Search results for "Drying"

Preparation and recrystallization behavior of spray-dried co-amorphous naproxen–indomethacin

2016

To improve the dissolution properties and the physical stability of amorphous active pharmaceutical ingredients, small molecule stabilizing agents may be added to prepare co-amorphous systems. The objective of the study was to investigate if spray-drying allows the preparation of co-amorphous drug-drug systems such as naproxen-indomethacin and to examine the influence of the process conditions on the resulting initial sample crystallinity and the recrystallization behavior of the drug(s). For this purpose, the process parameters inlet temperature and pump feed rate were varied according to a 2(2) factorial design and the obtained samples were analyzed with X-ray powder diffractometry and Fo…

Microencapsulation of antioxidant compounds through innovative technologies and its specific application in meat processing

2018

Background Meat has a complex physical structure and chemical composition that is very prone to oxidation. Plants are sources of biologically active compounds (antioxidants) of interest as potential raw materials for meat processing, primary as replacements for synthetic additives. Some examples are essential oils from aromatic plants that are usually unstable under common processing and storage conditions and exhibit strong smell and off flavour. Hence, stable delivery systems like encapsulation are required. Scope and approach Encapsulation, and particularly spray-drying, offers protection of active compounds, their controlled and targeted release in food products and ability to mask unac…

Influence of different histologic preparation methods on preservation of tissue antigens in the immunofluorescent antibody technique.

1975

Adhesion prophylaxis using a copolymer with rationally designed material properties.

2008

Physical barriers are the only licensed adjuncts for adhesion prophylaxis in the United States and Europe. Here, we investigate D,L-polylactide-epsilon-caprolactonetrimethylenecarbonate (PCT copolymer), which is a rationally designed biomaterial, as an adhesion barrier.PCT copolymer membranes were produced by polymerization of the monomers, dissolution in organic solvents, and subsequently processing them by means of modified phase inversion and freeze drying. In vitro cytotoxicity was assayed by fibroblast culture. In vivo adhesion prophylaxis was studied in a rat model that involved standardized traumatization by electrocautery and suturing. The quantity and quality of the resulting adhes…

Synthesis and processing of nanocrystalline tungsten carbide: Towards cemented carbides with optimal mechanical properties

2011

Abstract Nanocrystalline tungsten carbide has been obtained by reduction/carburization at low temperature from precursors obtained by freeze-drying of aqueous solutions. Nanocrystalline WC powders with a adequate content of carbon were mixed with submicrometric Cobalt powder (12 wt.%), obtained by same synthesis method, and sintered in vacuum furnace. The cemented carbides fabricated from experimental powders were compared with both commercial ultrafine and nanocrystalline WC-12Co mixtures consolidated by the same route. The synthesised powders were characterized by X-ray powder diffraction, elemental analysis and scanning and high resolution transmission electron microscopy. On the other h…

Microencapsulation of Phenolic Extracts from Cocoa Shells to Enrich Chocolate Bars

2021

AbstractCocoa bean shells were subjected to green extraction technologies, based on the absence of toxic organic solvents, to recover polyphenols; the extract was then encapsulated using a spray dryer and maltodextrin as coating agent. The best conditions observed in the spray drying tests (core-to-coating ratio 1:5; inlet temperature 150 °C; flow rate 6 ml min−1) were applied to produce the microcapsules used to enrich the same cocoa mass as the shells and processed for the preparation of the chocolate bars. Sensory analysis showed no significant differences between enriched chocolate bar and the unenriched reference one, except for the appearance. Both samples were then subjected to accel…

Formation of hierarchically ordered silicas prepared by spray drying of nanosized spheres

2002

We report on our strategy to synthesise defined arrangements of macro- and mesopores in one single material with spherical morphology using the spray drying technique. As starting materials, nano-sized silica spheres and colloidal suspensions were chosen. The intra-particle as well as inter-particle pore size was independently controlled which allowed to obtain materials with varied bimodal pore networks. The spherical agglomerates were characterised regarding their pore structural parameters and are potential adsorbents in liquid chromatographic separations.

The effect of thermal drying on the contents of condensed tannins and stilbenes in Norway spruce (Picea abies [L.] Karst.) sawmill bark

2021

Norway spruce (Picea abies (L.) Karst.) bark contains marked amounts of polyphenolic compounds. Condensed tannins (CTs) and stilbenes show commercial potential as antioxidants, antimicrobials, preservatives in food and cosmetic applications, technochemical products, and pharmaceuticals. Storing of bark before the conversion process leads to substantial losses of extractives compounds. In the present study, the potential of thermal drying for maintaining extractives content was assessed based on an experiment in which bark samples were dried in convection kilns at 40, 50, 60, and 70 °C temperatures. The development of CTs and stilbene contents and CT degradation were followed for 28–34 h. CT…

Cryo-negative staining

1998

Abstract A procedure is presented for the preparation of thin layers of vitrified biological suspensions in the presence of ammonium molybdate, which we termcryo-negative staining. The direct blotting of sample plus stain solution on holey carbon supports produces thin aqueous films across the holes, which are routinely thiner than the aqueous film produced by conventional negative staining on a continuous carbon layer. Because of this, a higher than usual concentration of negative stain (ca. 16% rather than 2%) is required for cryo-negative staining in order to produce an optimal image contrast. The maintenance of the hydrated state, the absence of adsorption to a carbon film and associate…

The Closed/Open Model for Lipase Activation. Addressing Intermediate Active Forms of Fungal Enzymes by Trapping of Conformers in Water-Restricted Env…

2001

The behavior of prototypic fungal lipases in a water-restricted environment has been investigated by exploiting the reported experimental strategy that allows the trapping (freeze-drying) of the enzyme in the conformation present in aqueous solution and to subsequently assay it in nonaqueous media [Mingarro, I., Abad, C., and Braco, L. (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 3308-3312]. We now report, using simple esterification as well as acidolysis (triglycerides as substrates) as nonaqueous model reactions, that the presence of a detergent (n-octyl-beta-glucopyranoside) in the freeze-drying buffer, at concentrations below the critical micellar concentration, generates different catalyti…