Water-soluble bases preparation

Ointments are semisolid preparations that are intended for external use. Ointments may contain either finely powdered drugs or their mixtures, liquids, and other drug forms incorporated into appropriate bases. They are applied to the skin for their physical effects as emollients (which make the skin more pliable), protectants, lubricants, and drying agents. Ointment bases are also used as vehicles in which to incorporate topical medications which exert specific effect. There are four types of ointment bases, namely, oleaginous, absorption, water removable, and water soluble bases. 

Extracts dried on to a water-soluble base are useful in the preparation of powdered drinks. Soft extracts tend to contain about 70% solid matter and can be mixed into a slun y with the substrate and spray-dried or dried in a vacuum oven. The substrate is usually essential to prevent the dried extract from reabsorbing moisture and turning back into a hard or sticky mass. The dried extracts can be dry-blended with other ingredients in a powdered drink formulation. 

Synthetic colours can be supplied as water soluble powders, prepared solutions, easily dispersed granules, pastes or gelatine sticks. Blocks of colour in vegetable fat are also available for use in fat-based products. The attraction of soluble powders is that they are the least expensive and can be made up as required for use although the other forms have the advantage that they are at a concentration that is ready to use - the disadvantage with the pre-prepared versions is, however, usually financial. 

Ointments utilize certain bases that act as vehicles to deliver the drug and to impart emollient and lubricant properties to the preparation. Usually, but not always, they contain medicinal substances. Properties of ointments may vary from product to product depending on their specific use, ease, and extent of application. In general, ointment bases may be classified into four general groups hydrocarbon, absorption, water-removable, and water-soluble bases. 

The use of Suzuki couphng for the synthesis of polyphenylene polymers was introduced by Rehahn, Schlueter and Wegner [Eq. (9)] [230]. Poly(p-2,5-di-n-hexylphe-nylene) was prepared in a biphasic mixture of benzene and water as a reaction medium, using sodium carbonate as a water-soluble base. This AB-type polymerizahon afforded polymers containing, e.g., an average of about 28 phenylene units. 

C7HgN402. Occurs to a small extent in tea, but is chiefly prepared synthetically. Like caffeine, it is a very weak base which forms water-soluble compounds with alkalis. It has a similar pharmacological mechanism to that of caffeine and is used, in combination with ethy-lenediamine. as a diuretic and a bron-chodilator. 

Copper(I) tends towards a tetrahedral coordination geometry in complexes. With 2,2 -bipyr-idine as a chelate ligand a distorted tetrahedral coordination with almost orthogonal ligands results. 2,2 -Bipyridine oligomers with flexible 6,6 -links therefore form double helices with two 2,2 -bipyridine units per copper(I) ion (J. M. Lehn, 1987,1988). J. M. Lehn (1990 U. Koert, 1990) has also prepared such helicates with nucleosides, e.g., thymidine, covalently attached to suitable spacers to obtain water-soluble double helix complexes, so-called inverted DNA , with internal positive charges and external nucleic bases. Cooperative effects lead preferentially to two identical strands in these helicates when copper(I) ions are added to a mixture of two different homooligomers. 

Somewhat analogous to these rice products is Oatrim, a material based on oat flour. It was developed at the Northern Laboratory of the USDA and is offered commercially by several firms. Oatrim contains 5% proteia, 5% P-glucan, 2% pentosans, and 83% maltodextrias. Unique properties are claimed based on the P-glucan component, and preparation of Oatrim is disclosed ia USDA pubHcations and patents. Briefly, oat flour is broken down by a-amylase, then the water-soluble component is dried and is the product of commerce, aimed at ground meat product usage. 

Almost all synthetic binders are prepared by an emulsion polymerization process and are suppHed as latexes which consist of 48—52 wt % polymer dispersed in water (101). The largest-volume binder is styrene—butadiene copolymer [9003-55-8] (SBR) latex. Most SBRlatexes are carboxylated, ie, they contain copolymerized acidic monomers. Other latex binders are based on poly(vinyl acetate) [9003-20-7] and on polymers of acrylate esters. Poly(vinyl alcohol) is a water-soluble, synthetic biader which is prepared by the hydrolysis of poly(viayl acetate) (see Latex technology Vinyl polymers). 

Metal- Working and Hydraulic Fluids. In the preparation of fluids for metal-working and hydrauflcs, the trend has been to replace organic-based materials with aqueous-based materials. Neodecanoic acid has found apphcation in these newer fluids as a corrosion inhibitor and a viscosity improver. For example, neodecanoic acid is used in an aqueous hydrauflc fluid concentrate for corrosion inhibition and improved antiwear properties (101), in the preparation of a thickened aqueous hydrauflc fluid to reduce viscosity loss (102), and in a water-soluble metal working oil to reduce corrosion (103). In a similar vein, neodecanoic acid has been used in antifreeze concentrates for corrosion inhibition (104). 

CP can also be prepared by the reaction of cellulose with phosphoms oxychloride in pyridine (37) or ether in the presence of sodium hydroxide (38). For the most part these methods yield insoluble, cross-linked, CP with a low DS. A newer method based on reaction of cellulose with molten urea—H PO is claimed to give water soluble CP (39). The action of H PO and P2 5 cellulose in an alcohol diluent gives a stable, water-soluble CP with a high DS (>5% P) (40). These esters are dame resistant and have viscosities up to 6000 mPa-s(=cP) in 5 wt % solution. Cellulose dissolved in mixtures of DMF—N2O4 can be treated with PCl to give cellulose phosphite [37264-91-8] (41) containing 11.5% P and only 0.8% Cl. Cellulose phosphinate [67357-37-5] and cellulose phosphonate [37264-91 -8] h.a.ve been prepared (42). 

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