| 1. |
- Ali, Abdullah, 1985-, et al.
(författare)
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Tactile friction of topical creams and emulsions : Friction measurements on excised skin and VitroSkin® using ForceBoard™
- 2022
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Ingår i: International Journal of Pharmaceutics. - : Elsevier B.V.. - 0378-5173 .- 1873-3476. ; 615
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Tidskriftsartikel (refereegranskat)abstract
- Tactile perception can be investigated through ex vivo friction measurements using a so–called ForceBoard™, providing objective assessments and savings in time and money, compared to a subjective human panel. In this work we aim to compare excised skin versus VitroSkin® as model substrates for tactile friction measurements. A further aim is to detect possible differences between traditional surfactant-based creams, and a particle-stabilized (Pickering) cream and investigate how the different substrates affect the results obtained. It was found that the difference in tactile friction between excised skin and VitroSkin® was small on untreated substrates. When topical creams were applied, the same trends were observed for both substrates, although the frictional variation over time relates to the difference in surface structure between the two substrates. The results also confirmed that there is a difference between starch-based Pickering formulations and surfactant-based creams after application, indicating that the latter is greasier than Pickering cream. It was also shown that the tactile friction of Pickering emulsions was consistently high even with high amounts of oil, indicating a non-greasy, and non-sticky formulation. The characteristics of starch-stabilized Pickering formulations make them promising candidates in the development of surfactant-free topical formulations with unique tactile properties. © 2022 The Authors
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| 2. |
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| 3. |
- Campos Pacheco, Jesús Enrique, et al.
(författare)
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Inhalable porous particles as dual micro-nano carriers demonstrating efficient lung drug delivery for treatment of tuberculosis
- 2024
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Ingår i: Journal of Controlled Release. - : Elsevier B.V.. - 0168-3659 .- 1873-4995. ; 369, s. 231-250
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Tidskriftsartikel (refereegranskat)abstract
- Inhalation therapy treating severe infectious disease is among the more complex and emerging topics in controlled drug release. Micron-sized carriers are needed to deposit drugs into the lower airways, while nano-sized carriers are of preference for cell targeting. Here, we present a novel and versatile strategy using micron-sized spherical particles with an excellent aerodynamic profile that dissolve in the lung fluid to ultimately generate nanoparticles enabling to enhance both extra- and intra-cellular drug delivery (i.e., dual micro-nano inhalation strategy). The spherical particles are synthesised through the condensation of nano-sized amorphous silicon dioxide resulting in high surface area, disordered mesoporous silica particles (MSPs) with monodispersed size of 2.43 μm. Clofazimine (CLZ), a drug shown to be effective against multidrug-resistant tuberculosis, was encapsulated in the MSPs obtaining a dry powder formulation with high respirable fraction (F.P.F. <5 μm of 50%) without the need of additional excipients. DSC, XRPD, and Nitrogen adsorption-desorption indicate that the drug was fully amorphous when confined in the nano-sized pores (9–10 nm) of the MSPs (shelf-life of 20 months at 4 °C). Once deposited in the lung, the CLZ-MSPs exhibited a dual action. Firstly, the nanoconfinement within the MSPs enabled a drastic dissolution enhancement of CLZ in simulated lung fluid (i.e., 16-fold higher than the free drug), increasing mycobacterial killing than CLZ alone (p = 0.0262) and reaching concentrations above the minimum bactericidal concentration (MBC) against biofilms of M. tuberculosis (i.e., targeting extracellular bacteria). The released CLZ permeated but was highly retained in a Calu-3 respiratory epithelium model, suggesting a high local drug concentration within the lung tissue minimizing risk for systemic side effects. Secondly, the micron-sized drug carriers spontaneously dissolve in simulated lung fluid into nano-sized drug carriers (shown by Nano-FTIR), delivering high CLZ cargo inside macrophages and drastically decreasing the mycobacterial burden inside macrophages (i.e., targeting intracellular bacteria). Safety studies showed neither measurable toxicity on macrophages nor Calu-3 cells, nor impaired epithelial integrity. The dissolved MSPs also did not show haemolytic effect on human erythrocytes. In a nutshell, this study presents a low-cost, stable and non-invasive dried powder formulation based on a dual micro-nano carrier to efficiently deliver drug to the lungs overcoming technological and practical challenges for global healthcare.
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| 4. |
- Digaitis, Ramūnas, PhD, et al.
(författare)
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Hydration and dehydration induced changes in porosity of starch microspheres
- 2022
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Ingår i: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 291, s. 119542-119542
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Tidskriftsartikel (refereegranskat)abstract
- Characterization and tuning of the porosity of amorphous starch materials are important for many applications, including controlled release of encapsulated proteins. The porosities of these materials in dry and hydrated states can have different physicochemical origins and properties. Here, porosities of dry cross-linked starch microspheres and their hydration-induced transformations were characterized by small angle X-ray scattering, scanning electron and optical microscopies, thermogravimetric analysis, sorption calorimetry, nitrogen sorption, and helium-pycnometry. The analyses revealed that dry microspheres consist of porous cores with pore diameters below 100 nm and shells which appeared to be denser but contained wider pores (100–300 nm). The outer crust of the microspheres shell is non-porous, which restricts diffusion of nitrogen, water, and ethanol. Partial hydration triggered an irreversible collapse of dry porosity at 12 wt% water. Further hydration resulted in interfacial changes and promoted wet porosity, related to characteristic distances between polymer chains.
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| 5. |
- Valetti, Sabrina, et al.
(författare)
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Can mesoporous nanoparticles promote bioavailability of topical pharmaceutics?
- 2021
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Ingår i: International Journal of Pharmaceutics. - : Elsevier BV. - 0378-5173 .- 1873-3476. ; 602
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Tidskriftsartikel (refereegranskat)abstract
- When applied to skin, particulate matter has been shown to accumulate in hair follicles. In addition to follicles, the skin topography also incorporates trench-like furrows where particles potentially can accumulate; however, the furrows have not been as thoroughly investigated in a drug delivery perspective. Depending on body site, the combined follicle orifices cover up to 10% of the skin surface, while furrows can easily cover 20%, reaching depths exceeding 25 mu m. Hence, porous particles of appropriate size and porosity could serve as carriers for drugs to be released in the follicles prior to local or systemic absorption. In this paper, we combine multiphoton microscopy, scanning electron microscopy, and Franz cell diffusion technology to investigate ex-vivo skin accumulation of mesoporous silica particles (average size of 400-600 nm, 2, and 7 mu m, respectively), and the potential of which as vehicles for topical delivery of the broad-spectrum antibiotic metronidazole. We detected smaller particles (400-600 nm) in furrows at depths of about 25 mu m, also after rinsing, while larger particles (7 mu m) where located more superficially on the skin. This implies that appropriately sized porous particles may serve as valuable excipients in optimizing bioavailability of topical formulations. This work highlights the potential of skin furrows for topical drug delivery.
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| 6. |
- Yang, Yanjie, et al.
(författare)
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Transport dynamics of droplet impact on the wedge-patterned biphilic surface
- 2020
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Ingår i: Experimental Thermal and Fluid Science. - : Elsevier BV. - 0894-1777 .- 1879-2286. ; 113
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Tidskriftsartikel (refereegranskat)abstract
- Droplet impact on biphilic surfaces with a wettability contrast has been intensively studied in recent years. In this work the effects of tilting and apex angles on droplet transport dynamics after impacting on a wedge-patterned biphilic surface at low Weber numbers were investigated experimentally. The biphilic surface was fabricated by applying a hydrophobic polymer coating on a bare silicon surface. According to the experimental results, a larger apex angle below 67.4° can accelerate the droplet effectively at first. Then the friction force controls the droplet movement and reduces the speed. The tilting angle along the hydrophilic direction activates the droplet. If the gravity component is opposite to the hydrophilic direction and the tilting angle is over 15°, the droplet can hardly move toward the hydrophilic area. By modeling the hydrodynamics of the droplet movement after impact on a biphilic surface with assumptions of no evaporation, no Marangoni effect, negligible dynamic contact angle variation and negligible rotation effect, the surface tension values versus the position at different apex angles are derived. The predicted position versus time trends agree well with the experimental data. This study aims to provide a better understanding of the mechanisms of droplet hydrodynamics on wedge-patterned biphilic surfaces at low Weber numbers.
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