Liquid products suspension

Solid oral dosage forms, particularly tablets, are the preferred type of formulation in the United States. Not only are these products widely accepted by consumers, but they are also relatively cheaper to develop and manufacture than oral liquids or suspensions, par-enterals, or suppositories. Figure 4 shows, quite clearly, that even the elderly primarily make use of solid oral dosage forms [162]. 

A. 2-Methyl-2-nitropro]f)ane. To a well-stirred suspension of 650 g. (4.11 moles) of potassium permanganate in 3 1. of water, contained in a 5-1. three-necked flask fitted with a reflux condenser, a mechanical stirrer, a thermometer, and a 250-ml. dropping funnel, is added dropwise and with stirring over a 10-minute period, 100 g. (1.37 moles) of i-butylamine (Note 1). When the addition is complete, the reaction mixture is heated to 55° over a period of approximately 2 hours, and then the reaction mixture is maintained at 55° with continuous stirring for 3 hours. The dropping funnel and reflux condenser are replaced by a stopper and a still head fitted for steam distillation and the product is steam distilled from the reaction mixture (Note 2). The liquid product is separated from the denser water layer and then diluted with 250 ml. of ether and washed successively with two 50-ml. portions of aqueous 2M hydrochloric acid and with 50 ml. of water. After the ethereal solution has been dried over anhydrous magnesium sulfate, the solution is fractionally distilled at atmospheric pressure to remove the ether. The residual crude product (Note 3) amounts to 106-128 g. and is sufficiently pure for use in the next step. In a typical run, distillation of 124 g. of the crude product afforded 110 g. (78%) of the pure 2-methyl-2-nitrobutane as a colorless liquid, b.p. 127-128°, d 1.3992. The material slowly solidifies on standing to a waxy solid, m.p. 25-26° (Note 4). 

Sales of Ca supplements alone were 875 million in the United States in 2002, and comprised 60% of all mineral supplement sales (Anonymous, 2004). In 2004, sales of Ca supplements increased by 9.3% (Uhland et ah, 2004), possibly to some extent in response to the Surgeon General s report on bone health that was issued that year. More recently in 2006, it was projected that dietary supplement sales in the United States would approach 5 billion (Anonymous, 2006). While Ca derived from a balanced diet is preferable, Ca supplements are a popular noncaloric alternative for increasing daily Ca intake. There are a vast number of oral Ca supplements available in the market place in the form of capsules, tablets, chewable tablets, effervescent tablets, liquids, powders, suspensions, wafers, and granules. However, not all Ca salts are equally soluble or bioavailable and the dose of Ca on the label of a supplement may not necessarily be reflective of the relative amount of available Ca once consumed. Furthermore, the same Ca salt may be more or less bioavailable depending on the production process and materials used to manufacture the supplement. 

Because interactions of products with closure systems are possible, liquids and suspensions undergoing stability studies should be stored on their side or inverted... 

When small particles are chosen, they have to be used in the form of a suspension in the liquid. The lower limit of particle size may be set by the nature of the catalyst, but is most likely to depend on how easily the particles can be separated from the liquid products. To avoid filtration, the most convenient way of separating the particles is to allow them to settle under gravity, and the minimum particle size is set accordingly. 

The pressure vessel is heated with agitation at 100° for 4 hours and at 130° for 6 hours. The vessel is allowed to cool to room temperature and the volatile by-products [Caution Toxic (Note 4)] are vented. The crude, fuming, liquid product (Note 5) is poured into a stirred suspension of 10 g. of finely divided sodium fluoride in 60 ml. of pentane (Note 6), the mixture is filtered, and the filtrate is fractionated through a 6-in. Vigreux column. 1,1,1-Trifluoroheptane is collected at 100-101°/760 mm., 1.3449. The yield is 21.7-24.6 g. (70-80%). 

The principal reactors used are fluidized bed reactors, called Synthol reactors, in which the feed gas entrains an iron catalyst powder in a circulating flow. The suspension enters the bottom of the fluidized bed reaction section, where the Fischer-Tropsch and the gas shift reactions proceed at a temperature of from 315 to 330°C. These reactions are highly exothermic, as described previously, and the large quantity of heat released must be removed. The products in gaseous form together with the catalyst are taken off from the top of the reactor. By decreasing the gas velocity in another section, the catalyst settles out and is returned for reuse. The product gases are then condensed to the liquid products. 

Reactions proceed faster and more smoothly when the reactants are dissolved, because of diffusion. Although reactions in the solid state are known [1] they are often condensations in which a molecule of water is formed and reaction takes place in a thin film of water at the boundary of the two solid surfaces. Other examples include the formation of a liquid product from two solids, e.g. dimethylimidazolium chloride reacts with aluminum chloride to produce the ionic liquid, dimethylimidazolium tetrachloroaluminate [2]. It is worth noting, however, that not all of the reactant(s) have to be dissolved and reactions can often be readily performed with suspensions. Indeed, so-called sol-id-to-solid conversions, whereby a reactant is suspended in a solvent and the product precipitates, replacing the reactant, have become popular in enzymatic transformations [3]. In some cases, the solvent may be an excess of one of the reactants. In this case the reaction is often referred to as a solvolysis, or, when the reactant is water, hydrolysis. 

Suspensions or dispersions of particles in a liquid medium are ubiquitous. Blood, paint, ink, and cement are examples that hint at the diversity and technological importance of suspensions. Suspensions include drilling muds, foodstuffs, pharmaceuticals, ointments and cremes, and abrasive cleansers and are precursors of many manufactured goods, such as composites and ceramics. Control of the structure and flow properties of such suspensions is often vital to the commercial success of the product or of its manufacture. For example, in consumer products, such as toothpaste, the rheology of the suspension can often determine consumer satisfaction. In ceramic processing, dense suspensions are sometimes molded (Lange 1989) and then dried and sintered or fired into optical components, porcelin insulators, turbine blades, fuel cells, and bricks (Rice 1990 Simon 1993). Crucial to the success of the processing is the ability to transform a liquid, moldable suspension into a solid-like one that retains its shape when removed from the mold. These examples could be multiplied many times over. 

Particles from gas-saturated solutions (or suspensions) (PGSS) SCF is dissolved in liquid product or solution in solvent, followed by rapid depressurization. 

Rheology is a product attribute frequently exploited in personal care products to create visual appeal to prospective consumers. Liquid products in transparent packaging may highlight the gel strength of the continuous phase with obvious suspension of the particulate phases. In certain instances, aeration may be introduced to emphasize the gel-like consistency of the product. Premium brand products may include stable suspensions captured within the gel matrix of encapsulated fragrances, moisturizers, exfoliating compounds, etc. 

The choice of packaging for ophthalmic products will depend on the type of dosage form, such as whether it is a liquid solution/suspension or semi-solid gel or ointment. Also, choice will depend on how the product is to be used by the patient, such as whether it is intended to... 

Liquid or semi-liquid products may be based on water, alcohol, solvents, oils, gels, etc., i.e. emulsions, suspensions, creams, ointments, solutions, etc. 

In immiscible liquid agglomeration, particles with a small amount of adsorbed binding liquid on their surfaces collide and coalesce to form larger entities. In the sol-gel process (see also Section 5.3.2, Fig. 5.52), another agglomeration technique that occurs in liquid phase, fine particles are initially suspended in a binder liquid. The suspension is then formed into spherical droplets and the excess binder is removed to solidify the droplets into a particulate product. 

A Slurry Bubble Column Reactor (SBCR) is a gas-liquid-solid reactor in which the finely divided solid catalyst is suspended in the liquid by the rising gas bubbles. SBCR offers many advantages over fixed-bed type reactors such as 1) improved heat transfer and mass transfer 2) isothermal temperature profile is maintained and 3) relatively low capital and operating cost. Fischer-Tropsch Synthesis (FTS) takes place in a SBCR where the synthesis gas is converted on catalysts suspended as fine particles in a liquid. The synthesis gas flows in a bubble phase through the catalyst/wax suspension. The volatile products are removed with unconverted gases, and the liquid products are separated firom the suspension. A gas distributor located in the bottom of the reactor produces the bubbles in the reactor. 

Similarly, Figs. 15.4 and 15.5 show examples of a liquid product such as an aqueous suspension. Figure 15.4 shows a typical standard protocol of an oral... 

Spray-drying is an operation by which a liquid product is atomized in a hot gas current to instantaneously obtain a powder with particle sizes range from 10-50 pm to 2-3 mm, depending on the starting feed material and operating condition. The gas can be air or more rarely nitrogen. The liquid may be a solution, an emulsion, or a suspension (Gharsallaoui et al., 2007). 

Products that are suitable for drying on a drum dryer are viscous liquids, slurries, suspensions, and pastes. The final dry products are typically in the form of porous flakes or powders. The drum dryer has been used extensively to dry chemicals and... 

The carrier introduced into the biotechnological product suspension changes the form of a substance being dried (from liquid or suspeusiou, a granulated product is obtained). 

In the fluidized bed, there are two phases (gas/liquid and solid). The particles are suspended by the gas bubbles and require a minimum speed of fluidization to keep them in suspension. With increasing gas flow, there will be formation of large bubbles and the solid particles are dragged, this affects the flow of gas and its contact with the particles. The yield to liquid products is high, about 70-75%, depending on the original material. 

---