5-Mercaptopyridoxine alkanesulfonates and methods of use and pharmaceutical compositions

#This invention is concerned with pharmaceutically acceptable alkanesulfonic acid addition salts of 2-methyl-3-hydroxy-4-hydroxymethyl-5-mercaptomethylpyridine, a physically, chemically, and pharmaceutically improved form of the known pharmacologically active 2-methyl-3-hydroxy-4-hydroxymethyl-5-mercaptomethylpyridine (5-mercaptopyridoxine or 5-MP).

#In particular, this invention is concerned with C.sub.1-4 alkanesulfonic and C.sub.1-4 alkanedisulfonic acid addition salts of 5-mercaptopyridoxine of formula: ##STR1## WHERE X is 1 or 2, and C.sub.1-4 alkane is either straight or branched chain; a process for their preparation, a method of treating rheumatoid arthritis and pharmaceutical compositions comprising a novel compound. Even more particularly, it is concerned with the ethane-1,2-disulfonic acid addition salt (edisylate) of 5-mercaptopyridoxine, a process for its preparation, a method of treating rheumatoid arthritis with it, and pharmaceutical compositions.

#The compound, 5-mercaptopyridoxine, has been reported to be pharmacologically active as a radiation protective agent and an anti-rheumatoid arthritic agent, preferably in the form of a salt with a pharmaceutically acceptable acid. The preferred salt is stated to be the hydrochloride or hydrobromide.

#A solution of 11.1 g. (0.05 mole) 5-mercaptopyridoxine hydrochloride in 40 ml. of water was mixed with a solution of 5.85 g. (0.025 mole) of disodium ethane-1,2-disulfonate in 40 ml. of water at room temperature. The mixture was cooled in an ice-bath until precipitation was substantially complete. The precipitate (1) was collected on a filter and the filtrate was concentrated to about 40 ml. and again cooled in an ice-bath until precipitation was substantially complete. The precipitate (2) was collected on a filter and the filtrate was concentrated to about 20 ml. and cooled in an ice-bath until precipitation was substantially complete. The precipitate (3) was collected on a filter. Precipitates (1), (2), and (3) were combined and recrystallized from methanol to give 6.5 g. of bis(2-methyl-3-hydroxy-4-hydroxymethyl-5-mercaptomethylpyridinium ethane-1,2-disulfonate, m.p. 178.degree.-180.degree. C.

#Employing the procedure substantially as described in Example 1, but substituting for the disodium ethane-1,2-disulfonic acid used therein, an equimolar amount of the di(metal) alkanedisulfonates, or two equimolar amounts of the metal alkane sulfonates depicted in Table I, there are produced the corresponding acid addition salts of 5-mercaptopyridoxine, also depicted in Table I, in accordance with Equation I. ##STR2## wherein X is 1 or 2, and

#a.sup. .crclbar. is an acid anion, and