Stability, transdermal penetration, and cutaneous effects of ascorbic acid and its derivatives

Physical Properties of an Ionic Liquid Composed of Two Water-Soluble Vitamins and Enhanced Skin Permeation of Both Vitamins

: A highly viscous substance was prepared by evaporating an ethanol solution containing two hydrophilic vitamins; vitamin C, and vitamin B6. The viscous substance and physical mixture of the two vitamins were tested using a differential scanning calorimeter and an X-ray diffractometer. The highly viscous substance was found to be a liquid crystal (LC) made of these two hydrophilic vitamins. Determination by proton nuclear magnetic resonance measurement suggested that intramolecular hydrogen bonding in vitamin B6 was eliminated by the LC formation. This LC compound showed high solubility in 1,3-butanediol (almost 87%). Much higher skin permeation of both vitamin C and B6 was also observed from the LC compound than that from the physical mixture. The present LC compound containing vitamin C and vitamin B6 may be useful for pharmaceutical and cosmeceutical applications.

Paper-Based Electrochemical Devices for the Pharmaceutical Field: State of the Art and Perspectives

The current international pharmaceutical scenario encompasses several steps in drug production, with complex and extremely long procedures. In the last few decades, scientific research has been trying to offer valid and reliable solutions to replace or support conventional techniques, in order to facilitate drug development procedures. These innovative approaches may have extremely positive effects in the production chain, supplying fast, and cost-effective quality as well as safety tests on active pharmaceutical ingredients (APIs) and their excipients. In this context, the exploitation of electrochemical paper-based analytical devices (ePADs) is still in its infancy, but is particularly promising in the detection of APIs and excipients in tablets, capsules, suppositories, and injections, as well as for pharmacokinetic bioanalysis in real samples.

PF-127 hydrogel plus sodium ascorbyl phosphate improves Wharton's jelly mesenchymal stem cell-mediated skin wound healing in mice

Background

Factors such as poor engraftment, retention, and survival of the transplanted stem cells are deemed to limit their therapeutic efficacy for wound regeneration. Hence, it is necessary to explore these issues in order to resolve them. In this study, we aim to investigate the role of Pluronic F-127 (PF-127) hydrogel plus antioxidant sodium ascorbyl phosphate (SAP) in enhancing Wharton’s jelly mesenchymal stem cell (WJMSC)-mediated effectiveness on full-thickness skin wound healing in mice.

Methods

First, the cytotoxicity of PF-127 and the biological effect of SAP on the survival of WJMSCs were tested in vitro using cell viability and proliferation assays. Next, a cell suspension containing WJMSCs, PF-127, and SAP was topically administered onto an 8-mm diameter excisional full-thickness wound bed. Eight days after transplantation, the mice were sacrificed and the skin tissue was excised for histological and immunohistochemical analysis. Finally, in vivo distribution of transplanted WJMSCs was traced to investigate cell engraftment and the potential therapeutic mechanism.

Results

PF-127 was found to be cytotoxic to WJMSCs while SAP significantly improved the survival of PF-127-embedded WJMSCs. When this combination was topically transplanted onto the wound bed, wound healing was facilitated and dermis regeneration was achieved on the 8th day after surgery, as evidenced by an increase in dermal thickness, newly developed hair follicles, and collagen fiber deposition accompanied by a reduction in scar width. Further, immunohistochemical analysis demonstrated a higher number of anti-inflammatory M2 macrophages, proliferating cells, and newly formed blood vessels in the WJMSCs/PF-127/SAP group relative to all other groups. In addition, in vivo tracking results revealed a highly enhanced engraftment of WJMSCs accumulated in the dermis in the WJMSCs/PF-127/SAP group.

Conclusions

SAP significantly improves the survival of WJMSCs in PF-127 encapsulation. Further, PF-127 plus SAP is an effective combination that enhances WJMSC engraftment in the dermis, which then promotes full-thickness wound healing through potential M2 macrophage formation and angiogenesis.

Evolution of the use of antioxidants in anti-ageing cosmetics

OBJECTIVE

Skin health and beauty are a cornerstone of general well-being in humans. Anti-ageing cosmetics are used to provide a healthy and youthful appearance. Among the different cosmetic actives, antioxidants are incorporated in anti-ageing products due to their beneficial effects in preventing and minimizing the signs of skin ageing. This work aims to understand how anti-ageing formulations changed in the past 7 years regarding pure antioxidants composition.

METHODS

Data were collected from anti-ageing formulations commercialized in main stores and pharmacies in the Portuguese market. The study started on 2011 and was updated with products launched or whose composition has been renewed on 2013, 2015 or 2018.

RESULTS

Ascorbic acid and tocopherol and their derivatives were consistently the most used antioxidants in anti-ageing formulations; followed by niacinamide and retinyl palmitate. Seven ascorbic acid derivatives are currently used in anti-ageing formulations while only three tocopherol derivatives were identified in this study. Several combinations of antioxidants were routinely found, mainly tocopherol (or tocopherol derivatives) with other antioxidants and tocopherol with tocopherol derivatives. We have not identified emerging antioxidants with great impact in anti-ageing formulations even though niacinamide and retinyl palmitate exhibited over 10% more usage in 2018.

CONCLUSION

This insight is relevant to the cosmetic industry providing a better understanding of the scientific-based formulation of modern cosmetics and supports the need for innovative antioxidants in anti-ageing cosmetics.

Efficacy and safety of a 3-in-1 antiaging night facial serum containing melatonin, bakuchiol, and ascorbyl tetraisopalmitate through clinical and histological analysis

BACKGROUND

Changes induced by intrinsic and extrinsic photoaging result in signs of skin aging including altered pigmentation and wrinkles. A 3-in-1 night facial serum (NFS) was developed to treat skin aging by antioxidative and retinoid-like mechanisms.

OBJECTIVE

To determine the clinical and histological effects of the 3-in-1 NFS on signs of skin aging, clinically and histologically.

METHODS & MATERIALS

Twenty-four subjects applied serum nightly for 12 weeks, and 12 subjects continued an extension study to 24 weeks. Clinical assessment of skin quality was performed by dermatologists. Skin biopsy was performed at 12 weeks to assess histological changes.

RESULTS

There was a global aesthetic improvement over the duration of the study: +1.21 points at 12 weeks; +1.25 at 24 weeks. Skin texture, pigmentation, erythema, skin tone, complexion, lines, and wrinkles all significantly improved (P < .05). There was also a significant reduction in photodamage, hyperpigmentation, and wrinkle scores, most notably horizontal forehead expression lines, and marionette lines (P < .05 for all). Dermal and epidermal thickness increased without reaching statistical significance.

CONCLUSION

The 3-in-1 NFS had clinically and statistically significant effects on signs of skin aging after 12 weeks, which became more pronounced after 24 weeks.

Vitamin C: One compound, several uses. Advances for delivery, efficiency and stability

Vitamin C (Vit C) is a potent antioxidant with several applications in the cosmetic and pharmaceutical fields. However, the biggest challenge in the utilization of Vit C is to maintain its stability and improve its delivery to the active site. Several strategies have been developed such as: controlling the oxygen levels during formulation and storage, low pH, reduction of water content in the formulation and the addition of preservative agents. Additionally, the utilization of derivatives of Vit C and the development of micro and nanoencapsulated delivery systems have been highlighted. In this article, the multiple applications and mechanisms of action of vitamin C will be reviewed and discussed, as well as the new possibilities of delivery and improvement of stability.

Relevant Topical Skin Care Products for Prevention and Treatment of Aging Skin

Options for skin care are varied. New products are introduced constantly and it is important for the practitioner to have an understanding of products that impart beneficial results for aging skin. Educating patients to use products with scientifically proven benefits leads to better outcomes. Patients should be encouraged to use daily sunscreen, a topical retinoid every night, and a topical antioxidant daily. Supplementing the routine skin care regimen with alpha hydroxy acids, growth factors, heparin sulfate, and defensins can be addressed individually. Exogenous stem cells do not have sufficient evidence to warrant recommending them currently.

New oral liposomal vitamin C formulation: properties and bioavailability

Vitamin C is the exogenous compound necessary for a variety of metabolic processes; therefore, the efficient delivery is critical for the maintenance of body homeostasis. Vitamin C pharmacokinetics and low quantities in processed foodstuff, necessitates its continuous supplementation. In the paper, we present the new liposomal formulation of vitamin C free of harmful organic solvents. The formulation was quantitatively characterized with respect to its chemically composition and nano-structuring. The vitamin C accessibility to cells from the formulation was evaluated using evidence derived from experiments performed on cell cultures. Finally, the enhanced bioavailability of vitamin C from the formulation was demonstrated in the medical experiment.

Clinical evidence of the efficacy and safety of a new 3-in-1 anti-aging topical night serum-in-oil containing melatonin, bakuchiol, and ascorbyl tetraisopalmitate: 103 females treated from 28 to 84 days

BACKGROUND

Topical melatonin is a potent antioxidant, yet there have been few clinical studies on its anti-aging effects on the skin.

OBJECTIVES

To clinically assess the anti-aging efficacy and safety of a new 3-in-1 night facial serum (NFS) combining melatonin with bakuchiol, a novel retinol-like ingredient, and ascorbyl tetraisopalmitate, in all skin types.

METHODS

Five clinical studies were performed, with a total of 103 subjects treated from 28 to 84 days. Under dermatologist supervision, a 3-month efficacy and safety study evaluated anti-aging properties by clinical scoring and instrumental evaluations. Two studies evaluated skin hydration properties for 12 hours after a single application of NFS. Two studies were performed in oily skin: a 1-month efficacy and safety study and a 1-month comedogenesis study.

RESULTS

After 12 weeks, clinical evaluation showed a statistically significant decrease in wrinkles (11%), an increase in skin firmness (8%), a reduction in redness (70%; P < 0.01 for all), and an overall improvement in skin quality and complexion. The reduction in wrinkles and the increase in skin firmness were also supported by instrumental evaluations (Dermatop and Dynaskin). Hydration levels increased significantly from 30 minutes until 12 hours and transepidermal water loss significantly decreased after 4H and 6H. Subjects favorably evaluated the efficacy and cosmetic properties of the serum, and it was well tolerated in all skin types including oily skin.

CONCLUSIONS

This 3-in-1 NFS showed significant clinical anti-aging effects when applied once daily and was well tolerated.

Enhanced vitamin C skin permeation from supramolecular hydrogels, illustrated using in situ ToF-SIMS 3D chemical profiling

Vitamin C (ascorbic acid) is a naturally occurring, powerful anti-oxidant with the potential to deliver numerous benefits to the skin when applied topically. However, topical use of this compound is currently restricted by an instability in traditional formulations and the delivery and eventual fate of precursor compounds has been largely unexplored. Time of flight secondary ion mass spectrometry (ToF-SIMS) is an emerging technique in the field of skin research and offers detailed chemical analysis, with high mass and spatial resolution, as well as profiling capabilities that allow analysis as a function of sample depth. This work demonstrates the successful use of ToF-SIMS to obtain, in situ, accurate 3D permeation profiles of both ascorbic acid and a popular precursor, ascorbyl glucoside, from ex vivo porcine skin. The significant permeation enhancing effect of a supramolecular hydrogel formulation, produced from an amphiphilic gemini imidazolium-based surfactant, was also demonstrated for both compounds. Using ToF-SIMS, it was also possible to detect and track the breakdown of ascorbyl glucoside into ascorbic acid, elucidating the ability of the hydrogel formulation to preserve this important conversion until the targeted epidermal layer has been reached. This work demonstrates the potential of ToF-SIMS to provide 3D permeation profiles collected in situ from ex vivo tissue samples, offering detailed analysis on compound localisation and degradation. This type of analysis has significant advantages in the area of skin permeation, but can also be readily translated to other tissue types.

Ascorbic acid encapsulated into negatively charged liposomes exhibits increased skin permeation, retention and enhances collagen synthesis by fibroblasts

Ascorbic acid (AA) is widely used in cosmetic formulations due to its antioxidant property and ability to increase collagen synthesis. Here, we encapsulated AA in vesicles with different lipid compositions. Negative liposome charge favored AA skin retention, with accumulation of 37 ± 12 and 74 ± 23 μg/cm² in the epidermis and dermis, respectively, after 6 hours. Drug flux was influenced by the formulation composition, and both the presence of cholesterol and the liposomes surface charge were able to increase the amount of AA crossing the skin. The formulation was stable for at least 30 days and promoted a 7-fold increase in flux compared to free AA. Additionally, liposomes were able to interact better with keratinocytes and fibroblasts membranes. In vitro efficacy studies demonstrated that associating AA to these liposomes resulted in increased effectiveness of type I collagen synthesis by fibroblasts and regeneration of UVA-induced damage in keratinocytes. Our results demonstrate the applicability of AA-negatively charged liposomes in promoting AA cutaneous permeation and increasing the retention and flux of this molecule in the skin. This formulation also increased AA stability and effectiveness, opening new perspectives for its application in view of reducing certain skin ageing outcomes.

Antioxidants from Plants Protect against Skin Photoaging

Exposure to UV light triggers the rapid generation and accumulation of reactive oxygen species (ROS) in skin cells, with consequent increase in oxidative stress and thus in photoaging. Exogenous supplementation with dietary antioxidants and/or skin pretreatment with antioxidant-based lotions before sun exposure might be a winning strategy against age-related skin pathologies. In this context, plants produce many secondary metabolites to protect themselves from UV radiations and these compounds can also protect the skin from photoaging. Phenolic compounds, ascorbic acid and carotenoids, derived from different plant species, are able to protect the skin by preventing UV penetration, reducing inflammation and oxidative stress, and influencing several survival signalling pathways. In this review, we focus our attention on the double role of oxidants in cell metabolism and on environmental and xenobiotic agents involved in skin photoaging. Moreover, we discuss the protective role of dietary antioxidants from fruits and vegetables and report their antiaging properties related to the reduction of oxidative stress pathways.

Vitamin C-linker-conjugated tripeptide AHK stimulates BMP-2-induced osteogenic differentiation of mouse myoblast C2C12 cells

Vitamin C-linker-conjugated Ala-His-Lys tripeptide (Vit C-AHK) is a derivative of Vitamin C-conjugated tripeptides, which were originally developed as a component of a product for collagen synthesis enhancement or human dermal fibroblast growth. Here, we investigated the effect of Vit C-AHK on bone morphogenetic protein (BMP)-2-induced osteoblast differentiation in a cell culture model. Vit C-AHK enhanced proliferation of C2C12 cells and induction of BMP-2-induced alkaline phosphatase, a typical marker of osteoblast differentiation. Vit C-AHK also stimulated the phosphorylation and translocation of Smad1/5/8 to the nucleus and phosphorylation of mitogen-activated protein kinases (MAPKs) including ERK1/2 and p38. In addition, Vit C-AHK enhanced the BMP-2-induced mRNA expression of osteoblast differentiation-related genes such as ALP, BMP-2, Osteocalcin, and Runx2. Our results suggest that Vit C-AHK exerts an enhancing effect on osteoblast proliferation and differentiation through activation of Smad1/5/8 and MAPK ERK1/2 and p38 signaling and without significant cytotoxicity. These results provide important data for the development of peptide-based bone-regenerative agents and treatment of bone-related disorders.

Calcium Hydroxylapatite Combined with Microneedling and Ascorbic Acid is Effective for Treating Stretch Marks

Background:

Stretch marks can have a negative psychological impact on some individuals. Methods are available for treating stretch marks, but high-quality evidence supporting their use is limited. We treat stretch marks using injections of diluted calcium hydroxylapatite (CaHA, Radiesse) filler combined with microneedling and topical ascorbic acid. This retrospective study evaluated the effectiveness of this combined therapy.

Methods:

Subjects presented with red (n = 25) or white (n = 10) striae on their buttocks, thighs, knees, abdomen, and breasts. CaHA filler was diluted 1:1 with lidocaine 2% without epinephrine. A maximum of 3.0 mL of filler was injected per patient at all skin depths using a 23G needle. This was immediately followed by microneedling and topical application of 20% ascorbic acid. Microneedling with ascorbic acid was repeated after 1 and 2 months. Skin biopsies were obtained from a patient who later underwent abdominoplasty.

Results:

The mean (±SD) pretreatment Manchester Scar Scale scores were 12.0 (±0.8), decreasing to 7.1 (±1.4) 1 month after the final treatment, indicating improvement in stretch mark appearance (P < 0.001). Subjects were very satisfied (n = 22; 62.9%), satisfied (n = 8; 22.9%), neither satisfied nor dissatisfied (n = 4; 11.4%), or unsatisfied (n = 1; 2.8%) with their treatment results. Analysis revealed a significant correlation between Scar Scale scores and Patient Satisfaction scores (r = 0.483; P = 0.003). Skin biopsies showed increased quantity and quality of collagen and elastin fibers in areas treated with combination therapy. Procedures were well tolerated.

Conclusion:

Combining 1:1 diluted CaHA with microneedling and topical ascorbic is safe and effective for treating stretch marks.

The Roles of Vitamin C in Skin Health

The primary function of the skin is to act as a barrier against insults from the environment, and its unique structure reflects this. The skin is composed of two layers: the epidermal outer layer is highly cellular and provides the barrier function, and the inner dermal layer ensures strength and elasticity and gives nutritional support to the epidermis. Normal skin contains high concentrations of vitamin C, which supports important and well-known functions, stimulating collagen synthesis and assisting in antioxidant protection against UV-induced photodamage. This knowledge is often used as a rationale for the addition of vitamin C to topical applications, but the efficacy of such treatment, as opposed to optimising dietary vitamin C intake, is poorly understood. This review discusses the potential roles for vitamin C in skin health and summarises the in vitro and in vivo research to date. We compare the efficacy of nutritional intake of vitamin C versus topical application, identify the areas where lack of evidence limits our understanding of the potential benefits of vitamin C on skin health, and suggest which skin properties are most likely to benefit from improved nutritional vitamin C intake.

Efficacy, Safety and Targets in Topical and Transdermal Active and Excipient Delivery

A key requirement for topical and transdermal active delivery is the effective delivery of an active to a desired target site, to achieve both safe and efficacious outcomes. This chapter seeks to explore the importance of the pharmacological, toxicological and therapeutic properties of actives and excipients, as well as the site of action as complementary components in percutaneous absorption. This is crucial for optimized topical and transdermal product design.

Effect of ultrasound and heat on percutaneous absorption of l-ascorbic acid: human in vitro studies on Franz cell and Petri dish systems

OBJECTIVE

Percutaneous absorption of l-ascorbic acid (LAA) is limited due to its high hydrophilicity and low stability. Here, we investigated the effect of post-dosing sonophoresis (329 kHz, 20 mW cm^-2 ) and heat (36°C) on transdermal delivery of LAA.

METHODS

Ultrasound/heat, heat and control treatments were applied on skin surface for 2 and 5 min after topical application of C14-labelled LAA aqueous solution. After 15 min post-exposure, radioactivity was measured in tape-striped stratum corneum (TS-SC), epidermis, dermis and receptor fluid. As Franz diffusion cell model may have different acoustic response than in vivo human tissues, a novel Petri dish model was developed and compared with Franz cell model on the effects of ultrasound/heat treatment on the skin permeability.

RESULTS

Five-min ultrasound/heat treatment significantly accelerated skin absorption/penetration of LAA; 2-min treatment showed no enhancement effect on Franz diffusion cell model at the end of experiment. The use of Petri dish model significantly increased LAA concentrations in epidermis after 5 min of ultrasound/heat treatment, compared to the results of Franz cell model.

CONCLUSION

Combination of ultrasound (329 kHz, 20 mW cm^-2 ) and heat (36°C) significantly enhanced LAA transdermal penetration, when the time of treatment was sufficient (5 min). As Petri dish model was designed to simulate acoustic respond of dense human tissue to ultrasound, the difference between Franz cell and Petri dish models suggests that the enhancement effect of ultrasound/heat on skin penetration in vivo may be greater than that determined on in vitro Franz cell model.

2-O-Acyl-3-O-(1-acyloxyalkyl) Prodrugs of 5,6-Isopropylidene-l-Ascorbic Acid and l-Ascorbic Acid: Antioxidant Activity and Ability to Permeate Silicone Membranes

2-O-Acyl-3-O-(1-acyloxyalkyl) prodrug derivatives, 15, of 5,6-isopropylidene-l-ascorbic acid, VCA, and l-ascorbic acid, VC, have been characterized by measuring (1) their solubilities in water (SAQ) and in 1-octanol (SOCT); (2) the ability of one member of the homologous series, 15a, to diffuse through a silicone membrane from its application in propylene glycol:water (PG:AQ), 30:70; (3) the ability of another member of the series, 15e, to express cellular antioxidant activity (CAA) in HaCaT cells; and (4) the ability of 15e to support cell viability in HaCaT cells. All of the prodrugs were more soluble in 1-octanol than VC or VCA were. 15a, which exhibited a good balance between SOCT and SAQ, was found to deliver approximately 15 times more 15a than VCA delivered VCA through a silicone membrane from PG:AQ, 30:70. Under those conditions, no VC permeated the membrane. 15e, which hydrolyzed to release acetaldehyde as a byproduct instead of the toxin formaldehyde, exhibited approximately 30 times the antioxidant activity of VC in CaHaT cells and supported cell viability up to 900 μM in HaCaT cells.

The role of the antioxidant ascorbic acid in the elicitation of contact allergic reactions to p-phenylenediamine

BACKGROUND

An allergic contact reaction is accompanied by high oxidative stress in the skin. Pretreatment of the skin with antioxidative substances could reduce the elicitation reaction.

OBJECTIVES

To investigate, in a proof-of-principle study, whether pretreatment of the skin with the antioxidant ascorbic acid reduces the elicitation reaction to a p-phenylenediamine (PPD)-containing hair dye in sensitized subjects.

METHODS

Twelve subjects with contact allergy to PPD, a documented skin reaction to a hair dye simulation exposure model and a history of hair dye-related skin complaints were included in this study. Skin areas on the forearms were, in a left versus right design, exposed to an emulsion with ascorbic acid and an emulsion without ascorbic acid, and then to a 2% PPD-containing hair dye testing formulation. In addition, control areas were exposed to the emulsions and to the PPD-containing hair dye formulation without pretreatment. Skin reactions were graded on day (D)2 and D3.

RESULTS

Pretreatment with ascorbic acid emulsion resulted in a reduction in the elicitation reaction in 7 of 12 subjects at D3 (p = 0.046). No statistically significant difference was observed at D2.

CONCLUSIONS

Pretreatment of the skin with the antioxidant ascorbic acid had an attenuating effect on the elicitation reaction to PPD in sensitized individuals.

The role of vitamin C in pushing back the boundaries of skin aging: an ultrasonographic approach

Background

Imagistic methods stand as modern, non-invasive, and objective means of assessing the impact of topical cutaneous therapies.

Objective

This study focuses on the evaluation, by high-frequency ultrasound, of the cutaneous changes induced by topical use of a vitamin C complex at facial level.

Methods

A vitamin C-based solution/Placebo moisturizer cream was applied at facial level of 60 healthy female subjects according to a predetermined protocol. Ultrasonographic images (Dermascan C, 20 MHz) were taken from zygomatic level initially, at 40 and 60 days after therapy. The following parameters were assessed for every subject: thickness of the epidermis and dermis (mm), the number of low (LEP), medium (MEP), high echogenic pixels (HEP), and the number of LEP in the upper dermis/lower dermis (LEPs/LEPi).

Results

LEP decreased significantly in all age categories during and after therapy, but especially in the first 2 age intervals, up to the age of 50 (P=0.0001). MEP and HEP, pixel categories that quantify protein synthesis also had an age-dependent evolution in the study, increasing significantly in all age categories but most of all in the first age interval (P=0.002). Our ultrasonographic data suggest that collagen synthesis increased significantly after topical vitamin C therapy, and is responsible for the increase in MEP and HEP and consequent decrease of the LEP.

Conclusion

Our study shows that topically applied vitamin C is highly efficient as a rejuvenation therapy, inducing significant collagen synthesis in all age groups with minimal side effects.

Photoprotective effect of botanicals and vitamins: A systematic review of clinical trials

BACKGROUND

Overexposure to solar radiation is a major contributor to skin cancer development and premature skin aging. Botanical extracts and vitamins may represent novel photoprotective agents.

OBJECTIVE

We sought to systemically review clinical evidence for the use of botanically derived agents and vitamins as photoprotective agents.

METHODS

We systematically searched Embase and PubMed databases. Two independent reviewers reviewed abstracts for inclusion. Additional relevant studies were identified by a manual review of reference lists. Data from eligible studies were extracted independently and discrepancies were resolved by consensus.

RESULTS

A total of 51 studies met inclusion criteria. Limited available evidence indicates that several botanical agents and vitamins in topical or oral forms may have promising photoprotective effects. However, generalizability of results is limited by small sample sizes.

CONCLUSION AND RELEVANCE

Botanical extracts and vitamins may add to the armamentarium of sun-protective agents. Additional high-quality trials are needed to strengthen support for their use.

Organic transdermal iontophoresis patch with built-in biofuel cell

A completely organic iontophoresis patch is reported. A built-in biofuel cell is mounted on the patch that generates transdermal iontophoretic administration of compounds into the skin. The amplitude of transdermal current is tuned by integrating a conducting polymer-based stretchable resistor of predetermined resistance.

Active ingredients against human epidermal aging

The decisive role of the epidermis in maintaining body homeostasis prompted studies to evaluate the changes in epidermal structure and functionality over the lifetime. This development, along with the identification of molecular mechanisms of epidermal signaling, maintenance, and differentiation, points to a need for new therapeutic alternatives to treat and prevent skin aging. In addition to recovering age- and sun-compromised functions, proper treatment of the epidermis has important esthetic implications. This study reviews active ingredients capable of counteracting symptoms of epidermal aging, organized according to the regulation of specific age-affected epidermal functions: (1) several compounds, other than retinoids and derivatives, act on the proliferation and differentiation of keratinocytes, supporting the protective barrier against mechanical and chemical insults; (2) natural lipidic compounds, as well as glycerol and urea, are described as agents for maintaining water-ion balance; (3) regulation of immunological pathogen defense can be reinforced by natural extracts and compounds, such as resveratrol; and (4) antioxidant exogenous sources enriched with flavonoids and vitamin C, for example, improve solar radiation protection and epidermal antioxidant activity. The main objective is to provide a functional classification of active ingredients as regulatory elements of epidermal homeostasis, with potential cosmetic and/or dermatological applications.

STYLAGE®: a range of hyaluronic acid dermal fillers containing mannitol. Physical properties and review of the literature

Dermatological procedures which are considered as being minimally invasive, such as those using injectable fillers based on hyaluronic acid, revolutionized aging treatment, especially of the face. By promoting the replacement of lost volume and attenuating grooves and wrinkles, they ensure a more youthful appearance and certain functional recovery of facial aesthetics. The authors review some of the main physicochemical characteristics of these dermal fillers, highlighting the product line Stylage®, the manufacture of which includes mannitol.