Crystals liquid formulations

The bacterial culture converts a portion of the supplied nutrient into vegetative cells, spores, crystalline protein toxin, soluble toxins, exoenzymes, and metabolic excretion products by the time of complete sporulation of the population. Although synchronous growth is not necessary, nearly simultaneous sporulation of the entire population is desired in order to obtain a uniform product. Depending on the manner of recovery of active material for the product, it will contain the insolubles including bacterial spores, crystals, cellular debris, and residual medium ingredients plus any soluble materials which may be carried with the fluid constituents. Diluents, vehicles, stickers, and chemical protectants, as the individual formulation procedure may dictate, are then added to the harvested fermentation products. The materials are used experimentally and commercially as dusts, wettable powders, and sprayable liquid formulations. Thus, a... 

Typically the formulation may contain up to 60% active with builder salts and a water level of about 30-40% [52]. The weight ratio of LAS/AE may range from 1.5 1 up to 4 1. The combination of LAS and AE is especially effective for two reasons. First, LAS and AE interact strongly to form the lamellar phase liquid crystals. Second, both ingredients can be introduced into the liquid formulation as a 95 + % active liquid to control the amount of water going into the formulation. LAS can be introduced into the formulation as sulfonic acid and neutralized in situ. 

The amorphous phase is not usually a desirable state for the API because the formation process is more random and difficult to control than a crystallization. A second dispersed liquid phase is usually formed just prior to freezing and may coalesce or disperse under the influence of hydrodynamic forces in the crystallizer, making the process sensitive to micro-mixing effects on scale up. Amorphous solids also have significantly lower thermodynamic stability than related crystalline material and may subsequently crystallize during formulation and storage. Because of the non-uniformity of the amorphous solid it can more easily incorporate molecules other than the API, making purification less effective. 

Liquid formulations can be used as pastes or slurries, dispersions, or emulsions (in aqueous or other solvents) to physically separate the compound to be protected. Dispersions, pastes, or slurries are not commonly used but are a feasible approach when highly concentrated products are needed. For instance, many early analytical enzymes were sold as crystal slurries to preserve stability. Dispersions can be prepared from dry materials. Most of the dispersions are visually cloudy in appearance due to the particle size of the dispersed compounds and are thus undesirable in most endproducts. 

Ritonavir (Norvir Abbott) is a drug for treating patients infected with human immunodeficiency virus-1 (HIV-1). In solid state the compound consists exclusively of one kind of monoclinic crystals. As this form, now called form I, was not sufficiently bioavailable by the oral route, a liquid formulation containing dissolved ritonavir in a hydroalcoholic solution was developed. It gave satisfactory results during the development and early manufacturing phases. However, in 1998, 2 years after the launch, a second form (form II) precipitated during shelf life. The new form is thermodynamically more stable and about 50% less water-soluble than form I. Within weeks-days, this new form was produced in all the production lines and Abbott had to stop the production of ritonavir. Finally, after considerable effort and expense, a new formulation of ritonavir was developed. 

Citrate compounds are salting-out electrolytes — they tie up water molecules in the liquid and as a result help force the formation of liquid crystals or lamellar stmctures. It is sometimes possible to reverse this trend by the addition of salting-in electrolytes, compounds with high lyotropic numbers (>9.5) which can raise the cloud point of a liquid formulation [26], This permits increased concentration without the onset of structuring. 

Irradiation. The liquid formulation was applied with a calibrated bar onto either a KBr crystal for infrared analysis, or a glass plate for hardness and gel fraction measurements. 10 to 20 pm thick films were exposed to the radiation of a 80 W/inch medium pressure mercury lamp, in the presence of air, at a passing speed of 60 m/min, which corresponds to a 0.1 s exposure at each pass. The incident light intensity (Iq) at the sample position was measured by radiometry (International Light IL-390) and... 

Other important uses of sorbitol as a humectant include formulation of cough syrups, multivitamin preparations, emulsions and suspensions. Because of its humectancy properties, sorbitol reduces the tendency of liquid formulations to crystallize. 

A suspension concentrate (SC) is formed by milling a solid AI in a carrier fluid. A solubility of 100 ppm or less in the carrier fluid is desirable to assure crystal growth due to Ostwald ripening is minimized. For most SC systems, the carrier fluid is water. These formulation types have the same advantages of other liquid formulations in ease of use, volumetric measurement, and rapid dispersion when diluted. Since the carrier fluid is usually water, SCs exhibit reduced flammability and lower phytotoxicity. SCs are generally nonstaining and have minimal odor. Reduced human toxicity and irritation as well as reduced phytotoxicity relative to an EC are additional benefits of SCs [12-14]. 

It is almost always desirable to have a homogenous enzyme formulation, that is, without precipitations. Unwanted crystallization in the liquid formulation of the enzyme can occur if the enzyme concentration, pH, ion strength, etc. are in the right range. This can be avoided by addition of polyols and adjustment of pH. Impurities remaining from the fermentation broth may also precipitate and can, to a certain degree, be handled by adjustment of the formulation. However, it is generally more optimal to solve these issues upstream in the production process, that is, in the fermentation or primary separation steps. 

The quantitative formulation of the coupling of the crystal-liquid transformation with a chemical reaction involves specifying the phases in which the reaction occurs and the modifications induced in the chemical potential of the repeating unit The reaction can be treated by the usual methods of chemical equilibrium, the results of which are then imposed on the conditions for phase equilibrium. The different possibilities must be individually treated following this procedure. 

Applications of photoelectron spectroscopy to molecular crystals, liquids, and solutions [64-67] inspired efforts to generalize the simple ESCA potential model to chemical shifts due to solvation [68-72], One has thus looked for formulations of the chemical shift for extended systems, other than when substituents have strong electropositive or electronegative character, and studied the response of the full spectmm upon condensation [68,72], One has addressed intermolecular interactions behind such shifts of both short- and long-range types, like exchange, electrostatic, polarization, and dispersion interactions. The theoretical models covering the polarization response can be classified as the dielectric [68], microscopic polarization [73], and reaction field models [71], Thelatter can be viewed as a supermolecular extension of the dielectric model. 

These concepts were implemented according to the following scheme the liquid element surrounding the bubble and the bulk are considered as two separate dynamic reactors that operate independent of each other and interact at discrete time intervals. In the beginning of the contact time, the interface is being detached from the bulk. When overcome by the bubble, it returns to the bulk and is mixed with it. Hostomsky and Jones (1995) first used such a framework for crystal precipitation in a flat interface stirred cell. To formulate it for a... 

S. Blenk, H. Ehrentraut, W. Muschik. Statistical foundation of macroscopic balances for liquid crystals in alignment tensor formulation. Physica A 77 119-138, 1991. 

A new class of solvents called ionic liquids has been developed to meet this need. A typical ionic liquid has a relatively small anion, such as BF4, and a relatively large, organic cation, such as l-butyl-3-methylimidazolium (16). Because the cation has a large nonpolar region and is often asymmetrical, the compound does not crystallize easily and so is liquid at room temperature. However, the attractions between the ions reduces the vapor pressure to about the same as that of an ionic solid, thereby reducing air pollution. Because different cations and anions can be used, solvents can be designed for specific uses. For example, one formulation can dissolve the rubber in old tires so that it can be recycled. Other solvents can be used to extract radioactive waste from groundwater. 

Lithium reacts with copper powder in a copper crucible at 200°C to yield yellow mixed crystals of the variable-phase LiCu4, whose formulation represents a maximum content of Li. A crystalline LiCu4 product is observed on copper surfaces exposed to liquid lithium. ... 

The experiments were conducted at four different temperatures for each gas. At each temperature experiments were performed at different pressures. A total of 14 and 11 experiments were performed for methane and ethane respectively. Based on crystallization theory, and the two film theory for gas-liquid mass transfer Englezos et al. (1987) formulated five differential equations to describe the kinetics of hydrate formation in the vessel and the associate mass transfer rates. The governing ODEs are given next. 

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