Caffeine preparations

The bronchodilating effect of caffeine has been recognized for hundreds of years. In the western world the first description of a caffeine preparation for asthma was made in 1859 (59) by a Scottish physician who recommended strong black coffee as a bronchodilator. In many parts of the world, however, use of xanthines is less frequent than in the United States. 

Spontaneous intracerebral hemorrhage occurred in a 72-year-old woman who had been taking GB 50 mg three times daily for 6 months (54). Bilateral subdural hematomas were discovered in a 33-year-old woman who had been taking 60 mg of GB twice daily for 2 year, acetaminophen, and occasionally an ergotamine/caffeine preparation (55). Bleeding time was elevated, but had normalized when checked approx 1 month after discontinuation of the product. 

C8H10N4O2. An alkaloid occurring in tea, coffee and guarana, from which it may be prepared by extraction, It is also manufactured by the methylation of theobromine and by the condensation of cyanoacetic acid with urea. Crystallizes with H2O or anhydrous from organic solvents. M.p. (anhydrous) 235"C, sublimes at 176 C. Odourless, and with a very bitter taste. Caffeine acts as a stimulant and diuretic, and is a constituent of cola drinks, tea and coffee. 

C7H9N402- M.p. 337 C, an alkaloid obtained from cacao seeds or prepared synthetically. Constitutionally it is similar to caffeine, and is also a weak base. It is usually administered as the sodium compound combined with either sodium ethanoate or sodium salicylate, and is employed almost entirely as a diuretic. Physiologically theobromine resembles caffeine, but its effect on the central nervous system is less, while its action on the kidneys, is more pronounced. 

C7HgN402. Occurs to a small extent in tea, but is chiefly prepared synthetically. Like caffeine, it is a very weak base which forms water-soluble compounds with alkalis. It has a similar pharmacological mechanism to that of caffeine and is used, in combination with ethy-lenediamine. as a diuretic and a bron-chodilator. 

Students determine the concentrations of caffeine, acetaminophen, acetylsalicylic acid, and salicylic acid in several analgesic preparations using both CZE (70 mM borate buffer solution, UV detection at 210 nm) and HPLC (C18 column with 3% v/v acetic acid mixed with methanol as a mobile phase, UV detection at 254 nm). 

The amount of caffeine in an analgesic tablet was determined by HPLC using a normal calibration curve. Standard solutions of caffeine were prepared and analyzed using a lO-pL fixed-volume injection loop. Results for the standards are summarized in the following table. 

Uses. Although cyanoacetic acid can be used in appHcations requiring strong organic acids, its principal use is in the preparation of malonic esters and other reagents used in the manufacture of pharmaceuticals, eg, barbital, caffeine, and B vitamins (see Alkaloids Hypnotics Vitamins). Cyanoacetic acid can be used for the preparation of heterocycHc ketones. 

Several selective interactions by MIP membrane systems have been reported. For example, an L-phenylalanine imprinted membrane prepared by in-situ crosslinking polymerization showed different fluxes for various amino acids [44]. Yoshikawa et al. [51] have prepared molecular imprinted membranes from a membrane material which bears a tetrapeptide residue (DIDE resin (7)), using the dry phase inversion procedure. It was found that a membrane which contains an oligopeptide residue from an L-amino acid and is imprinted with an L-amino acid derivative, recognizes the L-isomer in preference to the corresponding D-isomer, and vice versa. Exceptional difference in sorption selectivity between theophylline and caffeine was observed for poly(acrylonitrile-co-acrylic acid) blend membranes prepared by the wet phase inversion technique [53]. 

CmC, a preservative in commercial preparations of some intravenous drugs, activates CICR in a way similar to that of caffeine. 4-CmC is more potent than caffeine and shows isoform-dependent activation profiles it is much less effective in RyR3 than RyRl or RyR2. 

COPLAND E L, CLIFFORD M N and WILLIAMS c M (1998) Preparation of (-)-epigallocatechin gallate from commercial green tea by caffeine precipitation and solvent partition . Food Chem, 61, 81-7. 

Seasonal variations in the metabolic fate of adenine nucleotides prelabelled with [8—1-4C] adenine were examined in leaf disks prepared at 1-month intervals, over the course of 1 year, from the shoots of tea plants (Camellia sinensis L. cv. Yabukita) which were growing under natural field conditions by Fujimori et al.33 Incorporation of radioactivity into nucleic acids and catabolites of purine nucleotides was found throughout the experimental period, but incorporation into theobromine and caffeine was found only in the young leaves harvested from April to June. Methy-lation of xanthosine, 7-methylxanthine, and theobromine was catalyzed by gel-filtered leaf extracts from young shoots (April to June), but the reactions could not be detected in extracts from leaves in which no synthesis of caffeine was observed in vivo. By contrast, the activity of 5-phosphoribosyl-1-pyrophosphate synthetase was still found in leaves harvested in July and August. 

Tea , in this work, refers only to the plant Camellia sinensis, its leaves, and the extracts and infusions thereof. Leaf, bark, stem, root, or flower extracts of scores of other plants are also sold as teas , creating confusion. An important reason for the consumption of these other teas , a.k.a. herbal teas or tisanes , is their lack of methylxanthines, unlike beverages prepared from Camellia sinensis which are naturally rich in these substances, especially caffeine. 

Instant tea produced as described above will dissolve completely in hot water but not in cold water, as the caffeine-polyphenol complexes are insoluble under those conditions. Since virtually all instant tea manufacture in the U.S. is for iced tea preparation, process modification is required. This initial extract may be cooled to 5 to 10°C and the cold water insoluble material or cream be allowed to precipitate. Under these conditions, 20 to 35% of the extract solids may be separated by centrifugation. The supernatant solids will reconstitute in cold water after concentration and drying.105 It is also possible to process the cream to make a portion of it compatible with the product and thereby retain the caffeine and some polyphenolic components that are present in this fraction.106 Commercial use of the enzyme Tannase, which removes gallic acid from gallated tea polyphenols107 and reduces cream formation108 can be used to reduce cream losses and manufacture instant teas retaining more of the natural polyphenol content. 

The caffeine content of instant teas manufactured in the U.S. averages about 5%. When prepared as an iced beverage at 0.3% solids, 200 ml of beverage provides 30 mg of caffeine. 

As indicated previously, the average caffeine level of a cup of tea prepared by adding 180 ml of boiling water to a tea bag and brewing for 2 to 3 min is about 30 mg. This amount of caffeine appears to provoke minimal symptoms or irritability. 

Methods for the decaffeination of green coffee beans, mainly with solvents after a steaming, have already been described. Even with the selective adsorption techniques to remove only caffeine, it is unlikely that the full character of the starting beans can be realized in a final decaffeinated beverage the result is that Robusta coffees are generally used to prepare decaffeinated coffee. The cost is kept down and the treatment, anyway, reduces any harsh or bitter flavor that the Robusta coffee may have had. The resulting beverage will be relatively caffeine-free, but Robusta coffee will contribute more soluble carbohydrates, phenols, and volatile fatty acids, and much less of the diterpenes found in Arabica coffees. 

Chocolate liquor is the solid or semiplastic food prepared by finely grinding the nib of the cacao bean. It is commonly called baking chocolate, unsweetened chocolate, or bitter chocolate and, in Europe, is frequently referred to as chocolate mass or cocoa paste. Chocolate liquor is essentially the starting point from which all chocolate products are produced. Table 5 lists the theobromine and caffeine content of 22 various chocolate liquor samples determined by high pressure liquid chromatography (HPLC). The liquors averaged 1.22% theobromine and 0.214% caffeine.27- 28 The ratio of theobromine to caffeine ranged from 2.5 1 to 23.0 1. 

Two chocolate beverages made from unsweetened cocoa contained 228 and 284 mg theobromine per serving 32 Burg reported 272 mg theobromine and 6 mg caffeine per cup of beverage made from African cocoa, and 232 mg theobromine and 42 mg caffeine for a similar beverage made with South American cocoa.34 Both beverages were prepared according to manufacturer s directions. 

Bunker and McWilliams found that two beverages prepared from instant cocoa (with Dutch process cocoa) contained 10 to 17 mg caffeine per cup.37 Table 7 lists the theobromine and caffeine concentration of hot cocoa and chocolate milk prepared from instant mixes. Zoumas et al. analyzed five commercial hot cocoa mixes and reported an average of 65 mg per serving of theobromine and 4 mg per serving of caffeine.28 Similar results were reported by Blauch and Tarka.36... 

Chocolate milk samples prepared from sweetened cocoa powders averaged 58 mg per serving of theobromine and 5 mg per serving of caffeine.28 Analysis of a "home-style" recipe resulted in higher methylxanthine values — 94 mg theobromine and 10 mg caffeine per serving. However, the authors noted that this recipe also had a stronger chocolate flavor. The lower values reported by Zoumas et al. and Blauch and Tarka compared to others was attributed to the inability of older methods to separate theobromine and caffeine, and the lack of precision and accuracy of the older methods. A compendium of theobromine and caffeine values reported for chocolate beverages from both published and unpublished studies has been compiled in Table 8. 

Theobromine and Caffeine Concentration in Hot Cocoa and Chocolate Milk Prepared From Instant Mixes... 

Chocolate liquor is a semifinished product commonly called "baking" or unsweetened chocolate. The average theobromine and caffeine content of liquors has been reported at 1.2% and 0.21%, respectively. Cocoa powder, which is prepared after partial removal of the cocoa butter, contains about 1.9 to 2.7% theobromine and 0.16 to 0.26% caffeine. Milk chocolate averages 0.168% theobromine and 0.022% caffeine, thus providing about 65 mg of theobromine and less than 10 mg of caffeine in a 40-g serving. The methylxanthine content of chocolate foods has received only slight attention in the literature, yet is necessary in order to obtain an accurate assessment of the total amount of theobromine and caffeine that is ingested via the diet. 

Evaluation of health aspects of caffeine as a food ingredient SCOGS-89 Report, prepared by the Life Sciences Research Office of the Federation of American Societies for Experimental Biology and Medicine for the Bureau of Foods, FDA, US Dept, of Health, Education and Welfare, Washington, DC, 1978. 

By weight, tea leaves have double the caffeine as coffee beans 25 however, the caffeine content is greatly diluted during preparation. Caffeine in tea has been reported to range from 2.7 to 4.1% in selected varieties of tea,7 comparable with an estimate of 4% caffeine content in tea.26 While tea is the most commonly consumed caffeinated beverage, the caffeine content is only one third to one half that of coffee, contributing less to overall caffeine exposure than coffee. 

As shown in Table 9, the caffeine content of coffee, tea, and other products can vary dramatically.5 29 33 Caffeine content in a cup of coffee has been reported as 74 mg for percolated coffee and 112 mg for automatic drip coffee, showing substantial differences according to preparation.34 Instant coffee is significantly less at 66 mg and caffeine from decaffeinated coffee is negligible (1 to 3 mg caffeine). 

Total caffeine consumption will vary with a number of factors that are often difficult to disentangle. For caffeine exposure attributable to coffee, this includes brewing method and preparation type of coffee (Arabica, Robusta, instant), averaging to 1.3% caffeine for roasted beans 39 brand of coffee size of coffee cup and the volume of added ingredients, such as milk, cream sweeteners, and syrups. There are several different brewing or preparation techniques by which coffee can be prepared. Most notably, they differ in their final extraction of caffeine depending on the process. Filter coffee or automatic drip coffee results in approximately 97 to 100% caffeine extraction 37 however, regional differences in the volume of coffee... 

While percolators were long used and the most common method of coffee preparation up to 1975 (51%), automatic drip machines have steadily increased to be the method used for nearly half of all coffee prepared in 1981,41 as compared to only 7% automatic drip in 1975. This trend does impact caffeine exposure, as the different preparation methods have differential extraction of caffeine from the coffee that is used. 

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