LIQUID CHROMATOGRAPHY PURDUE UNIVERSITY …液相色谱渡大学….docVIP

LIQUID CHROMATOGRAPHY PURDUE UNIVERSITY INSTRUMENT VAN PROJECT HOW MUCH ASPIRIN, ACETAMINOPHEN, AND CAFFEINE ARE IN YOUR PAIN RELIEVER? USING HPLC TO QUANTITATE SUBSTANCES (Revised: 1-13-93) INTRODUCTION Headache, sore muscles, arthritis pain... How do you spell relief? Pain serves the useful function of alerting you when some component of a physiological system has gone awry. Ideally, the pain can be alleviated by removing the underlying cause. In many cases, however, the stimulus of pain is either not easily defined or is not readily removed; therefore, it is necessary to treat pain as a symptom. As a result, Americans spend millions of dollars annually on NON-NARCOTIC ANALGESICS sold as over-the-counter pain relievers. Pharmaceutical companies go to great lengths to convince you that Anacin? works twice as fast or that you can Nupe it with Nuprin?. But the bottom line is that there are only three non-narcotic pain relievers which are considered safe enough to be sold over-the-counter. The oldest of these is aspirin, which has the chemical name acetylsalicylic acid. Salicylates were discovered following the extraction of a naturally occurring substance, glycoside salicin, from willow bark. The original compounds were found to have medicinal value but also some side effects. Further investigations led to aspirin, an ester derivative of salicylic acid, which was first marketed commercially by the Bayer Company in Germany in 1899. Acetaminophen became available around 1950. While acetaminophen relieves pain and reduces fever, it does not relieve stiffness, redness and swelling of arthritis as aspirin does. Ibuprofen was first used predominantly for its anti-inflammatory activity. It was first released in 1984 for over-the-counter use and has now replaced some of the market share of aspirin-based compounds. Caffeine is not a pain reliever, although it is sometimes found in these products. Caffeine acts by stimulating the central nervous system, and when pres