Skin permeation behavior of elastic liposomes: role of formulation ingredients

Introduction: With the incorporation of edge activators into the lipid bilayer structure, elasticity properties are given to liposomes. Regardless of the debate over the precise permeation mechanism of elastic liposomes, these vesicles have been proven to enhance drug permeation into or through skin in most cases.

Areas covered: This article provides an overview of the formulation ingredients of elastic liposomes and their relationship with skin permeation behavior. The ingredients are divided into two categories of basic and optional ingredients. The effect of stability on permeation behavior of the vesicles is highlighted.

Expert opinion: More attention should be paid to the stability of elastic liposomes. The different stability properties of the elastic liposomes following administration can induce different skin permeation behaviors of the vesicles. It is necessary to select the optimum composition of the elastic liposomes in order to control the stability and permeation behavior of the vesicles into or through the skin. Moreover, for the development of elastic liposomes, particular attention should also be paid to the drug leakage from the vesicles during long-term storage. The application of optional ingredients to improve the stability and/or elasticity of the elastic liposomes is becoming a new trend.     

The effect of acellular dermal matrix on drain secretions after immediate prosthetic breast reconstruction

Abstract

In recent years the acellular dermal matrix (ADM) has gained popularity in prosthetic breast reconstruction. These procedures involve placement of a closed suction drain in the reconstructed breast. Although it is now widely accepted that ADM has an overall positive effect on the outcome of breast reconstruction, data regarding its effect on postoperative drain secretions is lacking. This study was designed to quantitatively evaluate the influence of ADM on postoperative drain secretions in the setting of immediate prosthetic breast reconstruction (IPBR). This is a prospective, comparative controlled study. Two groups of 16 patients each underwent skin sparing mastectomies (SSM) and IPBR with or without ADM. Closed suction drains were left in all the reconstructed breasts and daily secretion volumes were recorded and compared. Postoperative complications were also noted. Patients in the ADM group showed higher daily and overall secretion volumes compared with patients in the control group (p = 0.014) and the time for removal of the drains was higher by an average of 5 days (13 compared with 8 days, respectively; p = 0.004). There was no correlation between ADM and infection. This study provides the first objective evidence that ADM contributes to elevated and prolonged drain secretions when used for IPBR. This might affect possible prosthesis-related complications (e.g., rotation and malposition, capsular contraction, seroma formation, and infection). This study also noted erythema of the post-mastectomy skin flaps in selected patients, which may be attributable to a local inflammatory reaction to the ADM rather than infection.     

Dermal absorption and hydrolysis of methylparaben in different vehicles through intact and damaged skin: Using a pig-ear model in vitro

Currently, there is a trend to reduce of parabens use due to concern about the safety of their unmetabolised forms. This paper focused on dermal absorption rate and effectiveness of first-pass biotransformation of methylparaben (MP) under in-use conditions of skincare products. 24-h exposure of previously frozen intact and tapestripped (20 strips) pig-ear skin to nine vehicles containing 0.1% MP (AD, applied dose of 10 μg/cm²), resulted in 2.0–5.8%AD and 2.9–7.6%AD of unmetabolised MP, and 37.0–73.0%AD and 56.0–95.0%AD of p-hydroxybenzoic acid, respectively, in the receptor fluid. The absorption rate of MP was higher from emulsions than from hydrogels, from enhancer-containing vehicles than from enhancer-free vehicles, and when skin was damaged. Experiments confirmed that the freezing of pig-ear skin slightly reduces hydrolysis of MP.After 4-h exposure of intact freshly excised and intact frozen stored skin, amount of <LOQ-2.3%AD and 2.3–3.3%AD unmetabolised MP, respectively, were found in the receptor fluid. Taking into account the number of useful properties of MP, but also the potential of systemic availability of unmetabolised MP, we consider that MP is more suitable for preserving rinse-off topical products than for leave-on products. Risk of systemic absorption of parabens should also be explored via the skin with damaged barrier.     

磷酸锌改性异种脱细胞真皮基质的理化性能

目的:观察异种脱细胞真皮基质(Xeno-ADM)与不同浓度磷酸锌化学交联后的理化性能改变。方法:选择商用Xeno-ADM为材料,分成实验组和对照组,实验组浸泡磷酸锌矿化液,选择不同浓度和时间梯度;对照组浸泡双蒸水和不做处理。两组样本均进行相同的表面性能检测,评估改性的效果和探讨样本制备方法是否合理可靠。结果:通过ICP检测确定磷酸锌交联反应的最佳浓度是1.8g/100ml。通过扫描电镜和能谱仪观察到磷酸锌晶体覆盖Xeno-ADM全层。膜的表面亲水性能在交联后明显提高,拉伸实验显示力学性能有所改善。结论:磷酸锌与异种脱细胞真皮基质交联可形成稳定的化学结合,这种改性方法能提高膜的表面理化性能。     

Red grape (Vitis vinifera L.) flavonoids down‐regulate collagen type III expression after UV‐A in primary human dermal blood endothelial cells

Red grape (Vitis vinifera L.) flavonoids including flavan‐3‐ols (eg, catechin and epicatechin), flavonols (eg, quercetin) and anthocyanins (eg, malvidin) exert anti‐inflammatory and antioxidant activities. In the skin they also have a photoprotective action, and their effects have been extensively investigated in keratinocytes, melanocytes and fibroblasts. Despite their known effects also on blood vasculature, little is known on their activities on human dermal blood endothelial cells (HDBECs), which are critically involved in skin homeostasis as well as in the pathogenesis of neoplastic and inflammatory skin diseases. We sought to study the biological effects of selected red grape flavonoids in preventing the consequences of ultraviolet (UV)‐A irradiation in vitro. Our results show that red grape flavonoids prevent UV‐A‐induced sICAM‐1 release in HDBECs, suggesting that this cell type could represent an additional target of the anti‐inflammatory activity of flavonoids. In addition, flavonoids effectively inhibited UV‐A‐induced synthesis of collagen type III at both RNA and protein level, indicating that dermal blood microvasculature could be actively involved in ECM remodelling as a consequence of skin photo‐ageing, and that this can be prevented by red grape flavonoids.     

Atypical Fibroxanthoma Revisited

Atypical fibroxanthoma (AFX) represents a rare mesenchymal neoplasm arising predominantly in the head and neck area of elderly patients. Clinically, the neoplasm is characterized by a rapid and exophytic growth with frequent ulceration of the epidermis. Histopathologically, AFX represents a well-circumscribed, dermal-based neoplasm composed of a variable admixture of large histiocytoid cells, enlarged spindled and epithelioid tumor cells, and multinucleated tumor giant cells with bizarre and pleomorphic nuclei. If strict diagnostic criteria are applied, the clinical behavior of AFX is benign in most cases, and complete excision represents the treatment of choice.     

Incarcerated and eventrated abdominal wall hernia reconstruction with autologous double-layer dermal graft in the field of purulent peritonitis—A case report

IntroductionDouble-layer dermal grafts are used for the management of complicated abdominal wall hernias in obese, high risk patients. The method has not yet been used in case of emergency in septic/dirty environment.Case reportA 76-year old female patient (BMI 36.7 kg/m²) was admitted with mechanical bowel obstruction and sepsis caused by a third time recurred, incarcerated and eventrated abdominal wall hernia. During the emergency surgery perforation of the terminal ileum and the ascending colon was detected, along with a feculent peritonitis and extended abdominal wall necrosis. Extended right hemicolectomy and necrectomy of the abdominal wall were performed. The surgery resulted in an abdominal wall defect measuring 223 cm², for the management of which direct closure was not possible. Using a specific method, an autologous dermal graft was prepared from the redundant skin. The first dermal graft was placed under the abdominal wall with 5 cm overlap, and the second layer was placed onto the first layer with 3 cm overlap in a perforated fashion. The operating time was 250 min. No significant intra-abdominal pressure elevation was measured. No reoperation was performed. On the fifth postoperative day, the patient was mobilised. She was discharged in satisfactory general condition on the 18th postoperative day. There is no recurrent hernia 8 months after the surgery.DiscussionAbdominal wall reconstruction was possible in a necrotic, purulent environment by using a de-epithelised autologous double layer dermal graft, without synthetic or biological graft implantation. The advantage of the procedure was cost-effectivity, and the disadvantage was that only in an obese patient is the sufficient quantity of dermal graft available.ConclusionA homogeneous internal and perforated outer dermal graft was suitable for bridging the abdominal gap in the case of an obese, high risk patient. Autologous dermal grafts can be a safe and feasible alternative to biological meshes in emergency abdominal wall surgeries. Evaluation of a case series can be the next cornerstone of the method described above.     

Simulated Transfer of Liquids and Powders from Hands and Clothing to the Mouth

A series of laboratory experiments was carried out to assess transfer of liquids (vinegar) and powders (calcium acetate and magnesium carbonate) from hands, arms, gloves, respirators, clothing, and pens to the oral cavity or the perioral area (the area surrounding the mouth). Experiments were carried out with four volunteers. The donor area (the hands, arms, gloves, and so on) was loaded with a known mass of the test substance and was then brought into contact the receiver area (the oral cavity or the perioral area). The percentage of the substance on the donor that transferred to the receiver (the transfer efficiency or TE) was assessed using saliva samples and gauze wipes of the perioral area. Magnesium carbonate was measured on gauze and in saliva using inductively coupled plasma/atomic emission spectrometry. Calcium acetate and vinegar were measured using ion chromatography/electrochemical detection. Average transfer efficiencies were calculated for each substance and transfer scenario; these were compared using ANOVA and Kruskal-Wallis tests. Overall, direct transfer from the hands to the oral cavity was significantly higher (mean TE = 51.6) than indirect transfer from the hands to the oral cavity via the perioral area by licking the lips (mean TE = 11.5). The results suggested higher TEs for liquids than for solids and that hand-to-mouth TEs may increase with water solubility. Transfer from bare arms to the perioral area was higher than from arms covered by cotton sleeves for both liquids and powders. Although TE data are often required by models estimating exposure by inadvertent ingestion, relatively few published data are available. This study has provided evidence of some factors that may influence transfer of chemicals from hands or objects to the mouth (physical form, use of clothing, and so on) and has provided data that are essential for the development of predictive exposure models of inadvertent ingestion exposure.