Alternatives to freeze-drying

The problem of reducing sintering temperature is also crucial for Bao sSrg sTiOj, which possesses ferroelectric properties but is used more often as a material with a positive temperature coefficient of resistance (PTCR). The citrate synthesis method is often considered as an alternative to freeze-drying synthesis, but in the following case the solution of barium, strontium, and titanium citrates was dried by various methods (i.e., oven drying and freeze-drying). Careful... 

Gel filtration is a rapid and efficient alternative to dialysis for desalting and buffer exchange. It is used, for example, in the preparation of protein samples prior to freeze drying or fractionating by ion exchange chromatography. Applications include ... 

An alternative to freezing or preservation in liquid fixahon/preservation is imprinting tissue on nitrocellulose paper (30,31). Cross-sections of fresh tissue are directly imprinted onto nitrocellulose paper. This imprints cells onto the paper from the tissue and also preserves localization within the cross-section. This technique provides a rapid and inexpensive means to preserve dried cells without further fixation or refrigeration. Both DNA and RNA can be recovered from these imprints. 

Microorganisms are commonly stored on the appropriate solidified medium, either as slants or stabs (weeks) or for longer periods (months) as liquid cultures suspended in glycerol kept at low temperatures (—70°C/ —94°F). Alternatively, microorganisms can be preserved for very long term storage (years) by freeze-drying. Method 13.10.3 has been used to freeze-dry yeasts (C.M.L. Joseph, personal communication, 2005), and method 13.10.4 has been used successfully for lactic acid bacteria (Duke, 1979). 

After seeing the problems in convective drying because of capillary forces, one is inclined to test a drying technique that does not involve a Uquid/vapor phase boundary. The most evident alternative is freeze-drying, which is widely used for... 

Picric acid [88-89-1] M 229.1, m 122-123 , pK 0.33 (0.37). Crystd first from acetic acid then acetone, toluene, CHCI3, aqueous 30% EtOH, 95% EtOH, MeOH or H2O. Dried in a vacuum oven at 80° for 2h. Alternatively, dried over Mg(C104)2 or fused and allowed to freeze under vacuum three times. Because it is EXPLOSIVE, picric acid should be stored moistened with H2O, and only small portions should be dried at any one time. The dried acid should NOT be heated. 

Chase [2.32] presents an alternative method to monitor and control the freeze drying process by measuring the flow of nitrogen to keep the operation control pressure, pc, constant. The Mass Flow Controller (FMC) consists of a proportional valve, an integral flow meter and a capacitance manometer (CA). The CA measures the total pressure in the plant, the valve opens, if the pressure gets below the preset value and vice versa. The flow of... 

Tomato Tomato is also popular for the expression of biophamaceuti-cals due to the relative ease of processing of the fruit, and the fact that the fruit can be consumed fresh, thus providing stability of the recombinant protein at room temperatures. Tomato fruit has a short shelf life but, alternatively, can be freeze-dried, an inexpensive and well-established technology. Freeze-drying results in concentration of the protein and maintenance of batch consistency. 

While formulation of proteins in solution or suspension are less costly to produce, not all therapeutic proteins can be stably stored in solution or suspension, even when refrigerated (4°C) or frozen (-20°C). In those cases freeze-dried formulations of proteins may be used as an alternative. Freeze-drying or lyophifization typically produces an amorphous form of... 

Lactose may be obtained in two crystalline forms a-lactose and P-lactose (in addition to amorphous forms). The alpha form is obtained when water is incorporated into the lattice structure during crystallization (usually by supersaturation below 93.5°C) (5). Alternatively, the beta form does not contain water and exists as a non-hygroscopic and anhydrous form. Amorphous lactose is formed when either the crystallization is rapid or sufficient transient energy is introduced into the crystalline forms (74), i.e., spray drying (75), micronization and milling (76), freeze-drying, and anti-solvent crystallization (77). 

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