Comparative Analyses of Cyanoacrylates for Barrier Protection and Incontinence‐Related Wash‐Off Resistance

ABSTRACT

A comprehensive skincare regimen involves cleansing, moisturising, and using skin barrier protectants. Cyanoacrylate‐based protectants safeguard vulnerable skin from damage caused by moisture, friction, and shear. This research involved two ex vivo and two clinical studies comparing the wear duration and wash‐off resistance of a 100% cyanoacrylate and a solvent‐cyanoacrylate mixture. Effectiveness was assessed using an ex vivo porcine skin model simulating urinary incontinence, evaluated with Lucifer yellow dye penetration and Corneometry, and a clinical model using Corneometry. Two single‐blind clinical studies measured skin surface electrical capacitance in healthy volunteers. Study 1 (n = 42) evaluated the wear duration over 8 days, while Study 2 (n = 52) examined wash‐off resistance after nine washes with various cleansers. Ex vivo results showed that both products were effective under repeated moisture and abrasion conditions, with the 100% cyanoacrylate outperforming the solvent‐cyanoacrylate mixture. In clinical studies, both products maintained barrier protection throughout Study 1 (p < 0.007) and none of the cleansers significantly degraded either product in Study 2. In conclusion, the 100% cyanoacrylate provided superior protection compared to the solvent‐cyanoacrylate mixture. Both products demonstrated comparable wear duration and wash‐off resistance in clinical studies, but the 100% cyanoacrylate was more effective in ex vivo testing under harsh conditions.

Key Points.

• Understanding differences in skin barrier protectant (SBP) efficacy helps clinicians select the most appropriate product for patients at high risk of moisture‐associated skin damage.

• A novel method using Lucifer Yellow dye penetration proved effective for evaluating skin protectant barrier integrity and was combined with established techniques such as Corneometry to provide a comprehensive assessment of barrier performance.

• In clinical studies with healthy volunteers, both SBPs maintained an effective barrier with similar duration of wear and wash off resistance. Repeated exposure to skin cleansers did not reduce barrier performance, confirming compatibility with routine skin hygiene practices.

• In an ex vivo porcine skin model simulating urinary incontinence, SBP1 (100% cyanoacrylate) consistently maintained superior barrier integrity during combined moisture and abrasion, while SBP2 (solvent‐containing cyanoacrylate) was less effective.

• Both SBPs effectively protect at‐risk skin in scenarios involving moisture and friction. SBP1 demonstrates superior performance under simulated harsh conditions, suggesting it may be preferable for patients exposed to greater moisture and abrasion, such as during incontinence care.

1. Introduction

Skin, the largest organ of the human body, performs thermoregulatory, sensory, and immunological functions. Intact skin also acts as a protective barrier against a wide range of external forces such as mechanical trauma, infectious pathogens, noxious irritants, and moisture [1]. This protective function is achieved particularly by the outermost layer of the epidermis, the stratum corneum [2].

Prolonged exposure to moisture, such as urine, faeces, wound drainage, ostomy fluid, or perspiration, can compromise epidermal barrier integrity. This overhydration can lead to inflammation and a type of irritant contact dermatitis called moisture‐associated skin damage (MASD) [3, 4, 5]. MASD encompasses various conditions, including incontinence‐associated dermatitis (IAD), intertriginous dermatitis (ITD), periwound moisture‐associated dermatitis, and peristomal moisture‐associated dermatitis [1, 6, 7]. Skin maceration can also make it susceptible to frictional and shearing forces [8]. In addition to moisture, skin integrity can also be compromised by medical adhesives that can strip away the epidermis (Medical Adhesive‐Related Skin Injury [MARSI]) as well as aging, which is associated with epidermal thinning and reduced elasticity [9]. These factors make the skin more susceptible to damage from moisture exposure, friction, shear‐related injuries, and tears.

An essential component of a structured skincare regimen for preventing and managing MASD is the use of skin cleansers. These cleansers are vital for removing irritants and preparing the skin for subsequent steps, such as applying absorbent products and moisturisers. Cleansers are often delivered as a spray, foam, or pre‐moistened wipe. No‐rinse cleansers provide a gentle cleaning option that helps maintain skin integrity [10, 11]. After cleansing, use of a skin protectant or barrier product to shield the skin from further moisture damage is recommended [12, 13]. Skin protectants are designed to remain intact for several days, even during routine hygiene or incontinence care. However, these situations often involve exposure to cleansers, which may compromise the integrity and performance of the protectant. Understanding how different cleansers interact with barrier protectants, as well as their effectiveness over time and under the strain of washing and abrasion, is critical to ensure consistent protection.

Cyanoacrylate‐based liquid wound dressings are a class of skin barrier protectants (SBPs) that can be used on at‐risk skin [14]. These SBPs have a high affinity for moisture. Contact with moisture present in the skin triggers a “chain reaction,” leading to the formation of a polymeric substance that interacts with and adheres to the skin at the molecular level [14, 15], and protects it from moisture, friction, shear‐related breakdown, as well as minor skin tears or abrasions.

This research was conducted to compare the performance of two cyanoacrylate‐based skin barrier protectants (SBPs) and determine differences in their barrier effectiveness, duration of wear, and resistance to cleansing under simulated conditions. It includes two ex vivo preclinical studies and two clinical studies. The ex vivo studies utilized a porcine skin model of urinary incontinence to compare barrier effectiveness between the two SBPs under harsh simulated conditions of urinary incontinence. The clinical studies involved two distinct groups of healthy volunteers. Study 1 evaluated the duration of wear of the two SBPs to assess barrier protection over time. Study 2 examined the impact of different types of cleansers on the SBPs to determine their wash‐off resistance. Our findings show that one SBP demonstrated superior performance under harsh conditions, while the efficacy of neither SBP was affected by cleanser exposure—an important consideration for healthcare professionals when selecting products for patient care.

2. Materials

2.1. Skin Barrier Protectants

The two SBPs evaluated in this study were Medline Marathon XL No Sting Cyanoacrylate Skin Protectant, a 100% cyanoacrylate formulation (referred to as “SBP1”) and 3M Cavilon Advanced Skin Protectant, a solvent‐containing cyanoacrylate formulation (solvent‐cyanoacrylate mixture; referred to as “SBP2”).

2.2. Skin Cleansers

The skin cleansing agents used in the study were as follows: (1) Remedy Phytoplex Hydrating Cleansing Gel (henceforth referred to as “Cleanser A”); (2) Remedy Hydrating Cleansing Foam (“Cleanser B”); (3) Remedy Hydrating Cleansing Spray (“Cleanser C”); and (4) Remedy Intensive Skin Therapy PhosphoCleanse No‐Rinse Foam Cleanser (“Cleanser D”). Five sprays were used for spray cleansers or one pump for foam cleansers to ensure equal application of each cleanser.

2.3. Corneometer

A Corneometer CM 825 device (referred to as “Corneometer”) ([Courage‐Khazaka Electronic GMB]), measures the hydration level of the stratum corneum in terms of skin electrical capacitance (SEC; measured as arbitrary capacitance units [A.C.U.]) [16, 17, 18]. Presence of a skin protectant creates a barrier between the stratum corneum and the Corneometer probe. In this scenario, measurement of SEC helps provide a non‐invasive method to determine the effectiveness of the SBP barrier integrity through indirect measurement.

3. Methods

This research comprised four studies comparing the two SBPs. Two ex vivo studies used a porcine model of urinary incontinence to assess the barrier protection provided by the SBPs. One study measured SBP barrier effectiveness through measurement of SEC, while the other visualised dye penetration below the skin surface. Additionally, two clinical studies were conducted using SEC: one to determine the duration of wear and the other to evaluate wash‐off resistance. The methodologies of these studies are summarised in the sub‐sections below, with additional details provided in the Supporting Information.

3.1. Ex Vivo Porcine Skin Studies

3.1.1. Porcine Skin Model of Urinary Incontinence

Frozen porcine skin, comprising epidermal and dermal layers with a consistent thickness (1.524 mm ± 0.254 mm) (Stellen Medical LLC) was acclimated to normal room conditions. The epidermal surface was gently washed with five pumps of a mild skin cleanser (Remedy Phytoplex Cleanser No‐Rinse Foam, Medline Industries, LP), allowed to air dry, and test sites were marked with a marker. SBP1 and SBP2 (10 μL) were applied to treated test sites. Untreated sites were used as controls.

Simulated conditions of urinary incontinence were created by exposing skin to repeated rounds of moisture and mechanical challenge. Moisture exposure was achieved using Normal Simulated Urine (Carolina Biological Supply), which mimics key physical properties of urine such as pH and specific gravity for standardised testing. Each challenge cycle consisted of a moisture challenge in Normal Simulated Urine (30 min at 37 ± 2°C), followed by gentle cleaning and then abrasion (500 wipes with the weighted Tool 3 and moistened sponge accessory at a rate of 37 strokes/min) using the Elcometer 1720 Washability and Abrasion Tester. Skin was air dried between cycles. A total of four cycles were performed.

3.1.2. Lucifer Yellow Staining and Microscopy

Lucifer Yellow (RRID: AB_2536190) (1 mM) was applied to all test sites, except autofluorescence controls, and skin was incubated for 1 h at 37 ± 2°C, protected from light. Skin was washed in Dulbecco's Phosphate‐Buffered Saline (DPBS), test sites were harvested, fixed in 10% buffered formalin, transferred to a sucrose gradient, and frozen in Optimal Cutting Temperature (O.C.T.). Frozen tissue sections (8 μm) were mounted with Vectashield Antifade Mounting Medium with 4′,6‐diamidino‐2‐phenylindole (DAPI) (RRID: AB_2336789) and observed using a FluoView FV10i Confocal Laser Scanning Microscope (Olympus, Japan). Image stitching was performed by acquiring and merging a sequence of images into one expansive, comprehensive image.

3.1.3. Corneometry

The Corneometer was used to measure SEC. Measurements were taken before and after SBP application and after one and four rounds of moisture challenge and wash/abrasion. Three technical replicate measurements were taken per independent test site, and their mean was considered as the outcome measurement for that test site in a given cycle. Data were reported in arbitrary Corneometry units (A.C.U.) and presented as the mean A.C.U. ± standard deviation (n = 5 per group).

4. Clinical Studies

4.1. Inclusion and Exclusion Criteria for the Clinical Studies

Inclusion Criteria: Participants were required to be 18 years or older, able to understand and willing to follow study instructions.

Exclusion Criteria: The exclusion criteria common to both studies included individuals who were pregnant or breastfeeding, those with skin conditions that might interfere with Corneometer measurements (such as rash, irritation, sunburn, tattoo, birthmark, excessive hair, or any other dermal irregularities on the left or right volar forearm or inner elbow), and individuals with self‐reported allergies or sensitivities to ingredients present in either of the SBPs, components of the hypoallergenic bar soap used for bathing, or the exam gloves and non‐toxic marker used in the study. Additionally, individuals who could identify the manufacturer of the SBPs included in the study or those deemed inappropriate for the study by the Principal Investigator were excluded. For Study 1, an additional exclusion criterion was individuals whose self‐reported activities could affect friction on one arm more than the other.

Participants for the two clinical studies were recruited and screened to ensure they met inclusion criteria and none of the exclusion criteria. Informed consent was obtained from all participants, detailing the requirements, restrictions, procedures, and risks associated with study participation. Additionally, demographic information was collected from the participants.

4.2. Study 1: Duration of Wear of SBPs

Forty‐two healthy individuals were recruited for this single‐blind randomised study using inclusion and exclusion criteria mentioned above. Recruitment was followed by a washout period of at least 18 h before the initial visit, during which participants avoided applying cleansers, lotions, or perfumes to their forearms and inner elbows. During the initial visit, participants washed their forearms and inner elbows with hypoallergenic bar soap and dried them with paper towels. Six 2‐in. × 2‐in. squares were then marked on the participants' volar forearms and inner elbows, and baseline Corneometer measurements were taken.

All participants received both SBPs, which were randomised such that SBP1 or SBP2 was applied to the participants' dominant arm (“designated” SBP). The “designated” SBP and the “other” SBP were applied to the volar forearm and inner elbow “test sites” on the participant's dominant arm (as determined by the participant) and non‐dominant arms, respectively. A distinct area of each volar forearm was used as an “untreated control site”. Corneometer measurements were repeated on the same day after the SBPs dried for at least 1 min (post‐SBP). Subsequent measurements were taken once per day, 24 ± 4 h apart, over an eight‐day period. A two‐day break occurred over the weekend, resulting in measurements at approximately 24, 48, 72, 96, 120, 144, and 168 h (Figures 1 and 2).

FIGURE 1.

Diagrammatic representation of the methodology for Study 1.

FIGURE 2.

Randomization of untreated control sites and test sites on the volar forearms and inner elbows. The inner elbow test sites received the same SBP as the one applied to the test site of the same arm.

Participants were given specific instructions to minimise abrasion of their volar forearms and inner elbows. At the final study visit (168 h), the last set of Corneometer measurements was taken. Participants also completed surveys regarding their experience with the two SBPs at specific timepoints during the study. Adverse events were monitored throughout the study duration. Note: The Corneometer took five measurements for each site and the average SEC ± standard deviation was reported in A.C.U.

4.3. Study 2: Wash‐Off Resistance of SBPs

Fifty‐two healthy volunteers were recruited according to the inclusion and exclusion criteria. Participants first washed their forearms and inner elbows with standardised soap and dried them. They were then randomised into SBP1 or SBP2 groups, with 2‐in. × 2‐in. squares marked on each volar forearm. SBP1 or SBP2 was applied, and baseline Corneometer measurements were taken 1 min post‐SBP application. Five squares were included in the final analysis. Four of these served as test sites, each assigned to one of the cleansers labelled A through D, and the fifth served as the unwashed control site (Figures 3 and 4). Initially, five cleansers were tested in the study, but due to technical issues and user errors, the results for one cleanser were invalidated and excluded from the analysis.

FIGURE 3.

Diagrammatic representation of the methodology for Study 2.

FIGURE 4.

Untreated control site and test sites on the volar forearms for Study 2. All five sites were treated with the same SBP (either SBP1 or SBP2). Each cleanser (A–D) was then applied to one of the four SBP test sites for subsequent washes.

Cleansers A–D were applied sequentially to their designated test sites using a lint‐free wipe, followed by Corneometer measurements after a 10‐min wait. This process was repeated for eight rounds, with measurements taken after each round. Adverse events were monitored throughout the study. The Corneometer took five measurements for each test site, and the average SEC ± standard deviation was reported in A.C.U.

4.4. Statistical Analysis for Clinical Studies

Data were entered into Microsoft Excel and then imported into Stata version 18. Data were cleaned and checked for accuracy and no missing data were noted.

Descriptive statistics were computed to describe the study samples. Continuous level data were reported as mean (range) and categorical data were presented as frequencies and percentages (Table 1). Samples from clinical studies 1 and 2 were comparable with mean age in the 30s and total age ranges from 20s to 60s. Study 1 was 50% females and Study 2 had slightly more with 70% females. Study 1 also collected Fitzpatrick skin scores with the modal score of 3 (approximately 48%).

TABLE 1.

Sample characteristics: Healthy adults (Study 1 [n = 42]; Study 2 [n = 52]).

Characteristic	Study 1	Study 2
Age, years Mean (range)	35 (23–58)	31 (22–63)
Sex, n (%)
Female	21 (50.00%)	36 (69.00%)
Male	20 (47.62%)	16 (31.00%)
Declined to answer	1 (2.38%)	n/a
Fitzpatrick scale, n (%)		n/a
I	1 (2.38%)
II	15 (35.71%)
III	20 (47.62%)
IV	5 (11.90%)
V	1 (2.38%)
VI	0 (0.00%)

All study outcome measures were measured as continuous data. The independent variable of age was a continuous measurement, with sex (male/female) and the Fitzpatrick scale (I–VI) as categorical measurements (only measured in Study 1). Continuous data were analysed using box and whisker plots as well as the Shapiro–Wilkes test for normality. Since all continuous outcome measures were found to be normally distributed, parametric test statistics were used.

All continuous variables were determined to be normally distributed for both clinical studies. Independent sample t‐tests were used to determine significant differences between SBP1 and SBP2 Corneometer measurements at a given visit. Paired sample t‐tests were used to compare the SBP1 and SBP2 values across visits; the adjusted Bonferroni p‐value was set to 0.007. For Study 2, paired t‐tests within single cleansers were conducted to determine significant differences in Corneometer readings between washes. To account for 9 t‐tests (baseline v. wash 1, wash 1 v. wash 2, wash 2 v. wash 3, wash 3 v. wash 4, wash 4 v. wash 5, wash 5 v. wash 6, wash 6 v. wash 7, wash 7 v. wash 8, wash 8 v. wash 9), the adjusted Bonferroni p‐value was set to 0.0056.

Secondary endpoints included one categorical outcome on comfort level and all other survey results were dichotomous outcomes. The categorical outcome distributions were compared between SBP1 and SBP2 using Chi‐square tests. Proportion tests were used to examine significant differences between the proportion of people who reported “yes” between SBP1 and SBP2 products for the dichotomous outcomes. p < 0.05 was considered statistically significant.

5. Results

5.1. Ex Vivo Porcine Studies

5.1.1. Porcine Skin Electrical Capacitance

Skin protectant barrier efficacy was evaluated using an ex vivo porcine skin model of urinary incontinence. Porcine skin was exposed to conditions simulating urinary incontinence through repeated rounds of moisture challenge and abrasion. Each challenge cycle consisted of a 30‐min incubation in simulated urine, followed by gentle cleansing, and then some test sites underwent abrasion (500 wipes moistened sponge using the Elcometer 1720 Abrasion and Washability Tester and Tool 3 accessory), with 30 min of dry time between cycles. Using the Corneometer, SEC measurements were obtained on each test site before SBP application and following one and four cycles of moisture and abrasion challenge. The electrical capacitance of SBP1‐treated test sites remained consistent throughout the course of the experiment, with mean SEC around 1 A.C.U. for each cycle, regardless of challenge (*p < 0.005, compared to pre‐treatment baseline, $p < 0.005, compared to untreated test sites within the same cycle). In contrast, SBP2 treatment reduced electrical capacitance post‐application (#p < 0.005) but was not statistically different from baseline after moisture and abrasion challenge. SBP2 treatment was different from untreated control following the first moisture and abrasion challenge ($p < 0.005) but not different from untreated controls following the fourth moisture and abrasion challenge. In less harsh conditions of moisture challenge alone, SBP2 was statistically different from untreated control within the same cycle. These results demonstrate that the SEC was reduced following application of both skin protectant products but lost during harsh conditions combining moisture and abrasion challenge with SBP2 application, suggesting loss of barrier properties only with SBP2 (Figure 5).

FIGURE 5.

Effect of SBPs on porcine skin electrical capacitance after moisture challenge and abrasion. Corneometer measurements were taken before and after SBP application, and following one and four challenge cycles involving either moisture‐challenge alone or moisture combined with abrasion. Data are presented as the mean skin electrical capacitance (SEC) ± standard deviation (n = 5 per group). Statistical significance was determined as follows: *p < 0.005 compared to baseline, #p < 0.005 compared to post‐SBP application, $p < 0.05 compared to untreated control within the same cycle (n = 5 per group).

5.1.2. Visual Assessment of Marked Test Sites and Lucifer Yellow Dye Penetration

Test sites (three per group) were marked on porcine skin, treated with or without skin protectant, and then either left unchallenged or subjected to one or four cycles of simulated urine moisture exposure and abrasion using the Elcometer 1720 Abrasion and Washability Tester. Since test sites were drawn onto the skin using a marker and then covered with an SBP (or no product used as negative control), the ability of the SBP to prevent the marker from washing away over time was used as an indirect qualitative measure of its efficacy. Fading of the marker was observed following Cycle 1 in untreated groups and continued to diminish through Cycle 4. Marker fading was minor in both SBP1‐ and SBP2‐treated sites (Figures 6 and 7).

FIGURE 6.

Testing schematic for Lucifer yellow staining studies. The Elcometer carriage containing Tool 3 with a weighted sponge tool and moistened sponge accessory moved back and forth across the top portion of the test material. The bottom portion was used for autofluorescence and non‐abraded controls.

FIGURE 7.

Scanned test material: Barrier treatment and post‐cycle images. Scanned images of porcine skin before and after treatment with barrier products and after moisture challenge and wash abrasion cycles. Test sites #13–21 were processed for Lucifer Yellow staining following Cycle 1. Test sites #22–30 were processed following Cycle 4.

The Lucifer Yellow exclusion method relies on the principle that intact skin restricts the passage of hydrophilic molecules, while compromised skin permits deeper penetration. To evaluate the effectiveness of barrier products below the skin surface, a novel method was developed that utilises Lucifer Yellow, a small, water‐soluble fluorescent dye, for assessing penetration into porcine tissue sections. Healthy, intact skin limits the permeability of Lucifer Yellow, retaining it within the epidermis and preventing deeper penetration [19]. Conversely, damaged or compromised skin allows more dye to pass through, indicating a weakened barrier [20]. While Lucifer Yellow is widely used in dermatological research to assess skin barrier integrity, to our knowledge this is the first description of its application in the context of barrier products on the skin surface. Since effective skin protectants should create a physical barrier and moisture shield, product effectiveness was measured by evaluating Lucifer Yellow penetration in an ex vivo porcine skin model of urinary incontinence. Transverse sections were viewed in two ways: one providing detailed insights by observing individual panels, and the other allowing for visualisation of the entire section through image stitching.

In non‐abraded sites, Lucifer Yellow was retained in the epidermis in all skin protectant‐treated test sites and two of the three untreated sites. Test sites that underwent washing/abrasion demonstrated varying degrees of Lucifer Yellow penetration. After the first wash/abrasion cycle, all three untreated sites had multiple or large areas of Lucifer Yellow penetration throughout each section. Conversely, Lucifer Yellow remained in the epidermis in all SBP1‐treated sites, while one SBP2‐treated site had a prominent area of penetration. After four moisture/abrasion cycles, Lucifer Yellow penetration became more intense. Two of the three untreated sites had multiple or large areas of intense penetration, with one site missing a large section of the epidermal layer and showing Lucifer Yellow staining in the dermal layer. Conversely, Lucifer Yellow was retained in the epidermis in two out of three SBP1‐treated samples, with one showing only minor penetration. Lucifer Yellow penetration was significantly more pronounced in SBP2‐treated sites, with staining observed below the surface at one site and intense staining at another site where the epidermis was missing. Control test sites not treated with Lucifer Yellow were used to determine tissue autofluorescence and showed negligible staining (data not shown) (Figures 8 and 9).

FIGURE 8.

Effect of SBP1 and SBP2 on dye Lucifer yellow penetration. Confocal microscopy images of skin sections stained with Lucifer Yellow and DAPI, observed at 1× (top panel) and 3× (bottom panel) magnifications. DAPI, which stains nuclei, is shown in blue, while Lucifer Yellow appears in yellow. The skin protectant SBP1 effectively prevents the penetration of Lucifer Yellow dye, whereas SBP2 does not.

FIGURE 9.

Stitched images of Lucifer yellow‐stained tissue. Individual images were stitched together to create a confocal mosaic so that the entire section could be viewed in the same picture. DAPI‐stained nuclei appear blue and Lucifer yellow appears yellow.

6. Clinical Studies

6.1. Study 1

6.1.1. Duration of Wear of the SBPs

The duration of wear was evaluated by examining the mean SEC at each visit over a 168‐h study period. Mean baseline measurements before SBP application were 36.71 ± 9.99 for SBP1 and 36.31 ± 1.60 for SBP2. Both SBP1 and SBP2 application reduced mean SEC. The lowest mean measurement for SBP1 was post‐application (7.95 ± 5.31 A.C.U), while for SBP2, it was at 24 h (17.00 ± 6.06 A.C.U). Skin treated with SBP1 had statistically lower SEC post‐application compared to SBP2 (7.95 ± 5.31 A.C.U vs. 20.98 ± 1.34 A.C.U) and at 24 h (9.58 ± 7.80 A.C.U vs. 17 ± 6.06 A.C.U) (p < 0.007). No statistical difference was observed between the two SBPs at later time points.

Neither SBP1 nor SBP2‐treated test sites completely returned to untreated/baseline SEC levels by the end of the study. Paired sample t‐tests showed that SBP1‐treated test sites showed significantly lower SEC measurements at all time points compared to baseline, indicating that the presence of SBP1, and hence barrier protection, was maintained across all time points (p < 0.007). Similar results were observed with SBP2, with paired sample t‐tests indicating that SBP2 maintained barrier protection across all time points compared to baseline (p < 0.007) (Figure 10). Skin capacitance levels for untreated controls remained consistent across the duration of the study (data not shown).

FIGURE 10.

Duration of wear of the SBPs over time. Duration of wear was determined by evaluation of skin electrical capacitance (SEC) over time. Data are presented as mean SEC ± standard deviation. Independent sample t‐tests were conducted to determine significant differences between SBP1 and SBP2 Corneometer measurements at each timepoint (*p < 0.05). Paired sample t‐tests with Bonferroni adjustment were used for comparison to respective baseline values across timepoints (#p < 0.007 for SBP1 and &p < 0.007 for SBP2) (n = 42).

6.1.2. Participant Experience With the SBPs

Results of a participant survey showed that SBP2 was statistically significantly more comfortable than SBP1. However, SBP2 was also significantly more prone to adhering to clothing and accumulating dirt and debris compared to SBP1 (for additional details, refer to Table S1 in the Supporting Information).

6.2. Study 2

6.2.1. Evaluation of SBP Wash‐Off Resistance

The wash‐off resistance of the SBPs was assessed through a series of nine washes using four different skin cleansers. No significant changes were observed in the wash‐off resistance of the SBPs, with SBP1 having an average A.C.U. change of 1.3 ± 2.8 and SBP2 had an average A.C.U. change of 18.3 ± 7.51. The A.C.U. values were compared between washes for a series of nine washes and from baseline (Wash 0) to the final wash (Wash 9). Among the nine SBP–cleanser combinations and nine washes (81 paired t‐tests), none of the tests showed significant results (p > 0.0056). Hence, there was insufficient evidence to suggest any change in the effectiveness of the barrier function of either SBP1 or SBP2 between application and the final (wash 9) wash (Figure 11).

FIGURE 11.

Wash‐off resistance of SBPs following washes with skin cleansers. Corneometer measurements were taken before and after product application and following each of nine wash cycles. Four cleansers were independently tested. Data are presented as mean skin electrical capacitance (SEC) ± standard deviation. Paired t‐tests were conducted within single cleansers between washes with Bonferonni adjusted p‐value at 0.0056. No statistical differences were observed between washes for all cleansers tested (n = 52).

7. Discussion

The SBPs involved in this research have been used in multiple applications, including the prevention of at‐risk skin from various sources of moisture such as in the case of IAD [21, 22], peristomal MASD [23], management of periwound skin [24], skin excoriation [25], as well as the management of skin tears [26, 27].

These types of SBPs offer multiple advantages. They form a transparent, flexible film, allowing for better visualisation of the underlying skin and ease of application [28]. Additionally, these SBPs do not dissolve in water, making the film resistant to bodily fluids [14]. Furthermore, since the SBPs bond chemically with the skin, they are removed naturally as the stratum corneum sloughs off [14, 29]. Newer generations of cyanoacrylate SBPs, like SBP1, are typically solvent‐free, eliminating the stinging sensation associated with solvents. The absence of solvents also ensures that most of the product remains on the skin where it is applied [14].

The current research evaluated the effectiveness of two SBPs to form a barrier on the skin surface by utilizing pre‐clinical and clinical models. Our results suggest that the solvent‐free 100% cyanoacrylate formulation (SBP1) forms a long‐lasting, effective barrier even under harsh conditions of simulated urinary incontinence, while the solvent‐containing cyanoacrylate formulation (SBP2) was less effective.

Skin barrier efficacy was evaluated using three different methods—visual assessment of the surface, Lucifer Yellow penetration beyond the epidermis, and skin electrical capacitance using Corneometry. Each method provided unique insights into product effectiveness. Evaluating skin barrier properties through electrical capacitance and conductance is well established [30, 31, 32]. For instance, skin barrier function effectiveness was previously assessed by measuring changes in the water content of the stratum corneum via skin surface conductance testing. The superficial stratum corneum rapidly absorbs water when exposed to an aqueous environment, altering skin surface conductance. An effective barrier prevents this water uptake. A skin surface hygrometer (Skicon 200EX, I.B.S. Co. Ltd., Japan) non‐invasively evaluated skin surface conductance using a high frequency (3.5 MHz) electric current, indicating the degree of protection provided by barrier products after a single application and any reduction in barrier properties after repeated washing [32]. Similarly, hydration of the stratum corneum was measured using a Corneometer where capacitance reflects the water content of the outermost layer of the skin [30, 32].

Likewise, SEC is dependent upon the water content of the stratum corneum. It can be measured using a non‐invasive probe widely utilised in dermatology, the Corneometer, which has a depth of measurement of 10–20 μm [33]. In our research, we observed an immediate reduction in SEC following SBP application, with a more dramatic reduction occurring with SBP1 (Study 1). We propose that the difference in reduction may be due to product composition and thickness on the skin surface, as described by Gibson et al. [34]. In this study, standard transverse section microscopy of haematoxylin and eosin‐stained tissue coated with SBPs under differential interference contrast (DIC) lighting demonstrated that the cyanoacrylate‐only product (SBP1) was 5.1 times thicker than the solvent‐cyanoacrylate mixture product (SBP2). Furthermore, scanning electron microscopy demonstrated that SBP2 had decreased coverage when compared to SBP1, as SBP1 formed a thin, uniform film, whereas a lack of continuity from one cyanoacrylate cluster to the next was observed with SBP2, indicating breaks in the product [34]. Therefore, the increase in SEC observed with SBP2‐treated sites in our preclinical model of urinary incontinence can be presumed to be a measure of its breakdown.

The data presented in the current research suggest that both SBPs form effective barriers following application, but that barrier breakdown occurs during harsher conditions such as combined moisture challenge and abrasion, simulating urinary incontinence. While minimal difference was noted between products under clinical conditions (Study 1), the test sites were located on volar forearms of the volunteers, where little moisture exposure and abrasion is expected. On the other hand, the porcine skin model simulating urinary incontinence is an excellent pre‐clinical representation of a real‐world scenario, where SBPs would be exposed to moisture (for e.g., incontinence) and abrasion/friction (from diapers, clothing, and wiping). In this scenario, Lucifer Yellow penetration was more prominent in SBP2‐treated test sites compared to SBP1‐treated sites, with areas of missing epidermis observed only in SBP2‐treated sites.

The results from the clinical wash‐off resistance study (Study 2) indicated that the skin cleansers did not significantly affect the barrier function effectiveness of either SBP. These findings suggest that the cleansers are compatible with both SBP1 and SBP2, maintaining their integrity and effectiveness. The study is significant for clinical practice, as it helps to alleviate concerns that specific cleansers might degrade the efficacy of certain skin protectants. This evidence supports the continued use of these products in preventing and managing friction‐induced skin breakdown in patients.

Based on a participant survey assessment, SBP2 was reported to be more comfortable than SBP2. However, SBP2 collected more dirt and debris and was more likely to attach to clothing (Study 1). Interestingly, after reviewing the results of a study by Mathisen et al. [35], it is our inference that dust, dirt, and lint appear to accumulate in SBP2‐covered test sites, a phenomenon not observed in SBP1 test sites. This accumulation could presumably be due to the tackiness of the SBP2 product. Similarly, Gibson et al. [34] found that when filter paper was pressed onto SBP‐coated porcine skin, it adhered to SBP2 and removed a large contiguous portion of epithelium upon lifting. No visible skin cells were observed when the same was performed on SBP1‐coated skin.

The study's strengths include the robust methodology and adequate sample size used for the studies, which helps provide confidence in the results.

One of the limitations of the current research was that the Lucifer yellow penetration studies were conducted using porcine skin, which is thicker, more elastic, has less active melanocytes, and has a different hair follicle density and structure than human skin. However, porcine skin is the closest model to human skin in terms of proliferation index, structural, physiological, and histological characteristics and allowed the evaluation of the characteristics of the two SBPs by employing fluorescence and molecular biological techniques [36, 37]. For clinical Study 1, the use of a model representing urinary incontinence may have exposed the SBPs to greater strain, which would be expected in a scenario like IAD. Future studies can be considered to compare the duration of wear of the SBPs under such conditions. However, the two SBPs can be used on intact skin and in case of skin tears and prevention of MARSI, rendering the current results relevant. Another limitation is that the participants may not represent the skin characteristics of a broader patient population. Therefore, future studies should include participants representing a wider range of skin tones and characteristics. Additionally, clinical Study 2 was limited to a specific set of cleansers and skin protectants, which may not be generalizable to other products. Future research could explore the long‐term effects of repeated cleanser use on skin barrier protectants and other potential factors influencing their degradation. Furthermore, the interactions between different types of skin protectants and a broader range of cleansers could be examined.

8. Conclusions

The current research showed that SBP1 provided superior protection than SBP2. Both SBPs demonstrated comparable duration of wear and wash‐off resistance in healthy volunteers. However, SBP1 performed better during ex vivo testing under harsh conditions involving moisture and abrasion, showing superior effectiveness of SBP1 in such a scenario.

Funding

This work was supported by Medline Industries, LP.

Ethics Statement

The two clinical studies were approved by the Advarra Institutional Review Board (IRB): Study 1 (Pro00065625); Study 2 (Pro00066403). The protocol and informed consent form (ICF) for both studies were approved prior to enrollment of any study participants. These studies were conducted in accordance with US Food and Drug Administration (FDA) regulations (21 CFR Parts 50, 54, 56, and 312), the ethical principles of the Declaration of Helsinki, all applicable International Conference on Harmonization (ICH) and Good Clinical Practice (GCP) guidelines, and all local laws and regulations concerning clinical studies.

Conflicts of Interest

All authors have been employed full‐time at Medline Industries, LP since the initial planning of the work and at the time of manuscript submission.

Supporting information

Data S1: Supporting Information.

Pradhan M. A., Nicholson L. M., Coles L. S., Campbell J. J., and Curtis B. J., “Comparative Analyses of Cyanoacrylates for Barrier Protection and Incontinence‐Related Wash‐Off Resistance,” International Wound Journal 23, no. 1 (2026): e70807, 10.1111/iwj.70807.

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.