum and basis cream. However, MEDs were not changed with the application of glycerine and olive oil.

CONCLUSION

The application of white petrolatum and basis cream, which have blocking effects, immediately before UVB therapy is not recommended. However, glycerine and olive oil, which does not have any effect, can be used before phototherapy.

Tolerance profile of a sterile moisturizer and moisturizing cleanser in irritated and sensitive skin

BACKGROUND

This study evaluates the tolerance of preservative free sterile cleanser and sterile moisturizer in irritated and sensitive face skin.

MATERIALS AND METHODS

An exploratory, open-label study using the cleanser and the moisturizer in combination was performed with 98 patients with a documented history of allergic contact dermatitis. The 2 products could each be used once or twice daily for 28 days. The assessment parameters at baseline and end of treatment (day 28) included the intensity of erythema, dryness/scaling by the investigator and subjective signs (burning, pruritus and stinging), according to a defined 4-point scale (absent to severe). In addition, a global assessment of the change from baseline and the overall tolerance of the products were performed by the investigator at the end of treatment.

RESULTS

Ninety-four patients were included for the efficacy analysis and 96 patients for the safety analysis. At baseline, a majority of patients expressed some degree of erythema (63%), and dryness/scaling (56%). Fewer patients experienced subjective signs at baseline (44%). At the end of treatment, the results showed a statistically significant improvement of all the objective signs of irritated skin (P = .0001, Mac Nemar test), as well as the subjective signs of sensitive skin (P < 0.02). This was confirmed by the overall investigator assessment, showing an excellent or good response in 90% of the patients. In the safety analysis, 1 patient developed contact allergy to 1 ingredient of the test products (carbomer), and 3 patients exacerbated their dermatitis.

CONCLUSION

Taken together, these results suggest that adequately formulated cosmetics might reduce both irritated and sensitive skin, with clinical improvement of dryness, erythema and stinging.