Search results for " Drying"

Evaluation of drug-polymer solubility curves through formal statistical analysis: comparison of preparation techniques.

2014

ABSTRACT: In this study, the influence of the preparation technique (ball milling, spray drying, and film casting) of a supersaturated amorphous dispersion on the quality of solubility determinations of indomethacin in polyvinylpyrrolidone was investigated by means of statistical analysis. After annealing of the amorphous dispersions above the crystallization temperature for 2 h, the solubility curve was derived from the glass transition temperature of the demixed material using the Gordon–Taylor relationship and fitting with the Flory–Huggins model. The study showed that the predicted solubility from the ball-milled mixtures was not consistent with those from spray drying and film casting,…

The dynamics of (57)Fe nuclei in Fe(III)-DNA condensates.

2001

Abstract The dynamics of iron nuclei in the condensates obtained by interaction of Fe III with DNA, Fe III (DNA monomer) 2 , have been investigated by variable temperature 57 Fe Mossbauer spectroscopy. Studies were effected on gel and freeze-dried samples, obtaining nearly coincident values of the parameters isomer shift and nuclear quadrupole splitting in T ranges 20–260 K. Functions ln( A T / A 77.3 ) vs. T , here employed to investigate the dynamics of Fe nuclei, showed linear trends in the T ranges 20–150 and 150–260 K, respectively, the latter with larger slopes. Data coincided for gelled and freeze-dried specimens. No variation of δ or Δ E parameters occurred at the two T intervals, w…

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…

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

1975

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…

Optimised lyophilisation-based method for different biomolecule single-extractions from the same rat brain sample: Suitability for RNA and protein ex…

2019

Abstract Background Optimisation of tissue processing procedures in preclinical studies reduces the number of animals used and allows integrated multilevel study in the same sample. Multiple extraction of different biomolecules from the same sample has several limitations. New method Using brain samples from rats subjected to ischemic stroke, we combined lyophilisation of flash-frozen tissue, mechanical pulverisation and cryopreservation in a method to optimise tissue handling and preservation for independent RNA or protein single-extract methods, and subsequent RT-qPCR or Western blot analyses. Results Lyophilisation resulted in 70% tissue weight loss. RNA (OD260/280∼1.8) and protein yield…