Abstract: The present invention provides an improved process of preparing hydralazine hydrochloride, which involves the preparation of 1-chlorophthalazine salt and further reacting with hydrazine followed by purification of hydralazine hydrochloride, which is free of phosphate, does not contain any individual impurities more than 0.05%, total impurities less than 0.5%, and a hydrazine content of not more than 0.001%, and preferably less than 0.0003%. One benefit of improved purity is enhanced storage stability.

Abstract: A process of preparing a stable parenteral solution of a 1,4-dihydropyridine salt, such as nicardipine hydrochloride, in an acidic aqueous medium. The presence of L-arginine in the solution enhances the solubility of the salt, which is poorly soluble in water. An aqueous, injectable isotonic solution at pH about 3.5-3.6 consists essentially of nicardipine hydrochloride, L-arginine, and a sugar alcohol. An improved single pot manufacturing process for obtaining unsymmetrical 1,4-dihydropyridines by using more than one mole equivalent of aldehyde with respect to the other reactants (amino crotonate and acetoacetate ester). The reaction can be conducted in a solvent present at 20 times the amount of any one component. A process for changing one polymorph of nicardipine hydrochloride (Form A) into another (Form B), and a separate process for the reverse (Form B into Form A).

Abstract: The present invention provides an improved process of preparing hydralazine hydrochloride, which involves the preparation of 1-chlorophthalazine salt and further reacting with hydrazine followed by purification of hydralazine hydrochloride, which is free of phosphate, does not contain any individual impurities more than 0.05%, total impurities less than 0.5%, and a hydrazine content of not more than 0.001 %, and preferably less than 0.0003%. One benefit of improved purity is enhanced storage stability.

Abstract: The present invention provides an improved process of preparing hydralazine hydrochloride, which involves the preparation of 1-chlorophthalazine salt and further reacting with hydrazine followed by purification of hydralazine hydrochloride, which is free of phosphate, does not contain any individual impurities more than 0.05%, total impurities less than 0.5%, and a hydrazine content of not more than 0.001%, and preferably less than 0.0003%. One benefit of improved purity is enhanced storage stability.

Abstract: A process of preparing a stable parenteral solution of a 1,4-dihydropyridine salt, such as nicardipine hydrochloride, in an acidic aqueous medium. The presence of L-arginine in the solution enhances the solubility of the salt, which is poorly soluble in water. An aqueous, injectable isotonic solution at pH about 3.5-3.6 consists essentially of nicardipine hydrochloride, L-arginine, and a sugar alcohol. An improved single pot manufacturing process for obtaining unsymmetrical 1,4-dihydropyridines by using more than one mole equivalent of aldehyde with respect to the other reactants (amino crotonate and acetoacetate ester). The reaction can be conducted in a solvent present at 20 times the amount of any one component. A process for changing one polymorph of nicardipine hydrochloride (Form A) into another (Form B), and a separate process for the reverse (Form B into Form A).

Abstract: The present invention provides an improved process of preparing hydralazine hydrochloride, which involves the preparation of 1-chlorophthalazine salt and further reacting with hydrazine followed by purification of hydralazine hydrochloride, which is free of phosphate, does not contain any individual impurities more than 0.05%, total impurities less than 0.5%, and a hydrazine content of not more than 0.001%, and preferably less than 0.0003%. One benefit of improved purity is enhanced storage stability.