Effect of occlusion on human skin

Perianal Ulcers from Antihemorrhoidal Ointment: A Case Report and Literature Review

ABSTRACT

Perianal ulcers (PAUs) related to antihemorrhoidal product use have been recently reported in the literature through a few case reports. However, other etiologies of PAU must be ruled out, including infectious disease, inflammatory disease, malignancy, pressure injuries, radiotherapy, and other topical drugs. In this report, the authors describe two cases of PAUs due to an antihemorrhoidal ointment. In case 1, a 68-year-old woman with a history of hemorrhoids presented with PAUs after using an antihemorrhoidal ointment for 2 months. The ulcers were assessed through a histopathologic study and treated with calcium alginate dressings, with complete re-epithelialization occurring after 2 months. In case 2, a 58-year-old woman with a history of hemorrhoids developed painful PAUs while using an antihemorrhoidal ointment for 2 months. No other probable cause was found, and the ulcers were treated by discontinuing the ointment. The ulcers showed marked improvement, and complete re-epithelialization occurred after 6 weeks without additional treatment.

Strategies in surface engineering for the regulation of microclimates in skin-medical product interactions

There is a growing number of personal healthcare devices that are in prolonged contact with the skin. The functionality of these products is linked to the interface formed by the contact between the medical apparatus and the skin. The interface can be characterised by its topology, compliance, and moisture and thermal regulating capabilities. Many devices are, however, described to have suboptimal and occlusive contacts, resulting in physiological unfavourable microclimates at the interface. The resulting poor management of moisture and temperature can impact the functionality and utility of the device and, in severe cases, lead to physical harm to the user. Being able to control the microclimate is therefore expected to limit medical-device related injuries and prevent associated skin complications. Surface engineering can modify and potentially enhance the regulation of the microclimate factors surrounding the interface between a product's surface and the skin. This review provides an overview of potential engineering solutions considering the needs for, and influences on, regulation of temperature and moisture by considering the skin-medical device interface as a system. These findings serve as a platform for the anticipated progress in the role of surface engineering for skin-device microclimate regulation.

In vitro methods for screening transdermal formulations

This article provides a review of the critical in vitro assays utilized in transdermal drug development. In vitro assays such as percutaneous absorption testing and dissolution (drug release) testing are powerful tools for screening potential transdermal compounds and drug quality control, respectively. Several 2D single-cell cultures and 3D human skin equivalents are available for screening compounds with low irritation and sensitization potential. The role of each assay and its limitations and challenges will be further discussed below.

Challenges and opportunities in dermal/transdermal delivery

Transdermal drug delivery is an exciting and challenging area. There are numerous transdermal delivery systems currently available on the market. However, the transdermal market still remains limited to a narrow range of drugs. Further advances in transdermal delivery depend on the ability to overcome the challenges faced regarding the permeation and skin irritation of the drug molecules. Emergence of novel techniques for skin permeation enhancement and development of methods to lessen skin irritation would widen the transdermal market for hydrophilic compounds, macromolecules and conventional drugs for new therapeutic indications. As evident from the ongoing clinical trials of a wide variety of drugs for various clinical conditions, there is a great future for transdermal delivery of drugs.

Practical management of cutaneous reactions to the methylphenidate transdermal system: recommendations from a dermatology expert panel consensus meeting

BACKGROUND

Psychostimulants remain the most-used medications for attention-deficit/hyperactivity disorder (ADHD). The methylphenidate transdermal system (MTS) is the first stimulant patch dosage formulation to be approved by the US Food and Drug Administration for the treatment of the symptoms of ADHD in children aged 6 to 12 years. The MTS patch is approved to be applied once daily to the hip and worn for 9 hours. While cutaneous reactions may occur with any formulation of medication, they are more likely with transdermal administration.

OBJECTIVE

The purpose of this commentary was to describe the types of cutaneous reactions that have been reported with transdermal systems in general, review the cutaneous adverse events seen in clinical trials with the MTS specifically, and provide practical management suggestions for prevention and treatment of these potential cutaneous reactions.

METHODS

In September 2007, a group of child psychiatrists, pediatricians, developmental pediatricians, and pediatric neurologists who treat ADHD and have had experience in their practices with MTS convened to discuss cutaneous reactions in relation to its use. Information collected from this meeting and from the clinical trials database of the sponsor was reviewed by a panel of 3 dermatologic clinical experts in contact dermatitis and 1 pediatric dermatologist. The panel's recommendations form the basis for this report.

CONCLUSIONS

Mild to moderate erythema is a common cutaneous effect with MTS use, and is generally not a cause for discontinuation if seen in isolation. Irritant contact dermatitis is relatively common and can be reduced and treated by alternating patch application sites, moisturizing, gentle skin care, and application of topical corticosteroids at the previous patch sites if needed. Allergic contact dermatitis (ACD) and allergic contact urticaria are rare when MTS is worn as directed in the prescribing information. MTS should be discontinued if ACD is suspected.

Short- and long-term effects of single and repetitive glove occlusion on the epidermal barrier

The aim of this study was to analyse the occlusive effects of glove materials (polyvinyl chloride, natural rubber latex) on epidermal barrier function and to relate the findings to the definitions of wet work in the current German ordinance on hazardous substances (2007) and in the German technical regulations on hazardous substances (TRGS 401; 2008). Short-term effects of wearing gloves once for 4 h, as well as the long-term effects of wearing gloves for 4 h daily for 7 days were assessed in a group of 20 healthy volunteers using non-invasive methods (transepidermal water loss (TEWL), capacitance, skin colour, skin surface pH). Data were collected 30 min and 3 h after single use, as well as 1 day after a 1-week application. TEWL and capacitance data showed hyperhydration of the horny layer 30 min after a 4-h occlusion as compared to baseline (p < 0.05). Three hours later, full recovery to basal values was observed. Additionally, a significant long-term effect after daily occlusion for 4 h for 7 days could not be demonstrated. In current literature, there is controversial evidence concerning the effects of glove occlusion. This study could not verify significant damage to skin barrier after 7 days of repeated occlusion 4 h daily in healthy volunteers. These findings require further discussion regarding the definitions in the current German ordinance on hazardous substances and in the TRGS 401.

Development and characterization of film forming polymeric solutions for skin drug delivery

Film forming polymeric solutions as a novel approach for skin drug delivery were developed and characterized concerning their mechanical properties and water vapor permeability. They were developed by varying type and content of the film forming polymer as well as nature and content of the plasticizer. The resulting formulations were evaluated according to five criteria: drying time, cosmetic attractiveness, outward stickiness, integrity on skin (after 18 h) and viscosity. Among the 14 tested polymers 10 film formers yielded formulations with a positive evaluation in all five test criteria. Selected formulations were then investigated for tensile strength and elongation at break in vitro and for water vapor permeability in vitro (WVP) and in vivo (TEWL). Their mechanical properties determined in vitro were found to be not predictive for the flexibility and abrasion resistance observed on living skin. Similar to this, the results derived from the WVP and the TEWL methods were not in accordance with each other. Obviously, the investigated in vitro methods do not characterize the properties of the thin films on living skin satisfactorily. Nevertheless, the identified film forming solutions are a promising approach and will provide the basis for the further development of this novel dosage form.

Topical Bioavailability of Triamcinolone Acetonide: Effect of Occlusion

BACKGROUND/AIMS

Occlusion by covering the skin with an impermeable wrap enhances skin hydration, affects drug absorption and can induce the formation of a drug reservoir within the stratum corneum. This is desired in local therapy with topical corticosteroids. The aim of the study was to investigate the effect of occlusion before (experiment 1) and after (experiment 2) application on the penetration of triamcinolone acetonide (TACA) into the stratum corneum.

METHODS

The experiments were conducted on the forearms of 10 healthy volunteers. In experiment 1, 100 microg/cm(2) TACA in acetone were applied on 3 sites per arm, one arm having been pre-occluded for 16 h. In experiment 2, the same dose was applied on 2 sites per arm, and one arm was occluded after application until skin sampling. Stratum corneum samples were removed by tape stripping at 0.5, 4 and 24 h (experiment 1) and 4 and 24 h (experiment 2) after application. Corneocytes and TACA were quantified by ultraviolet-visible spectroscopy and HPLC, respectively. The total TACA amount penetrated into the stratum corneum was evaluated by multifactor ANOVA.

RESULTS

TACA penetration into the stratum corneum with and without pre-occlusion (experiment 1) showed no significant difference and decreased with time. Occlusion after application (experiment 2) produced a marked TACA accumulation within the stratum corneum, which persisted for 24 h.

CONCLUSION

Pre-occlusion showed no effect on the topical bioavailability of TACA in the stratum corneum. In contrast, post-occlusion enhanced the TACA penetration by a factor of 2, favouring the development of a drug reservoir.

Biophysical effects of repetitive removal of adhesive dressings on peri-ulcer skin

OBJECTIVE

To study the effect of repeated removal of four different adhesive dressings on peri-ulcer skin using quantitative non-invasive techniques.

METHOD

Forty-five patients with open (n = 29) or healed (n = 16) venous leg ulcers were included. Peri-ulcer skin was treated for 14 days with patches of two different hydrocolloid-based adhesive dressings, one polyurethane adhesive and one soft silicone adhesive dressing. Normal skin of the patients' ventral forearm was also treated identically. Adhesive patches of the dressings were replaced every second day. The skin barrier function was assessed by measuring transepidermal water loss and stratum corneum hydration by measuring electrical conductance.

RESULTS

Thirty-nine patients completed the study. The hydrocolloid adhesives increased transepidermal water loss and conductance while the polyurethane and soft silicone adhesives did not influence these parameters significantly compared with adjacent non-treated peri-ulcer skin. For normal forearm skin, similar relative effects among the four adhesives were found.

CONCLUSION

Repetitive treatment with hydrocolloid-based adhesive dressings induced major functional alterations of the stratum corneum. In contrast, a polyurethane adhesive and a soft silicone adhesive dressing did not alter transepidermal water loss or conductance of peri-ulcer skin.

The transdermal revolution

Historically, developments in transdermal drug delivery have been incremental, focusing on overcoming problems associated with the barrier properties of the skin, reducing skin irritation rates and improving the aesthetics associated with passive patch systems. More-recent advances have concentrated on the development of non-passive systems to aid delivery of larger drug molecules, such as proteins and nucleotides, as the trend for discovering and designing biopharmaceuticals continues. Fundamentally, improvements in transdermal delivery will remain incremental until there is wider acceptance of this route of administration within the pharmaceutical industry. Only then will the transdermal revolution live up to its true potential.

Skin occlusion and irritant and allergic contact dermatitis: an overview

Occlusion, widely used to enhance percutaneous absorption of drugs, also increases penetration of other chemicals and antigens, and hence may exacerbate irritant and allergic contact dermatitis. This overview summarizes the adverse effects of occlusion.

Glove powder affects skin roughness, one parameter of skin irritation

Most patients with immediate-type-hypersensitivity to natural rubber latex (NRL) give a history of hand eczema. Susceptibility to allergens is increased by irritant hand eczema due to damage to the skin barrier. Therefore, especially for employees in medical or paramedical professions, reduction in skin irritation is of importance. The present study reports the effect of glove powder on skin roughness, one feature of skin irritancy. Skin replicas, performed before and after wearing different types of gloves, were evaluated by laser profilometry. Significant alteration of skin roughness was evident and determined by different factors. Use of unpowdered Biogel gloves on prepowdered hands results in an increase in skin roughness, in contrast to the use of Biogel gloves on hands without any pre-application. On the other hand, powdered Manex neoderm gloves show no influence on the skin structure, whereas powdered Peha taft gloves also increase the roughness of the skin. Other potential candidates causing skin morphology alteration could be the glove pH, rubber chemicals with irritant potential and other characteristics of gloves, which are already under investigation.