Lyophilization drying

Two complexes of FeCl, with NH OH were received in crystalline state-one-brown by precipitation from the solution (HI) and pink-brown compound was received by lyophilic drying of the solution (IV). 

Corvelyn, S. and Remon, J.P. (1998) Formulation of a lyophilized dry emulsion tablet for poorly soluble drugs. Int. J. Pharm., 166 65-74. 

Interesting data about the effect of deuterated water molecules on electron transfer processes in reaction centres of PS1 of plants have been obtained [215, 216]. Earlier [217], it was found out that, in lyophilically dried leaves of plants which were kept in the dark, there occurs a recombination of charges whose efficiency in the temperature range 77-300 K depends on the water content in the leaves. A detailed study of the effect of replacing H20 by D20 in the leaves containing 10% of the normal water content on the kinetics of recombination reaction (1) in the temperature range 77-300 K has been made [215, 216]. 

Endothermic Fusion Vaporization Sublimation Desorption Desolvation Melting of drug substances purity evaluations Evaporation of liquid or semisolid excipients Removal of frozen water during lyophilization Drying of wet granulated formulations Removal of stoichiometric water from crystalline hydrates... 

The lyophilized dry cake should be stored in 4°C until use and re-suspended at a concentration of 10 mg/mL in water immediately before using. 

In Example 11-5, freeze crystallization of imipenem. which has lower stability in solution at room temperature, is presented. In this process, the product is rapidly frozen to an amorphous solid state to conserve its chemical purity. The temperature is then raised (still below the fieezing temperature at this stage), and the amoiphous solid converts to a crystalline solid over time. After the completion of the solid-state transition phase, the lyophilization drying cycle is initiated. 

Oysters and cockles Lyophilization (drying procedure) allows butyltin species to be stable if stored at — 20° C and in the dark 150 days 5... 

Calcium Colorimetry Phosphorus Tubers Eggs, vegetables Lyophilization, dry ashing EDTA titrimetry... 

Sodium, potassium, magnesium, zinc, and copper Tubers Lyophilization, dry ashing... 

Procedure All the samples are treated before irradiation. For example, hair and nails are carefully cleaned blood and urine are frozen and lyophilized. Dried samples are then put into seaied polyethylene containers, in which they are irradiated for 10-60 hr with a thermal neutron flux of 10 °-10 n cm" sec . They are left to decay for several hours. Hair and nails are directly counted on a Ge(Li) detector for 1-2.5 hr whereas thp other systems analyzed are digested and passed through an anion exchange resin. The fraction containing the W isotope is counted on the Ge(Li) detector for 1-5 hr. 

The loading efficiency of dsDNA within the PBCA capsule was estimated using the following procedure. After synthesis, the PBCA capsules were separated from the oil phase and lyophilized. Dry nanocapsules were dissolved in 3 ml of chloroform, and dsDNA was extracted with 15 ml of demineralized water for 5h. The dsDNA containing water phase was first separated from the poly-mer/chloroform phase via centrifugation, and then concentrated to the initial volume that was loaded during the capsule formulation. The amount of extracted dsDNA was determined from the resolved agarose gel electrophore-... 

N-Nitrosonormeperidinic acid shaken 9 hrs. over a steam bath at 95 with 6 M NaOD in D2O (prepared from NagO), frozen, lyophilized, dry ethanol added followed by drop wise addition of SOCI2 with ice-cooling and agitation, urea added, refluxed 3 hrs., and the product isolated as the hydrochloride -> nor-meperidine-2,2,6,6-d4 hydrochloride. Y 60%. - Denitrosation is due to the action of HCl generated in the mixture. Also tritiation s. P. S. Portoghese and D. L. Larson, J. Med. Chem. 16, 420 (1973). 

Most proteins are obtained as a lyophilized (dried) powder consisting of up to 100% protein. Specifications will indicate what proportion is the protein of interest, and howll much buffer salt and other protein is present. Other proteins may only be available as a suspension in salt. Store opened and unopened bottles in a refrigerator, preferably in alphabetically labelled small boxes or drawers. 

Lyophilization. LyophiLization is essentially a drying technology. Some dmgs and biologicals are thermolabile and/or unstable in aqueous solution. Utilization of freeze drying permits the production of granules or powders that can be reconstituted by the addition of water, buffered solution, or mixed hydrophilic solvents just prior to use, eg, certain antibiotic suspensions. 

Drying is an operation in which volatile Hquids are separated by vaporization from soHds, slurries, and solutions to yield soHd products. In dehydration, vegetable and animal materials are dried to less than their natural moisture contents, or water of crystallization is removed from hydrates. In freeze drying (lyophilization), wet material is cooled to freeze the Hquid vaporization occurs by sublimation. Gas drying is the separation of condensable vapors from noncondensable gases by cooling, adsorption (qv), or absorption (qv) (see also Adsorption, gas separation). Evaporation (qv) differs from drying in that feed and product are both pumpable fluids. 

Freeze drying, or lyophilization, is normally reserved for temperature-sensitive materials such as vaccines, enzymes, microorganisms, and therapeutic proteins, as it can account for a significant portion of... 

Oxidation of C9-Amine (3) with Lead Tetraacetate. C9-Amine hydrochloride (53 mg., 0.17 mmole) was dissolved in 0.1 ml. of water and 5 ml. of acetic acid and to the solution was added lead tetraacetate (190 mg., 0.3 mmole) at 16°-18°C. in 10 minutes. Insoluble material was removed by filtration, and the filtrate was dried by lyophilization. The residue was dissolved in 5 ml. of water and the solution was placed on a column of Amberlite CG-50 (ammonium form, 1 x 10 cm.) followed by a similar treatment as described in the case of periodate oxidation. N-Cyano derivative (5.1 mg.) was obtained and proved to be identical with the N-cyano derivative obtained from the periodate oxidation. 

A large amount of water is added to the dehydrated material in order to cause it to swell the swollen structure is preserved when the material is frozen and subsequently dried in vacuo (in the frozen state) to a low moisture content. Some leaching occurs during the treatment with water and this, undoubtedly, further contributes to the increase in the porosity of the solid. Drying of the lyophilized substance can.be completed in a relatively short time in a vacuum oven at an elevated temperature, or at room temperature in the presence of an efficient water adsorbent. 

The efficacy of lyophilization is demonstrated by the fact that the speed of drying of diced carrots (approximately 0.5-cm. cubes) in a vacuum oven was much greater than that... 

A comparison of the drying curves for lyophilized and unlyophilized sweet potatoes is shown in Figure 7. It is seen that the same and constant loss of weight (8.2%) was reached with the lyophilized samples at both 60° and 70° C. No such indication is shown by the unlyophilized samples at either temperature. 

The lyophilization procedure, as described, is suitable for materials such as vegetables, that do not usually contain much nonaqueous volatile matter. For other materials, rich in these volatiles, a modification of the procedure would be required. The volatiles could in some cases be extracted with a solvent and dried separately (28), or the substances evolved in the drying could be collected and analyzed for the amount of nonaqueous material. 

Figure 7. Drying Curves for Lyophilized and Unlyophilized Sweet Potatoes at 60° and 70° C. (27)...

Several variations of the solvent removal technique were developed (6,7). For the PCPP-SA, 20 80, M = 16,000, microspheres were prepared as follows 1 g polymer was dissolved in 1 ml methylene chloride, drug or dye was suspended in the solution, mixed, dropped into silicon oil containing 1-5% of Span 85, and stirred at a known stirring rate. Stirring was done using an overhead stirrer and a three-blade impeller. After 1 hr, petroleum ether was introduced and stirring was continued for another hour. The microspheres were isolated by filtration, washed with petroleum ether, dried overnight in a lyophilizer, sieved, and stored in a freezer. 

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