Citrate salt

The Ga and Ga isotopes were studied, eg, as citrate salts, for detection of tumors. Ga concentrates in bone tissues and Ga seem to have a tumor-specific affinity. Additional data are available (41,42). 

Direct. Some radionucHdes are packaged in solution for direct sampling (qv) via a septum and injection into the patient. GalHum-67 is a marker of inflammation, infection, and various tumor types. Its half-life is 78.3 h and it is suppHed as the gallium citrate salt. Indium-111 chloride is suppHed for the labeling of white blood ceUs. The In chloride is mixed with oxine (9-hydroxyquinoline) to form a lipophilic, cationic In oxine complex, which enters the white blood ceU. The complex dissociates within the ceU, and the cationic In " ion is trapped within the ceU, owing to its charge. 

Salt Formation. Citric acid forms mono-, di-, and tribasic salts with many cations such as alkahes, ammonia, and amines. Salts may be prepared by direct neutralization of a solution of citric acid in water using the appropriate base, or by double decomposition using a citrate salt and a soluble metal salt. 

The mono- and disodium citrate salts are made by limiting the amount of sodium available by using only one mole of base for each mole of citric acid for the monosodium citrate and two moles for the disodium citrate. The result is primarily the mono or disalt with small amounts of the other forms and citric acid being present. Other salts that have been offered commercially are shown in Table 5. 

It was estimated that 1990 U.S. citric acid and citrate salt consumption was 152,000 t. Citric acid represents approximately 90% of this volume. This citric acid/citrate use and its historical distribution in various markets is described in Table 9. From Table 9 it can be seen that although citric acid usage in the United States has shown steady growth at an average aimual rate of 4.4% from 1986—1990, the end use patterns have been quite stable. 

Medical Uses. Citric acid and citrate salts are used to buffer a wide range of pharmaceuticals at their optimum pH for stabiUty and effectiveness (65—74). Effervescent formulations use citric acid and bicarbonate to provide rapid dissolution of active ingredients and improve palatabiUty. Citrates are used to chelate trace metal ions, preventing degradation of ingredients. Citrates are used to prevent the coagulation of both human and animal blood in plasma and blood fractionation. Calcium and ferric ammonium citrates are used in mineral supplements. 

Agricultural Use. Citric acid and its ammonium salts are used to form soluble chelates of iron, copper, magnesium, manganese, and zinc micronutrients in Hquid fertilizers (97—103). Citric acid and citrate salts are used in animal feeds to form soluble, easily digestible chelates of essential metal nutrients, enhance feed flavor to increase food uptake, control gastric pH and improve feed efficiency. 

Concrete, Mortar, and Plaster. Citric acid and citrate salts are used as admixtures in concrete, mortar, and plaster formulations to retard setting times and reduce the amount of water requited to make a workable mixture (172—180). The citrate ion slows the hydration of Portland cement and acts as a dispersant, reducing the viscosity of the system (181). At levels below 0.1%, citrates accelerate the setting rate while at 0.2—0.4% the set rate is retarded. High early strength and improved frost resistance have been reported when adding citrate to concrete, mortar, and plaster. 

The citrate salt of isoaminile [77-51-0] (50) is a nitrile used as an antitussive in numerous European countries. In clinical trials it was shown to be as effective as codeine or chlophedianol, with few mild side effects. Isoaminile citrate is longer acting than chlophedianol and does not cause the respiratory depression of codeine (68). 

A mixture of 20 g of 1. [p.((3.diethylaminoethoxy)phenyl]-1,2-diphenylethanol in 200 cc of ethanol containing an excess of hydrogen chloride was refluxed 3 hours. The solvent and excess hydrogen chloride were removed under vacuum, and the residue was dissolved in a mixture of ethyl acetate and methylene chloride. 1-[p-((3.diethylaminoethoxv)phenyl] -1,2-diphenylethylene hydrochloride was obtained, melting at 148° to 157°C. This hydrochloride salt was treated with N-chlorosuccinimide in dry chloroform under reflux. The product then obtained was converted to the free base and treated with citric acid. The dihydrogen citrate salt of 1-[p-((3-diethylaminoethoxy)phenyl]-1,2-diphenylchloroethylene was obtained, melting at 116.5° to 118°C. 

Two concentrations of citrate have been routinely used as anticoagulant for tests such as PT and APTT (either 0.129 or 0.105 M). The effective molarity depends on whether the dihydrate or the anhydrous citrate salt was used in preparation of the citrate solution. A 3.2% solution of sodium citrate prepared using the dihydrate salt is 0.105 M. However, the molarity of a 3.2% solution of sodium citrate prepared with the anhydrous salt is 0.124 M. Similarly, a 3.8% solution of sodium cit-... 

Uptake by FeoB is inhibited by the energy poisons 1 111 FCCP, DCCD, and vanadate. Both Fe3+ and Fe2+ serve equally well as iron sources, but Fe3+ provided as a citrate salt is immediately reduced to Fe2+, as demonstrated by the formation of the magenta-coloured Fe2+-ferrocine complex. 

CAS 4368-28-9 39920-04-2 (Racemic mixture) 629653-73-2 (Acetate salt) 18660-81-6 (Citrate salt) 17522-62-2 (Formate salt) 4664-41-9 (Hydrobromide salt) 4664-40-8 (Picrate salt) 129497-92-3 (Trifluoroacetate salt)... 

Various carboxylic acid salts have also been reported. Gallardo35 produced the maleate salt of neomycin which, it was claimed, improved the aqueous stability of the antibiotic. A practically tasteless compound, the citrate salt,has been described by Szyszka3 . Neomycin mandelate has been claimed to be particularly useful in the treatment of urogenital infections3 while the di-hydroxy-dinaphthylmethane-dicarboxylate4(3 and the pamoate salts43,67,68 have a low intestinal absorption and are thus effective treatments for intestinal infections. 

Heaney, R. P., Dowell, R., and Barger-Lux, M. J. (1999). Absorption of calcium as carbonate and citrate salts with some observations on method. Osteoporos. Int. 9,19-23. 

Theophylline is frequently used as a bronchodilator in the treatment of asthma. The importance of the methylxanthines in the management of bronchial asthma is discussed more fully in Chapter 39. Caffeine as the citrate salt (Cafcit) is used for the short-term management of apnea in premature infants (28-33 weeks of gestational age). 

N NMR data for sildenafil and its citrate salt in solution (DMSO- s) as well as that of the salt in the solid state are reported for 81. Most interesting is the large shift obtained in solution and in the solid state for N-2 and N-4 linked to a double bond (21.6 and 11.3). 

Diethylcarbamazine, a synthetic piperazine derivative, is marketed as a citrate salt. It is rapidly absorbed from the gastrointestinal tract after a 0.5 mg/kg dose, peak plasma levels are reached within 1-2 hours. The plasma half-life is 2-3 hours in the presence of acidic urine but about 10 hours if the urine is alkaline, a Henderson-Hasselbalch trapping effect (see Chapter 1). The drug rapidly equilibrates with all tissues except fat. It is excreted, principally in the urine, as unchanged drug and the N-oxide metabolite. Dosage may have to be reduced in patients with persistent urinary alkalosis or renal impairment. 

Colloidal bismuth compounds Subsalicylate and citrate salts available. OTC preparations popular and have some value in travelers diarrhea due to adsorption of toxins... 

Citric acid and its citrate compounds are widely used in hundreds of applications. Global production of citric acid in 2005 was 1.6 million tons, with China producing approximately 40% of the world supply. In the United States, approximately 65% of citric acid use is in the food and beverage industry. Citric acid is used as an acidulant to impart tartness, to control pH, as a preservative and antioxidant, as a metal chelator, and to stabilize color and taste. Citrate salts can be used as mineral and metal dietary supplement for example, calcium citrate... 

It is necessary to adjust the Ca, Mg, phosphate, and citrate content of the concentrate to control aggregation and precipitation of the proteins and minerals during sterilization. By controlling protein aggregation, this adjustment provides optimum viscosity to stabilize the protein, mineral, and milk fat emulsion systems during prolonged storage of the sterile product. Some milk concentrates are stabilized by addition of Ca and Mg salts, whereas others are stabilized by addition of phosphate or citrate salts (Parry, 1974). Chemical compounds approved for addition to evaporated milk include calcium chloride, sodium citrate, and disodium phosphate (CFR 1982). 

Sildenafil. The citrate salt is the drug Viagra, widely used to treat male sexual disfunction. 

Chemical Name 2-(Diethylamino)ethyl-2-phenylbutyrate, citrate salt... 

Chemical Name Ethanamine, 2-(4-(4-chloro-l,2-diphenyl-l-butenyl)phenoxy)-N,N-dimethyl-, (Z)-, citrate salt (1 1)... 

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