CLINICAL STUDIES ON THE FOLLOWING INGREDIENTS:
The Influence of the Acyl Chain on the Transdermal Penetration-Enhancing Effect of Synthetic Phytoceramides
Background/Aims: The skin has become very attractive as a route for drug administration. Optimization of topical drug formulations by the addition of penetration enhancers may facilitate the passage of drugs through the stratum corneum. Methods: In this paper, the skin penetration effect of phytosphingosine and 9 derived phytoceramides (PCERs) on 3 transdermal model drugs (i.e. caffeine, testosterone, ibuprofen) was investigated via Franz diffusion cell experiments using split-thickness human skin. Azone was included as a positive control. Results: The main finding in our study was that the PCERs exerted a compound-dependent penetration-enhancing effect. Some of the investigated PCERs exhibited a penetration-enhancing ratio of more than 2 (mean ± SE): for caffeine PCER1 (2.48 ± 0.44), PCER2 (2.75 ± 0.74), PCER3 (2.62 ± 0.93) and PCER6 (2.70 ± 0.45) and for testosterone PCER1 (2.08 ± 0.56), PCER2 (2.56 ± 0.13), PCER3 (3.48), PCER4 (2.53), PCER5 (2.04 ± 0.14), PCER6 (2.05 ± 0.48) and PCER10 (4.84 ± 0.79), but none of them had an influence on ibuprofen. Conclusion: The investigated PCERs exhibited a penetration-enhancing effect on caffeine and testosterone but not on ibuprofen.
Veryser, Lieselotte, et al. “The influence of the acyl chain on the transdermal penetration-enhancing effect of synthetic phytoceramides.” Skin pharmacology and physiology 28.3 (2015): 124-136.
Phytosphingosine, sphingosine and dihydrosphingosine ceramides in model skin lipid membranes: permeability and biophysics
Ceramides based on phytosphingosine, sphingosine and dihydrosphingosine are essential constituents of the skin lipid barrier that protects the body from excessive water loss. The roles of the individual ceramide subclasses in regulating skin permeability and the reasons for C4-hydroxylation of these sphingolipids are not completely understood. We investigated the chain length-dependent effects of dihydroceramides, sphingosine ceramides (with C4-unsaturation) and phytoceramides (with C4-hydroxyl) on the permeability, lipid organization and thermotropic behavior of model stratum corneum lipid membranes composed of ceramide/lignoceric acid/cholesterol/cholesteryl sulfate. Phytoceramides with very long C24 acyl chains increased the permeability of the model lipid membranes compared to dihydroceramides or sphingosine ceramides with the same chain lengths. Either unsaturation or C4-hydroxylation of dihydroceramides induced chain length-dependent increases in membrane permeability. Infrared spectroscopy showed that C4-hydroxylation of the sphingoid base decreased the relative ratio of orthorhombic chain packing in the membrane and lowered the miscibility of C24 phytoceramide with lignoceric acid. The phase separation in phytoceramide membranes was confirmed by X-ray diffraction. In contrast, phytoceramides formed strong hydrogen bonds and highly thermostable domains. Thus, the large heterogeneity in ceramide structures and in their aggregation mechanisms may confer resistance towards the heterogeneous external stressors that are constantly faced by the skin barrier.
Školová, Barbora, et al. “Phytosphingosine, sphingosine and dihydrosphingosine ceramides in model skin lipid membranes: permeability and biophysics.” Biochimica et Biophysica Acta (BBA)-Biomembranes 1859.5 (2017): 824-834.
Delivery of oat-derived phytoceramides into the stratum corneum of the skin using nanocarriers: Formulation, characterization and in vitro and ex-vivo penetration studies
Deficiency or altered composition of stratum corneum (SC) lipids such as ceramides (CERs), causing skin barrier dysfunction and skin dryness, have been associated with skin diseases such as atopic dermatitis and psoriasis, and aging. Replenishing the depleted native CERs with exogenous CERs has also been shown to have beneficial effects in restoring the skin barrier. Phyto-derived CERs such as oat CERs were shown to be potential for skin barrier reinforcement. To effect this, however, the oat CERs should overcome the SC barrier and delivered deep into the lipid matrix using the various novel formulations. In an attempt to demonstrate the potential use of oat CERs, lecithin-based microemulsions (MEs) and starch-based nanoparticles (NPs) were formulated and characterized. Besides, ME gel and NP gel were also prepared using Carbopol®980 as a gelling agent. The in vitro release and penetration (using artificial four-layer membrane system) and ex vivo permeation (using excised human skin) of oat CERs from the various formulations were investigated. The results revealed ME enhanced the in vitro release and penetration oat CERs compared to the other formulations. On the other hand, the NPs retarded the release of oat CERs and small quantities of oat CERs incorporated into NP gel penetrated into the deeper layers of the multilayer membranes. The penetration-enhancing effect of ME was also observed in the ex vivo permeation studies where significant quantities of oat CERs were found in the acceptor compartment. Compared to the ME, the ME gel exhibited reduced depth and extent of oat CERs permeation. As compared to NP gel, ME gel enhanced the degree of permeation of oat CERs into the deeper layer of the skin. Generally, the gel formulations were effective in concentrating oat CERs in the SC where they are needed to be.
Tessema, Efrem N., et al. “Delivery of oat-derived phytoceramides into the stratum corneum of the skin using nanocarriers: Formulation, characterization and in vitro and ex-vivo penetration studies.” European Journal of Pharmaceutics and Biopharmaceutics 127 (2018): 260-269.
Novel phytoceramides containing fatty acids of diverse chain lengths are better than a single C18-ceramide N-stearoyl phytosphingosine to improve the physiological properties of human stratum corneum
Ceramides in the human stratum corneum (SC) are a mixture of diverse N-acylated fatty acids (FAs) with different chain lengths. C24 is the major class of FAs of ceramides. However, there are also other classes of ceramides with diverse chain lengths of FAs, and these lengths generally range from C16 to C26. This study aimed to prepare several types of phytoceramide containing diverse chain lengths of N-acylated FAs and compare them with C18-ceramide N-stearoyl phytosphingosine (NP) in terms of their effects on the physiological properties of the SC. We chose natural oils, such as horse fat oil, shea butter, sunflower oil, and a mixture of macadamia nut, shea butter, moringa, and meadowfoam seed oil, as sources of FAs and phytosphingosine as a sphingoid backbone to synthesize diverse phytoceramides. Each phytoceramide exhibited a distinctive formation of the lamellar structure, and their FA profiles were similar to those of their respective natural oil. The skin barrier properties, as analyzed in human skin, clearly demonstrated that all the phytoceramides improved the recovery rate of the damaged SC and enhanced hydration better than C18-ceramide NP did. In conclusion, natural oil-derived phytoceramides could represent a novel class of ceramides for cosmetic applications in the development of an ideal skin barrier moisturizer.
Oh, Myoung Jin, et al. “Novel phytoceramides containing fatty acids of diverse chain lengths are better than a single C18-ceramide N-stearoyl phytosphingosine to improve the physiological properties of human stratum corneum.” Clinical, cosmetic and investigational dermatology 10 (2017): 363.
Ceramides Create Youthful Skin from Within
Young people’s skin naturally contains ceramides that produce a moist, plump, wrinkle-free appearance.
Oral ceramides have grown in popularity because people feel the moist suppleness of youthful skin return within a short time after taking one small capsule each day.
Clinical studies have shown that oral phytoceramide dramatically hydrates, smooths, and rejuvenates aging and wrinkled skin.
A proprietary oral ceramide can permeate the skin from the inside out to nourish aging dermal layers analogous to how young skin is maintained.
The four layers of the epidermis contain ceramides that play a critical role in creating the natural barrier that holds in moisture, keeps out infection—and prevents wrinkles.1
First detected in 1884, ceramides have been added to some topical skin care creams since the early 1990s by major cosmetic companies to replenish the age-related loss.1 Touted as a way to diminish fine lines, wrinkles, and dryness, their effects were generally modest.2-4
To solve this problem, researchers developed an FDA-approved, oral ceramides capsule that delivers them internally—from the bloodstream—where they move up through the skin’s inner layers to dramatically hydrate, smooth, and rejuvenate aging and wrinkled skin.
Downey, Michael. “Skin-Aging Effects of Declining Ceramide Levels.”
A Prospective, Randomized, Double-Blind, Placebo-Controlled Trial of Retinol Palmitate (Vitamin A) for Symptomatic Chronic Radiation Proctopathy
Seven of ten retinol palmitate patients responded, whereas two of nine responded to placebo (P = 0.057). Mean pre-post-treatment change in Radiation Proctopathy System Assessments Scale (Δ Radiation Proctopathy System Assessments Scale) in the retinol palmitate group was 11 ± 5, whereas Δ Radiation Proctopathy System Assessments Scale in the placebo group was 2.5 ± 3.6 (P = 0.013, Mann-Whitney U test). Additionally, all five placebo nonresponders who were crossed over to treatment with retinal palmitate responded to treatment.
In our trial, retinol palmitate significantly reduced rectal symptoms of radiation proctopathy, perhaps because of wound-healing effects. The current results can serve as the foundation for future trials examining retinol palmitate in the multi-institutional setting.
A Prospective, Randomized, Double-Blind, Placebo-Controlled Trial of Retinol Palmitate (Vitamin A) for Symptomatic Chronic Radiation proctopathy.Eli D. Ehrenpreis, Ashesh Jani, Josh Levitsky, Joseph Ahn, John Hong. Diseases of the Colon & Rectum. January 2005, Volume 48, Issue 1, pp 1-8.
Effect of Process Variables on the Microencapsulation of Vitamin A Palmitate by Gelatin-Acacia Coacervation
Microcapsules of vitamin A palmitate were prepared by gelatin-acacia complex coacervation. The effects of colloid mixing ratio, core-to-wall ratio, hardening agent, the concentration of core solution, and drying method on the coacervation process and the properties of the microcapsules were investigated. The microcapsules of vitamin A palmitate were prepared using different weight ratios of gelatin and acacia, that is, 2:3, 1:1, and 3:2 under controlled conditions. The other factors studied were 1:1, 1:2, and 1:3 core-to-wall ratios; 30, 60, and 120 min of hardening time; 2, 5, and 10 ml of formaldehyde per 280 g of coacervation system as a hardening agent; and 30%, 40%, and 50% w/w vitamin A palmitate in corn oil as a core material. The drying methods used were air drying, hot air at 40°C, and freeze-drying. The results showed that spherical microcapsules were obtained for all conditions except for 30 min of hardening time, which did not result in microcapsules. The optimum conditions for free-flowing microcapsules with a high percentage of the entrapped drug were 1:1 gelatin-to-acacia ratio and 1:2 core-to-wall ratio when hardening with 2 ml formaldehyde for 60 min and using 40% w/w vitamin A palmitate in corn oil as the core concentration. In addition, drying the microcapsules by freeze-drying provided microcapsules with excellent appearance.
Effect of Process Variables on the Microencapsulation of Vitamin A Palmitate by Gelatin-Acacia Coacervation.Varaporn Buraphacheep Junyaprasert, Ampol Mitrevej, Nuttanan Sinchaipanid, Prapaporn Boonme & Dale Eric Wurster. Drug Development and Industrial PharmacyVolume 27, Issue 6, January 2001, pages 561-566. DOI:10.1081/DDC-100105181
Inclusion complexation of vitamin palmitate with β-cyclodextrin in aqueous solution
Study of the inclusion complex between vitamin A palmitate and β-cyclodextrin in aqueous solution was performed to determine the stoichiometry and the association constant of the complex by the phase solubility diagram and fluorescence intensity measurements.
Inclusion complexation of vitamin a palmitate with β-cyclodextrin in aqueous solution.Giovanni Filippo Palmieri, Pascal Wehrlé, Guy Duportail & AndrÉ Stamm. Drug Development and Industrial PharmacyVolume 18, Issue 19, January 1992, pages 2117-2121. DOI:10.3109/03639049209040925
Protective effect against sunburn of combined systemic ascorbic acid (vitamin C) and d-α-tocopherol (vitamin E)
Background: UV radiation causes acute adverse effects like sunburn, photosensitivity reactions, or immunologic suppression, as well as long-term sequelae like photoaging or malignant skin tumors. UV radiation induces tissues to produce reactive oxygen species, eicosanoids, and cytokines. Inhibition of these mediators might reduce skin damage. Antioxidants such as ascorbic acid and d-α-tocopherol have been found to be photoprotective in some in vitro studies and animal experiments. Objective: Our purpose was to assess the protective effect of systemic vitamins C and E against sunburn in human beings. Methods: In a double-blind placebo-controlled study, each of 10 subjects took daily either 2 gm of ascorbic acid (vitamin C) combined with 1000 IU of d-α-tocopherol (vitamin E) or placebo. The sunburn reaction before and after 8 days of treatment was assessed by determination of the threshold UV dose for eliciting sunburn (minimal erythema dose [MED]) and by measuring the cutaneous blood flow of skin irradiated with incremental UV doses against that of nonirradiated skin. Results: The median MED of those taking vitamins increased from 80 to 96.5 mJ/cm2 (p < 0.01), whereas it declined from 80 to 68.5 mJ/cm2 in the placebo group. Cutaneous blood flow changed significantly (p < 0.05) for most irradiation doses with decreases in those given vitamins and increases in the placebo group. Conclusion: Combined vitamins C and E reduce the sunburn reaction, which might indicate a consequent reduced risk for later sequelae of UV-induced skin damage. The increase of sunburn reactivity in the placebo group could be related to “priming” by the previous UV exposure. (J Am Acad Dermatol 1998;38:45-8.)
Eberlein-König, Bernadette, Marianne Placzek, and Bernhard Przybilla. “Protective effect against sunburn of combined systemic ascorbic acid (vitamin C) and d-α-tocopherol (vitamin E).” Journal of the American Academy of Dermatology 38.1 (1998): 45-48.
Topical ascorbic acid on photoaged skin. Clinical, topographical and ultrastructural evaluation: double‐blind study vs. placebo
Abstract: Vitamin C is known for its antioxidant potential and activity in the collagen biosynthetic pathway. Photoprotective properties of topically applied vitamin C have also been demonstrated, placing this molecule as a potential candidate for use in the prevention and treatment of skin aging.
A topically applied cream containing 5% vitamin C and its excipient was tested on healthy female volunteers presenting with photoaged skin on their low‐neck and arms in view to evaluate efficacy and safety of such treatment. A double‐blind, randomized trial was performed over a 6‐month period, comparing the action of the vitamin C cream vs. excipient on photoaged skin. Clinical assessments included evaluation at the beginning and after 3 and 6 months of daily treatment. They were performed by the investigator and compared with the volunteer self-assessment. Skin relief parameters were determined on silicone rubber replicas performed at the same time‐points. Cutaneous biopsies were obtained at the end of the trial and investigated using immunohistochemistry and electron microscopy. Clinical examination by a dermatologist as well as self‐assessment by the volunteers disclosed a significant improvement, in terms of the ‘global score’, on the vitamin C‐treated side compared with the control. A highly significant increase in the density of skin microrelief and a decrease of the deep furrows were demonstrated. Ultrastructural evidence of the elastic tissue repair was also obtained and well corroborated the favorable results of the clinical and skin surface examinations.
Topical application of 5% vitamin C cream was an effective and well‐tolerated treatment. It led to a clinically apparent improvement of the photodamaged skin and induced modifications of skin relief and ultrastructure, suggesting a positive influence of topical vitamin C on parameters characteristic for sun‐induced skin aging.
Humbert, Philippe G., et al. “Topical ascorbic acid on photoaged skin. Clinical, topographical and ultrastructural evaluation: double‐blind study vs. placebo.” Experimental Dermatology 12.3 (2003): 237-244.
Topical vitamin C protects porcine skin from ultraviolet radiation‐induced damage
Summary Ultraviolet radiation damage to the skin is due, in part, to the generation of reactive oxygen species. Vitamin C (l‐ascorbic acid) functions as a biological co‐factor and antioxidant due to its reducing properties. Topical application of vitamin C has been shown to elevate significantly cutaneous levels of this vitamin in pigs, and this correlates with the protection of the skin from UVB damage as measured by erythema and sunburn cell formation. This protection is biological and due to the reducing properties of the molecule. Further, we provide evidence that the vitamin C levels of the skin can be severely depleted after UV irradiation, which would lower this organ’s innate protective mechanism as well as leaving it at risk of impaired healing after photoinduced damage. In addition, vitamin C protects porcine skin from UVA‐mediated phototoxic reactions (PUVA) and therefore shows promise as a broad‐spectrum photoprotectant.
Darr, D., et al. “Topical vitamin C protects porcine skin from ultraviolet radiation‐induced damage.” British Journal of Dermatology 127.3 (1992): 247-253.
Topical melatonin in combination with vitamins E and C protects skin from ultraviolet-induced erythema: a human study in vivo.
In this randomized, double-blind human study, the short-term photoprotective effects of different antioxidants and their combinations were evaluated in vivo. Vitamin C (ascorbic acid), vitamin E (alpha-tocopherol) and melatonin (N-acetyl-5-methoxytryptamine) were topically applied, alone or in combination, 30 min before ultraviolet-irradiation of the skin. The erythemal reaction was evaluated visually and non-invasively using different bioengineering methods (skin color and skin blood flow). The results showed a modest protective effect of the vitamins when applied alone and a dose-dependent photoprotective effect of melatonin. Topical application of combinations of both vitamins, or of melatonin with vitamins, enhanced the photoprotective response. Better protection was obtained by using the combination of melatonin with both vitamins. The role of reactive oxygen species and oxygen-derived free radicals, as well as potential sun screening properties of the employed antioxidants, are discussed in view of possible mechanisms to explain this elevated photoprotective effect.
Darr, D., et al. “Topical vitamin C protects porcine skin from ultraviolet radiation‐induced damage.” British Journal of Dermatology 127.3 (1992): 247-253.
Antioxidant activity of fresh apples
Vitamin C is used as a dietary supplement because of its antioxidant activity, although a high dose (500 mg) may act as a pro-oxidant in the body1,2. Here we show that 100 g of fresh apples has an antioxidant activity equivalent to 1,500 mg of vitamin C and that whole-apple extracts inhibit the growth of colon- and liver- cancer cells in vitro in a dose-dependent manner. Our results indicate that natural antioxidants from fresh fruit could be more effective than a dietary supplement.
Eberhardt, Marian V., Chang Yong Lee, and Rui Hai Liu. “Nutrition: Antioxidant activity of fresh apples.” Nature 405.6789 (2000): 903.
Ferulic Acid Stabilizes a Solution of Vitamins C and E and Doubles its Photoprotection of Skin
Ferulic acid is a potent ubiquitous plant antioxidant. Its incorporation into a topical solution of 15% L-ascorbic acid and 1% α-tocopherol improved the chemical stability of the vitamins (C+E) and doubled photoprotection to solar-simulated irradiation of skin from 4-fold to approximately 8-fold as measured by both erythema and sunburn cell formation. Inhibition of apoptosis was associated with reduced induction of caspase-3 and caspase-7. This antioxidant formulation efficiently reduced thymine dimer formation. This combination of pure natural low molecular weight antioxidants provides meaningful synergistic protection against oxidative stress in skin and should be useful for protection against photoaging and skin cancer.
Lin, Fu-Hsiung, et al. “Ferulic acid stabilizes a solution of vitamins C and E and doubles its photoprotection of skin.” Journal of Investigative Dermatology 125.4 (2005): 826-832.
Topical Use of Caffeine With Hydrocortisone in the Treatment of Atopic Dermatitis
In a double-blind study, topically applied caffeine 30%-hydrocortisone 0.5% in the hydrophilic ointment was compared to betamethasone valerate 0.1% cream and to hydrocortisone 0.5% in the hydrophilic ointment. Eighty-three patients were evaluated over a three-week period for pruritus, erythema, scaling, lichenification, excoriation, oozing, and global impression. The betamethasone and caffeinehydrocortisone groups performed significantly better than the hydrocortisone group on three of the seven scales: lichenification, excoriation, and global impression. Also, the betamethasone group differed significantly from the hydrocortisone group on six of the seven scales but did not differ significantly from the caffeine-hydrocortisone group on any scale. It is suggested that caffeine is effective because it elevates local levels of cyclic adenosine-3′, 5′-monophosphate by inhibiting phosphodiesterase.
Kaplan, Robert J., et al. “Topical use of caffeine with hydrocortisone in the treatment of atopic dermatitis.” Archives of Dermatology 114.1 (1978): 60-62.
Quantitative detection of caffeine in human skin by confocal Raman spectroscopy – A systematic in vitro validation study
For rational development and evaluation of dermal drug delivery, the knowledge of rate and extent of substance penetration into the human skin is essential. However, current analytical procedures are destructive, labor intensive and lack a defined spatial resolution. In this context, confocal Raman microscopy bares the potential to overcome current limitations in drug depth profiling. Confocal Raman microscopy already proved its suitability for the acquisition of qualitative penetration profiles, but a comprehensive investigation regarding its suitability for quantitative measurements inside the human skin is still missing.
In this work, we present a systematic validation study to deploy confocal Raman microscopy for quantitative drug depth profiling in human skin. After we validated our Raman microscopic setup, we successfully established an experimental procedure that allows correlating the Raman signal of a model drug with its controlled concentration in human skin. To overcome current drawbacks in drug depth profiling, we evaluated different modes of peak correlation for quantitative Raman measurements and offer a suitable operating procedure for quantitative drug depth profiling in human skin.
In conclusion, we successfully demonstrate the potential of confocal Raman microscopy for quantitative drug depth profiling in human skin as a valuable alternative to destructive state-of-the-art techniques.
Franzen, Lutz, Juliane Anderski, and Maike Windbergs. “Quantitative detection of caffeine in human skin by confocal Raman spectroscopy–a systematic in a vitro validation study.” European Journal of Pharmaceutics and Biopharmaceutics 95 (2015): 110-116.