Acetylsalicylic acid procedure

Enteric Film Coating of Acetylsalicylic Acid Crystals (Aqueous) page 2 3. Coating procedure (Fluidized bed, Aeromatic Streal)... 

Repeat procedure no. 4 two more times you will use a total of 40 mL of ethanol in the four extractions. Report after each extraction if the extract carries acetylsalicylic acid. Enter these observations on your Report Sheet (4, 5, and 6). 

Summary In this procedure, picric acid is prepared by the reaction of common aspirin (acetylsalicylic acid) with potassium or sodium nitrate in the presence of excess concentrated sulfuric acid. After the reaction, the entire mixture is then drowned into an excessive amount of ice water, whereby the picric acid precipitates, and is then collected by filtration, washed, and then dried. 

Sometimes, chemists prepare molecules that do not occur in nature (although they may be similar to those in nature), because these molecules have superior properties to their naturally occurring relatives. Aspirin, or acetylsalicylic acid (Section 2.7), is a well known example. Acetylsalicylic acid is prepared from phenol, a product of the petroleum industry, by a two-step procedure (Figure 7.23). Aspirin has become one of the most popular and widely used drugs in the world because it has excellent analgesic and anti-inflammatory properties, and it is cheap and readily available. 

This class of haptens includes those that have a carboxyl group, such as acetylsalicylic acid (aspirin) or the peptides angiotensin and brady-kinin. In addition, many haptens, such as some steroids, may have reactive groups to which a carboxyl group can be attached as, for example, by reaction with succinic anhydride (see below). For conjugation to proteins, the same procedures may be used regardless of whether the carboxyl group is present as an inherent part of the hapten or as an added moiety. 

In this demonstration, we first isolate the active ingredient of the modem form of aspirin, acetylsalicylic acid, using a time-honored organic chemistry procedure called extraction. The preparation of purple-cabbage indicator is a type of organic extraction the organic purple dye is extracted from the cabbage with water. Here we use alcohol to extract acetylsalicylic acid from aspirin. 

The method is based on the fonmation of codeine-picrate ion pair and extraction into chloroform at pH 6.5. This pH is important for minimizing interferences. The procedure was developed for determination of codeine in acetylsalicylic acid tablets but may be adapted to other preparations. 

Practically all kinds of classical analytical procedures (acid-base, redox, precipitation, and com-plexometric titrations as well as gravimetry) fall into this category. An example from the field of titrations is the transformation of acetylsalicylic acid to sodium acetylsalicylate with sodium hydroxide as the titrant, or to sodimn salicylate and sodium acetate if the method is based on the... 

Several authors have worked on TLC of the more frequently occurring mixed pharmaceutical preparations such as, the analgesic-antipyretic mixture of caflFeine, phenacetin, acetylsalicylic acid and salicylamide (Table 121/1) or the anti-rheumatic preparation in Table 121/4. In this connection, one may mention here also the separations and quantitative evaluations of the analgesic mixtures, caffeine-benzyl mandelate-aminopyrine-phenacetin and caffeine-propylphenazone-phenacetin-pyrithyldione [66, 72, 96] (cf. p. 147). Other TLC separation procedures which have been described are of the components of an analgesic powder on ion exchange layers [135] an anti-influenza elixir, with semi-quantitative evaluation [114] the water-soluble vitamins in a commercial vitamin preparation [67] and the fat-soluble vitamins in such preparations [21]. Further extensive information about the analysis of commercial preparations is to be found elsewhere [19, 63, 65 and 75]. 

I would like to mention next the combination of acetylsalicylic acid, phenacetin, caffeine, and codeine, commonly called APC C, of which there are great quantities sold in Canada every year. Despite the fact that these products have been on the market for about 25 years, until as recently as 1954-no satisfactory quantitative method for the determination of the codeine phosphate content was available. At that time two methods were developed in our laboratory in order to cope with these products. Briefly, the procedures are as follows. 

A Simultaneous determination of AA and acetylsalicylic acid. The procedure is based on application of two potential pulses 0.17 125 0.7-2.9 Pharmaceuticals 2012 241... 

X Griseofulvin—determination in blood by the spectrofluorimetric method of Bedford, Child and Tomich. The only known metabolite, 6-desmethyl-griseofulvin, does not fluoresce and the extraction procedure recommended does not remove fluorescent substances from the blood. More recently, however, it has been shown by the same workers that certain drugs, such as acetylsalicylic acid and quinine, may cause high results. The method is based on extraction of the antibiotic into ether, evaporation of the extract to dryness and solution of the residue in 1 per cent aqueous ethanol. The fluorescence of this solution is compared with that of a standard griseofulvin solution, both solutions being activated at 295 mfi and analysed at 450 m. ... 

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