A hydrolysis method for tert-butyl ester in gadolinium-based contrast agent comprises hydrolyzing the tert-butyl ester with a catalyst. The preparation method of the catalyst comprises the following steps: subjecting zirconia and titanium tetrachloride to reaction in the presence of sulfuric acid and water at 60° C. to 90° C. until solids are dissolved, adding silica to perform reaction for 1 to 5 h, filtering to obtain solids, washing and calcining the solids. This hydrolysis method does not introduce other substances that are difficult to remove, such as acids, and provides high hydrolysis efficiency and high purity of the obtained product.

A process for making a complexing agent with an enantiomeric excess of at least 60%, wherein said process comprises the following steps: (a) reacting an aqueous slurry of alanine with an enantiomeric excess of at least 60% with formaldehyde and hydrocyanic acid, thereby forming an aqueous solution of alanine-bisacetonitrile, (b) saponifying the alanine-bisacetonitrile from step (a) by combining the aqueous solution obtained in step (a) with an aqueous solution of alkali metal hydroxide.

A process for making a complexing agent with an enantiomeric excess of at least 60%, wherein said process comprises the following steps: (a) reacting an aqueous slurry of alanine with an enantiomeric excess of at least 60% with formaldehyde and hydrocyanic acid, thereby forming an aqueous solution of alanine-bisacetonitrile, (b) saponifying the alanine-bisacetonitrile from step (a) by combining the aqueous solution obtained in step (a) with an aqueous solution of alkali metal hydroxide.

Various embodiments of the present invention are directed to switchable carboxybetaine-based polymers, hydrogels, and/or elastomers, along with novel related monomers, crosslinkers, and methods. Under acidic conditions, the materials undergo self-cyclization and can catch and kill bacteria. Under neutral/basic conditions, these materials undergo ring-opening and can release killed bacterial cells and resist protein adsorption and bacterial attachment. These smart polymers, hydrogels and elastomers also show excellent mechanical properties making them highly desirable for many biomedical applications.

Various embodiments of the present invention are directed to switchable carboxybetaine-based polymers, hydrogels, and/or elastomers, along with novel related monomers, crosslinkers, and methods. Under acidic conditions, the materials undergo self-cyclization and can catch and kill bacteria. Under neutral/basic conditions, these materials undergo ring-opening and can release killed bacterial cells and resist protein adsorption and bacterial attachment. These smart polymers, hydrogels and elastomers also show excellent mechanical properties making them highly desirable for many biomedical applications.

The present invention relates to nitric oxide releasing prodrugs of known drugs or therapeutic agents wherein the drug or therapeutic agents contain at least one carboxylic acid group. The invention also relates to processes for the preparation of these nitric oxide releasing prodrugs, to pharmaceutical compositions containing them and to methods of using these produgs.

The present invention relates to nitric oxide releasing prodrugs of known drugs or therapeutic agents wherein the drug or therapeutic agents contain at least one carboxylic acid group. The invention also relates to processes for the preparation of these nitric oxide releasing prodrugs, to pharmaceutical compositions containing them and to methods of using these produgs.

A method of obtaining a complex acidic salt of a divalent metal and a dicarboxylic acid includes heating water in a reactor; adding a dicarboxylic acid to the heated water; stirring the water to dissolve the dicarboxylic acid in the heated water to produce a solution or a suspension of the dicarboxylic acid in the heated water; adding MeO to the solution or the suspension, where Me is a divalent metal; continuing the stirring of the solution or suspension until formation of the complex acidic salt Me(AcH).sub.2.nH.sub.2O begins, where Ac is an anion of the dicarboxylic acid, and n=0-8; cooling the complex acidic salt to below a temperature of crystallization; sedimenting the complex acidic salt; filtering the complex acidic salt to remove water from the complex acidic salt; and drying the complex acidic salt.

A method of obtaining a complex acidic salt of a divalent metal and a dicarboxylic acid includes heating water in a reactor; adding a dicarboxylic acid to the heated water; stirring the water to dissolve the dicarboxylic acid in the heated water to produce a solution or a suspension of the dicarboxylic acid in the heated water; adding MeO to the solution or the suspension, where Me is a divalent metal; continuing the stirring of the solution or suspension until formation of the complex acidic salt Me(AcH).sub.2.nH.sub.2O begins, where Ac is an anion of the dicarboxylic acid, and n=0-8; cooling the complex acidic salt to below a temperature of crystallization; sedimenting the complex acidic salt; filtering the complex acidic salt to remove water from the complex acidic salt; and drying the complex acidic salt.

A method of obtaining a complex acidic salt of a divalent metal and a dicarboxylic acid includes heating water in a reactor; adding a dicarboxylic acid to the heated water; stirring the water to dissolve the dicarboxylic acid in the heated water to produce a solution or a suspension of the dicarboxylic acid in the heated water; adding MeO to the solution or the suspension, where Me is a divalent metal; continuing the stirring of the solution or suspension until formation of the complex acidic salt Me(AcH).sub.2.nH.sub.2O begins, where Ac is an anion of the dicarboxylic acid, and n=0-8; cooling the complex acidic salt to below a temperature of crystallization; sedimenting the complex acidic salt; filtering the complex acidic salt to remove water from the complex acidic salt; and drying the complex acidic salt.