Acetylsalicylic acid aspirin tablets

Dennis Veere has ingested an unknown number of acetylsalicylic acid (aspirin) tablets. Acetylsalicylic acid is rapidly converted to salicylic acid in the body. The initial effect of aspirin is to produce a respiratory alkalosis caused by a stimulation of the "metabolic" central respiratory control center in the hypothalamus. This increases the rate of breathing and the expiration of COj. This is followed by a complex metabolic acidosis caused partly by the dissociation of salicylic acid (salicylic acid <-> salicylate -I- H, pKa = -3.5). 

APC tablet (aspirin, phenacetin, caffeine, any supplier). If these tablets are not available, a laboratory mixture may be prepared by mixing 226.8 mg of acetylsalicylic acid (aspirin), 32.4 mg of caffeine, and 162 mg of phenacetin for this experiment. This laboratory mixture will suffice as an APC tablet. ... 

With reference to the structures of acetylsalicylic acid (aspirin, Chapter 2 opening molecule) and acetaminophen (the active ingredient in Tylenol), explain each statement (a) Acetaminophen tablets can be stored in the medicine cabinet for years, but aspirin slowly decomposes over time (b) Children s Tylenol can be sold as a liquid (acetaminophen dissolved in water), but aspirin cannot. 

Lau, A.H. Chang, C.W. Schlesinger, P.K. Evaluation of a potential drug interaction between sucralfate and aspirin. Clin.Pharmacol.Ther, 1986, 39, 151-155 [plasma pharmacokinetics extracted metabolites, salicylic acid, salicyluric acid a-phenylcinnamic acid (IS) gradient column temp 30] Mamolo, M.G. Vio, L. Maurich, V. Higb-pressure liquid chromatographic analysis of paracetamol, caffeine and acetylsalicylic acid in tablets. Salicylic acid quantitation. Farmaco.[Prat]., 1985, 40, 111— 123 [tablets simultaneous ac etcuninophen, caffeine, phenazone, salicylic acid]... 

Many pharmaceutical compounds contain chromophores that make them suitable for analysis by UV/Vis absorption. Products that have been analyzed in this fashion include antibiotics, hormones, vitamins, and analgesics. One example of the use of UV absorption is in determining the purity of aspirin tablets, for which the active ingredient is acetylsalicylic acid. Salicylic acid, which is produced by the hydrolysis of acetylsalicylic acid, is an undesirable impurity in aspirin tablets, and should not be present at more than 0.01% w/w. Samples can be screened for unacceptable levels of salicylic acid by monitoring the absorbance at a wavelength of... 

Several aspirin tablets are ground to a fine powder in a mortar and pestle. A 0.1013-g portion of the powder is placed in a 1-L volumetric flask and diluted to volume with distilled water. A portion of this solution is filtered to remove insoluble binders, and a 10.00-mL aliquot transferred to a 100-mL volumetric flask containing 2.00 ml of 4 M NaOH. After diluting to volume the fluorescence of the resulting solution is found to be 8.69. What is the %w/w acetylsalicylic acid in the aspirin tablets ... 

The preparation of an ion-selective electrode for salicylate is described. The electrode incorporates an ion-pair of crystal violet and salicylate in a PVC matrix as the ion-selective membrane. Its use for the determination of acetylsalicylic acid in aspirin tablets is described. A similar experiment is described by Creager, S. E. Lawrence, K. D. Tibbets, C. R. in An Easily Constructed Salicylate-Ion-Selective Electrode for Use in the Instructional Laboratory, /. Chem. Educ. 1995, 72, 274-276. 

Each Alka-Seltzer tablet contains 1916 mg of sodium bicarbonate, 1000 mg of citric acid (Fig. 9.1.2), and 325 mg of aspirin or acetylsalicylic acid (Fig. 9.1.3). Bromo Seltzer also contains sodium bicarbonate and citric acid as well as acetaminophen (Fig. 9.1.4). Several equilibria describe the action of bicarbonate-based antacid tablets. First of all, sodium bicarbonate dissolves completely in aqueous solution to generate sodium ions and bicarbonate ions ... 

A typical aspirin tablet contains 324 mg of aspirin (acetylsalicylic acid, C9H8O4), a monoprotic acid having Ka = 3.0 X 10-4. If you dissolve two aspirin tablets in a 300 mL glass of water, what is the pH of the solution and the percent dissociation ... 

J. Fogel, P. Epstein, and P. Chen, Simultaneous high-performance liquid chromatography assay of acetylsalicylic acid and salicylic acid in film-coated aspirin tablets, J. Chromatogr., 317 501 (1984). 

In the present experiment, we measure the amount of the active ingredient, acetylsalicylic acid (see also Experiment 35), in common aspirin pills. Companies use different fillers and in different amounts, but the active ingredient, acetylsalicylic acid, must be the same in every aspirin tablet. We separate the acetylsalicylic acid from the filler based on their different solubilities. Acetylsalicylic acid is very soluble in ethanol, while neither starch, nor other polysaccharides, or even mono- and disaccharides used as a fillers, are soluble in ethanol. Some companies may use inorganic salts as fillers but these too are not soluble in ethanol. On the other hand, some specially formulated aspirin tablets may contain small amounts of ethanol-soluble substances such as stearic acid or vegetable oil. Thus the ethanol extracts of aspirin tablets may contain small amounts of substances other than acetylsalicylic acid. 

No historical perspective of natural product derived drugs would be complete without a discussion of aspirin (acetylsalicylic acid)—probably the most widely utilised drug of all time when the numbers of tablets consumed worldwide on an annual basis are considered. Even today, where presumably the major pharmacological effect is modulation of the cyclooxygenase isoforms, its full activity is still not fully defined. 

Place ten to fifteen aspirin, plain or buffered, into a glass container. With your safety glasses on, pour in a half cup (120 milliliters) of rubbing alcohol 70 percent isopropyl alcohol works just fine. This amount should be enough to cover the tablets with some to spare. It doesn t take much solvent to extract the acetylsalicylic acid from the tablets. 

By law all drugs sold in the United States must meet purity standards set by the Food and Drug Administration, and so all aspirin is essentially the same. Each 5-grain tablet contains 0.325 g of acetylsalicylic acid held together with a binder. The remarkable difference in price for aspirin is primarily a reflection of the advertising budget of the company that sells it. 

A degradant is defined as a compound that cumulates during the storage of bulk drug or finished formulation. For example, the vinegar-like odor of old aspirin tablets is due to acetic acid, which is a degradant due to hydrolysis of acetylsalicylate, which is an ester. 

Acetylsalicylic acid (C9Hg04) is a monoprotic acid commonly known as aspirin. A typical aspirin tablet, however, contains only a small amount of the acid. In an experiment to determine its composition, an aspirin tablet was crashed and dissolved in water. 

A relatively nonpolar molecule, acetylsalicylic acid has the ability to penetrate membrane barriers that are also made up of nonpolar molecules. However, inside the membrane are many small water pockets, and when an acetylsalicylic acid molecule enters such a pocket, it ionizes into and acetylsalicylate ions. These ionic species become trapped in the interior regions of the membrane. The continued buildup of ions in this fashion weakens the structure of the membrane and eventually causes bleeding. Approximately 2 ml of blood are usually lost for every aspirin tablet taken, an amount not generally considered harmful. However, the action of aspirin can result in severe bleeding in some individuals. It is interesting to note that the presence of alcohol makes acetylsalicylic acid even more soluble in the membrane, and so further promotes the bleeding. 

Aspirin (acetylsalicylic acid) is absorbed from the stomach in the free (non-ionized) acid form. If a patient takes an antacid that adjusts the pH of the stomach contents to 2.95 and then takes two 5-grain aspirin tablets (total 0.65 g), how many grams of aspirin are available for immediate absorption from the stomach, assuming immediate dissolution Also assume that aspirin does not change the pH of the stomach contents. The pZ of aspirin is 3.50, and its formula weight is 180.2. 

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