Phthalyl-sulfathiazole

Antidiarrhoeal formulations containing phthalyl sulfathiazole or sulfaguanidine or succinyl sulphathiazole. 

Fig.4.24. Separation of 12 sulfa drugs (see text for details). Peaks 1 = phthalyl sulfathiazole 2 = sulfaquinoxaline 3 = sulfabenzamide 4 = sulfisoxazole S = sulfachlorpyridazine 6 = sulfadimethoxine ...

Figure 1. Plot for particle size distribution of phthalyl-sulfathiazole-stabilized system.

Simultaneous diaveridine, phthalyl sulfathiazole, pyrimethamine, succinyl sulfathiazole, sulfabenzamide, sulfacetamide, sulfachloropyrideizine, sulfadiazine, sulfadimethoxine, sulfaguanidine, sulfamerazine, sulfameter, sulfamethazine, sulfamethizole, sulfamethox-yp3Tidazine, sulfamoxole, sulfanilamide, sulfaniUc acid, sulfapjnidine, sulfaquinoxaline, sulfathiazole, sulfisomidine, sulfisoxazole, trimethoprim... 

The structure of sulfonamides is shown for representative purposes. Among the several thousand compounds in existence, about 25-30 have found widespread use. Sulfanilamide itself is, by present-day standards, very inactive. It was the development of heterocyclic derivatives that produced the highly potent sulfathiazole (9.90). When a succinyl or phthalyl group is attached to the aniline nitrogen, the inactive acylanilide derivatives will not be absorbed from the intestinal tract. Slow deacylation by intestinal... 

Sulfathiazole is available for oral use and is also included in some parenteral formulations in combination with other sulfonamides. It is also used as a feed additive for growth promotion purposes. It is more toxic than sulfamethazine and sulfadimethoxine but is safe when used as the phthalyl derivative. 

Table XIa and b shows the effect of altering the. V -substituent on the biliary excretion of some sulfonamides in the rat. The extent of biliary excretion of the succinyl (Table XIa) and phthalyl (Table Xlb) derivatives of sulfanilamide, sulfacetamide, and sulfathiazole was measured for 24 hours in biliary-cannulated rats. All the compounds are found unchanged in the bile and, therefore, any differences in their biliaiy excnitioii must reflect their affinity for hepatobiliary elimination. In both the succinyl and phthalyl series, the biliary excretion of the sulfathiazole derivative Avas much higher than either tlie corresponding sulfanilamide or sulfacetamide...

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