Citric acid preparations

Pharmacologic therapy with sodium bicarbonate or citrate/citric acid preparations maybe needed in patients with stage 3 CKD or higher to replenish body stores of bicarbonate. Calcium carbonate and calcium acetate, used to bind phosphorus in sHPT, also aid in increasing serum bicarbonate levels, in conjunction with other agents. 

In patients with Stage 3 or higher CKD, the use of aUcalinizing salts, such as sodium bicarbonate or citrate/citric acid preparations, is useful to replenish depleted body bicarbonate stores. Sodium bicarbonate tablets are manufactured in 325- and 650-mg strengths (a 650-mg tablet contains 7.7 mEq sodium and 7.7 mEq bicarbonate). Shohl s solution and Bicitra contain 1 mEq/mL of sodium and the equivalent of 1 mEq/mL of bicarbonate as sodium citrate/citric acid. Citrate is metabolized in the liver to bicarbonate, and citric acid is metabolized to CO2 and water. Polycitra, which contains potassium citrate, (1 mEq/mL of sodium, 1 mEq/mL of potassium, and 2 mEq/mL of bicarbonate) should not be used in patients with severe CKD since hyperkalemia may result. 

Deflnition Diammonium salt of citric acid, prepared by partially neutralizing citric acid with ammonia Empirical C6H14N2O7 Formula (NH4)2HC6Hs07 Properties Wh. fine gran, or cryst. ammoniacal odor sol. in 1 part water si. sol. in alcohol m.w. 226.19 sp.gr. 1.48... 

It is then diluted with a chilled aq. solution of citric acid [prepared by dissolving citric acid (146 g) in water (100 mL) at 25 °C], and stirred with a glass rod until... 

For tartaric and citric acids, preparation of amine salt, page 125. For most aliphatic and aromatic acids, the following derivatives can be recommended ... 

Sulphuric add test. Heat 0 5 g. of citric acid or a citrate with 1 ml. of H2SO4 CO and COg are evolved and the mixture turns yellow, but does not char. Acetone dicarboxylic acid, OC(CH2COOH)g, is also formed, and is tested for after heating the mixture for 1 minute cool, add a few ml. of water and make alkaline with NaOH solution. Add a few ml. of a freshly prepared solution of sodium nitroprusside and note the intense red coloration (see Test 4 a) for ketones, p. 346). 

Linalool has been used to prepare a mixture of terpenes useful for enhancing the aroma or taste of foodstuffs, chewing gums, and perfume compositions. Aqueous citric acid reaction at 100°C converts the linalool (3) to a complex mixture. A few of the components include a-terpineol (34%) (9), Bois de Rose oxide (5.1%) (64), ocimene quintoxide (0.5%) (65), linalool oxide (0.3%) (66), tij -ocimenol (3.28%) (67), and many other alcohols and hydrocarbons (131). 

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. 

Salads. A combination of citric acid and ascorbic acid is used as an alternative to sulfites in prevention of enzymatic browning in fresh prepared vegetables (56). 

Beet extract is also used as a colorant. Extract is sold as either a concentrate prepared by evaporating beet juice under vacuum to a total soHds content of 40—60%, or as a powder made by spray-dryiag the concentrate. Both products usually contain ascorbic or citric acid as a stabilizer, and a preservative such as sodium propionate. On a dry-weight basis, beet extract typically contains between 0.4 and 1.0% betanin, 80% sugar, 8% ash, and 10% cmde proteia. 

Bismuth citrate [813-93-4]—The synthetically prepared crystalline salt of bismuth and citric acid, principally BiC H O. ... 

Ferric ammonium citrate [1185-57-5]—A mixture of complex chelates prepared by the iateraction of ferric hydroxide with citric acid ia the presence of ammonia. The chelates occur ia brown and green forms, are dehquescent ia air, and are reducible by light. 

Example. The Pechini method for fuel cell electrode preparation. La, Ba, Mn niU ates - - CgHgO — citrate complex - - C2FI6O2 — gel. Metal nitrates are complexed with citric acid, and then heated with ethylene glycol to form a transparent gel. This is then heated to 600 K to decompose the organic content and then to temperatures between 1000 and 1300K to produce tire oxide powder. The oxide materials prepared from the liquid metal-organic procedures usually have a more uniform particle size, and under the best circumstances, this can be less than one micron. Hence these particles are much more easily sintered at lower temperatures than for the powders produced by tire other methods. 

Aconitic acid has been prepared from citric acid by the action of sulfuric acid or hydrogen chloride, or by heating. It has been prepared also from methyl acetylcitrate and from acetylcitric anhydride. The method described is essentially that of Hentschel. Phosphoric acid (85 per cent) can be used in place of sulfuric acid, but much closer regulation of the conditions seems necessary and the yield is not greatly improved. 

The practice of corrosion inhibition requires that the inhibitive species should have easy access to the metal surface. Surfaces should therefore be clean and not contaminated by oil, grease, corrosion products, water hardness scales, etc. Furthermore, care should be taken to avoid the presence of deposited solid particles, e.g. stones, swarf, building materials, etc. This ideal state of affairs is often difficult to achieve but there are many cases where less than adequate consideration has been given to the preparation of systems to receive inhibitive treatment. Acid treatments, notably with 3-5% citric acid, with or without associated detergent washes, are often recommended and adopted for cleaning systems prior to inhibition. However, it is not always appreciated that these treatments will not remove particulate material particularly when, as is often the case, the material is insoluble in acids. 

Procedure. Prepare a buffer solution (pH 7) by dissolving 3.7 g pure citric acid and 23.6 g of potassium dihydrogenphosphate in 1 L of distilled water. 

Add to the sample solution (containing 1 -25 g of Mo) 4 mL of 1 3 sulphuric acid, 3 drops of 85 per cent phosphoric(V) acid, and 0.5 g of citric acid. Dilute with water to 20 mL and add 2 mL of dithiol solution. Allow to stand at room temperature for 2 hours. Extract the molybdenum complex with 13 mL and 10 mL portions respectively of re-distilled butyl acetate, and make up to 25.0 mL with this solvent in a graduated flask filter through glass wool if not entirely clear. Determine the absorbance of the solution at 670 nm. Prepare a calibration curve as detailed in Section 6.14. 

A suspension of lithium methoxide (prepared from 1.00 g (31.2 mmol) of methanol in 50 mL of THF and 17.7 mL (27.2 mmol) of 1.54 M butyllithium in hexane) is transferred via a cannula into a — 78 C sol ution of 5.86 g (27.1 mmol) of 2-[(/ )-(/T)-1-chloro-2-butenyl]-4,4,5,5-tctramethyl-l,3,2-dioxaborolane in 100 mL of THF. The solution is warmed, becoming homogeneous at 0 JC, and stirred for 1 h. Solvents arc removed in vacuo and the residue dissolved in 150 mL of petroleum ether (bp 40 -60 °C). This solution is washed with a citric acid/boric acid/phosphate buffer (pH 3) until the aqueous phase shows a pH of 4. The aqueous phase is extracted with 50 mL of petroleum ether (bp 40 - 60 rC). The combined organic extracts are dried over MgS04 and concentrated in vacuo to give a slightly tan oil yield 5.34 g (90%) ca. 90% ee. 

CHROMIUM TRIOXIDE-PYRIDINE COMPLEX, preparation in situ, 55, 84 Chrysene, 58,15, 16 fzans-Cinnamaldehyde, 57, 85 Cinnamaldehyde dimethylacetal, 57, 84 Cinnamyl alcohol, 56,105 58, 9 2-Cinnamylthio-2-thiazoline, 56, 82 Citric acid, 58,43 Citronellal, 58, 107, 112 Cleavage of methyl ethers with iodotri-methylsilane, 59, 35 Cobalt(II) acetylacetonate, 57, 13 Conjugate addition of aryl aldehydes, 59, 53 Copper (I) bromide, 58, 52, 54, 56 59,123 COPPER CATALYZED ARYLATION OF /3-DlCARBONYL COMPOUNDS, 58, 52 Copper (I) chloride, 57, 34 Copper (II) chloride, 56, 10 Copper(I) iodide, 55, 105, 123, 124 Copper(I) oxide, 59, 206 Copper(ll) oxide, 56, 10 Copper salts of carboxylic acids, 59, 127 Copper(l) thiophenoxide, 55, 123 59, 210 Copper(l) trifluoromethanesulfonate, 59, 202... 

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. 

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