Salicylic acid estimation

The biotransformation of salicylic acid to salicyluric acid in Rhesus monkey has also been reported by Wan et al. (13). The dose of salicylic acid given intravenously to the monkey is equivalent to a 625-mg, dose for a 70-kg. man. The terminal half life for the animal studied was 50 min. (Fig. 8), which is shorter than the 3-4-hr. average half-life in man. The clearance value for salicylic acid estimated from the area under the curve was 10 ml/min or 1.8 ml/min/kg, in marked contrast to the data obtained for benzoic acid in rabbits where clearance was found to be between 44 and 115 ml/min or 12.6-28.8 ml/min/kg. In a single intravenous study in the monkey, benzoic acid was found to have a plasma clearance of 140 ml/min or 38.1 ml/min/kg. Plasma clearance of salicylic acid in man, at a dose level of about 500 mg administered intravenously, was found to be in the range of 0.57 ml/min/kg body weight according to the data of Riegelman et at. (14). The fraction of the dose excreted as salicyluric acid in 16 hr. was found to be 72%. 

Substances suitable for the estimation acetanilide, sucrose, glucose, cinnamic acid, diphenyl amine, salicylic acid, vanillin, />"bromoacetanilide, toluene p-sul phonamide. 

Szabo, G., Guczi, J., Bulman, R.A. (1995) Examination of silica-salicylic acid and silica-8-hydroxyquinoline HPLC stationary phases for estimation of the adsorption coefficient of soil for some aromatic hydrocarbons. Chemosphere 30, 1717-1727. 

Once absorbed, aspirin is rapidly converted to salicylic acid. After i.v. administration, the half life of aspirin in the human organism was found to be only 15 minutes191 by Rowland and Riegelman who also estimated that only 20% of the in vivo hydrolysis takes place in blood.192... 

In the absence of knowledge of the surface area of cement hydrates available for adsorption at the time of addition, it is difficult to estimate how many layers of water-reducing admixture molecules are adsorbed, but attempts have been made [40] indicating that over 100 layers may be formed with calcium lignosulfonate and salicylic acid at normal levels of addition. However, these calculations were based on specific surface areas of 0.3-1.0 m g-l, whereas other studies [27, 38, 39] have indicated... 

By using experimentally obtained data for 1 mM salicylic acid, a plot of reciprocal analytical signal versus reciprocal a, yielded a linear relationship for the pH range 1.65-3.01. This result supported the solvent extraction model. The corresponding estimate of capacity ratio and distribution coefficient using this treatment was 8.5. 

Eugenol (80-90%), acetyleugenol (2-3%), caryophyllene, furfural, methyl amyl ketone, salicylic acid (small quantity) Clove stem oil, cedarwood, copaiba or gurjun oil, phenol, oil of turpentine. Chief test estimation of eugenol... 

Swan, T.H., Mack, Jr., E. (1925) Vapor pressures of organic crystals by an effusion method. J. Am. Chem. Soc. 47, 2112-2116. Swift, Jr., E., Hochanadel, H.P. (1945) The vapor pressure of trimethylamine from 0 to 40°C. J. Am. Chem. Soc. 67, 880-881. Szabo, G., Guczi, J., Bulman, R.A. (1995) Examination of silica-salicylic acid and silica-8-hydroxyquinoline HPLC stationary phases for estimation of the adsorption coefficient of soil for some aromatic hydrocarbons. Chemosphere 30, 1717-1727. 

Except for theophyllin, the solubilities are similar at a dissolution temperature (Td) and a dissolution pressure (Pd) of 65°C and 250bar, respectively, the mole fractions are of 2.5e-4 for anthracene, 5e-4 for caffeine and 6.5e-4 for salicylic acid. Theophyllin is an order of magnitude lower, with a value of 0.2e-4. The mole fractions allow one to estimate the maximum production rate for the experimental set up. Assuming a recovery of produced particles of 100%, and no dilution required for processing, the production rates are 1.0, 1.2, 0.5 and 0.04 g/h for caffeine, salicylic acid, anthracene and theophyllin, respectively (conditions Pd = 220bar, Td=65°C, capillary =1.5cm x 75pm flow rate of liquid C02=11.2ml/min)... 

Toxicity. The estimated minimum lethal dose is 15 g. Plasma concentrations of salicylic acid greater than 300 pg/ml are likely to produce toxic reactions and concentrations greater than 500 pg/ml are associated with moderate to severe intoxication. The maximum permissible atmospheric concentration is 5 mg/m. ... 

Humic substances, humic and fulvic acids, are essentially a mixture of compounds of different molecular weights. The total number of base-titratable groups is in the range of 10-20 meq per gram of carbon. Chelation by neighboring carboxyl and phenolic groups is the major mode of metal complexation. Compounds such as malonic acid, phthalic acid, salicylic acid, and catechol serve as convenient monomeric model compounds for estimating the coordi-native properties of humic substances. 

Aspirin (acetyl salicylic acid) is a well-known analgesic. Processes for preparing aspirin are described in U.S. 3,235,583, U.S. 3,373,187 (both to Norwich Pharmacal), and U.S. 2,890,240 (to Monsanto). Estimate the cost of production by each route. 

Salicylic acid is used as a raw material for making aspirin, as well as a starting material for dyes and as a pharmaceutical compound. It is made by heating sodium phenolate with carbon dioxide under pressure, and the process is described in several of the standard reference works listed in Chapter 8. Estimate the cost of production. 

Heideman et. ah (51) developed a rapid HPLC method for the estimation of salicylic acid in aspirin tablets. Method involves the blending of tablets with acidic ethanol to extract the aspirin and salicylic acid rapidly. The resulting preparation is then immediately injected on to a 4.6 mm x 3 cm 5 micron reverse-phase column. Aspirin and free salicylic acid are determined simultaneously. The run time is less than 2 minutes. 

PAMPA-pKa fiux optimized design (pOD)-permeabiiity Iso-pH mapping unstirred PAMPA was used to measure the effective permeability, Pe, as a function of pH from 3 to 10, of five weak monoprotic acids (ibuprofen, naproxen, ketoprofen, salicylic acid, benzoic acid), an ampholyte (piroxicam), five monoprotic weak bases (imipramine, verapamil, propranolol, phenazopyridine, metoprolol), and a diprotic weak base (quinine). The intrinsic permeability, Po, the UWL permeability, Pu, and the apparent pKa (pKa.fiux) were determined from the pH dependence of log Pg. The underlying permeability-pH equations were derived for multiprotic weak acids, weak bases, and ampholytes. The average thickness of the UWL on each side of the membrane was estimated to be nearly 2000 p, somewhat larger than that found in Caco-2 permeability assays (unstirred). As the UWL thickness in the human intestine is believed to be about forty times smaller, it is critical to correct the in vitro permeability data for the effect of the UWL. Without such correction, the in vitro permeability coefficient of lipophilic molecules would be indicative only of the property of water. In single-pH PAMPA (e.g., pH 7.4), the uncertainty of the UWL contribution can be minimized if a specially selected pH (possibly different from 7.4) were used in the assay. From the analysis of the shapes of the log Pe-pH plots, a method to improve the selection of the assay pH, called pOD-PAMPA, was described and tested. From an optimally selected assay pH, it is possible to estimate Pg, as well as the entire membrane permeability-pH profile. 

Since systems 3.4 are hydrolyzed faster, by up to an order of magnitude, than similar derivatives of salicylic acid, EMs of up to 10 may be estimated. However, it is not generally possible to measure EMs systematically because the necessary control - the corresponding intermolecular reaction - is often too slow to be observed above background. The most relevant measure of catalytic efficiency, for comparison with similar reactions in enzyme active sites (where pH is not simply meaningful) is the ratio of the rates of the pH-independent reactions (Eig. 2.1) in the presence and absence of the catalytic group. We use this parameter in the discussion which follows. 

Amyloglucosidase and Sanzyme were obtained from Novo-Nordisk Bio-medical Group, Bangalore and Uni-Sankyo Limited, Hyderabad respectively. Locally available cornstarch was used as a source of carbohydrate polymer. Powdered chitin from crab shels was purchased from Sigma Chemical Company, U.S.A. Reducing values were determined by 3,5-dinitro salicylic acid method [6]. Protein content in Amyloglucosidase was estimated by Folin-phenol method [7]. 

Bismuth compounds have been used to treat a variety of gastrointestinal diseases and symptoms for centuries, although their mechanism of action remains poorly understood. Pepto-Bismol (bismuth subsalicylate is an over-the-counter preparation estimated to be used by 60% of American households. It is a crystal complex consisting of trivalent bismuth and salicylate suspended in a mixture of magnesium aluminum silicate clay, hi the low pH of the stomach, the bismuth subsalicylate reacts with hydrochloric acid to form bismuth oxychloride and salicylic acid. While 99% of the bismuth passes unaltered and unabsorbed into the feces, the salicylate is absorbed in the stomach and small intestine. Thus, caution should be used in patients taking salicylates for other indications. 

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