Salicylic acid advantages

The iodometric method has the advantage over the permanganate method (Section 10.95) that it is less affected by stabilisers which are sometimes added to commercial hydrogen peroxide solutions. These preservatives are often boric acid, salicylic acid, and glycerol, and render the results obtained by the permanganate procedure less accurate. 

The advantages of combination salicylic acid/ TCA peeling include ... 

Despite the many simple methods for preparation of carboxylic esters and thioesters, in some instances, use of 1-acylbenzotriazoles 915 as O and S acylating agents may be advantageous. For example, easy to prepare salicylic acid derivative 941 reacts with cyclopentanol under microwave irradiation to give 92% yield of cyclopentyl salicylate in 10 min <2006JOC3364>. In another example, L-phenylalanine derivative 942 reacts with benzyl mercaptan... 

A review by Galli et al. describes several buffer-absorbing chromophores as co-ions. These include phthalate, PDG (2,6-pyridinedicarboxylic acid), PMA (1,2,4,5-benzenetetra-carboxylic acid or pyromellitic acid), TMA (trimellitic acid), MES, 2,4-dihydrobenzoic acid with s-aminocaproic acid, p-hydroxybenzoate, p-anisate, 3,5-dinitrobenzoic acid, salicylic acid with TRIS, benzoic acid with tris (hydroxymethyl)aminomethane (TRIS), and many others. On the other hand, some inorganic chromophores such as chromate (Figure 9) or molybdate may be added to a buffer. A BGE-containing chromate should have a pH above 8, because it precipitates below this value. The advantage of a TRIS buffer or buffers at around pH 6 is that carbonate will not interfere with the separation because it is not soluble in TRIS or at lower pHs. 

The influence of a cream containing 20% glycerin and its vehicle on skin barrier properties has been investigated. Recent studies have shown that polymers offer several advantages and can be used in skin care products. Phase diagrams were determined for lactic and isohexanoic hydroxy acids as well as salicylic acid with water, a nonionic surfactant and a paraffinic oil, to outline the influence of hydroxy acids on the structure in a model for a skin lotion. The results showed the influence of the acid to be similar to that of the oil but that the difference in chain length between the two alpha acids had only insignificant influence. The results are discussed from two aspects the structures involved in the lotion as applied, and the action of the lotion residue on the skin after the evaporation of the water. 

There are oral formulations that deliver drug to the lower intestine. In mesalazine 5-amino-salicylic acid is formulated in a polymer-coated oral preparation. Olsalazine is a dimer of 5-aminosalicylate linked by an azo bond. Balsalazide is delivered to the colon where it is cleaved by bacterial azoreduction to release equimolar quantities of mesalazine and 4-aminobenzoyl-/i-alanine. The newer 5-ASA preparations were shown to be superior to placebo and tended towards therapeutic benefit over sulfasalazine. However, considering their relative costs, a clinical advantage to using the newer 5-ASA preparations in place of sulfasalazine appears unlikely. 

Solvent extraction offers unique advantages among separation techniques. A system based on extraction into a polymer [poly(vinyl chloride)] as solvent was examined here because of possible advantages in speedy simplicity, sample size, solvent handlingy etc.f especially when coupled with flow injection and an amperometric detector. Solutes examined included salicylic acid and 8-hydroxy quinoline. The apparatus typically consisted of 0.8-mm i.d. X 170-cm coiled tubing that could be connected directly to the injection loop of a flow-injection amperometric detector system containing a nickel oxide electrode. 

A systematic investigation of the copper-catalyzed reaction between 2-bromobenzoic acid and the anions of 1,3-dicarbonyl compounds has established the optimum conditions for the direct arylation of the /3-dicarbonyl moiety (75T2607). The use of sodium hydride as the base and copper(I) bromide as catalyst is recommended. The absence of a protic solvent ensures that competitive attack on the bromobenzoic acid by a solvent-derived base leading to a salicylic acid is eliminated. For larger scale reactions the addition of toluene offers some practical advantages. 

Equation (3.110) is more direct than Equation (3.115). An advantage of Equation (3.115) is that it is not necessary to analyze the concentration of the weak acid in the oil phase. Figure 3.19 shows the effect of the pH on the partition coefficient of a slightly soluble weak acid (i.e., salicylic acid). The apparent partition coefficient becomes the true partition coefficient when the weak acid is essentially in the unionized form (low pH). 

Others. Ammonium, lithium, and. strontium. salts of salicylic acid have also found use. They offer no distinct advantage over. sodium salicylate. 

Paints and liquids contain 11-17% salicylic acid, often in a collodion-based vehicle. Collodions contain pyroxylin, a nitrocellulose derivative, dissolved in a volatile solvent such as ether, acetone or alcohol. On application, the solvent evaporates, leaving on the skin an adherent, flexible, water-repellent film containing the medicament. This has the advantage of maintaining the salicylic acid at the site of application and also assists skin maceration by preventing moisture evaporation. Liquid preparations are usually applied daily for several days until the corn or callus can be easily removed. 

It is sometimes of advantage to transfer a dissolved solid from one solvent (usually water) to another which is more volatile (e.g. ether, benzene, chloroform, light petroleum etc.). Thus salicylic acid dissolved in water cannot easily be recovered by evaporating the solution to dryness, owing to its volatility in steam. When the aqueous solution is shaken with a relatively small amount of ether in a separating funnel and the mixture allowed to settle, a good deal of the salicylic acid is transferred to the ether when the upper ether layer is separated and deprived of the ether by distillation, the extracted salicylic acid remains in the distillation flask. 

The ortho-, meta- and para-cresotinic acids were originally claimed by Stockman to possess a powerful specifie aetion in acute rheumatic conditions, though having no advantages over salicylic acid. All three compounds possess anti-inflammatory activity in the mouse . 

Additional evidence that SA is transported from infected leaves to uninfected leaves comes from the experiments of Shulaev et al. [93]. They took advantage of the fact that in tobacco, the terminal step in SA biosynthesis is the Oj-dependent hydroxylation of benzoic acid to salicylic acid, a reaction catalyzed by benzoic acid 2-hydroxylase [94]. TMV-inoculated lower leaves of tobacco were enclosed in an 02-rich environment. The newly synthesized SA in these leaves was thus 0-labeled. Any radiolabeled SA detected in the upper uninoculated leaves would therefore have been synthesized and exported from the TMV-inoculated leaf. Approximately 70% of the SA in the upper uninfected leaves was found to be 0-labeled, confirming that SA is systemically transported from the infected leaf [93]. Similarly, the synthesis and transport of SA has been studied in cucumber using radiolabeled benzoic acid (BA) [95]. After administering C-labeled BA to cucumber cotyledons infected with C. lagenarium, C-SA was detected in the upper uninoculated leaves prior to the development of SAR. This C-SA was presumably synthesized in the infected cotyledons and subsequently transported to the uninoculated portions of the plant. 

In the technical literature, this approach was considered, in only a few studies. For instance, Ag, Au, Cd, Cr, Hg, Ni and Pt dissolved as metal cations in water media were successfully photoreduced in the presence of methanol, formic acid, salicylic acid, EDTA, phenol and nitrobenzenes (Burns et al., 1999 Prairie et al., 1993). Furthermore, the reduction of these inorganic species can be enhanced in the presence of the described organic molecules (hole scavengers) (Buttler and Davis, 1993 Chen and Ray, 2001 R airie et al., 1993). Thus, there is evidence of the importance of the combined organic and inorganic pollutant photoconversion and this topic deserves continued attention in order to take full advantage of enhancement effects. 

Due to its physical properties, such as an acid taste without any corrosive action, acetylsalicylic acid differs advantageously from salicylic acid and is being examined for its usefulness with just this in mind. 

The advantages and drawbacks of willow bark over acetylsalycilic acid can be deduced from these facts. Sahein irritates the stomach less than salicylic acid or even Aspirin. Other properties are not so favorable, though its effect takes a lot of time to develop (as salicin must be transformed to salicyhc acid), and does not inhibit blood clot formation. Most importantly, its dose cannot be set with the required... 

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