Liquid preparation

When [EMIMJCl is present in a molar excess over AICI3, only equilibrium (2.1-1) need be considered, and the ionic liquid is basic. When a molar excess of AICI3 over [EMIMJCl is present on the other hand, an acidic ionic liquid is formed, and equilibria (2.1-2) and (2.1-3) predominate, further details of the anion species present may be found elsewhere [23]. The chloroaluminates are not the only ionic liquids prepared in this manner. Other Eewis acids employed have included AlEtCl2 [24], BCI3 [25], CuCl [26], and SnCl2 [27]. In general, the preparative methods employed for all of these salts are similar to those indicated for AlCl3-based ionic liquids as outlined below. 

Table 2.1-1 Examples of ionic liquids prepared by anion metathesis.

Ionic liquid synthesis in a commercial context is in many respects quite different from academic ionic liquid preparation. While, in the commercial scenario, labor-intensive steps add significantly to the price of the product (which, next to quality, is another important criterion for the customer), they can easily be justified in academia to obtain a purer material. In a commercial environment, the desire for absolute quality of the product and the need for a reasonable price have to be reconciled. This is not new, of course. If one looks into the very similar business of phase-transfer catalysts or other ionic modifiers (such as commercially available ammonium salts), one rarely finds absolutely pure materials. Sometimes the active ionic compound is only present in about 85 % purity. However, and this is a crucial point, the product is well specified, the nature of the impurities is known, and the quality of the material is absolutely reproducible from batch to batch. 

Ionic liquids prepared as low-melting salts. .. [NR3R ]Cl/ZnCl2 University of Leicester, UK 2000 29... 

For the results reported in both Table 7.2-3 and Table 7.2-4, the only reported detail concerning the ionic liquid was that it was [EMIM][C1-A1C13]. No details of the aluminium(III) chloride content were forthcoming. As with most of the work presented in this chapter, data are taken from the patent literature and not from peer reviewed journals, and so many experimental details are not available. This lack of clear reporting complicates issues for the synthetic polymer chemist. Simpler and cheaper chloroaluminate(III) ionic liquids prepared by using cations derived from the reaction between a simple amine and hydrochloric acid (e.g., Me3N-E3Cl and... 

As with tablets and capsules, the prescribed dose of the drug may not be die same as what is on hand (or available). For example, die physician may order 20 mg of an oral liquid preparation and the bottle is labeled as 10 mg/5 mL. 

Whenever the dose to be administered is different from that listed on the label, the volume to be administered must be calculated. To determine the volume to be administered, die formula for liquid preparations is used. The calculations are die same as tiiose given in the preceding section for parenteral dru s in disposable syringes or cartridges. 

Solutions that contain sodium citrate/citric acid (Shohl s solution and Bicitra) provide 1 mEq/L (1 mmol/L) each of sodium and bicarbonate. Polycitra is a sodium/potassium citrate solution that provides 2 mEq/L (2 mmol/L) of bicarbonate, but contains 1 mEq/L (1 mmol/L) each of sodium and potassium, which can promote hyperkalemia in patients with severe CKD. The citrate portion of these preparations is metabolized in the liver to bicarbonate, while the citric acid portion is metabolized to C02 and water, increasing tolerability compared to sodium bicarbonate. Sodium retention is also decreased with these preparations. However, these products are liquid preparations, which may not be palatable to some patients. Citrate can also promote aluminum toxicity by augmenting aluminum absorption in the GI tract. 

Hydroxyurea is available in 200-, 300-, 400-, and 500-mg capsules. Extemporaneous liquid preparations can be prepared for children who cannot swallow capsules. Doses should start at 10 to 15 mg/kg daily in a single dose, which can be increased... 

Enteral nutrition (EN) is broadly defined as delivery of nutrients via the gastrointestinal (GI) tract. This could include normal oral feeding as well as delivery of nutrients in a liquid form by a tube. Sometimes when the term enteral nutrition is used, only tube feedings are included hence the terms enteral nutrition and tube feedings are often used synonymously. The bulk of this chapter will include information regarding delivery of feedings via tubes. Formulas for EN usually are delivered in the form of commercially prepared liquid preparations, although some products are produced as powders for reconstitution. 

Nature of the process miscible liquids, preparation of solutions, or dispersion of immiscible liquids. 

In liquid preparations containing organic solvents, drug concentration changes can occur through loss of solvent to the atmosphere. Similarly, flavors and aromas in formulations may diminish in strength as volatile components pass out of the preparation. 

The sucrose content of oral liquids may cause significant problems when these products are prescribed for long-term therapy (e.g., asthma, seizure control, recurrent infections). Oral liquid preparations can represent a substantial carbohydrate load to children with labile diabetes, particularly if a child is ingesting more than one liquid medication with a high sugar content. 

Both solid and liquid dosage forms may contain saccharin. Saccharin is a nonnutritive sweetening agent, which is 300 times as sweet as sucrose. In a survey of sweetener content of pediatric medications, seven out of nine chewable tablets contained saccharin (0.45-8.0 mg/tablet) and sucrose or mannitol. Seventy-four of the 150 liquid preparations investigated contained saccharin (1.25-33 mg/5 mL) [62], Saccharin is a sulfanamide derivative that should be avoided in children with sulfa allergies [54],... 

Ethanol has long been employed as a solvent in pharmaceuticals. Since it also acts as a preservative and flavoring agent, it is second only to water in its use in liquid preparations. It has also been suggested that it may enhance the oral absorption of some active ingredients [71],... 

Additionally, when reviewing the various liquid preparations available in the OTC market today, one can see that many of these products are now sugar- or sodium-free or both. Indeed, decreased sodium and sugar levels are beneficial to the entire population. This would seem to suggest that every elfort should be made to keep sodium and sucrose contents to an absolute minimum in products intended for use in older patients. 

The adhesive cements, or simply adhesives, are viscous liquid preparations used mainly for joining together different objects or parts of objects into coherent units, for sizing (sealing) porous surfaces, and as binders in the preparation of paints (see Textbox 18). Until the end of the nineteenth century the only adhesives known to humans were of natural origin, derived either from vegetable secretions or from animal fluids and tissues. Few modern adhesives are now derived from natural substances most are artificial, human-made (synthetic) substances developed since the twentieth century. 

Cao, S.W. and Zhu, Y.J. (2009) Iron oxide hollow spheres microwave-hydrothermal ionic liquid preparation, formation mechanism, crystal phase and morphology control and properties. Acta Materialia, 57 (7), 2154-2165. 

Dyson recently warned that chloride impurities present in ionic liquids prepared by the classical metathesis reaction may cause severe catalyst inhibition. This may be aggravated by the fact that metal-chloride dissociation is disfavored in ionic liquids, in spite of their polar nature [77]. 

Percent weight-in-volume, % w/v number of grams of a constituent (solute) in 100 mL of liquid preparation (solution)... 

The carriers were impregnated to different compositions in terms of vanadium content, K/V ratio, Na/V ratio, Cs/V ratio and sulphur content, cf. Fig. 8. The exact sulphur content is less important since the melt, according to reaction (2), takes up an equilibrium amount of SO3 corresponding to a sulphur to alkali metal molar ratio of about 1 during operation in synthesis gas. The impregnation was carried out by submerging the pellets for a period of time in a surplus of aqueous impregnation liquid prepared from sulphuric acid and water-... 

Gareil, P. and Rosset, R. Analysis 10 (1982) 397. La chromatographie en phase liquide preparative par d veloppment par elution. 

The provision of liquid preparations of substances that are either insoluble or unstable in the desired vehicle (such as suspensions)... 

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