Lyophilised solution

Lyophilised solution Glass vial containing powdered material (Cr-species, pesticides)... 

The present state of the art of Cr speciation leaves much to be desired and compels to improve quality assessment. In order to meet the requirements of the directives, the reliability of the methods needs to be improved substantially. Appropriate reference materials certified for Cr(III) and Cr(VI), which are at present non existing, would provide both an effective and economical way for the laboratories to check and improve their performance which justified the production of a lyophilised solution for the certification of Cr-species [36,37]. 

A batch of 1100 vials containing a lyophilised solution, similar to the previous A sample was prepared. The preparation of the samples was performed under class 100 clean room facilities. All laboratory ware pipettes, volumetric flasks etc. was thoroughly cleaned by leaching in diluted acids. 

Initially fermentation broth has to be characterised on the viscosity of the fluid. If the presence of the biomass or cells causes trouble, they have to be removed. Tire product is stored inside the cells, the cells must be ruptured and the product must be freed. Intracellular protein can easily be precipitated, settled or filtered. In fact the product in diluted broth may not be economical enough for efficient recovery. Enrichment of the product from the bioreactor effluents for increasing product concentration may reduce the cost of product recovery. There are several economical methods for pure product recovery, such as crystallisation of the product from the concentrated broth or liquid phase. Even small amounts of cellular proteins can be lyophilised or dried from crude solution of biological products such as hormone or enzymes.2,3... 

Protein content Bradford s test was performed to determine the protein content (mg g ) of the lyophilisates. A sample of the lyophilisate (2.5 mg) was dissolved in glycylglycine (Gly-Gly) buffer (1.5 mL). An ahquot of this solution (20 gL) was diluted with glycylglycine (Gly-Gly) buffer (30 gL) and Bradford s solution (950 gL) was added. After 5 min, the absorbance was measured at 595 nm. The concentration of FSA is calculated from the interpolation of the calibration curve of bovine serum albumin (BSA) 437 mg total protein/gram of lyophihsate. 

In order to obtain a thermodynamically stable micro emulsion, the analysis of the phase behaviour is indispensable. With bovine serum albumin instead of an enzyme (because of the cost of the bio-catalyst) phase behaviour studies are shown in Fig. 2. A strong shift of the phase boundary is observed, yielding a system that solubilises much less water in the presence of the protein. In case of hydrophobic enzymes, the addition of dry lyophilised protein to an already prepared reverse micellar solution can also work well [53]. 

Mo blue was prepared via a modified literature procedure [14]. To a dispersion of 0.5 g Mo powder in 20 ml water was added 1 ml aqueous 35 % H2O2. After overnight stirring, and removal of residual Mo metal by filtration, the blue compound was isolated by lyophilisation of the solution. For immobilization of Mo blue on the LDH, the compound was dissolved in a minimal amount of water (e.g. 0.075 g Mo blue in 0.4 ml water), and 100 ml isopropanol was added. The LDH (1.5 g) was suspended in this solution. Visual inspection shows that after 30 minutes, uptake of the Mo blue by the LDH is essentially complete. The LDH was isolated by centrifugation and lyophilized. 

Dissolve the active ingredient in the well stirred solution of Kollidon 12 PF and after freeze-drying, fill 500-mg-portions of the dry lyophilisate into ampoules. 

This process, frequently called lyophilisation, is necessary when water is to be removed from solutions containing heat-labile materials so that conventional distillation, even under reduced pressure, would cause extensive losses by decomposition. Examples are to be found in the removal of water from aqueous solutions of enzymes, polysaccharides, peptides, etc. In principle the aqueous solution is frozen in a suitable solid carbon dioxide freezing mixture (see Section 2.12), and the ice is sublimed off to leave a dry residue.42... 

Figure 2.89 illustrates a commercially available Quickfit lyophiliser (Bibby Science Products) accommodating a single flask of such a size that the volume of aqueous solution to be treated is one-quarter its total capacity. The charged flask is rotated in a dry ice-acetone bath so that an even layer of frozen solution is obtained over the inside. The flask is immediately attached to the refrigerant chambers which are filled with a Cardice-acetone mixture. An oil vacuum pump is connected to the refrigerant chamber via the supplementary trap, which if possible should be immersed in a Dewar flask filled with liquid nitrogen such a cooled trap provides maximum protection for the vacuum pump. Vacuum is... 

When lyophilising from trays in a shelf freeze dryer try transferring the solution to Gortex... 

Tekely and co-workers74 75 were the first to reveal that SS 31P NMR spectroscopy yields an unambiguous visualisation of the presence and the nature of singly and/or doubly ionised phosphate groups in lyophilisates prepared from parent solutions at different pH values. Employing O-phospho-L-serine as a model sample, they showed that both isotropic and anisotropic parameters are very sensitive to the change of the ionisation state (Figure 16). 

Figure 16 Experimental (left) and simulated (middle) low spinning speed (to, = 2.0 kHz) CSA sideband manifolds of phosphate groups in L-O-phosphoserine lyophilised from solutions at different pH values. For better visualisation of the changes in the CSA tensor after secondary ionisation, the corresponding simulated static powder spectra are also included (right).Taken from Ref. [74]. Reproduced by permission of The Royal Society of Chemistry.

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