The Experts below are selected from a list of 2112 Experts worldwide ranked by ideXlab platform
Mitsuhiro Shikida - One of the best experts on this subject based on the ideXlab platform.
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Four-Sided Tip-Separable Micro-Needle Device With Large Barb Formed By Anisotropic Wet Etching For Trans-Dermal Drug Delivery System
2019 20th International Conference on Solid-State Sensors Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII), 2019Co-Authors: Mizuki Sakamoto, Yoshihiro Hasegawa, Kazuhiro Taniguchi, Mitsuhiro ShikidaAbstract:A novel type four-sided tip-separable microneedle device with a large barb was proposed for separating a needle tip easily during the skin insertion in the trans-Dermal Drug Delivery systems. The proposed microneedle device was composed of a sharp needle tip and a base one, and the former was placed on the latter with the 45° off rotation angle in the needle axis for increasing the barb area in the tip needle. A symmetry property of a single crystallographic Si(100) substrate was applied to produce two Si master needles producing both tip and base needle structures respectively, and they were fabricated by anisotropic wet etching. Finally, a polymer based four-sided tip-separable microneedle device with the large barb was successfully produced by applying a mold process to the fabricated two Si master needles.
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Fabrication of Sharp Tip-Separable Microneedle Device for Trans-Dermal Drug Delivery Systems
Proceedings, 2017Co-Authors: Yuki Nabekura, Hitoshi Fukuyu, Yoshihiro Hasegawa, Mitsuhiro ShikidaAbstract:An alignment mechanism for producing a sharp tip-separable microneedle device for trans-Dermal Drug Delivery systems has been developed. The needle and base parts were placed on a mechanical precision motion stage to align their central axes. The overlapping region between them in the height direction was controlled by inserting a thickness gauge between them. A 400-μm-high sharp tip-separable microneedle device was successfully produced by using the developed alignment mechanism with an accuracy of less than 19 μm. We also demonstrated that it can be used to produce an arrayed tip-separable microneedle device.
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Sharp tip-separable microneedle device for trans-Dermal Drug Delivery systems
2015 Transducers - 2015 18th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS), 2015Co-Authors: Kazuo Imaeda, Kazuhiro Bessho, Mitsuhiro ShikidaAbstract:We developed a sharp tip-separable microneedle device for trans-Dermal Drug Delivery systems (DDSs). Two differently shaped Si-microneedles, eight-sided and rhombic pyramids, were first fabricated by photolithography and anisotropic wet etching. Then, a tip-separable biodegradable microneedles tips was fabricated using a molding process. Thanks to the sharpness of the Si-microneedles, sharp biodegradable tips with the radius of less than 1.0 μm could be fabricated. Finally, the tip-separable microneedle device was successfully used to penetrate a piece of mouse skin.
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Fabrication of rounded knife-edged structure for trans-Dermal Drug Delivery system
2013 Transducers & Eurosensors XXVII: The 17th International Conference on Solid-State Sensors Actuators and Microsystems (TRANSDUCERS & EUROSENSORS X, 2013Co-Authors: Katsuhiko Bessho, Chikara Miyake, Mitsuhiro ShikidaAbstract:We propose a rounded knife-edge structure having a large surface area to increase the dosage amount in the trans-Dermal Drug Delivery system. We fabricated a Si rounded knife-edge structure as the original master by anisotropic wet etching. We then replicated the same shape with biodegradable hyaluronic acid-based material by a molding process. We evaluated the penetration performance of the fabricated knife-edged structures into an artificial skin of a silicone rubber sheet and confirmed that both the Si and biodegradable knife-edged structures successfully penetrated the sheet with an applied load of 180 g. We also fabricated an arrayed biodegradable rounded knife-edged structure that successfully penetrated mouse skin.
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Fabrication of a hollow needle structure by dicing, wet etching and metal deposition
Journal of Micromechanics and Microengineering, 2006Co-Authors: Mitsuhiro Shikida, Takehiko Hasada, Kazuo SatoAbstract:We previously proposed a novel fabrication process, which combined mechanical dicing and anisotropic wet etching, to reduce the cost of micro-electro-mechanical system devices, and fabricated various solid-type microneedle structures using this process for trans-Dermal Drug Delivery systems. The current research involved us enhancing our previous processes by applying metal plating and using a minimum number of photolithography steps, and we fabricated a hollow-type micro-needle structure, in which a flow channel was formed at the center of the needle projection, for supplying medical solutions from the area behind the needle. We fabricated two different shaped needle structures, pyramidal and flattened needles. The height and pitch of both needle types were 120–250 µm and 230–280 µm, respectively. The developed process is useful for producing disposable microneedles for bio-medical applications.
Reinhard H.h. Neubert - One of the best experts on this subject based on the ideXlab platform.
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Photothermal imaging in 3D surface analysis of membrane Drug Delivery
European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V, 2009Co-Authors: B. Gotter, W. Faubel, Reinhard H.h. NeubertAbstract:Various methods exist for research into the penetration process in the human nail plate and for investigation of Dermal Drug Delivery. Application of spectroscopic methods in this scientific field is gaining importance. However, no method meets all demands of the large variety of applications. An alternative optical technique for the characterisation of samples is the photothermal spectroscopy. Photoacoustic techniques, photothermal radiometry, and photothermal beam deflection spectroscopy (PDS) are non-destructive analytical techniques that take advantage of the so-called photoacoustic and photothermal phenomena. PDS, in conjunction with an appropriate scanner, allows for depth profiling and is a promising technique for studies of three-dimensional Drug diffusion into artificial and biological membranes. The objective of this article is to demonstrate the use of PDS imaging for pharmaceutical applications and Drug Delivery studies, with two experiments being used as examples: the follow-up of lateral dithranol penetration into an artificial membrane and depth-resolved measurement of the distribution of a model Drug within a keratin membrane from bovine hoof.
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hydrophilic silica aerogels as Dermal Drug Delivery systems dithranol as a model Drug
European Journal of Pharmaceutics and Biopharmaceutics, 2008Co-Authors: U Guenther, Irina Smirnova, Reinhard H.h. NeubertAbstract:A special class of porous silica materials, silica aerogels, was recently shown to be a potential candidate for oral Drug Delivery systems. It was demonstrated, that stability of Drugs and their dissolution rate can essentially be improved through the adsorption on to these materials. In this work, Drug loaded silica aerogels are firstly applied as Dermal Drug Delivery systems. Dithranol is used as a representative Drug since there is a need to enhance its Dermal availability. The unstable and nearly water-insoluble Drug exhibits a poor penetration. Release of dithranol from aerogels into various semi-solid formulations and its dissolution as well as the release and penetration into artificial membranes were investigated by Fourier-transform infrared attenuated total reflection (FTIR-ATR) spectroscopy. Two model membranes (one hydrophilic and one lipophilic) were applied. Several formulations were tested and the most promising one was used in order to study the penetration of dithranol into human stratum corneum (SC). Dithranol adsorbed on hydrophilic silica aerogels exhibited superior penetration behaviour compared to that of the standard ointment (dithranol in white soft paraffin).
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Microemulsions as colloidal vehicle systems for Dermal Drug Delivery. Part V: Microemulsions without and with glycolipid as penetration enhancer.
Journal of pharmaceutical sciences, 2005Co-Authors: Reinhard H.h. Neubert, Ulrike Schmalfuß, Raik Wolf, Wolfgang WohlrabAbstract:The aim of this study was to investigate the Dermal administration of a highly hydrophilic model Drug, diphenhydramine (DPH), in colloidal systems with an aqueous colloidal phase in the presence of a glycolipid (GL) as a penetration modifier. Dermal penetration of DPH, GL, and isopropylpalmitate (IPP) from ME systems without GL and with GL as well as from a hydrogel used as standard formulation were estimated in vitro using human skin. The penetration of the Drug, the oil (IPP), and the GL was measured with highly sensitive HPLC, HPLC-MS, and GC-MS assays, respectively. It could be shown that penetration modifier GL is penetrating very fast, and to a high extent into and through the human skin. In contrast, the penetration of IPP used as oily phase in the ME is limited. When incorporated in the ME systems GL and DPH was accumulated in the viable epidermis and in the dermis. Using ME containing a penetration modifier such as GL, a slight additional enhancing effect could be observed, particularly concerning the penetration of DPH into the acceptor fluid when a highly hydrophilic Drug such as DPH was applied.
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microemulsions as colloidal vehicle systems for Dermal Drug Delivery part iv investigation of microemulsion systems based on a eutectic mixture of lidocaine and prilocaine as the colloidal phase by dynamic light scattering
Journal of Pharmacy and Pharmacology, 2003Co-Authors: Anuj Shukla, Annett Krause, Reinhard H.h. NeubertAbstract:Stable oil-in-water (o/w) microemulsions used as vehicles for Dermal Drug Delivery have been developed using lidocaine (lignocaine) and prilocaine in oil form (eutectic mixture), a blend of a high (Tween 80, hydrophilic-lipophilic balance (HLB) = 15.0) and a low (Poloxamer 331, HLB = 1.0) HLB surfactant and propylene glycol-water as hydrophilic phase. These microemulsions were able to solubilize up to 20% eutectic mixture of lidocaine and prilocaine without phase separation. The dispersity of the oil phase was investigated by dynamic light scattering. Small colloidal droplets for stable microemulsions of 5~10 nm were observed. At constant surfactant and hydrophilic phase concentration, increasing the total Drug concentration in the microemulsion resulted in an increase in the droplet size of the dispersed, colloidal phase. It was observed that a monolayer of surfactant surrounds the oil (eutectic mixture) core. Colloidal droplets of the microemulsion interact via hard sphere with supplementary attractive interaction. This observed interparticle attractive interaction could explain the observed phase behaviour with respect to change in the basicity of the hydrophilic phase as well as the increase in volume fraction of the dispersed, colloidal phase. It was also observed that the stability and size of this dispersed phase depends on the pH of the composition. Because these microemulsions formed stable, isotropic systems in the range of pH 9.5 to 10.4 with alkali buffer or NaOH solution instead of water as hydrophilic phase, so one can produce microemulsions in this pH area.
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microemulsions for Dermal Drug Delivery studied by dynamic light scattering effect of interparticle interactions in oil in water microemulsions
Journal of Pharmaceutical Sciences, 2003Co-Authors: Anuj Shukla, Martin Janich, Konstanze Jahn, Reinhard H.h. NeubertAbstract:Abstract Dynamic light scattering (DLS) was used to study the droplet size and the droplet interaction of o/w microemulsions (MEs) consisting of oils, a blend of a high and a low hydrophilic–lipophilic balance (HLB) surfactant, and a hydrophilic phase (propylene glycol/water). Like many MEs, these systems could not be diluted to infinite dilution without phase separation. Consequently, to allow a meaningful calculation of droplet diameter from data obtained from DLS, it is necessary to correct scattering measurements in high concentration regions for the nonideality arising from interparticle interaction. Scattering data were corrected for interparticle interaction using a suitable interaction model proposed for our systems. From the total interparticle interaction energy, coagulation time was calculated. The ratio between rapid and slow coagulation was of the order of 10 100 , which is consistent with the observed stability of the MEs studied. © 2003 Wiley‐Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 92:730–738, 2003
Joke A Bouwstra - One of the best experts on this subject based on the ideXlab platform.
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Diffusion profile of macromolecules within and between human skin layers for (trans)Dermal Drug Delivery
Journal of the mechanical behavior of biomedical materials, 2015Co-Authors: Am Anne Römgens, Joke A Bouwstra, Dan L. Bader, Fpt Frank Baaijens, Cwj Cees OomensAbstract:Delivering a Drug into and through the skin is of interest as the skin can act as an alternative Drug administration route for oral Delivery. The development of new Delivery methods, such as microneedles, makes it possible to not only deliver small molecules into the skin, which are able to pass the outer layer of the skin in therapeutic amounts, but also macromolecules. To provide insight into the administration of these molecules into the skin, the aim of this study was to assess the transport of macromolecules within and between its various layers. The diffusion coefficients in the epidermis and several locations in the papillary and reticular dermis were determined for fluorescein dextran of 40 and 500 kDa using a combination of fluorescent recovery after photobleaching experiments and finite element analysis. The diffusion coefficient was significantly higher for 40 kDa than 500 kDa dextran, with median values of 23 and 9 µm2/s in the dermis, respectively. The values only marginally varied within and between papillary and reticular dermis. For the 40 kDa dextran, the diffusion coefficient in the epidermis was twice as low as in the dermis layers. The adopted method may be used for other macromolecules, which are of interest for Dermal and transDermal Drug Delivery. The knowledge about diffusion in the skin is useful to optimize (trans)Dermal Drug Delivery systems to target specific layers or cells in the human skin.
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from the structure of the skin barrier and Dermal formulations to in vitro transport models for skin absorption skin research in the netherlands and in germany
Skin Pharmacology and Physiology, 2013Co-Authors: Maike Windbergs, Ulrich F. Schaefer, Steffi Hansen, Claus-michael Lehr, A Schroeter, Joke A BouwstraAbstract:This review presents an overview of German and Dutch research institutions and their studies in the field of skin Drug Delivery and adjacent topics. In the Netherlands, the involved research groups are mainly localized in Leiden, whereas in Germany the skin research institutions are spread over the whole country. The scientific studies in the Netherlands focus on the in-depth analysis of human skin composition and its individual components as well as on the development and characterization of Dermal Drug Delivery systems ranging from liquid crystalline systems and vesicles up to microneedles with an emphasis on examining the interactions of these Drug Delivery systems with the human skin in vitro and in vivo. In Germany, the individual areas of research span from in-depth investigations on various Drug Delivery systems intended for skin application and the development of novel in vitro models for skin absorption testing up to in vivo studies focusing on the biological performance of topically applied actives. Furthermore, sophisticated analytical techniques are
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Microneedle technologies for (trans)Dermal Drug and vaccine Delivery.
Journal of controlled release : official journal of the Controlled Release Society, 2012Co-Authors: Koen Van Der Maaden, Wim Jiskoot, Joke A BouwstraAbstract:Microneedles have been used for the Dermal and transDermal Delivery of a broad range of Drugs, such as small molecular weight Drugs, oligonucleotides, DNA, peptides, proteins and inactivated viruses. However, until now there are no microneedle-based (trans)Dermal Drug Delivery systems on the market. In the past decade various types of microneedles have been developed by a number of production processes. Numerous geometries of microneedles have been designed from various materials. These microneedles have been used for different approaches of microneedle-based (trans)Dermal Drug Delivery. Following a brief introduction about Dermal and transDermal Drug Delivery, this review describes different production methods for solid and hollow microneedles as well as conditions that influence skin penetration. Besides, the four microneedle-based (trans)Dermal Drug Delivery approaches are discussed: "poke and flow", "poke and patch", "poke and release", and "coat and poke". A separate section of this review is devoted to the use of microneedles for the Delivery of therapeutic proteins and vaccines. Finally, we give our view on research and development that is needed to render microneedle-based (trans)Dermal Drug Delivery technologies clinically useful in the near future.
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vesicles as a tool for transDermal and Dermal Delivery
Drug Discovery Today: Technologies, 2005Co-Authors: Loan P Honeywellnguyen, Joke A BouwstraAbstract:TransDermal and Dermal Drug Delivery is problematic because the skin, as a natural barrier, has a very low permeation rate. Therefore several methods have been assessed to increase this rate locally and temporarily. One approach is the use of vesicle formulations. In this paper the effectiveness of conventional and deformable vesicles as Drug Delivery systems as well as their possible mode of action as permeation enhancers or transDermal Drug carriers will be discussed.
Yuki Nabekura - One of the best experts on this subject based on the ideXlab platform.
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Fabrication of Sharp Tip-Separable Microneedle Device for Trans-Dermal Drug Delivery Systems
Proceedings, 2017Co-Authors: Yuki Nabekura, Hitoshi Fukuyu, Yoshihiro Hasegawa, Mitsuhiro ShikidaAbstract:An alignment mechanism for producing a sharp tip-separable microneedle device for trans-Dermal Drug Delivery systems has been developed. The needle and base parts were placed on a mechanical precision motion stage to align their central axes. The overlapping region between them in the height direction was controlled by inserting a thickness gauge between them. A 400-μm-high sharp tip-separable microneedle device was successfully produced by using the developed alignment mechanism with an accuracy of less than 19 μm. We also demonstrated that it can be used to produce an arrayed tip-separable microneedle device.
Yoshihiro Hasegawa - One of the best experts on this subject based on the ideXlab platform.
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Four-Sided Tip-Separable Micro-Needle Device With Large Barb Formed By Anisotropic Wet Etching For Trans-Dermal Drug Delivery System
2019 20th International Conference on Solid-State Sensors Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII), 2019Co-Authors: Mizuki Sakamoto, Yoshihiro Hasegawa, Kazuhiro Taniguchi, Mitsuhiro ShikidaAbstract:A novel type four-sided tip-separable microneedle device with a large barb was proposed for separating a needle tip easily during the skin insertion in the trans-Dermal Drug Delivery systems. The proposed microneedle device was composed of a sharp needle tip and a base one, and the former was placed on the latter with the 45° off rotation angle in the needle axis for increasing the barb area in the tip needle. A symmetry property of a single crystallographic Si(100) substrate was applied to produce two Si master needles producing both tip and base needle structures respectively, and they were fabricated by anisotropic wet etching. Finally, a polymer based four-sided tip-separable microneedle device with the large barb was successfully produced by applying a mold process to the fabricated two Si master needles.
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Fabrication of Sharp Tip-Separable Microneedle Device for Trans-Dermal Drug Delivery Systems
Proceedings, 2017Co-Authors: Yuki Nabekura, Hitoshi Fukuyu, Yoshihiro Hasegawa, Mitsuhiro ShikidaAbstract:An alignment mechanism for producing a sharp tip-separable microneedle device for trans-Dermal Drug Delivery systems has been developed. The needle and base parts were placed on a mechanical precision motion stage to align their central axes. The overlapping region between them in the height direction was controlled by inserting a thickness gauge between them. A 400-μm-high sharp tip-separable microneedle device was successfully produced by using the developed alignment mechanism with an accuracy of less than 19 μm. We also demonstrated that it can be used to produce an arrayed tip-separable microneedle device.