Formulating Sustainable Emulsions: Mandelic Acid and Essential Oils as Natural Preservatives

Emulsion products with natural antimicrobials are becoming increasingly popular for topical application. Mandelic Acid is interesting in cosmetics due to its potent exfoliating properties, which have driven advancements in skincare technologies. Essential oils have various properties, of which the most useful in cosmetics are those that do not cause irritation, smell pleasant, and have other beneficial properties such as antimicrobial effects. Emulsions with Mandelic Acid and essential oils from Satureja montana, Lemongrass, and Litsea cubeba were formulated and microbiologically tested for their preservative effectiveness. The effect of the treatments on skin condition was monitored by non-invasive diagnostic methods, such as hydration, transepidermal water loss, and pH value. Sensory analysis revealed that the matrix containing Mandelic Acid alone or combined with Litsea Cubeba Oil was the best-performing formulation, consistent with the compliant results of antimicrobial efficacy. The topical form of this cosmetic product has demonstrated excellent preservative activity and desirable biophysical efficacy on the skin.

Cocos nucifera and glycerine afterwork moisturizers for secondary prevention of hand dermatitis among fabric worker: a randomized, double-blind, cross over trial

The use of skin barrier-enhancing topical medication is a favorable approach for the treatment of occupational hand dermatitis (OHD). Cocos nucifera or coconut oil is one of the best sources of lipid enriched with laurate acid, and glycerin is a well-known humectant that improves skin hydration. This study is aimed is to evaluate the effectiveness of C. nucifera and glycerin for secondary prevention of OHD among batik (Indonesian traditional fabric) workers. In a randomized, double-blind, crossover trial, the effect of glycerine-C. nucifera cream versus glycerin-only was considered with multiple afterwork applications of moisturizer over a 2-week period on batik workers with OHD. Assessment of trans-epidermal water loss (TEWL), skin capacitance, and a clinical assessment using the Hand Eczema Severity Index (HECSI) were carried out at day 0 and 14. The results show thirty-two batik dyeing and/or rinsing workers were enrolled in the study with mild to moderate OHD. Clinical improvement was demonstrated by 20% decrease in HECSI and TEWL, and 20% increase in skin capacitance. Both moisturizers were equally effective for the secondary prevention of OHD. As a conclusion, glycerine-C. nucifera and glycerin-only cream are equally effective for secondary prevention for OHD among batik worker to reduce the prevalence of hand dermatitis.

Evaluation of the Safety of Cosmetic Ingredients and Their Skin Compatibility through In Silico and In Vivo Assessments of a Newly Developed Eye Serum

The term "risk assessment" is often substituted with "safety assessment", to demonstrate the safe properties of cosmetic ingredients and formulations. With respect to the actual legislative framework, the proper use of in silico evaluation could offer a representative non-animal substitute for the toxicity evaluation of cosmetic ingredients. The in silico assessment needs to be integrated with other lines of proof (in vitro and/or in vivo data) in the form of a complex methodology in order to demonstrate the safety evaluation of cosmetic ingredients/products. The present study aimed to develop and characterize a new cosmetic formulation, designed for the skin care of the periorbital area. Quality control comprising stability, physicochemical, and microbiological evaluation was performed. Another objective of this study was to present a screening model for the safety evaluation of the cosmetic formulation by identifying individual ingredients, and to confirm the skin compatibility based on in vivo evaluation. The results demonstrated the in silico and in vivo safety profile of the cosmetic ingredients used in the present formulation. In silico evaluation, using a novel, specific software applicable for the risk evaluation of ingredients and formulations, showed that the incorporated ingredients were non-mutagenic and non-sensitizing, and considering the margin of safety (MoS), the cosmetic raw materials could be considered safe. Skin compatibility was confirmed by the patch test performed under dermatological control, evidencing the "non-irritating" potential of the developed cosmetic formulation.

Nasal Spray Formulations Based on Combined Hyalurosomes and Glycerosomes Loading Zingiber officinalis Extract as Green and Natural Strategy for the Treatment of Rhinitis and Rhinosinusitis

A total green nanotechnological nasal spray has been manufactured and proposed as an alternative treatment of rhinitis and rhinosinusitis. It was obtained by combining the strengthening effect of liposomes on barrier function, the hydrating and lubricating properties of sodium hyaluronan and the anti-inflammatory and antioxidant activities of the extract of Zingiber officinalis. To this purpose, the extract was loaded in special phospholipid vesicles immobilized with hyaluronic acid (hyalurosomes), which were further enriched with glycerol in the water phase. Liposomes and glycerosomes were prepared as well and used as reference. Vesicles were oligolamellar and multicompartment, as confirmed by cryogenic transmission electron microscopy (cryo-TEM) observation, small in size (~140 nm) and negatively charged (~-23 mV). Spray characteristics were evaluated by using the Spraytec® and instant images, from which the plume angle was measured. The range of the droplet size distribution and the narrow spray angle obtained suggest a good nebulization and a possible local deposition in the nasal cavity. In vitro studies performed by using human keratinocytes confirmed the high biocompatibility of vesicles and their ability to effectively counteract oxidative damage on cells induced by hydrogen peroxide. The overall collected data suggest that our vesicles are suitable as nasal spray.

Formulation of Edible Bird's Nest (Aerodramus fuciphagus) from Central Kalimantan as Skin Whitening and Moisturizing Cream

Context

Indonesia is the largest producer of edible bird's nest (EBN) in the world. Previous research proved that epidermal growth factor (EGF) was detected from edible bird's nest extract. EGF will increase the metabolism of skin cells and can lighten the skin EGF will increase the metabolism of skin cells and can lighten the skin.

Aims

This research aimed to formulate and prove the lightening and the moisturizing effect of EBN cream on white mice.

Materials and Methods

The 28 mice were divided into four group treatment. EBN 40% were formulated into cream with two formula types: water in oil (W/O) and oil in water (O/W). Before the treatment, white mice were exposed to UVA radiation until skin color level was 4. For 14 days, white mice were treated and observed skin color level and moisture content by skin analyzer.

Results

The skin color level was 1 on day 8 (O/W), on day 9 (W/O), on day 8 (positive control), and showed skin color level was 4 on day 14 (negative control). The average water content on day 14 was 53.70 ± 1.21 (O/W), 50.13 ± 1.39 (W/O), 53.88 ± 0.88 (positive control), and 21.48 ± 2.90 (negative control).

Conclusion

No significant difference was observed in lightening effect (Sig. 0.495) and moisturizing effect (Sig. 0.564) between O/W cream and W/O creams. W/O cream has good adhesion and O/W cream has good dispersion.

Hair Follicle Targeting and Dermal Drug Delivery with Curcumin Drug Nanocrystals-Essential Influence of Excipients

Many active pharmaceutical ingredients (API) possess poor aqueous solubility and thus lead to poor bioavailability upon oral administration and topical application. Nanocrystals have a well-established, universal formulation approach to overcome poor solubility. Various nanocrystal-based products have entered the market for oral application. However, their use in dermal formulations is relatively novel. Previous studies confirmed that nanocrystals are a superior formulation principle to improve the dermal penetration of poorly soluble API. Other studies showed that nanocrystals can also be used to target the hair follicles where they create a drug depot, enabling long acting drug therapy with only one application. Very recent studies show that also the vehicle in which the nanocrystals are incorporated can have a tremendous influence on the pathway of the API and the nanocrystals. In order to elucidate the influence of the excipient in more detail, a systematic study was conducted to investigate the influence of excipients on the penetration efficacy of the formulated API and the pathway of nanocrystals upon dermal application. Results showed that already small quantities of excipients can strongly affect the passive dermal penetration of curcumin and the hair follicle targeting of curcumin nanocrystals. The addition of 2% ethanol promoted hair follicle targeting of nanocrystals and hampered passive diffusion into the stratum corneum of the API, whereas the addition of glycerol hampered hair follicle targeting and promoted passive diffusion. Propylene glycol was found to promote both pathways. In fact, the study proved that formulating nanocrystals to improve the bioefficacy of poorly soluble API upon dermal application is highly effective. However, this is only true, if the correct excipient is selected for the formulation of the vehicle. The study also showed that excipients can be used to allow for a targeted dermal drug delivery, which enables to control if API should be delivered via passive diffusion and/or as drug reservoir by depositing API in the hair follicles.

Favorable effect of creams with skimmed donkey milk encapsulated in nanoliposomes on skin physiology

The use of donkey milk has a long history in external dermal application for cosmetic and medical purposes. The encapsulation of different drugs into nanoliposomes and nutrients may have many benefits for the delivery of the targeted substance. The aim of the present study is to test creams with nanoliposomes encapsulated with skimmed donkey milk, reported in our registered patent, compared with effect of the placebo cream and the untreated skin. To investigate the effect of formulated cream, we have measured the electrical capacitance, transepidermal water loss and the skin pH value. The study included 15 healthy volunteers (11 women and 4 men). The patented creams exhibited satisfactory moisturizing properties very soon after application, while hydration was reached earlier in the spots treated with night cream. Transepidermal water loss slightly decreased only after 4 weeks of treatment in each of the spots assessed. The pH value was similar after each of the treatments. Tested creams may enhance the moisture of skin very soon after application, in this way potentially enable deeper permeation of phospholipids and essential proteins, without changing the pH. It may also contribute to additional anti-aging effects.

Ethanol-Based Disinfectants Containing Urea May Reduce Soap Sensitivity

BACKGROUND

The use of disinfectants is crucial to preventing the spread of nosocomial infections in health care workers. As many as 25 applications of hand disinfectants is a realistic default value during a working day. However, alcohol-based hand disinfectants may weaken skin barrier function and induce dryness and eczema, which decrease their acceptance.

OBJECTIVE

To evaluate the effect of ethanol-containing disinfectants with 5% urea on skin barrier function and on sensitivity to an irritant soap (sodium lauryl sulfate [SLS]).

METHODS

Twenty healthy volunteers treated one of their forearms twice daily for 17 days with an ethanol-containing gel with 5% urea. Two types of gels with urea were tested. Treatment was randomized to left or right forearm, and the contralateral forearm served as untreated control. Transepidermal water loss, skin capacitance (dryness), and sensitivity to SLS were evaluated.

RESULTS

Twice-daily application of the urea-containing ethanol gels lowered transepidermal water loss, prevented dryness, and reduced sensitivity to SLS compared with the untreated control skin.

CONCLUSIONS

Improved barrier function using this ethanol gel with urea may have relevance in daily disinfectant procedures.

Hydration and Barrier Potential of Cosmetic Matrices with Bee Products

Honey, honey extracts, and bee products belong to traditionally used bioactive molecules in many areas. The aim of the study was primarily to evaluate the effect of cosmetic matrices containing honey and bee products on the skin. The study is complemented by a questionnaire survey on the knowledge and awareness of the effects and potential uses of bee products. The effect of bee molecules at various concentrations was observed by applying 12 formulations to the skin of the volar side of the forearm by non-invasive bioengineering methods on a set of 24 volunteers for 48 h. Very good moisturizing properties have been found in matrices with the glycerin extract of honey. Matrices containing forest honey had better moisturizing effects than those containing flower honey. Barrier properties were enhanced by gradual absorption, especially in formulations with both glycerin and aqueous honey extract. The observed organoleptic properties of the matrices assessed by sensory analysis through 12 evaluators did not show statistically significant differences except for color and spreadability. There are differences in the ability to hydrate the skin, reduce the loss of epidermal water, and affect the pH of the skin surface, including the organoleptic properties between honey and bee product matrices according to their type and concentration.

Anatomical site variation of water content in human skin measured by the Epsilon: A pilot study

Background

This pilot study aimed to investigate the anatomical site variation of water content of the stratum corneum (SC) on the body by measuring skin capacitance with the Epsilon, a new generation corneometer with multiple sensors. Secondly, values of the Epsilon were compared to values measured by conventional single sensor corneometers.

Methods

The hydration status of SC was measured in 15 healthy Caucasian volunteers with the Epsilon at five body sites (cheek, lower forearm, mid‐calf, lower back and abdomen). Transepidermal water loss (TEWL) was measured with the Aquaflux to get more insight into the condition of the skin barrier. A literature search was performed to compare Epsilon values with conventional corneometers.

Results

The tested anatomical locations showed significant differences in water content (P < 0.001) with large interindividual variations; highest values were found in the cheek (11.64ε) and lowest values in the mid‐calf (4.43ε). No correlation between water content and TEWL was found. In general, Epsilon values were lower compared to values of conventional corneometers, with a similar trend.

Conclusion

This pilot study showed significant variations in water content at different skin locations measured by the Epsilon. Moreover, the Epsilon measured consistent lower values compared to single sensor corneometers. Further validation of the device is recommended.

Herbal Gel Formulation Developed for Anti-Human Immunodeficiency Virus (HIV)-1 Activity Also Inhibits In Vitro HSV-2 Infection

Herpes simplex virus-2 (HSV-2) infection is the most common cause of genital ulcers. The impact of ulcers also demonstrates a strong link to the human immunodeficiency virus (HIV) infection. Complications, drug resistance, and side-effects of anti-viral drugs make the treatment of HSV-2 infection challenging. Herbal medicines have shown potential against HSV-2 and HIV infections. In this context, polyherbal gel formulation comprising 50% ethanolic extracts from Acacia catechu, Lagerstroemia speciosa, Terminalia chebula and Phyllanthus emblica has been developed. The gel formulation significantly exhibited virucidal activity against both HIV-1 and HSV-2 infections with IC₅₀, 55.93 ± 5.30 µg/mL and 27.26 ± 4.87 µg/mL, respectively. It also inhibited HSV-2 attachment and penetration to the Vero cells with an IC₅₀ = 46.55 ± 1.25 µg/mL and 54.94 ± 2.52 µg/mL respectively, which were significantly lower than acyclovir. However, acyclovir is more potent in post-infection assay with an IC₅₀ = 0.065 ± 0.01 µg/mL whereas gel formulation showed an IC₅₀ = 469.05 ± 16.65 µg/mL under similar conditions. Gel formulation showed no inhibitory effect on the viability of lactobacilli, human vaginal keratinocyte cells (Vk2/E6E7), and the integrity of the Caco-2 cells monolayer. Gel formulation did not lead to any significant increase in the secretion of pro-inflammatory cytokines and mutagenic index. The proposed gel formulation may be a promising candidate microbicide for the prevention of sexually transmitted HIV-1 and HSV-2.

In vivo efficacy and properties of semisolid formulations containing panthenol

BACKGROUND

Panthenol is an active substance used in dermatology to protect the health of the skin, to treat defects in the morphology of the stratum corneum. In cosmetology, hydrating, softening, and barrier function of panthenol are utilized. Detailed studies evaluating the efficacy of panthenol in cosmetic and pharmaceutical semisolid formulations and establishing its optimum concentration are needed.

OBJECTIVES

To investigate whether an addition of 5-13 wt% panthenol in o/w and w/o emulsions increases hydration and supports the barrier properties of the skin. Rheological properties and sensory analysis of prepared formulations are supplemented.

METHODS

Noninvasive instrumental methods in vivo were used. The hydration and barrier effect of semisolid formulations on the skin were observed for 48 hour; testing was conducted on 40 women. The effect was compared with formulations without any content of panthenol. The rheological and organoleptic properties of the formulations were evaluated.

RESULTS

After applying either form of the formulations containing 7-11 wt% of panthenol hydration of the skin increased, transepidermal water loss decreased. pH of the skin shifted toward neutral after application of tested formulations. The rheological properties of the formulations were influenced by the type of vehicle, the amount of panthenol, and temperature. Sensory evaluation of both semisolid forms revealed statistically significant differences in o/w formulations with regard to spreadability.

CONCLUSIONS

The presence of panthenol in an o/w and w/o semisolid formulations significantly enhances skin barrier repair and hydration of the stratum corneum. Better vehicle for the active substance as regards hydration proved o/w formulations.

Regression of cutaneous xerosis with emollient treatment in sub-Saharan African patients

Emollients have proven effective in improving cutaneous xerosis in various populations; however, no clinical data are available for African patients. The observational study "Xerafrica" was conducted by dermatologists in seven sub-Saharan countries to assess the evolution of xerosis after an 8-week treatment with an emollient. Patients were children above 3 years or adults. Secondary objectives were to assess pruritus, improvement in symptoms, quality of life, satisfaction, and tolerance. An analysis of 185 patients was made. After 8 weeks of emollient treatment, the relative reduction of the "Scaling Roughness Redness Cracks" (SRRC) score was -83.9% and -80.4% in children and adults, respectively. The effect was significantly stronger when topical steroids were co-prescribed with the emollient and in patients with co-dermatosis. To a lesser extent, the effect of emollient was also observed at week 4. Similarly, pruritus and quality of life strongly improved during follow-up. Skin lesions improved in almost all patients, with a high level of satisfaction noted by both dermatologists and patients. The "Xerafrica" study addressed, for the first time, the treatment of xerosis by emollients in an African population. In this specific context, the emollient markedly reduced xerosis as soon as 4 weeks and resolved it almost totally by 8 weeks. The study confirms, under real-life conditions, the efficacy and tolerability of an emollient in improving xerosis.

A new topical panthenol-containing emollient: skin-moisturizing effect following single and prolonged usage in healthy adults, and tolerability in healthy infants

PURPOSE

Two studies were conducted with a new topical panthenol-containing emollient (NTP-CE) to investigate the skin-moisturizing effect in healthy adults and tolerability in healthy infants.

METHODS

In Study 1 (N = 44), a single skin application of NTP-CE was performed followed by a 4-week twice-daily application. Skin hydration and stratum corneum (SC) water content change (using Raman spectroscopy) were measured. In the 4-week Study 2 (N = 65, aged 3-25 months), NTP-CE tolerability was assessed using a 5-point scoring system; skin hydration was determined in a subset (N = 21).

RESULTS

In Study 1, mean AUC_{0 - 24 h} for skin capacitance change from baseline was 302.03 i.u. with NTP-CE and -15.90 i.u. in control areas (p < .001). With NTP-CE (at 4 h), the water content within the upper SC part was reduced (-45.10 vs. -13.39 g/cm², p = .013) and the water gradient increased (0.51 vs. 0.11 g/cm⁴, p = .036), indicating relocation of water into deeper layers. In Study 2, there was no statistically significant change from baseline in mean cutaneous tolerability scores. At days 7, 14, and 28, skin hydration had increased by 42%, 54%, and 49%, respectively (all p < .001).

CONCLUSIONS

Single and prolonged NTP-CE usage is associated with sustained and deep skin moisturization. NTP-CE is well tolerated by healthy infants.

Bespoke contrast-matched diblock copolymer nanoparticles enable the rational design of highly transparent Pickering double emulsions

We report the preparation of highly transparent oil-in-water Pickering emulsions using contrast-matched organic nanoparticles. This is achieved via addition of judicious amounts of either sucrose or glycerol to an aqueous dispersion of poly(glycerol monomethacrylate)56-poly(2,2,2-trifluoroethyl methacrylate)500 [PGMA-PTFEMA] diblock copolymer nanoparticles prior to high shear homogenization with an equal volume of n-dodecane. The resulting Pickering emulsions comprise polydisperse n-dodecane droplets of 20-100 μm diameter and exhibit up to 96% transmittance across the visible spectrum. In contrast, control experiments using non-contrast-matched poly(glycerol monomethacrylate)56-poly(benzyl methacrylate)300 [PGMA56-PBzMA300] diblock copolymer nanoparticles as a Pickering emulsifier only produced conventional highly turbid emulsions. Thus contrast-matching of the two immiscible phases is a necessary but not sufficient condition for the preparation of highly transparent Pickering emulsions: it is essential to use isorefractive nanoparticles in order to minimize light scattering. Furthermore, highly transparent oil-in-water-in-oil Pickering double emulsions can be obtained by homogenizing the contrast-matched oil-in-water Pickering emulsion prepared using the PGMA56-PTFEMA500 nanoparticles with a contrast-matched dispersion of hydrophobic poly(lauryl methacrylate)39-poly(2,2,2-trifluoroethyl methacrylate)800 [PLMA39-PTFEMA800] diblock copolymer nanoparticles in n-dodecane. Finally, we show that an isorefractive oil-in-water Pickering emulsion enables fluorescence spectroscopy to be used to monitor the transport of water-insoluble small molecules (pyrene and benzophenone) between n-dodecane droplets. Such transport is significantly less efficient than that observed for the equivalent isorefractive surfactant-stabilized emulsion. Conventional turbid emulsions do not enable such a comparison to be made because the intense light scattering leads to substantial spectral attenuation.

A new topical panthenol-containing emollient: Results from two randomized controlled studies assessing its skin moisturization and barrier restoration potential, and the effect on skin microflora

PURPOSE

Two randomized, intra-individual comparison studies were performed in healthy subjects to evaluate the skin moisturization and barrier restoration potential of a new topical panthenol-containing emollient (NTP-CE) (Study 1), and its effect on skin microflora (Study 2).

METHODS

In Study 1 (N = 23), two skin areas, one challenged with 0.5% sodium dodecyl sulfate (SDS) solution and one unchallenged, were treated with NTP-CE for 3 weeks. Transepidermal water loss (TEWL), skin hydration, and intercellular lipid lamellae (ICLL) organization were measured at regular intervals during the study. In Study 2 (N = 20), quantitative bacterial cultures were obtained over 6 h from a skin area undergoing wash stress with 10% SDS with subsequent single application of NTP-CE.

RESULTS

In Study 1, mean AUC for TEWL reduction from baseline was more pronounced with NTP-CE compared with control (-168.36 vs. -123.38 g/m²/h, p = 0.023). NTP-CE use was also associated with statistically significant improvements in stratum corneum hydration and an increase in mean ICLL length from baseline (day 22: 120.61 vs. 35.85 nm/1000 nm², p < 0.001). In Study 2, NTP-CE use had no negative impact on bacterial viability.

CONCLUSIONS

NTP-CE use has favorable and lasting effects on barrier function and repair as well as skin hydration without negatively influencing bacterial viability.

Effect of vehicle on the performance of active moisturizing substances

PURPOSE

The work is aimed at the description and study of the hydration effect of different active substances (hyaluronic acid, sericin, glycerol, and urea) incorporated in two different vehicles commonly used for compounding pharmaceutical ingredients, gel, and emulsion.

METHODS

The effects of the formulations were investigated by instrumental methods in vivo after their administration to the skin of volar forearms in a group of 20 healthy volunteers (women, mean age of 28 years). Hydration effect was observed by corneometry and barrier properties (TEWL) by tewametr at regular time intervals (1-26 h) after application of the prepared samples.

RESULTS

The results indicate that the active substances incorporated in the emulsion moisturize the skin better compared to the same substances contained in the gel. Furthermore, it was found that these ingredients, whether they are present in the emulsion or in the gel, prevent TEWL in a similar manner.

CONCLUSION

The study showed that differences exist among the tested active ingredients in their ability to moisturize the skin. These differences are dependent not only on the type and concentration of the active substance used but also on the type of vehicle in which they are applied. It was also found that the active substances influence the viscosity of the prepared formulations.

Characterization of an antioxidant surfactant-free topical formulation containing Castanea sativa leaf extract

CONTEXT

Inclusion of antioxidants in topical formulations can contribute to minimize oxidative stress in the skin, which has been associated with photoaging, several dermatosis and cancer.

OBJECTIVE

A Castanea sativa leaf extract with established antioxidant activity was incorporated into a semisolid surfactant-free formulation. The objective of this study was to perform a comprehensive characterization of this formulation.

MATERIALS AND METHODS

Physical, microbiological and functional stability were evaluated during 6 months storage at 20 °C and 40 °C. Microstructure elucidation (cryo-SEM), in vitro release and in vivo moisturizing effect (Corneometer® CM 825) were also assessed.

RESULTS AND DISCUSSION

Minor changes were observed in the textural and rheological properties of the formulation when stored at 20 °C for 6 months and the antioxidant activity of the plant extract remained constant throughout the storage period. Microbiological quality was confirmed at the end of the study. Under accelerated conditions, higher modifications of the evaluated parameters were observed. Cryo-SEM analysis revealed the presence of oil droplets dispersed into a gelified external phase. The release rate of the antioxidant compounds (610 ± 70 µgh(-0.5)) followed Higuchi model. A significant in vivo moisturizing effect was demonstrated, that lasted at least 4 h after product's application.

CONCLUSION

The physical, functional and microbiological stability of the antioxidant formulation was established. Specific storage conditions should be recommended considering the influence of temperature on the stability. A skin hydration effect and good skin tolerance were also found which suggests that this preparation can be useful in the prevention or treatment of oxidative stress-mediated dysfunctions.

Bacterial cellulose membranes as drug delivery systems: an in vivo skin compatibility study

Bacterial cellulose (BC) is a highly pure form of cellulose, produced in the form of a swollen membrane by several bacteria that demonstrated to be able to modulate the skin release of model drugs. In the present study, the skin irritation potential of BC was evaluated in human subjects. BC membranes with and without glycerin (acting as plasticizer) were tested. No significant differences were observed for transepidermal water loss (TEWL) measurements in comparison with negative control, 2 and 24 h after patch removal, which is an indicator of an absence of barrier disruption. Similar results were found for erythema. Clinical scores were zero at both times for all volunteers, with the exception of five volunteers that exhibited weak reactions. BC with glycerin provided a skin moisturizing effect statistically higher than the negative control (p=0.044), which was not observed for BC alone. The good skin tolerance found after a single application under occlusion reinforces the putative interest of BC membranes as supports for drug topical delivery. Besides modifying the mechanical properties, the inclusion of glycerin results in a skin moisturizing effect which could be clinically relevant for the treatment for skin diseases characterized by dryness, such as psoriasis and atopic dermatitis.

Effect of moisturizers on epidermal barrier function

A daily moisturizing routine is a vital part of the management of patients with atopic dermatitis and other dry skin conditions. The composition of the moisturizer determines whether the treatment strengthens or deteriorates the skin barrier function, which may have consequences for the outcome of the dermatitis. One might expect that a patient's impaired skin barrier function should improve in association with a reduction in the clinical signs of dryness. Despite visible relief of the dryness symptoms, however, the abnormal transepidermal water loss has been reported to remain high, or even to increase under certain regimens, whereas other moisturizers improve skin barrier function. Differing outcomes have also been reported in healthy skin: some moisturizers produce deterioration in skin barrier function and others improve the skin. Possible targets for barrier-influencing moisturizing creams include the intercellular lipid bilayers, where the fraction of lipids forming a fluid phase might be changed due to compositional or organizational changes. Other targets are the projected size of the corneocytes or the thickness of the stratum corneum. Moisturizers with barrier-improving properties may delay relapse of dermatitis in patients with atopic dermatitis. In a worst-case scenario, treatment with moisturizing creams could increase the risks of dermatitis and asthma.

Treating atopic dermatitis: safety, efficacy, and patient acceptability of a ceramide hyaluronic acid emollient foam

Advances in current understanding of the pathophysiology of atopic dermatitis have led to improved targeting of the structural deficiencies in atopic skin. Ceramide deficiency appears to be one of the major alterations in atopic dermatitis and the replenishment of this epidermal component through topically applied ceramide based emollients appears to be safe, well tolerated, and effective. Recently a ceramide hyaluronic acid foam has become commercially available and increasing evidence supports its safety and efficacy in patients who suffer from atopic dermatitis.

Xerosis of the feet: a comparative study on the effectiveness of two moisturizers

The treatment for xerosis (dry skin) is the repeated use of moisturizers to hydrate the skin. Their use is based on sound evidence of the importance of maintaining the skin's water content. Although the skin on the plantar surface of the foot is very thick, it is highly visco-elastic and copes with high levels of frictional, compressive and shear stresses applied to it by being supple and well hydrated. Problems arise when the skin becomes dry and loses its elastic properties. Fissures can occur which are often painful and can act as portals for infection. This article describes a double-blind clinical study to evaluate and compare the effectiveness of two commonly used moisturizers and to see if one was significantly better than the other at hydrating the skin of the feet. The two creams used were Aqueous Cream BP and CCS Foot Care Cream. Skin hydration levels were measured before any application of moisturizer and again after two weeks of twice daily application. Results showed that the regular use of both moisturizers had a significant hydrating effect on the skin. However, CCS Foot Care Cream had a significantly greater hydrating effect than Aqueous Cream BP.

Evaluation of functional stability and batch-to-batch reproducibility of a Castanea sativa leaf extract with antioxidant activity

A growing body of evidence suggests that free radicals are generated by UV irradiation being responsible for skin injury. In this regard, the topical use of formulations composed of plant extracts with antioxidant activity could represent a useful strategy for the prevention of photoaging and oxidative-stress-mediated diseases. The aim of this study was to assess the reproducibility of the extraction method and the functional stability of a Castanea sativa leaf extract in view of its application as topical antioxidant. Measurements of 1,1-diphenyl-2-picryl hydrazyl (DPPH) scavenging activity, total phenols (measured by the Folin Ciocalteu assay) and phenolic composition (high-performance liquid chromatography unit coupled to a UV detector) were carried out on three different batches. The influence of pH and temperature on the extract's DPPH scavenging activity was assessed in aqueous and glyceric solutions (0.025% w/v) over a 3-month period. Minor differences were found between the three extract batches for all the evaluated parameters, and therefore the reproducibility of the extraction method can be inferred. pH presented a great influence in the extract functional stability. Major antioxidant activity decrease was found at pH 7.1, while lower changes were observed at pH 5. Glyceric solutions were stable throughout the test period. At 40 degrees C and pH 5, a marked decrease of activity was observed. Again, glyceric solutions were the most stable, even at 40 degrees C. Proper selection of pH and solvent is mandatory to ensure the stability of the studied extract after being incorporated in semisolid forms. In view of these results, glycerine is proposed as the best vehicle for topical formulations incorporating C. sativa leaf extract, which should have a pH around 5.

Emollient, humectant, and fluorescent alpha,beta-unsaturated thiol esters for long-acting skin applications

We describe compounds in which an emollient or a humectant bears an alpha,beta-unsaturated thiol ester capable of reacting with nucleophilic amino acids in stratum corneum proteins. These compounds should serve as long-lasting moisturizers for skin. The emollient derivatized was octadecyl propanoate, and the humectant was poly(ethylene glycol). These hydrophobic and hydrophilic compounds, as well as a fluorescent, dansyl-containing thiol ester, were found to react within minutes with the thiol N-acetylcysteamine upon addition of a catalytic amount of an organic base in chloroform. The structures of the products resulting from conjugate addition to the unsaturated thiol esters were determined by NMR spectroscopy. In the case of the alpha,beta,gamma,delta-unsaturated (sorboyl) thiol ester, both the 1,4-addition product and the beta,gamma-unsaturated-1,6-addition product formed, followed by diadduct. An in vivo test of the fluorescent alpha,beta-unsaturated thiol ester showed that this compound persisted on skin for 3 weeks vs. 6 days for the non-bonding control compound.

Measuring the effects of topical moisturizers on changes in stratum corneum thickness, water gradients and hydration in vivo

BACKGROUND

Moisturizers are the most commonly used topically applied product for the treatment of dry skin conditions. They affect many properties and functions of the stratum corneum but some moisturizers have been reported to be detrimental to barrier function. Stratum corneum barrier function is a composite of its total structure and thickness but few studies have taken this into account. As a biosensor, the stratum corneum (SC) will change its structure in response to treatment and a swelling effect has been clearly demonstrated by skin hydration. Recently several moisturizing agents have been shown to have an effect on SC swelling behaviour with conflicting results. However, there is a paucity of data reported for measuring the effects of long-term usage of moisturizers on SC thickness in vivo as, until recently, traditional techniques did not have the resolution to measure the effects of moisturizers on nonpalmoplantar body sites. The development of confocal Raman spectroscopy for use in human subjects provides noninvasive, real-time, in vivo measurement of SC water concentration profiles and we have also used this state of the art equipment to measure the effect of the long-term use of moisturizers on SC thickness for the first time.

OBJECTIVES

To validate the use of confocal Raman spectroscopy (CRS) to measure SC thickness and then use it to investigate the short- and long-term effects of moisturizers (one of which is known to improve SC barrier function) on SC thickness, water gradients and hydration.

METHODS

Two studies were conducted: (i) to validate the use of CRS for measuring SC thickness through comparison with optical coherence tomography (OCT); and (ii) once validated to use CRS to measure the long-term effects of three commercially available moisturizers (A, B, C) on SC thickness and water gradients, together with total hydration, over a 3-week period (2 weeks of treatment and 1 week regression) and compare the spectroscopy-derived hydration value with instrumentally derived capacitance hydration values.

RESULTS

(i) A strong, positive correlation in SC thickness was obtained between CRS and OCT (OCT-derived thickness = 0.96 x CRS-derived thickness, r(2) = 0.93; P <0.0001). OCT was shown, however, to have a lower resolution than CRS in distinguishing SC thickness on thinner nonpalmoplantar body sites. Using the CRS method, differences in SC thickness were readily apparent on different body sites (cheek 12.8 +/- 0.9 microm, volar forearm 18.0 +/- 3.9 microm, leg 22.0 +/- 6.9 microm). (ii) Examining the effects of moisturizers in a blinded, randomized 3-week study in human volunteers (n = 14) demonstrated that only one commercially available formulation (A) changed SC water gradients, thickness and hydration as measured by CRS. These hydration data did not directly correlate with capacitance hydration values.

CONCLUSIONS

(i) In vivo CRS was validated as a technique to measure SC thickness on both palmoplantar and, particularly, on nonpalmoplantar skin sites. (ii) Moisturizers improve skin moisturization but in this study only formulation A improved SC thickness, water gradients and hydration as measured by CRS. We hypothesize that this was due to compositional differences between the products. We believe that niacinamide (nicotinamide, vitamin B(3)) is probably contributing significantly to this effect, as it has been proven to increase epidermal lipogenesis and SC barrier function in other studies. These results show that by using CRS, we were able for the first time to determine the effect of moisturizer on multiple SC barrier endpoints including SC thickness, and water content as a function of depth and total SC water content.

Glycerol and the skin: holistic approach to its origin and functions

Glycerol is a trihydroxy alcohol that has been included for many years in topical dermatological preparations. In addition, endogenous glycerol plays a role in skin hydration, cutaneous elasticity and epidermal barrier repair. The aquaporin-3 transport channel and lipid metabolism in the pilosebaceous unit have been evidenced as potential pathways for endogenous delivery of glycerol and for its metabolism in the skin. Multiple effects of glycerol on the skin have been reported. The diverse actions of the polyol glycerol on the epidermis include improvement of stratum corneum hydration, skin barrier function and skin mechanical properties, inhibition of the stratum corneum lipid phase transition, protection against irritating stimuli, enhancement of desmosomal degradation, and acceleration of wound-healing processes. Even an antimicrobial effect has been demonstrated. Topical application of glycerol-containing products improves skin properties in diseases characterized by xerosis and impaired epidermal barrier function, such as atopic dermatitis. The increase of epidermal hydration by glycerol is critical in skin conditions aggravated by dry and cold environmental conditions, e.g. winter xerosis. This paper provides a review on effects of glycerol on the skin, the mechanisms of its action, and the potential applications of glycerol in dermatology.

Do moisturizers work?

Moisturizers are used on large body surfaces to maintain the smoothness of the skin and to break the dry-skin cycle. Many healthcare professionals and patients overlook the importance of moisturizers and do not consider them to be 'active' treatments. However, evidence from clinical and experimental studies shows that moisturizers enhance both the smoothness and hydration of skin. Different moisturizers have different ingredients, and each may have a different mode of action. Some smooth the skin, others affect barrier function. Some enhance barrier function in both diseased and normal skin. Others impair barrier function in both diseased and normal skin. Defective barrier function may trigger the development of eczema. The composition of a particular moisturizer should reflect its desired therapeutic effect, i.e. a moisturizer to diminish dryness may need different ingredients from those required to improve barrier function. The content of excipients, such as emulsifiers, chelating agents and antioxidants, may have greater impact than is commonly believed. Greater tailoring of moisturizers will improve their efficacy. Confidence in the therapeutic effects of moisturizers will be enhanced by well-designed randomized controlled trials.

The clinical benefit of moisturizers

Moisturizing creams marketed to consumers often contain trendy ingredients and are accompanied by exciting names and attractive claims. Moisturizers are also an important part of the dermatologist's armamentarium to treat dry skin conditions and maintain healthy skin. The products can be regarded as cosmetics, but may also be regulated as medicinal products if they are marketed against dry skin diseases, such as atopic dermatitis and ichthyosis. When moisturizers are used on the so-called dry skin, many distinct disorders that manifest themselves with the generally recognized symptoms of dryness are treated. Dryness is not a single entity, but is characterized by differences in chemistry and morphology in the epidermis depending on the internal and external stressors of the skin. Patients and the society expect dermatologists and pharmacists to be able to recommend treatment for various dry skin conditions upon evidence-based medicine.

LEARNING OBJECTIVE

Upon completing this paper, the reader should be aware of different types of moisturizers and their major constituents. Furthermore, s/he will know more about the relief of dryness symptoms and the functional changes of the skin induced by moisturizers.