Transepidermal water loss and skin conductance as barrier integrity tests

Abstract

In vitro skin permeation studies are commonly used in the risk assessment of toxic compound skin exposure. The present study examined the utility of transepidermal water loss (TEWL) and electrical conductance as barrier integrity tests before skin permeation studies in vitro using a large number of skin samples and fentanyl. TEWL and conductance of the skin samples were measured before the permeation experiments in Franz diffusion cells in vitro with a vapometer and low voltage application, respectively. The data were analyzed based on the in vitro permeation results and in vivo skin absorption information from the transdermal fentanyl product labels. The results showed poor correlations between TEWL and electrical conductance for the skin samples. Weak correlations between fentanyl delivery rate (flux × area) and TEWL and skin conductance were observed. For comparison, TEWL and conductance were also examined after skin perturbation with a syringe needle, and both TEWL and conductance values of the skin samples increased after the perturbation. The data suggest that either TEWL of 10 g/m2/h or skin conductance of 0.07 mS/cm2 can be used as exclusion criteria in skin integrity testing to remove skin samples with high permeabilities under the in vitro conditions studied.

Resistivity Technique for the Evaluation of the Integrity of Buccal and Esophageal Epithelium Mucosa for In Vitro Permeation Studies: Swine Buccal and Esophageal Mucosa Barrier Models

“…This suggests that ER could detect invisibly damaged epithelium, under the conditions employed in the present study. The effect of physical damage on ER was observed previously for esophageal epithelium mucosa [ 28 ] and skin samples [ 25 , 34 , 35 ].…”

“…Skin integrity is typically assessed prior to transdermal permeation assays. Among the different methods available, measuring electrical resistance (ER) across the skin has been used since the 1990s [ 22 , 23 ], and is considered to be simple, fast, safe, and cost-effective [ 24 , 25 , 26 ].…”

Rheological and Drug Delivery Characteristics of Poloxamer-Based Diclofenac Sodium Formulations for Chronic Wound Site Analgesia

“…Transepidermal water loss (TEWL) was chosen to measure barrier integrity before and after tape stripping in our studies due to the ease of use and because skin TEWL values increase as barrier integrity decreases, presenting a quantitative way to assess barrier disruption [ 54 , 55 ]. TEWL increased by about five times with tape stripping, proving that the skin barrier was significantly disrupted ( Figure 7 ).…”

Apremilast Microemulsion as Topical Therapy for Local Inflammation: Design, Characterization and Efficacy Evaluation

“…Normal hydration levels maintain SC flexibility and its viscoelastic characteristics in addition to facilitating the enzymatic reactions involved in the maturation of corneocytes [ 86 , 87 ]. Destabilization or damage to the skin surface by exposure to physical or chemical agents can cause changes in TEWL and SCH [ 88 , 89 , 90 ]. In this study, the evaluation of these parameters confirmed that APR-ME does not alter sebaceous function nor compromise the integrity of the skin barrier.…”