Citric acid anhydrous

Diethylethanolamine manufacture, 2 130 physical properties of, 2 124t Diethyl ether, 10 538, 539, 568, 575 solubility of aminophenols in, 2 653t solubility of higher alcohols in, 2 3t solubility of anhydrous citric acid in, 6 634t... 

Oxalate is found to be a frequent impurity in pharmaceutical substances belonging to the category of either organic acids e.g.. anhydrous citric acid, tartaric acid or salts of organic acids e.g., ferrous gluconate, sodium citrate, potassium citrate and sodium cromoglycate. The presence of this impurity is due to the following two prime factors, namely ... 

Anhydrous Citric Acid Dissolve 0.8 g in 4 ml DW, add 3 ml HC1 and boil for 1 minute with 1 g granulated zinc. Allow to stand for 2 minutes, decant the liquid into a test-tube containing 0.25 ml phenyl-hydrazine HC1 and heat to boiling. Cool rapdily, transfer to a graduated cylinder, add an equal volume of HC1 and 0.25 ml potassium hexacyanoferrate (III), shake and allow to stand for 30 minutes. Any pink colour produced is not more intense than that produced by treating 4 ml of a 0.01% w/v soln. of oxalic acid at the same time and the same manner (360 ppm, calculated as anhydrous oxalic acid). 

Examples of solvent-mediated transformation monitoring include the conversion of anhydrous citric acid to the monohydrate form in water [235,236], CBZ with water [237] and ethanol-water mixtures [238,239], and cocrystallization studies of CBZ, caffeine, and theophylline with water [240]. Raman spectroscopy was used to monitor the crystallization rate and solute and solvent concentrations as griseofulvin was removed from an acetone solution using supercritical CO2 as an antisolvent [241]. Progesterone s crystallization profile was monitored as antisolvent was added [242]. 

Citric acid solution- Dissolve 2 42 g of anhydrous citric acid in 250 mL of distilled water... 

Acidity (% w/w) as anhydrous citric acid (or malic acid, as appropriate). 

A. Multiply the number of milliliters of standard alkali used in the titration by 0.2. The result will be percent by weight of anhydrous citric acid by weight of concentrate. Example 18.9 ml of standard alkali X 0.2 = 3.78% anhydrous citric acid. 

There are burettes on the market which are direct reading and are marked "percent Anhydrous Citric Acid." These burettes are used by the Florida State Department of Agriculture in their fresh fruit inspection work. This calibration of the burette is... 

To prepare solutions of the sample being tested, dissolve 160 g of anhydrous Citric Acid sample in 320 mL of water (or 174 g of Citric Acid monohydrate sample in 306 mL of water). Divide the test solution equally between two 250-mL separators, S3 and S4. Add 5 mL of No-Indicator Buffer Solution to S3, and 5 mL of Buffered Indicator Solution to S4. 

Atrovent HFA (BI) Ipratropium bromide November 2004 HFA 134a, purified water, dehydrated alcohol, anhydrous citric acid Solution... 

Information from Heckel plots indicates that anhydrous citric acid is predominantly fragmented during compression. The elastic deformation and consequently the elastic recovery during decompression are low. " ... 

A comparison of the formation of carbon dioxide from effervescent tablets based on anhydrous citric acid, ascorbic acid or tartaric acid, and NaHCOs in stoichiometric proportions indicated that ascorbic acid and anhydrous citric acid behaved similarly. 

Fig. 1 Sorptionisotherms of some hygroscopic acids. Key x axis = relative humidity, % y axis = moisture content, % O = citric acid monohydrate A = anhydrous citric acid = tartaric acid. (Adapted from Ref. . )...

Anhydrous citric acid and NaHCOs were granulated with ethanol in a twin-screw extruder at powder flow rates of 60-90 kg/h in a continuous processJ The air suspension coating-reacting technique also is used in the production of effervescent granulates. 

Anhydrous citric acid Buffer agent, pH adjustment, solubilizing agent, stabilizer iv, im, other inj. 

FIGURE 16.8. An example of a distance matrix for anhydrous citric acid (Refs. 49,50), and its monohydrate (Ref. 51). Both are numbered in the same way. Shown is half the matrix (which is symmetrical with all diagonal terms equal to zero), i.e., Aij = Aji and An = 0. Distances (in A) are given for anhydrous citric acid (upper entry). 

Nordman, C. E., Weldon, A. S., and Patterson, A. L. X-ray crystal analysis of the substrates of aconitase. II. Anhydrous citric acid. Acta Cryst. 13, 418-426... 

Citric acid (as either the monohydrate or anhydrous material) is widely used in pharmaceutical formulations and food products, primarily to adjust the pH of solutions. It has also been used experimentally to adjust the pH of tablet matrices in enteric-coated formulations for colon-specific drug delivery. Citric acid monohydrate is used in the preparation of effervescent granules, while anhydrous citric acid is widely used in the preparation of effervescent tablets.Citric acid has also been... 

Citric acid occurs naturally in a number of plant species and may be extracted from lemon juice, which contains 5-8% citric acid, or pineapple waste. Anhydrous citric acid may also be produced industrially by mycological fermentation of crude sugar solutions such as molasses, using strains of Aspergillus niger. Citric acid is purified by recrystallization the anhydrous form is obtained from a hot concentrated aqueous solution and the monohydrate from a cold concentrated aqueous solution. 

See Section 17 for anhydrous citric acid animal toxicity data. 

Anhydrous citric acid fumaric acid malic acid sodium citrate dihydrate tartaric acid. 

Heat of combustion -1985 kj/mol (-474.5 kcal/mol) Hygroscopicity at relative humidities between about 25-50%, anhydrous citric acid absorbs insignificant amounts of water at 25°C. However, at relative humidities between 50% and 75%, it absorbs significant amounts, with the monohydrate being formed at relative humidities approaching 75%. At relative humidities greater than 75% substantial amounts of water are absorbed by the monohydrate. 

Comments the EINECS number for anhydrous citric acid is 201-069-1. 

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