| 1. |
- Lademann, Jürgen, et al.
(author)
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Drug delivery with topically applied nanoparticles : science fiction or reality
- 2013
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In: Skin Pharmacology and Physiology. - : S. Karger. - 1660-5527 .- 1660-5535. ; 26:4-6, s. 227-233
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Journal article (peer-reviewed)abstract
- The efficacy of topically applied drugs is determined by their action mechanism and their potential capacity of passing the skin barrier. Nanoparticles are assumed to be efficient carrier systems for drug delivery through the skin barrier. For flexible nanoparticles like liposomes, this effect has been well demonstrated. The penetration properties of solid nanoparticles are currently under intensive investigation. The crucial advantage of nanoparticles over non-particulate substances is their capability to penetrate deeply into the hair follicles where they can be stored for several days. There is no evidence, yet, that solid particles ≥40 nm are capable of passing through the healthy skin barrier. Therefore and in spite of the long-standing research efforts in this field, commercially available solid nanoparticle-based products for drug delivery through the healthy skin are still missing. Nevertheless, the prospects for the clinical use of nanoparticles in drug delivery are tremendous. They can be designed as transport systems delivering drugs efficiently into the hair follicles in the vicinity of specific target structures. Once deposited at these structures, specific signals might trigger the release of the drugs and exert their effects on the target cells. In this article, examples of such triggered drug release are presented.
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| 2. |
- Mak, Wing Cheung, 1977-, et al.
(author)
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Drug delivery into the skin by degradable particles
- 2011
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In: European journal of pharmaceutics and biopharmaceutics. - : Elsevier. - 0939-6411 .- 1873-3441. ; 79:1, s. 23-27
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Journal article (peer-reviewed)abstract
- Recently, it was demonstrated that particles could be utilized as carrier systems for drugs into the hair follicles. In the present study, a two-component drug delivery system is presented consisting of degradable particles loaded with fluorescein isothiocyanate and a separate protease formulation for degradation. The particles were applied alone, 30 min previous to the protease application and simultaneously with the protease onto porcine skin. Subsequently, biopsies were removed, and the penetration depths of the particles were analyzed using laser scanning microscopy.The obtained results demonstrate that the particles alone achieved a penetration depth of around 900 μm. Similar results were obtained for the successive application of particles and protease, whereas a release of the fluorescent dye was only observed in the upper 250 μm corresponding to the penetration depth of the protease. In the case of the simultaneous application, the particles were partly dissolved before application, leading to a reduced particle size and diminished penetration depth.The results revealed that degradable particles are a promising tool for drug delivery into the skin.
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| 3. |
- Patzelt, Alexa, et al.
(author)
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Do nanoparticles have a future in dermal drug delivery?
- 2017
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In: Journal of Controlled Release. - : ELSEVIER SCIENCE BV. - 0168-3659 .- 1873-4995. ; 246, s. 174-182
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Journal article (peer-reviewed)abstract
- More and more investigations confirm that nanoparticles are incapable of overcoming the intact skin barrier in vivo. Do nanoparticles still have a future in dermal drug delivery? Unlike many other topically applied substances, nanoparticles have not been reported to utilize the intercellular penetration pathway and preferentially make use of the follicular penetration pathway. Deep penetration into the follicular ducts has been described for a variety of particles and appears to be strongly influenced by particle size. For targeted drug delivery, smart nanoparticles are required which are able to release their loaded drugs subsequent to internal or external trigger stimuli, and thereby enable the translocation of the active agents into the viable epidermis. In the recent manuscript, three nanoparticles systems are summarized and compared which release their model drugs upon different trigger mechanisms. The BSA hydrogel nanoparticles release their model drug TRITC-dextran by passive diffusion due to a concentration gradient via a porous surface. The protease-triggered controlled release BSA nanoparticles release their model drug if they are applied simultaneously with protease nanoparticles, resulting in an enzymatic degradation of the particles and a release of the model drug FITC. Finally, the IR-triggered controlled release AuNP-doped BSA nanoparticles release their model drug FITC after photoactivation with wIRA. For all three nanoparticle systems, the release of their model drugs could be observed. For the first nanoparticle system, only low follicular penetration depths were found which might by due do an agglomeration effect. For the last two nanoparticle systems, deep follicular penetration and even an uptake by the sebaceous glands were verified. In conclusion, it could be demonstrated that nanoparticles do have a future in dermal drug delivery if smart nanoparticle systems are utilized which are able to release their drug at specific times and locations within the hair follicle. (C) 2016 Elsevier B.V. All rights reserved.
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| 4. |
- Tran, Ngo Bich Nga Nathalie, et al.
(author)
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Gradient-dependent release of the model drug TRITC-dextran from FITC-labeled BSA hydrogel nanocarriers in the hair follicles of porcine ear skin
- 2017
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In: European journal of pharmaceutics and biopharmaceutics. - : ELSEVIER SCIENCE BV. - 0939-6411 .- 1873-3441. ; 116, s. 12-16
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Journal article (peer-reviewed)abstract
- Hair follicle research is currently focused on the development of drug-loaded nanocarriers for the targeting of follicular structures in the treatment of skin and hair follicle-related disorders. In the present study, a dual-label nanocarrier system was implemented in which FITC-labeled BSA hydrogel nanocarriers loaded with the model drug and dye TRITC-dextran were applied topically to porcine ear skin. Follicular penetration and the distribution of both dyes corresponding to the nanocarriers and the model drug in the follicular ducts subsequent to administration to the skin were investigated using confocal laser scanning microscopy. The release of TRITC-dextran from the particles was induced by washing of the nanocarriers, which were kept in a buffer containing TRITC-labeled dextran to balance out the diffusion of the dextran during storage, thereby changing the concentration gradient. The results showed a slightly but statistically significantly deeper follicular penetration of fluorescent signals corresponding to TRITC-dextran as opposed to fluorescence corresponding to the FITC-labeled particles. The different localizations of the dyes in the cross-sections of the skin samples evidenced the release of the model drug from the labeled nanoparticles. (C) 2016 Elsevier B.V. All rights reserved.
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| 5. |
- Wing Cheung, Mak, et al.
(author)
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Triggering of drug relase of particles in hair follicles
- 2012
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In: Journal of Controlled Release. - : Elsevier. - 0168-3659 .- 1873-4995. ; 160, s. 509-514
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Journal article (peer-reviewed)abstract
- Particulate drug delivery via hair follicles represents a promising concept, although requirements are high. This process must be realized at the desired depth and at the appropriate time, due to the fact that the particles themselves are not able to overcome the follicular skin barrier.In the present study, a novel triggering concept for the release of a model drug from the delivering particles is presented based on the application of two different particle types of the same size, where one particle type is the drug carrier, and the second one is loaded with a protease. The latter particle type is supposed to interact with the drug-carrying particles to trigger the drug release. A mixture of both particles was applied onto porcine skin samples, followed by follicular analysis. As a control, the particles were applied unaided without protease, whereas one skin area remained untreated. The investigations revealed that the protease was able to release the model drug from the delivering particles in significant depths within the hair follicle (866 ± 62 nm). Additionally, an uptake of the model drug in the sebaceous gland was observed after release providing a promising novel approach for the development of treatment strategies for different skin diseases.
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