Proteins lyophilised

Because of their potential instability in solution, therapeutic proteins are often formulated as lyophilised powders. Even in this 

---

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]. 

Hsu CC, Ward CA, Pearhnan R, Nguyen HM, Yeung DA, Curley JG. Determining the optimum residual moisture in lyophilised protein pharmaceuticals. Dev Biol Stand 74 255-271, 1992. 

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. 

Each lyophilisate for one immunising dose of diphtheria, tetanus toxoids and pertussis with Haemophilus b conjugate vaccine contains Haemophilus influenzae type b polysaccharide conjugated to tetanus protein 10 meg, purified diphtheria toxoid 1 immunising dose, purified tetanus toxoid 1 immunising dose, Bordetella pertussis minimum of 4.1 lU. 

Protein A (100 ig of lyophilised powder able to bind 7.3 Ag of human IgG, catalogue number P9151). Hydroquinone (Sigma), hydrogen peroxide (Merck, Germany). 

Dialysis, ultrafiltration and lyophilisation are processes that are used to change the composition of the medium in which macromolecules are dissolved. The focus of our discussion is on proteins, and we consider methods that can be applied widely, from the processing of cell extracts to preparation of samples for experiments. 

A year later the same research group presented a second rather different approach [160] in which they described the production of abiotic receptors by imprinting of proteins. The basic idea was once again to induce a certain conformation into the tertiary structure of a protein using a template and then to freeze it in . Bovine serum albumin (BSA) was dissolved in water, containing either p-hydroxybenzoic acid or tartaric acid. After lyophilisation the protein was washed with anhydrous solvent to remove the template. The resultant imprinted proteins bound up to 30-fold more of the template in anhydrous... 

Another example in this direction has been reported by Ohya and co-workers [28]. By using a method analogous to that of Keyes et al., they have induced catalytic activity in BSA by molecular imprinting. However, unlike the cross-linking reaction employed by Keyes et al. to stabilise the conformation of the imprinted protein, these authors resorted to lyophilisation to lock-in the conformation. The enzymatic activity of this synthetic enzyme was demonstrated with a dehydrofluori-nation reaction. 

Johnson RE, Kirchoff CE, Gand HE. Mannitol-sucrose mixtures versatile formulations for protein lyophilisation. / Pharm Sci 2002 91(4) 914-922. 

During lyophilisation of any protein formulation, there is a need to include a lyoprotectant such as polyols to prevent freeze-drying-induced denaturation. 

---