Soluble aspirin tablets

Aspirin BP In fine powder form for preparation of Soluble Aspirin Tablets and Soluble Aspirin, Phenacetin and Codeine Tablets... 

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. 

Soluble, effervescent tablets are prepared by compression. In addition to active ingredients, they contain mixtures of acids (citric acid, tartaric acid) and sodium bicarbonate (NaHCOs) that release carbon dioxide when dissolved in water. The United States Pharmacopeia (USP) 24 includes the following seven monographs Acetaminophen for Effervescent Oral Solution Aspirin Effervescent Tablets for Oral Solution Potassium Bicarbonate Effervescent Tablets for Oral Solution Potassium Bicarbonate and Potassium Chloride for Effervescent Oral Solution Potassium Bicarbonate and Potassium Chloride Effervescent Tablets for Oral Solution Potassium and Sodium Bicarbonates and Citric Acid for Oral Solution and Potassium Chloride, Potassium Bicarbonate, and Potassium Citrate Effervescent Tablets for Oral Solution. ... 

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. 

Stillings M, Havlik I, Chetty M, Clinton C, Schall R, Moodley I, Muir N, Little S. Comparison of the pharmacokinetic profiles of soluble aspirin and solid paracetamol tablets in fed and fasted volunteers. CurrMedRes Opin (2000) 6, 115-24. 

Compound Tablets of Aspirin and Opium, B.P.C.y Tablets of Aspirin and Phenacetin, B,P.C, Compound Tablets of Codeine, B,P, and Soluble Compound Tablets of Codeine, B.P,y see under Acetysalicylic Acid, p. 13. 

Bayer first sold aspirin powder to the public in 1899, and introduced a water-soluble tablet in 1900. The company estimates that 50 billion tablets are now consumed yearly on a worldwide basis. In addition to tablets, the French prefer their aspirin in suppository form, while the Italians prefer it fizzy. Aspirin is no longer just taken for headaches and aches and pains. According to Bayer market research, palliation of heart disease is now the number one use of aspirin. 

Aspirin is distributed in water-soluble tablets, cutting the cost of the medication in half. 

Test the solubility of your sample in toluene and in hot water and note the peculiar character of the aqueous solution when it is cooled and when it is then rubbed against the tube with a stirring rod. Note also that the substance dissolves in cold sodium bicarbonate solution and is precipitated by addition of an acid. Compare a tablet of commercial aspirin with your sample. Test the solubility of the tablet in water and in toluene and observe if it dissolves completely. Compare its behavior when heated in a melting point capillary with the behavior of your sample. If an impurity is found, it is probably some substance used as binder for the tablets. Is it organic or inorganic To interpret your results, consider the mechanism whereby salicylic acid is acetylated. 

If the dissolution of the drug is slow or controlling the rate of absorption (Step I), then dissolution is the rate-determining step. Factors controlling dissolution, such as solubility, ionization, or surface area, will then control the overall dissolution process. Figure 9.16 describes the absorption of aspirin from solution and from two different types of tablets. 

Salsalate, or salicylsalicylic acid, (pKa 3.5 [COOH], 9.8 [AR-OH]) is a dimer of salicylic acid. It is insoluble in gastric juice but is soluble in the small intestine, where it is partially hydrolyzed to two molecules of salicylic acid and absorbed. On a molar basis, it produces 15% less salicylic acid than aspirin. It does not cause Gl blood loss and can be given to aspirin-sensitive patients. Salsalate is available as capsules and tablets. 

Soluble Tablets of Aspirin, B.P, Contain 5 grains of aspirin with citric acid and calcium carbonate. 

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