Tape Stripping In Combination Research Articles

Development of a Tape-Stripping Liquid Chromatography-Mass Spectrometry Method for Evaluating Skin Deposition of Topical Tazarotene.

Standard in vitro and ex vivo techniques for evaluating topical drug penetration utilize skin that is physiologically unlike living skin and cannot assess intra-dermal drug deposition. We combined tape stripping with liquid chromatography-heated electrospray ionization-mass spectrometry (LC-ESI-MS) to assess in vivo deposition of tazarotene after application of 0.1% cream and 0.045% lotion formulations. Ten healthy adult female participants had ~0.1 g of tazarotene lotion and cream applied to two sites each on opposite forearms. After 3 and 6 hours, 21 tape strips were used to sample progressively deeper skin layers. LC-ESI-MS was used to determine percent recovery of the applied tazarotene dose and the concentration of tazarotene recovered from even-numbered tape strips. At both sampling times, percent recovery was slightly higher with tazarotene 0.045% lotion versus 0.1% cream, though tazarotene concentrations were approximately 2-fold higher for cream than lotion at both superficial and deep skin layers. Absolute differences in tazarotene concentrations between 0.1% cream and 0.045% lotion decreased in progressively deeper skin layers, from 0.8 μg/mL at tape strip 2 to 0.09 μg/mL at tape strip 20 (6 hours post-application). Tape stripping plus LC-ESI-MS—a consistent, accurate, and non-invasive method for assessing drug delivery into layers of living skin—can be used to assess in vivo deposition of topical formulations. Results from this study, when combined with clinical data, suggest that small tazarotene-deposition differences between lotion and cream in deeper skin layers are not clinically relevant; however, lower-dose 0.045% lotion may minimize tazarotene skin exposure versus 0.1% cream, potentially resulting in a more favorable tolerability profile. J Drugs Dermatol. 2021;20(10):1105-1111. doi:10.36849/JDD.6211.

Advancement in Atopic Dermatitis Research Through the Use of a Novel Skin Tape Strip Mass Spectrometry Based Processing Protocol

Allergic skin diseases, including Atopic Dermatitis (AD), severely impair the quality of life of affected patients. AD development is linked to a damaged skin barrier function that can precede clinical AD manifestations by many months. Currently there are no effective tools to predict the development of AD or to characterize the efficacy of applied therapy. Therefore, novel approaches to advance mechanistic understanding of AD as well as clinical management of AD and related skin diseases are needed.We have developed a novel protocol that allows the assessment of skin stratum corneum lipid species and filaggrin breakdown products using minimally invasive tape stripping in combination with liquid chromatography tandem mass spectrometry. Our approach requires only two tape strips to provide quantitative data on multiple lipid species as well as on the degradation products of filaggrin, a major skin protein responsible for skin barrier, pH and moisturizing properties. The hallmark of our approach is in the ability to normalize targeted mass spectrometric data per sample total protein content that was never done before. Our approach also allows to use the same sample for proteomics studies. We have applied our novel protocol to evaluate the difference between lesional and non‐lesional stratum corneum of AD subjects and to compare AD subjects with healthy individuals. The comparison of stratum corneum from 25 healthy adult subjects and 30 AD adult patients using our methodology confirmed previously known information about the shift towards short chain ceramide species in AD lesional skin and also revealed novel factors associated with AD development. Thus, total levels of sphingomyelins, and especially those with short chain fatty acids, were found to be increased several fold in atopic lesional skin. Furthermore, lysophosphatidylcholines demonstrated a profound redistribution towards the prevalence of short chain species not only in lesional but also in non‐lesional skin of AD subjects. These novel findings suggest a global shift in fatty acid biosynthesis that might be triggered by hyperactivated type 2 immune response. In fact, the RNAseq analysis performed on stratum corneum from same subjects revealed the downregulation of expression of fatty acid elongases ELOVL3 and ELOVL6 that may explain the observed global redistribution of the long chain and short chain lipids. Furthermore, the modeling of the effect of type 2 cytokines on sphingolipids using human differentiated keratinocytes in vitro confirmed the ability of type 2 cytokines IL‐4 and IL‐13 to provoke similar changes in sphingolipids. Our current ongoing studies further validate the power of the developed methodology and the value of lysophosphatidylcholines as biomarkers of atopic disease.In conclusion, skin tape stripping in conjunction with our unique processing protocol and targeted mass spectrometric methodology opens novel possibilities in clinical research by unveiling novel biomarkers of skin diseases and by allowing clinical studies in the skin using minimally invasive methodology.Support or Funding InformationNIH/NIAID grant U19 AI117673, NIH/NIAMS grant R01 AR41256This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Novel concentrated water-in-oil emulsions based on a non-ionic silicone surfactant: Appealing application properties and tuneable viscoelasticity

Silicone excipients are non-irritating ingredients that are extensively used in topical formulations. In the present study, innovative water-in-oil emulsions with a high water content stabilised by a non-ionic silicone surfactant were developed. Effects of formulation composition on its properties and stability were investigated. It was possible to prepare highly stable emulsions with a water volume fraction of up to 80%. The emulsions exhibited desirable application properties such as non-sticky and cooling qualities. A dependency of the viscosity on the water fraction was found; this offers the opportunity to create emulsions with fine-tuned rheological properties.Furthermore, it could be shown in skin studies that the in vitro release of a hydrophilic model drug is influenced by the configuration of the oil phase. The penetration of the silicone surfactant and the other deployed additives was monitored using combined tape stripping and ATR-FTIR experiments, revealing that the compounds remain in the superficial layers of the stratum corneum, thus minimising the risk for skin irritation.

An in vivo model to evaluate the efficacy of barrier creams on the level of skin penetration of chemicals

The reservoir function and the barrier function are important properties of the skin. The reservoir function is dependent on the barrier function which, however, needs support by protective measures, in particular under working conditions. Barrier creams represent a possibility to protect the skin. In the present study, a method was developed to investigate the effectiveness of reservoir closure by different formulations. Patent Blue V in water was used as a model penetrant. Its penetration, with and without barrier cream treatment, was analyzed by tape stripping in combination with UV/VIS spectroscopic measurements. The investigations showed that the stratum corneum represents a reservoir for topically applied Patent Blue V in water. Furthermore, the barrier investigations showed that vaseline and bees wax form a 100% barrier on the skin surface. The third barrier cream, containing waxes and surfactant, only partially showed a protective effect against the penetration of Patent Blue V in water. Strong interindividual differences were observed for this barrier product. In conclusion, it was assumed that the application of barrier creams cannot replace other protective measures and should be maximally used to inhibit low-grade irritants or in combination with other protectants or in body areas where other protective measures are not applicable.

The Number of Stratum corneum Cell Layers Correlates with the Pseudo-Absorption of the Corneocytes

The removal of the stratum corneum (SC) using adhesive tapes is a common technique in cutaneous studies. The determination of the varying amounts of the SC removed would be a helpful tool in such investigations. In the present study, the cell layers of porcine SC were counted before and after removal of several tape strips using histological techniques. In addition, the pseudo-absorption of the corneocytes reflecting the amount of these cells was determined using spectroscopy. Different amounts of SC were removed using 20 tape strips. The spectroscopically determined data correlate linearly with the number of removed cell layers. Based on these results, the pseudo-absorption of the corneocytes can be used to calculate the absolute number of cell layers removed with a standard deviation of less than 11%. In this way, the SC can be quantified using the procedure of tape stripping in combination with the spectroscopic determination of the corneocytes.

Determination of penetration profiles of topically applied substances by means of tape stripping and optical spectroscopy: UV filter substance in sunscreens

Penetration profiles of topically applied drugs and cosmetic products provide important information on their efficacy. The application of tape stripping in combination with UV/VIS spectroscopy is checked to determine the local position of topically applied substances inside the stratum corneum, the penetration profile. The amount of corneocytes removed with each tape strip is quantified via the particle-dependent absorption, the pseudoabsorption, in the visible spectral range. The concentration of a typical UV filter substance, 4-methylbenzylidene camphor, is determined by optical spectroscopy using the tape strips removed originally. In this case, a time-dependent increase in the absorbance must be taken into account. Laser scanning microscopic investigations confirm that the nonhomogeneous distribution of the filter substance, on the strips, can explain this spectroscopic behavior. When reaching a homogeneous distribution, the UV spectroscopic signal reflects the correct concentration. These spectroscopic values are compared with high performance liquid chromatography (HPLC) data. The values obtained with both methods for the concentrations of 4-methylbenzylidene camphor are in good agreement. The data obtained are used to illustrate the determination of a penetration profile of a UV filter substance. The results demonstrate that the described protocol is well suited to characterize, in a simple manner, topically applied substances that have a characteristic UV/VIS absorption band.

Lateral Spreading of Topically Applied UV Filter Substances Investigated by Tape Stripping

The lateral spreading of topically applied substances is a competitive process to the penetration into the stratum corneum (SC). The penetration of topically applied UV filter substances into the human SC and the lateral spreading were investigated in vivo. Tape stripping in combination with spectroscopic measurements was used to study both processes of two UV filter substances. The concentration of both UV filters was determined inside and outside the application area by varying the application and tape stripping protocol. A spreading of the topically applied substances from the treated to the untreated areas was observed, which caused a concentration gradient. This lateral spreading depends on the time between application and tape stripping and the size of the treated skin area. Significant amounts of topically applied substances were found adjoining the application area, due to the lateral spreading which takes place on the skin surface. In general, the lateral spreading must be considered to be a competitive process when studying penetration processes of topically applied substances. It has to be considered during drug treatment of small limited skin areas and for the interpretation of recovery rates obtained in penetration studies.

Determination of stratum corneum lipid profile by tape stripping in combination with high-performance thin-layer chromatography.

Intercellular lipids in the stratum corneum (SC) are responsible for the barrier function of mammalian skin. The main components of the SC lipids are ceramides, cholesterol, and free fatty acids, as established by thin-layer chromatographic analysis of lipids extracted from the human and mammalian SC. Up to now, for lipid analysis the extracts of the entire SC has been used and information on whether the lipid composition changes with the depth in the SC is scarce. Tape stripping is a technique which removes corneocyte layers step by step with an adhesive film. The use of this technique for lipid analysis was hampered by the contamination of lipid extracts with compounds co-extracted from the tape with organic solvents used for the extraction of SC lipids. The aim of the present study was to establish a suitable analytical method for the determination of the local SC lipid composition. For this purpose, the SC samples were collected by sequential stripping with Leukoplex tape in five healthy volunteers. The lipids were extracted with ethyl acetate:methanol mixture (20:80) and separated by means of HPTLC. The results of this study revealed that the free fatty acid level is highest and the cholesterol and ceramide levels lowest in the uppermost SC layers (about 4 strippings). The levels remained unchanged in the underlying SC layers. In these layers, the ceramide level was about 60 wt% and the free fatty acid and cholesterol levels were about 20 wt% each. Ceramides could be separated into seven different fractions and the relative amounts of individual ceramide fractions did not significantly change with the SC depth. Cholesterol sulfate levels were about 5% of total cholesterol and did not change with the SC depth, except for the for the first strip where the level was about 1%. The method developed makes it possible to study the differences in the SC lipid profile in healthy and diseased human skin with relation to the SC lipid organization and to the skin barrier function in vivo.

Penetration of Titanium Dioxide Microparticles in a Sunscreen Formulation into the Horny Layer and the Follicular Orifice

Coated titanium dioxide (TiO₂) microparticles are commonly used as UV filter substances in commercial sunscreen products. The penetration of these microparticles into the horny layer and the orifice of the hair follicle was investigated. The distribution of the microparticles in the horny layer was analyzed using the method of tape stripping in combination with spectroscopic measurements. Deeper layers of the stratum corneum were devoid of TiO₂ even after repetitive application of sunscreen preparation when analyzing interfollicular areas. Only in the areas of the pilosebaceous orifices could microparticles be identified. The penetration of TiO₂ was investigated in histological skin sections. A biopsy was taken from a skin area from which the horny layer had been removed by tape stripping. In isolated areas, a penetration of coated TiO₂ into the open part of the follicle was observed. The amount of TiO₂ found in a given follicle was less than 1% of the applied total amount of sunscreens. A penetration of microparticles into viable skin tissue could not be detected.

Determination of the Horny Layer Profile by Tape Stripping in Combination with Optical Spectroscopy in the Visible Range as a Prerequisite to Quantify Percutaneous Absorption

A new method was developed to determine the horny layer profile of volunteers using tape stripping in combination with UV/visible spectroscopy. The optical absorbance and the weight of corneocyte aggregates were compared as parameters for the determination of the mass of the horny layer particles fixed to the individual tapes. It was shown that the potential disturbances influencing both parameters must be considered critically before calculating the correlation factor, found as R²_mean = 0.93 ± 0.05. It was proven that the absorbance in the visible range is better suited than the weight to quantify the amount of corneocyte aggregates removed by a single strip. The new method allows an exact anatomical localization of the individual tapes and all data obtained within the depth profile of the stratum corneum. This was exemplified by the determination of the penetration of chemical and physical UV filters into the horny layer.