CS243600B1 - Method of 2-(p-aminpbenzenesul-fonamido)-4,6-dimethylpyrimidine's sodium salt purification - Google Patents

Description

(54) A method for purifying 2- (p-aminobenzenesulfonamido) -4,6-dimethylpyrimidine sodium salt

The present invention relates to a process for the purification of the sulfadimidine sodium salt, i.e. 2- (p-aminobenzenesulfonamido) -4,6-dimethylpyrimidine of formula I

CH, ³ tl)

Sulfadimidine, i.e. 2- (p-aminobenzenesulfonamido) -4,6-dimethylpyrimidine, is a short-acting sulfonamide. It is used in sulfonamide-sensitive infections. It is a short-acting sulfonamide chemotherapeutic agent with bacteriostatic action.

Recently, a very pure injectable product has been desired, although it has been prepared in the laboratory (by this technology, sodium sulfadimidine for injection is prepared by reacting sodium hydroxide with sulfadimidine in an aqueous medium, after filtration the sodium salt precipitates with ethyl alcohol, washed with ethanol and dried). However, under operating conditions, this process failed to produce the product of the desired quality. The product did not comply with the color of the solution, the content of sulphate ions and part of the production even with higher pH of the solution.

In the laboratory, a purification procedure was prepared in the presence of zinc and oxygen-free activated carbon. In this procedure, the sulfadimidine sodium is dissolved in distilled or deionized water, zinc and deoxygenated activated carbon are added, and the product is isolated after filtration and crystallization.

Using the above-mentioned procedure in the presence of zinc and deoxygenated activated carbon, the product was found to meet all analytical criteria, both on a laboratory and on an industrial scale.

The procedure in the presence of zinc and deoxygenated activated carbon suppresses undesired reactions whose products deteriorate the substance quality. The presence of zinc during cleaning is not a problem as it is removed during filtration.

The preparation process according to the invention is undemanding, technically feasible and the product is obtained in high quality.

The examples illustrate but do not limit the scope of the invention.

Example 1

0.2 g of zinc dust are stirred in 220.0 ml of distilled water and 200.0 g of sulfadimidine sodium are added. The reaction mixture is then heated to 68-70 ° C. After all the sodium salt has dissolved, 0.5 g of oxygen-free activated carbon is introduced into the reaction mixture. The mixture is filtered, the filtrate is cooled to 8-11 ° C, the crystallized product is filtered off with suction, washed with 120.0 ml of ethyl alcohol cooled to 0-5 ° C and dried at 70 ° C.

78.0 g of sulfadimidine sodium salt for injection are obtained in the quality according to PNY 51-16-84.

Example 1 and d 2

The mother liquors after preparation of sodium sulfadimidine for injection prepared from 200.0 g of sodium sulfadimidine according to Example 1 were charged with 0.2 g of zinc dust and 80.0 g of sulfadimidine sodium. The reaction mixture is then heated to 68-70 ° C. After all the sodium salt has dissolved, 0.5 g of oxygen-free activated carbon is introduced into the reaction mixture. The mixture is filtered, the filtrate is cooled to 8-11 ° C, the crystallized product is filtered off with suction, washed with 120.0 ml of ethyl alcohol cooled to 0-5 ° C and dried at 70 ° C.

88.8 g of sulfadimidine sodium salt for injection are obtained in the quality according to PNY 51-16-84.

Example 3

The mother liquors after preparation of sodium sulfadimidine for injection prepared from 80.0 g of sodium sulfadimidine according to Example 2, supplemented with distilled water to a volume of 220.0 ml, were charged with 0.2 g of zinc dust and 80.0 g of sulfadimidine sodium. The reaction mixture is then heated to 68-70 ° C. After all the sodium salt has dissolved, 0.5 g of oxygen-free activated carbon is introduced into the reaction mixture. The mixture is filtered, the filtrate is cooled to 8-11 ° C, the crystallized product is washed with 120.0 ml of ethyl alcohol cooled to 0-5 ° C and dried at 70 ° C.

86.0 g of sulfadimidine sodium salt for injection are obtained in the quality according to PNY 51-16-84.

Claims (1)

SUBJECT A process for purifying 2- (p-aminobenzenesulfonamido) -4,6-dimethylpyrimidine sodium in an aqueous medium, characterized in that the purification is carried out in the presence of 0.10 to 0.25 weight percent zinc and 0.12 to 0.38 weight percent percent of deoxygenated activated carbon, based on the amount of 2- (p-aminobenzenesulfonamido) -4,6-dimethylpyrimidine sodium salt contained in the feed, by heating the mixture to 68-70 ° C, filtering and crystallizing the sodium salt from the cooled filtrate to a temperature of 8-11 ° C.