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Item type:Publication, Access status: with files , Evaluation of the orally administered calcium alginate aerogel on the changes of gut microbiota and hepatic and renal function of Wistar rats(Public Library of Science (PLoS), 2021-04-28); ; ; ; The present study evaluates the effect of calcium alginate aerogel as a potential drug carrier, on the liver and kidney functions, and on the gut microbiota of Wistar rats. The studied alginate aerogel was prepared in the form of nanoparticles using the jet cutting technique, and they were characterized in terms of specific surface areas, outer morphology and particle size distribution. For the in vivo study, calcium alginate aerogel was administered orally, and liver and kidney functions were tested for one week and for four weeks in two distinct studies. During the short-term in vivo study, feces samples were collected for bacterial DNA extraction followed by 16S rRNA gene sequencing analyses to detect changes in gut microbiota. Results showed that the prepared alginate aerogel has an average BET-specific surface area of around 540 m /g, with a pore volume of 7.4 cc/g, and pore width of 30–50 nm. The in vivo study revealed that the levels of the studied kidney and liver enzymes didn’t exceed the highest level of the normal range. The study of gut microbiota showed different patterns; certain groups of bacteria, such as Clostridia and Bacteriodia, increased during the aerogels regime and continued to increase after the aerogel was stopped. While other groups such as Erysipelotrichia, and Candidatus saccharibacteria increased during aerogels treatment, and then decreased again after one month. Members of the Bacilli class showed a unique trend, that is, after being the most abundant group (63%) at time 0, their relative abundance decreased dramatically until it reached < 5%; which was the case even after stopping the aerogel treatment. 2Publicationtype: Journal ArticleScopus© Citations 10 147 135 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Application of Aquasolv Lignin in ibuprofen-loaded pharmaceutical formulations obtained via direct compression and wet granulationAS (Aquasolv) Lignin produced via Liquid Hot Water Pretreatment and Enzymatic Hydrolysis has shown potential as an active pharmaceutical ingredient and/or excipient in solid dosage forms. Moreover, lignin is safe to consume and presents antioxidant and antidiabetic capacity, properties that can add to solid dosage forms in pharmaceuticals. This work aimed to evaluate the performance of tablets produced via direct compression and wet granulation when lignin is used in combination with commercial excipients. In order to find optimal tablet performance, different lignin formulations were assessed, and the concentrations were given by extreme vertices mixture design (13 formulations). The blends were composed of AS Lignin, Microcrystalline Cellulose, and Lactose monohydrate and the optimized blend was found to be 14.53 w/w% of disintegrant, 26.57 w/w% of binder and 58.9 w/w% of AS lignin. This proportion was further used to evaluate the performance of lignin-based tablets in drug release, using Ibuprofen as a drug model (50 w/w% and 70 w/w%) and for comparison of direct compression with wet granulation. Direct compressed tablets resulted in higher drug dissolution rates when compared with wet granulation, nevertheless; both tableting techniques showed promising results for lignin. More than 5 formulations tested in this work are compliant with International Pharmacopoeia regulations for solid dosage pharmaceutical forms, thus AS Lignin shows potential to be used as an excipient in pharmaceutical formulations. Industrial relevance: Industrially, AS Lignin appears as promising excipient in the pharmaceutical technologies as well as boost in the biorefining technologies in the following years. Lignin produced is free of sulfur, can be labelled as clean and environmentally-friendly and in this study, was proven this non-cytotoxic AS lignin can be used for excipients and drug carriers. The findings in this paper showed the use of product formulation for life science purposes, thus stressing one of possibilities for lignin valorization in biorefineries.Publicationtype: Journal ArticleScopus© Citations 16 84 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Pulmonary drug delivery with aerogels: engineering of alginate and alginate–hyaluronic acid microspheresIn this study, the aerogel technology was used to prepare pulmonary drug carriers consisting of alginate and alginate–hyaluronic acid by an emulsion gelation technique and supercritical CO2 drying. During the preparation process, the emulsification rate and inner phase viscosity were varied to control the diameter of aerogel microspheres. Results showed that the aerogel microspheres were highly porous (porosity > 98%) with low densities in the range between 0.0087 and 0.0634 g/cm3 as well as high surface areas between 354 and 759 m2/g. The obtained microspheres showed aerodynamic diameter below 5 µm making them suitable for pulmonary drug delivery. An in vitro drug release study with the model drug sodium naproxen was conducted and a non-Fickian drug release mechanism was observed, with no significant difference between the release profiles of alginate and alginate–hyaluronic acid microspheres. During the emulsion gelation step, the feasibility of using the capillary number to estimate the largest stable droplet size in the emulsions was also studied and it was found that using this number, the droplet size in the emulsions may well be predicted.Publicationtype: Journal ArticleScopus© Citations 18 134 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Alginate and hybrid alginate-hyaluronic acid aerogel microspheres as potential carrier for pulmonary drug delivery(2019-08); ; ; ; The aim of the present study was the preparation of aerogel microspheres based on alginate and hyaluronic acid for the potential application in pulmonary drug delivery. Both polymers are commonly used in the pharmaceutical and medical fields because of their nontoxicity, biodegradability and biocompatibility characteristics. The bio-based microspheres were produced using an emulsion gelation process with a subsequent drying step by supercritical CO 2 . The microspheres were characterized by FTIR and SEM. Furthermore, their BET surface area, particle size distribution, and their aerodynamic properties were determined. The microspheres showed a low density in the range of 0.035 – 0.063 g/cm 3 and a high porosity of 97.6–98.7 %, as well as good in vitro aerodynamic properties with d A values of about 5 μm. The obtained properties of the alginate- hyaluronic acid microspheres suggest that they are potentially suitable as drug carrier for pulmonary delivery.Publicationtype: Journal Article231 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , A novel process for coating of silica aerogel microspheres for controlled drug release applications(Elsevier, 2012-02-10); ; ; ; Aerogels are nanoporous materials with an open-pore structure and high specific surface area. Because of their outstanding properties they have been investigated in immense fields of applications like novel insulation materials, catalysts and catalysts carrier, optics, waste treatment and drug delivery systems. However, the limitation of aerogels (specially hydrophilic ones) in a number of applications is their open-pore structure, allowing the penetration of liquids therein resulting in destruction of their textural properties. Applying a polymeric coating layer on aerogels surface can be a solution for this problem and can open a wide window of new applications for aerogels, especially in pharmaceutical industry. This work suggests a novel process for coating of aerogels with polymeric materials using spouted bed technology. Firstly, spherical silica aerogel particles with a high surface area up to 1100 m 2/g and particles diameter ranging from 200 μm to few millimetres were produced. Then, the aerogel particles were loaded with a model drug (Ibuprofen) by adsorption from supercritical CO2 phase. The loaded aerogel particles were coated with different polymeric materials in a slit-shaped spouted fluidized bed with two horizontal gas inlets and adjustable gas supply. The corresponding polymers were sprayed as an aqueous suspension or as melts. The process conditions for coating (coating material, fluidization air flow rate, temperature, etc.) were optimized accordingly. The physical, mechanical, structural and release properties of the resulting formulations were evaluated. This technology allows to provide a specific release mechanism of pharmaceuticals (thermal, pH-sensitive or enzyme triggered release) from aerogels and to broaden aerogel applications in pharmaceutical technology.Publicationtype: Journal Article36 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Tableting properties of silica aerogel and other silicates(Taylor & Francis, 2011-10-01); ; ; ; Context: In solid oral dosage forms silicates are commonly used as glidants in low concentration. However, due to their large specific surface area, silicates may also be used as carrier materials for drugs. Moreover, silicates allow amorphisation of drugs by co-grinding or processing with supercritical fluids. Objective: The aim of this study was to investigate the physical and the tableting properties of Silica Aerogel (special type of silica with an extremely large specific surface area), Neusilin ® US2 (magnesium aluminometasilicate), Florite ® (calcium silicate) and Aerosil ® 200 (colloidal silica). Materials and methods: Powder blends of Avicel ® PH102 (microcrystalline cellulose) and different amounts of the respective silicate were compacted and analyzed for their tabletability (tensile strength vs. compaction pressure) as well as their Heckel plot. Results and discussion: With Neusilin ® the tabletability appeared to be independent of the silicate concentration, whereas with Florite ® an increasing silicate concentration led to a higher tensile strength. In contrast, the addition of Silica Aerogel and Aerosil ® resulted in a decrease of the tensile strength. With Aerosil ® a maximum tolerable concentration of 20% [w/w] was determined. Plastic deformation of all powder blends decreased with increasing silicate concentration. This effect was most pronounced with Aerosil ® and least with Florite ®. Conclusion: Tablets with acceptable tensile strength were obtained with all plain silicates except for Aerosil ®. Therefore, these silicates may be used in tablet formulations, e.g. as carrier materials for liquid or amorphous drugs.Publicationtype: Journal ArticleScopus© Citations 39 39 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Enhancement of griseofulvin release from liquisolid compacts(Elsevier, 2011-08-09); ; ; ; The potential of hydrophilic aerogel formulations and liquisolid systems to improve the release of poorly soluble drugs was investigated using griseofulvin as model drug. The in vitro release rates of this drug formulated as directly compressed tablets containing crystalline griseofulvin were compared to aerogel tablets with the drug adsorbed onto hydrophilic silica aerogel and to liquisolid compacts containing the drug dissolved or suspended in PEG 300. Furthermore, the commonly used carrier and coating materials in liquisolid systems Avicel® and Aerosil® were replaced by Neusilin®, an amorphous magnesium aluminometasilicate with an extremely high specific surface area of 339 m 2/g to improve the liquisolid approach. Both the liquisolid compacts containing the drug dissolved in PEG 300 and the aerogel tablets showed a considerably faster drug release than the directly compressed tablets. With liquisolid compacts containing the drug suspended in PEG 300, the release rate increased with rising fraction of dissolved drug in the liquid portion. It could be shown that Neusilin® with its sevenfold higher liquid adsorption capacity than the commonly used Avicel® and Aerosil® allows the production of liquisolid formulations with lower tablet weights.Publicationtype: Journal ArticleScopus© Citations 56 22