-
Acta Dermato-venereologica Dec 2019Barrier damage, dry skin and itch are intricately linked and form the basis of many common skin diseases. Damage from environmental insults, or genetic or inflammatory... (Review)
Review
Barrier damage, dry skin and itch are intricately linked and form the basis of many common skin diseases. Damage from environmental insults, or genetic or inflammatory causes, can impair the skin barrier, resulting in an increase in transepidermal water loss and activation of itch-associated nerve fibres. The itch-scratch cycle can perpetuate skin barrier damage and itch. Topical therapeutic strategies are utilised to overcome dry skin and itch, primarily in the form of emollients. Recent advances in our understanding of the mechanisms underlying itch have enabled the development of new topical therapies, which may be incorporated into existing treatment regimes. Ultimately, treatment of dry skin and itch must be highly tailored to the individual according to their needs.
Topics: Administration, Topical; Emollients; Female; Forecasting; Germany; Humans; Male; Pruritus; Skin; Skin Absorption; Skin Diseases
PubMed: 31454051
DOI: 10.2340/00015555-3296 -
Indian Journal of Dermatology,... 2017Peptides are known to have diverse biological roles, most prominently as signaling/regulatory molecules in a broad variety of physiological processes including defense,... (Review)
Review
Peptides are known to have diverse biological roles, most prominently as signaling/regulatory molecules in a broad variety of physiological processes including defense, immunity, stress, growth, homeostasis and reproduction. These aspects have been used in the field of dermatology and cosmetology to produce short, stable and synthetic peptides for extracellular matrix synthesis, pigmentation, innate immunity and inflammation. The evolution of peptides over the century, which started with the discovery of penicillin, has now extended to their usage as cosmeceuticals in recent years. Cosmeceutical peptides may act as signal modulators of the extracellular matrix component, as structural peptides, carrier peptides and neurotransmitter function modulators. Transdermal delivery of peptides can be made more effective by penetration enhancers, chemical modification or encapsulation of peptides. The advantages of using peptides as cosmeceuticals include their involvement in many physiological functions of the skin, their selectivity, their lack of immunogenicity and absence of premarket regulatory requirements for their use. However, there are disadvantages: clinical evidence for efficacy is often weak, absorption may be poor due to low lipophilicity, high molecular weight and binding to other ingredients, and prices can be quite high.
Topics: Administration, Topical; Animals; Cosmeceuticals; Cosmetics; Humans; Peptide Fragments; Peptides; Skin Absorption
PubMed: 27451932
DOI: 10.4103/0378-6323.186500 -
Journal of Controlled Release :... Aug 2022Microneedles are a rapidly developing method for the transdermal delivery of therapeutic compounds. All types of microneedles, whether solid, hollow, coated, or... (Review)
Review
Microneedles are a rapidly developing method for the transdermal delivery of therapeutic compounds. All types of microneedles, whether solid, hollow, coated, or dissolving function by penetrating the stratum corneum layer of the skin producing a microchannel through which therapeutic agents may be delivered. To date, coated and hollow microneedles have been the most successful, despite suffering from issues such as poor drug loading capabilities and blocked pores. Dissolving microneedles, on the other hand, have superior drug loading as well as other positive attributes that make it an ideal delivery system, including simple methods of fabrication and disposal, and abundantly available materials. Indeed, dissolvable microneedles can even be fabricated entirely from the therapeutic agent itself thus eliminating the requirement for additional excipients. This focused review presents the recent developments and trends of dissolving microneedles as well as potential future directions. The advantages, and disadvantages of dissolving microneedles as well as fabrication materials and methods are discussed. The potential applications of dissolving microneedles as a drug delivery system in different therapeutic areas in both research literature and clinical trials is highlighted. Applications including the delivery of cosmetics, vaccine delivery, diagnosis and monitoring, cancer, pain and inflammation, diabetes, hair and scalp disorders and inflammatory skin diseases are presented. The current trends observed in the microneedle landscape with particular emphasis on contemporary clinical trials and commercial successes as well as barriers impeding microneedle development and commercialisation are also discussed.
Topics: Administration, Cutaneous; Drug Delivery Systems; Microinjections; Needles; Pharmaceutical Preparations; Skin; Skin Absorption
PubMed: 35662577
DOI: 10.1016/j.jconrel.2022.05.045 -
European Journal of Pharmaceutics and... Jan 2023The role of inorganic nanoparticles in our society is increasing every day, from its use in sunscreens to their introduction in analytical laboratories, pharmacy,... (Review)
Review
The role of inorganic nanoparticles in our society is increasing every day, from its use in sunscreens to their introduction in analytical laboratories, pharmacy, medicine, agricultural and other uses. Therefore, in order to establish precautions as well as correct handling of this type of material by operators, it is important to determine the ability of these compounds to travel through the different layers of the skin and to study their possible toxicological effects. In this sense, several authors have studied the ability of inorganic nanoparticles to penetrate the skin barrier by diverse methodologies in in vivo and in vitro modes. In the first case, most of the studies have been performed with animal skins that can imitate the human one (porcine, mouse and guinea pigs, among others), although human skin from surgery have been also explored. However, the use of animals is a common model that should be avoided in the following years due to ethical issues. In this sense, the use of in vitro methodologies is also usually selected to study the dermal absorption of nanoparticles through the skin. Nevertheless, most of the studies are performed with authentic animal skins, instead of the use of synthetic skins that imitate the permeability of our skin system, which has been scarcely studied. In addition, most of the literature is focused in achieving high-transdermal uptake to use nanoparticles (not only inorganic) as carriers for drugs, but little efforts have been done in the study of their inherent percutaneous absorption and toxicity. For these reasons, this review covers the current state-of-the-art of dermal absorption of inorganic nanoparticles in skin and their possible toxicity taking into account that people can be in contact with these nanomaterials in daily life, work or other places. In this sense, the observed results showed that the nanoparticles rarely reach the blood circulatory system, and no big toxicological effects were commonly found when in vivo and actual skin was used. In addition, similar results were found when synthetic skins were used, demonstrating the possibility of avoiding animals in these studies. In any case, more studies covering the dermal absorption of nanoparticles should be performed to have a better understanding of how nanoparticles can affect our health.
Topics: Humans; Animals; Mice; Guinea Pigs; Skin Absorption; Skin; Administration, Cutaneous; Nanoparticles; Nanostructures
PubMed: 36549398
DOI: 10.1016/j.ejpb.2022.12.010 -
Skin Pharmacology and Physiology 2008
Topics: Administration, Topical; Animals; Humans; Pharmacokinetics; Skin Absorption
PubMed: 18319607
DOI: 10.1159/000119708 -
Basic & Clinical Pharmacology &... Jul 2014Studies on percutaneous penetration are needed to assess the hazards after unintended occupational skin exposures to industrial products as well as the efficacy after... (Review)
Review
Studies on percutaneous penetration are needed to assess the hazards after unintended occupational skin exposures to industrial products as well as the efficacy after intended consumer exposure to topically applied medicinal or cosmetic products. During recent decades, a number of methods have been developed to replace methods involving experimental animals. The results obtained from these methods are decided not only by the chemical or product tested, but to a significant degree also by the experimental set-up and decisions made by the investigator during the planning phase. The present MiniReview discusses some of the existing and well-known experimental in vitro and in vivo methods for studies of percutaneous penetration together with some more recent and promising methods. After this, some considerations and recommendations about advantages and limitations of the different methods and their relevance for the prediction of percutaneous penetration are given. Which method to prefer will depend on the product to be tested and the question asked. Regulatory guidelines exist for studies on percutaneous penetration, but researchers as well as regulatory bodies need to pay specific attention to the vehicles and solvents used in donor and sampling fluids so that it reflects in-use conditions as closely as possible. Based on available experimental data, mathematical models have been developed to aid predictions of skin penetration. The authors question the general use of the present mathematical models in hazard assessment, as they seem to ignore outliers among chemicals as well as the heterogeneity of skin barrier properties and skin conditions within the exposed populations.
Topics: Animals; Environmental Pollutants; Humans; Microdialysis; Models, Biological; Perfusion; Risk Assessment; Skin; Skin Absorption
PubMed: 24373389
DOI: 10.1111/bcpt.12188 -
Indian Journal of Dermatology,... 2013Acitretin, a synthetic retinoid has gradually replaced etretinate in today's dermatologic practice because of its more favorable pharmacokinetics. Acitretin over the... (Review)
Review
Acitretin, a synthetic retinoid has gradually replaced etretinate in today's dermatologic practice because of its more favorable pharmacokinetics. Acitretin over the past 20 years has proven useful in a number of difficult-to-treat hyperkeratotic and inflammatory dermatoses and nonmelanoma skin cancers. It is effective both as monotherapy and in combination with other drugs for hyperkeratotic disorders. It is considered to be an established second line treatment for psoriasis and exerts its effect mainly due to its antikeratinizing, antiinflammatory, and antiproliferative effect. Its antineoplastic properties make it a useful agent for cancer prophylaxis. Evidence-based efficacy, side-effect profile, and approach to the use of acitretin would be discussed in this review. In addition to its approved uses, the various off label uses will also be highlighted in this section. Since its use is limited by its teratogenic potential and other adverse effects, including mucocutaneous effects and hepatotoxicity, this review would summarize the contraindications and precautions to be exercised before prescribing acitretin.
Topics: Acitretin; Animals; Antineoplastic Agents; Cell Differentiation; Dermatology; Humans; Keratolytic Agents; Precancerous Conditions; Skin Absorption; Skin Diseases
PubMed: 24177607
DOI: 10.4103/0378-6323.120721 -
Biopharmaceutics & Drug Disposition Jul 2019Topical nonsteroidal anti-inflammatory drug formulations are used commonly to treat musculoskeletal pain and inflammation. Drug properties and formulation composition...
PURPOSE
Topical nonsteroidal anti-inflammatory drug formulations are used commonly to treat musculoskeletal pain and inflammation. Drug properties and formulation composition are the primary determinants of the transdermal drug delivery rate. The ex vivo transdermal flux through human skin of three topical diclofenac formulations was compared.
METHODS
The formulations tested were hydrogel 1% diclofenac sodium and two emulsion gels (1.16%/2.32% diclofenac diethylamine, equivalent to 1%/2% diclofenac sodium). Human abdominal skin obtained during unrelated surgical procedures was stored at -20 °C until use. Skin specimens were thawed, prepared and placed in Franz diffusion cells (stratum corneum facing donor cell). The test formulation (~200 mg) was applied to the donor cell skin surface, and the receptor compartment was periodically sampled over 48 hours. The drug concentration in the receptor medium was determined by a validated HPLC method. Raman spectral imaging was performed to visualize the location and distribution of diclofenac.
RESULTS
After 5 hours, the cumulative amount of hydrogel diclofenac transiting the skin was about 10 times that of the emulsion gel 1.16% (P=0.0004) and about twice that of the emulsion gel 2.32% (P=0.022). Similar results were seen after 9 hours. Raman spectroscopy showed that the hydrogel formulation was a homogeneous mixture of its various components, including diclofenac. The emulsion gels were non-homogeneous, with diclofenac in close proximity to the lipophilic (paraffin) phase.
CONCLUSIONS
The transdermal transit of diclofenac from the hydrogel demonstrated a faster onset and a greater absorption rate than either emulsion gel formulation, suggesting that the hydrogel formulation may have a faster onset of action in underlying tissues vs. the emulsion gel products.
Topics: Anti-Inflammatory Agents, Non-Steroidal; Diclofenac; Female; Humans; Hydrogels; In Vitro Techniques; Permeability; Skin; Skin Absorption
PubMed: 31242332
DOI: 10.1002/bdd.2194 -
Proceedings of the American Thoracic... May 2010Numerous occupational and environmental exposures that increase asthma risk have been identified. Research and prevention have focused primarily on the respiratory... (Review)
Review
Numerous occupational and environmental exposures that increase asthma risk have been identified. Research and prevention have focused primarily on the respiratory tract. However, recent studies suggest that the skin may also be an important route of exposure and site of sensitization that contributes to asthma development. Factors that impair skin barrier function, such as filaggrin gene mutations or skin trauma, may facilitate allergen entry and promote Th2-like sensitization and subsequent asthma. Animal studies demonstrate that skin exposure to chemical and protein allergens is highly effective at inducing sensitization, with subsequent inhalation challenge eliciting asthmatic responses. A similar role for human skin exposure to certain sensitizing agents, such as isocyanates, is likely. Skin exposure methodologies are being developed to incorporate skin exposure assessment into epidemiology studies investigating asthma risk factors.
Topics: Allergens; Asthma; Dermatitis, Atopic; Environmental Exposure; Filaggrin Proteins; Humans; Skin Absorption
PubMed: 20427586
DOI: 10.1513/pats.201002-025RM -
Expert Opinion on Drug Metabolism &... Apr 2014Our skin is exposed daily to substances; many of these are neutral and safe but others are potentially harmful. In order to estimate the degree of toxicity and damage to... (Review)
Review
INTRODUCTION
Our skin is exposed daily to substances; many of these are neutral and safe but others are potentially harmful. In order to estimate the degree of toxicity and damage to skin tissues when exposed to harmful substances, skin toxicology studies are required. If these studies are coupled with suitably designed mathematical models, they can provide a powerful tool that allows appropriate interpretation of data. This work reviews mathematical models that can be employed in skin toxicology studies.
AREAS COVERED
Two types of mathematical models and their suitability for assessing skin toxicology are covered in this review. The first is focused on predicting penetration rate through the skin from a solute's physicochemical properties, while the second type of models transport processes in skin layers using appropriate equations with the specific aim of predicting the concentration of a given solute in viable skin tissues.
EXPERT OPINION
Mathematical models are an important tool for accurate valuation of skin toxicity experiments, estimation of skin toxicity and for developing new formulations for skin disease therapy. Comprehensive mathematical models of drug transport in skin, especially those based on more physiologically detailed mechanistic considerations of transport processes, are required to further enhance their role in assessing skin toxicology.
Topics: Biological Transport; Humans; Models, Theoretical; Permeability; Skin; Skin Absorption; Skin Physiological Phenomena
PubMed: 24490982
DOI: 10.1517/17425255.2014.882318