Sulphonamides stability

G Alfredsson, A Ohlsson. Stability of sulphonamide drugs in meat during storage. Food Additiv Contain 15 302-306, 1998. 

The first step in the reaction is therefore addition of the nitrene to the aromatic double bond forming an aziridine 26 71>. This intermediate can now collapse to the sulphonamide 27 and an aryne which produces tars 68>. Ring opening to form an aniline derivative 28 — a formal insertion product — is another possibility of stabilization. 

Most of the drugs have got the property to promote relatively stable oil in water emulsions. A study of a sulphonamide drug sulpha-pyridine reveals that it yields a stable emulsion. The emulsion behaviours have been interpreted by studying flocculation, coalescence, electro-kinetic potential, potential energies and stability factors. These studies were made as a function of nucleic acids, DNA and RNA (Deoxy-ribonucleic acid and Ribonucleic acid) which were chosen in accordance with their biological significance. 

To compare the effect of carbazole component of sulphonamides on light stabilizing activity there has been carried out their synthesis on the basis of coke-chemical indan (Table 21). 

As it is seen from Table 21 all indan - sulphonamides facilitate CDA photo stabilization. It may be noted that, with some exception, introduction of different substituents into indan -sulphonamides greatly influences their stabilizing activity. 

Comparison of data on light stabilizing activity of indan - sulphonamides with results, obtained for sulphonamides on the basis of carbazole, shows that substitution of indan fragment for carbazole cycle leads to the increase of conjugation effect and, as a result, to the increase of light protective effect by 15-26%(Tablc 22). 

A most logical H-bonding mechanism which is believed to act competitively perhaps explains the action of some sulphonamide carbonic anhydrase inhibitors which predominantly exhibit both diuretic and antiglaucoma activities. It is, however, assumed that carbonic acid being the normal substrate which not only fits into a cavity but also complexes with the corresponding enzyme carbonic anhydrase (CA) as illustrated in Fig. 14.1(a). Consequently, this complex is strongly stabilized by four H-bonds. 

Dns-amides are stable to acid hydrolysis, and fairly stable even to hydrolysis with bases. However, transfer of dansyl groups to other bases occurs in mild alkali this reaction must be borne in mind when hydrolysis is carried out in alkaline media. In Table 1 some data concerning the stability of Dns derivatives to hydrolysis are summarized. Phenolic esters are much less stable than the sulphonamides, therefore it is possible to split off the 0-E)ns from 0,N-bis-Dns-aminophenok with melhanolic KOH 128]. This is of analytical interest because the N-Dns-derivatives of tyramine, synephrine etc. have much higher fluorescence efficiencies than the corresponding 0,N-bis-Dns-deiivatives. The derivatives of imidazoles and esters are unstable, both in acid and alkaline media. Dns-deiivatives of imidazoles, can, however, be selectively cleaved with formic acid [29]. This feature of Dns-imidazole derivatives can be exploited in the deler-mination of histamine and methylhistamines [30]. 

As Kauss [2] has pointed out, effects obtained using external Ca at concentrations higher than 1 /xM are as likely to result from the permissive effect of membrane stabilization as from any requirement for this ion to cross the plasma membrane in order to be effective as a second messenger. There is an added complication for plant cells in that external Ca, even at 5 mM, can dramatically affect ethylene production [3] with consequent effects on development. Corriveau and Krul [4] deduced from the inhibitory effect of 10 M Ag " on the response of soybean hypocotyls to BA that in this system ethylene mediates cytokinin action, a proposal in need of further investigation by quantitative studies and the use of more stringent controls. The interplay between cytokinins, ethylene and Ca is likely to prove difficult to untangle. Cytokinins and external Ca " can act synergistically to promote ethylene biosynthesis [5] and inhibitory effects of trifluoperazine, a phenothiazine, and W-5, a (comparatively inactive) naphthalene sulphonamide [6] may implicate calmodulin somewhere in this messy relationship. 

Several successful applications of fused-core columns for the analysis of emerging contaminants in environmental samples are described in the literature, including the analysis of pharmaceuticals and their metabolites in wastewater [13], personal care products (PCPs antimicrobials, preservatives), benzotriazole UV stabilizers and organophosphorus compounds in fish tissue [14], sulphonamide antibiotics in fish [15],... 

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