Alexa Teichmann

Charité Universitätsmedizin Berlin, Berlín, Berlin, Germany

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Publications (23)55.49 Total impact

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    ABSTRACT: Vehicle dependent effects on the penetration behavior of drugs following topical application are well known from the literature. In this context, many reports concerning the enhancing activities for hydrophilic as well as lipophilic substances by colloidal drug carrier systems, particularly microemulsions, are available. However, there is little knowledge about the localization of the drugs within the skin and the stratum corneum, respectively. In the present study, the lipophilic dye curcumin incorporated in an oil-in-water microemulsion and in an amphiphilic cream was applied onto the skin of human volunteers. Using the method of tape stripping to remove the stratum corneum (SC), the depth profiles of the dye within the horny layer were compared. Applying the microemulsion, a deeper part of the SC was accessible by a number of 20 tapes removed and significantly smaller amounts of curcumin were found on the skin surface. Also differences in the distribution and localization of the dye within the stratum corneum were observed by laser scanning microscopy. Furthermore, curcumin was detected in hair follicles. It was obvious that the microemulsion led to a penetration into the complete follicular infundibula, whereas, following application of the cream, a fluorescence signal was only received from the follicular orifices.
    European Journal of Pharmaceutics and Biopharmaceutics 12/2007; 67(3):699-706. DOI:10.1016/j.ejpb.2007.04.006 · 4.25 Impact Factor
  • M Ossadnik · V Czaika · A Teichmann · W Sterry · H-J Tietz · J Lademann · S Koch
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    ABSTRACT: Investigations concerning the penetration of topically applied drugs are the subject of a multiplicity of research, as the exact knowledge of these mechanisms is the prerequisite for the optimization of such substances. As the hair follicles represent a good long-term reservoir for topically applied substances, it can be assumed that they also represent a reservoir for microorganisms residing on and in the skin. Therefore, the hair follicles must be seen as one main site of action for antimicrobial substances and a simple non-invasive in vivo method for the determination of penetration of antimicrobial substances into the hair follicles. The aim of the present study was to show that differential stripping, by removing the hair follicle content selectively, represents a suitable method to demonstrate the penetration of antifungal substances into the hair follicles. The follicular casts, removed from skin areas of human volunteers, which were partially pre-treated with brilliant green (well-known antifungal properties), were applied on agar plates inoculated with Candida albicans. The results showed inhibited growth of C. albicans, if the follicular casts were removed from skin areas pre-treated with brilliant green. This indicates clear evidence that brilliant green had penetrated into the hair follicles. Therefore, differential stripping represents a suitable method to determine the penetration of antifungal substances into the hair follicles, which is of clinical importance for the optimization of topical antifungal therapeutics.
    Mycoses 12/2007; 50(6):457-62. DOI:10.1111/j.1439-0507.2007.01415.x · 1.81 Impact Factor
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    ABSTRACT: Often barrier creams (BC) do not fulfil their protecting behaviour, even when promised by the manufacturers. Therefore, it is of great importance to develop standardized in vivo techniques to prove the potency of BC in humans. In the present study, 3 promising techniques for the analysis of BC were evaluated: laser scanning microscopy, laser doppler flowmetry, and the tape-stripping procedure. Sodium fluorescein and glycerol trinitrate acted as hydrophilic model-penetrating substances. By means of these methods, 3 different BC were tested and compared for their potency. The investigations showed that primarily the tape-stripping procedure and also the laser scanning microscopy are promising tools for the evaluation of BC. In contrast, the laser doppler flowmetry represents a less feasible technique. In addition, the evaluation of BC showed that Vaseline enfolds a 100% barrier on the skin surface for the penetration of a hydrophilic dye, whereas BC1 only partially showed a protective effect and BC2 exhibited almost no potency. In conclusion, it can be referred that laser scanning microscopy and the tape-stripping procedure represent 2 non-invasive in vivo techniques, which enable a fast investigation concerning the potency of BC.
    Contact Dermatitis 07/2007; 56(6):347-54. DOI:10.1111/j.1600-0536.2007.01125.x · 3.62 Impact Factor
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    ABSTRACT: Optical, non-invasive methods, such as fluorescence laser scanning microscopy (LSM) and optical coherent tomography (OCT), have become efficient tools for the characterization of the skin structure in vivo, as well as real-time investigation of distribution and penetration of topically applied substances. In the present paper, the results obtained with both non-invasive methods - OCT and LSM - were compared to conventional light microscopy of histological sections. Skin structure and the distribution of topically applied particulate and non-particulate substances on the skin surface and in the epidermis were analyzed. None of the methods used are suitable for the realization of all diagnostic tasks, however, each method has advantages for particular applications. Fluorescence LSM is well suited for the investigation of the upper 150 microm of the skin as well as for the investigation of the kinetics of substances applied onto or into the epidermis. OCT can be applied for the investigation of vertical cross-sections of the skin up to a depth of 2 mm, albeit at lower resolution than achieved by LSM or conventional light microscopy. Conventional light microscopy of histological sections of biopsy specimens produces familiar high-resolution images of deeper tissue layers. However, the analysis of the kinetic processes is limited in this case. LSM- and OCT-measurements are efficient non-invasive tools for the characterization of morphological structures of the skin. On the one hand, the optical methods have a clear advantage in the case of kinetic measurements. On the other hand, histological investigations are characterized by a high information density and a high resolution, also in deep tissue layers. The selection of the best method for the analysis of the skin morphology depends on the target and the task of the investigation.
    Skin Research and Technology 06/2007; 13(2):119-32. DOI:10.1111/j.1600-0846.2007.00208.x · 1.54 Impact Factor
  • A. Teichmann · H. Richter · F. Knorr · Ch. Antoniou · W. Sterry · J. Lademann
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    ABSTRACT: In the present study, the ability of a shampoo formulation containing caffeine as well as the fluorescent dye fluorescein to penetrate into hair follicles was investigated by in vivo laser scanning microscopy. A contact time of two minutes between the shampoo and the skin surface was sufficient for the formulation to penetrate deeply into the hair follicles and to remain there for up to 48 hours, even after washing. As hair follicles are surrounded by a close network of capillaries, dendritic cells and stem cells, they represent an important target for drug delivery. The results of the present study demonstrated that in vivo laser scanning microscopy is an efficient tool for the investigation of the dermatopharmacokinetics of topically applied molecules and their penetration pathways, as the method yields space- and timeresolved measurements. (© 2007 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)
    Laser Physics Letters 06/2007; 4(6):464 - 468. DOI:10.1002/lapl.200710007 · 2.96 Impact Factor
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    ABSTRACT: The penetration and storage behavior of dye-containing nanoparticles (diameter 320 nm) into the hair follicles was investigated. The results were compared to the findings obtained with the same amount of dye in the non-particle form. In the first part of the experiments, the penetration of the dye into the hair follicles was investigated in vitro on porcine skin, which is an appropriate model for human tissue. It was found that the nanoparticles penetrate much deeper into the hair follicles than the dye in the non-particle form, if a massage had been applied. Without massage, similar results were obtained for both formulations. Subsequently, the storage behavior of both formulations in the hair follicles was analyzed in vivo on human skin by differential stripping. Using the same application protocol, the nanoparticles were stored in the hair follicles up to 10 days, while the non-particle form could be detected only up to 4 days. Taking into consideration the surface structure of the hair follicles, it was assumed that the movement of the hairs may act as a pumping mechanism pushing the nanoparticles deep into the hair follicles.
    European Journal of Pharmaceutics and Biopharmaceutics 06/2007; 66(2):159-64. DOI:10.1016/j.ejpb.2006.10.019 · 4.25 Impact Factor
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    N Otberg · A Teichmann · U Rasuljev · R Sinkgraven · W Sterry · J Lademann
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    ABSTRACT: Follicular drug delivery is the prerequisite for an effective treatment of androgenetic alopecia or other reasons of premature hair loss. The follicular penetration of caffeine, applied topically in a shampoo formulation for 2 min, was measured with highly sensitive surface ionization in combination with mass spectroscopy, a selective method for the detection of very small quantities of transcutaneously absorbed substances in the blood. An experimental protocol, developed to selectively block the follicular pathway within the test area, was used. Based on this principle, a clear distinction between interfollicular and follicular penetration of topically applied caffeine was feasible. After 2 min, caffeine penetrated via the hair follicles and stratum corneum. It was found that the penetration via hair follicles was faster and higher compared with the interfollicular route and that hair follicles are the only pathway for fast caffeine absorption during the first 20 min after application.
    Skin pharmacology and physiology 06/2007; 20(4):195-8. DOI:10.1159/000101389 · 1.96 Impact Factor
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    ABSTRACT: Tape stripping in combination with spectroscopic measurements is a suitable method for the non-invasive determination of the dermatopharmacokinetics of topically applied substances. The penetration profiles obtained by these methods represent a cut to the stratum corneum, where the distribution of the topically applied substances is shown. For the penetration of these penetration profiles knowledge regarding the penetration pathways is necessary. Laser scanning microscopy is a well-suited method for the analysis of the penetration pathways. In the present paper, the results obtained by the combined tape stripping method and laser scanning microscopy were compared for the interpretation of penetration profiles concerning the penetration pathways of the topically applied substances. (© 2007 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)
    Laser Physics Letters 05/2007; 4(5):395 - 398. DOI:10.1002/lapl.200610117 · 2.96 Impact Factor
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    ABSTRACT: The sun protection factor (SPF) describes the protective behavior of sunscreens insufficiently, because this factor takes into account only the UVB spectral range, and strains the volunteers during its determination by invasively invoking an erythema. A new noninvasive method is proposed that is based on the UV spectroscopic measurement of tape strips taken from a sunscreen-treated skin area. The resulting sum transmission spectra of the tape strips reflect the in-vivo distribution of the absorber on the skin and quantify the protective efficacy of the applied sunscreens over the complete UV spectral range. The spectroscopic data provide a basis for the calculation of a universal sun protection factor (USPF). The comparison of the concrete values of USPF and SPF results in the following statements. 1. An unique functional correlation is not to be expected because a different UVB / UVA dependence exists. 2. The size of the differences between both values is influenced clearly by the intensity relation of the average sum transmission in the UVB in comparison to the UVA range. 3. The USPF values objectively assess the efficacy of sunscreens considering a protection against all irradiation injuries.
    Journal of Biomedical Optics 01/2007; 12(4):044013. DOI:10.1117/1.2753365 · 2.75 Impact Factor
  • T. Rieger · A. Teichmann · H. Richter · W. Sterry · J. Lademann
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    ABSTRACT: The occurrence of skin irritation and contact dermatitis is a common problem in various occupational groups. The use of barrier creams represents a frequently utilized prophylactic measure for the protection of the skin, even if their effectiveness is hotly debated. Up to now, a number of in-vivo and in-vitro methods are in existence for the evaluation of barrier creams (BC), which have shown different results regarding the effectiveness of BC. The aim of the present study was the application of the in-vivo laser scanning microscopy for the evaluation of barrier creams. Therefore, sodium fluorescein was applied topically to track its penetration. Three different barrier creams were investigated (Vaseline (B) and 2 different commercially available barrier creams (C and D)) and compared to a reference area (A). It was shown that Vaseline represents a 100% protection against sodium fluorescein as no fluorescence could be detected in the stratum corneum. For barrier cream C, only a weak fluorescent signal was detectable, while in the case of barrier cream D, the fluorescent signal was comparable to that of the reference skin area. The present study revealed that the laser scanning microscopy represents an adequate, non-invasive, quick in-vivo technique for the evaluation of BC that even tracks low differences of effectiveness, which enables the ranking of BC. (© 2007 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)
    Laser Physics Letters 01/2007; 4(1):72 - 76. DOI:10.1002/lapl.200610076 · 2.96 Impact Factor
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    ABSTRACT: The efficacy of sun protection, mostly realized by the application of sunscreen formulations, is commonly described by the sun protection factor (SPF). Previous investigations have shown that the efficacy of the sun protection inter alia depends on the homogeneity of the distribution of the topically applied sunscreen formulation on the human skin. Therefore, suitable methods are required to determine the homogeneity of topically applied substances on the skin surface. This study provides and compares two different methods, which enable this determination. Laser scanning microscopy allows the analysis of tape strips removed from skin treated with a sunscreen. These reflect the inhomogeneous distribution on the skin that can complementary be determined directly, utilizing a dermatological laser scanning microscope. For the second method, a chromatic confocal setup was utilized, which enables the study of the microtopography of skin replicas before and after the application of a sunscreen product. The two methods were applied for the evaluation of three different sunscreen formulations for each method. A correlation of the homogeneity of distribution with the in vivo SPF could be confirmed. Both methods are suitable to investigate the homogeneity of the tested sunscreen formulations, although they provide different advantages and disadvantages.
    Journal of Biomedical Optics 11/2006; 11(6):064005. DOI:10.1117/1.2409291 · 2.75 Impact Factor
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    ABSTRACT: The skin represents the largest organ of our organism and is the barrier to the environment. UV sun radiation and environmental hazards damage our skin. Therefore, it is the aim of skin care products to protect the skin from damage and stimulate the regeneration. The efficacy of skin care products for barrier improvement is usually analyzed by transepidermal water loss measurements (TEWL). This method is suitable for the investigation of the untreated skin. Topically applied products can influence the TEWL measurements. In vivo laser scanning microscopy is a new approach for analyzing the barrier function of the skin. This method is not disturbed by topically applied formulation. In the present paper, laser scanning microscopy was used in comparison to TEWL measurements for the characterization of the skin care product Bedan-Gesichtscreme®. (© 2006 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)
    Laser Physics Letters 10/2006; 3(10):507 - 509. DOI:10.1002/lapl.200610031 · 2.96 Impact Factor
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    ABSTRACT: Reactive free radicals can be produced in the skin by the action of environmental factors, such as sun radiation and toxins. These radicals can damage the DNA, proteins and lipids of the living cells. The consequences can be skin aging, immune suppression and even skin cancer. Humans have developed a protective mechanism against the action of free radicals in the form of antioxidant substances. Several of these antioxidants cannot be produced by humans and have to be acquired via food, such as carotenoids. Optical, non-invasive methods, like resonance Raman spectroscopy, allow a qualitative and quantitative online detection of the kinetics of antioxidants such as carotenoids in the skin. By employing this method it has been shown that the uptake of carotenoids in food can lead to an accumulation in the skin. On the other hand, stress, illness and UV-radiation can reduce the concentration of antioxidant substances in the skin. A high concentration of antioxidant substances is protective and associated with a reduction in skin wrinkling.
    Der Hautarzt 05/2006; 57(4):286, 288-90. DOI:10.1007/s00105-006-1093-z · 0.54 Impact Factor
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    ABSTRACT: Hair follicles represent a long-term storage of topically applied drugs and cosmetics in the skin. Analyzing the penetration of particle-and nonparticle-containing formulations by laser scanning microscopy, it was found, surprisingly, that particles at a size similar to the thickness of the keratin cells of the hair penetrate more efficiently into the hair follicles. These results were obtained from in vitro and in vivo investigations. It seems that the moving hairs in the follicles act as a geared pump because of the zigzag structure of the surface of the hairs. This pumping effect probably pushes particles with the corresponding size deep into the hair follicles.
    Laser Physics 04/2006; 16(5):747-750. DOI:10.1134/S1054660X06050033 · 1.03 Impact Factor
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    ABSTRACT: Nanoparticles represent an important drug carrier system. Recently, we have reported on the penetration and storage behavior of particular and non-particular substances revealing the superiority of particular substances in the range of 300-400 nm. In this regard, it was assumed that the rigid hair shaft acts as a geared pump, moving the particles deeper into the hair follicle. In the present investigation, the storage reservoir capacity of the stratum corneum and the hair follicle infundibulum and canal are compared. Interestingly, we could demonstrate a 10 times longer storage within the hair follicles. These results underscore the importance of the hair follicle for drug delivery purposes, mainly highlighting new possibilities for the future concerning retarded delivery, application frequency, and galenic design.
    Skin pharmacology and physiology 02/2006; 19(4):232-6. DOI:10.1159/000093119 · 1.96 Impact Factor
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    ABSTRACT: Investigations into the penetration pathways of topically applied substances through the skin play an important role in dermatological science. Recently, the hair follicles have increasingly been recognized as an important pathway for percutaneous penetration, although the role of the follicles has still not been clarified in detail. Therefore, the aim of the present study was to develop an in vivo method for the analysis of the follicular rate of penetration processes. In order to reach this goal, the follicles were excluded from the penetration process of topically applied substances. Different study designs were evaluated, and we were able to show that the application of nail varnish to each follicular orifice represents an effective method of blocking the follicles selectively against the penetration of topically applied substances. In dermatological science, there is new information on the physiology of skin penetration processes, thus allowing examination of the follicular rate of penetration and improvement of the pharmacokinetics of topically applied substances.
    Skin pharmacology and physiology 02/2006; 19(4):216-23. DOI:10.1159/000093117 · 1.96 Impact Factor
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    ABSTRACT: 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.
    Contact Dermatitis 02/2006; 54(1):5-13. DOI:10.1111/j.0105-1873.2006.00749.x · 3.62 Impact Factor
  • Alexa Teichmann · M Ossadnik · H Richter · W Sterry · J Lademann
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    ABSTRACT: Recently, hair follicles were shown to be of great importance concerning the penetration and reservoir behavior of topically applied substances. Especially microparticles are known to be efficient drug carriers into the hair follicles. It has been shown in various investigations that, depending on their size, microparticles can be utilized to enhance the penetration of substances into the hair follicles. In the present study, it was investigated whether they could also be used to block the hair follicles to stop penetration. For this purpose, the follicular penetration of a sodium fluorescein-containing hydrogel and follicular reservoir depletion were investigated by means of differential stripping in vivo. In a second study design, the skin areas were pretreated with microparticles 5 microm in diameter. Subsequently, the follicular penetration of sodium fluorescein-containing hydrogel was likewise investigated by differential stripping. The results showed that the hair follicle infundibula contained a significant fluorescent signal when sodium fluorescein in hydrogel was applied. In contrast, in the case of pretreatment with microparticles, only a very low fluorescence signal was measurable in the hair follicle infundibula. The microparticles clearly blocked the follicular orifices so that a penetration of sodium fluorescein was almost completely inhibited. This was confirmed by histological investigations. Thus, depending on their size, microparticles act as efficient drug carriers or can be utilized as follicle blockers to stop the penetration of topically applied substances. This could be very useful in skin protection to prevent the storage of harmful topically applied substances in the hair follicles, known to represent long-term reservoirs.
    Skin pharmacology and physiology 02/2006; 19(2):101-5. DOI:10.1159/000091977 · 1.96 Impact Factor
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    ABSTRACT: The determination of penetration pathways of topically applied substances into the skin is the subject of several investigations. Recently, follicular penetration has become a major focus of interest. To date, a direct, non-invasive quantification of the amount of topically applied substance penetrated into the follicles had not been possible. The development of such a method was the aim of this study. Therefore, the advantages of both stripping techniques, tape stripping and cyanoacrylate skin surface biopsy, were combined and evaluated. Tape stripping was used to remove the part of the stratum corneum that contained the topically applied dye. Subsequently, the follicular contents were ripped off by cyanoacrylate skin surface biopsy. The combined method termed "differential stripping" was evaluated in vitro and in vivo, and the amount of topically applied fluorescent dye penetrated into the hair follicles was quantified after different penetration times. After 30 min, 5% of the recovered concentration of sodium fluorescein was found in the follicular infundibula, where it was still detectable after 48 h. Altogether, the results of this investigation revealed that differential stripping is a new method that can be used to study the penetration of topically applied substances into the follicular infundibula non-invasively and selectively.
    Journal of Investigative Dermatology 09/2005; 125(2):264-9. DOI:10.1111/j.0022-202X.2005.23779.x · 6.37 Impact Factor
  • A Teichmann · U Jacobi · H-J Weigmann · W Sterry · J Lademann
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    ABSTRACT: Investigations on the stratum corneum (SC) reservoir for topically applied substances are of importance in dermatologic science in order to assess the pharmacokinetics of these substances. In the present study, an in vivo method was developed to determine the SC reservoir quantitatively and to investigate the temporal behavior of this reservoir. Therefore, increasing amounts of an oil-in-water emulsion (o/w emulsion) containing 4% of a chemical UV filter were topically applied onto the flexor forearms of 5 healthy volunteers. The saturation of the SC reservoir was determined utilizing the tape stripping technique 1 and 6 h after application. The capacity of the SC reservoir for the o/w emulsion was found to be approximately 2.7 mg/cm(2). Furthermore, a correlation of the capacity of the SC with transepidermal water loss was observed. Extending the time between the topical application and SC removal did not affect the distribution or the recovery rate of the UV filter in the SC. The results indicate that the reservoir of the SC is limited. This is reflected by the saturation level, which depends on the individual volunteer and, presumably, the topically applied substances and formulations used. The results show that the method developed is suited to quantitatively determine in vivo the SC reservoir for topically applied substances.
    Skin pharmacology and physiology 03/2005; 18(2):75-80. DOI:10.1159/000083707 · 1.96 Impact Factor