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US 9,435,785 B2Granted
Methods for analyzing cysteamine compositions
AssigneeRaptor Pharmaceuticals Inc.
InventorsKathlene Powell, Ramesh Muttavarapu
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Abstract
Methods of analyzing purity of compositions comprising cysteamine and detecting impurities in cysteamine compositions are described.
Claims18
A method of analyzing purity of a composition comprising cysteamine comprising:
- (i) injecting a sample solution comprising cysteamine onto a reverse-phase HPLC column;
- (ii) eluting the sample from the column using a mobile phase comprising an alkyl sulfonic acid, a buffer, acetonitrile, and methanol;
- and
- (iii) measuring the eluted sample using a UV detector at a wavelength of about 170 nm to about 250 nm;
- wherein the sample is eluted using a gradient elution, the elution comprising gradient eluting the sample using first and second mobile phases,
- wherein the first mobile phase comprises:
- about 75% to about 95% by volume of an aqueous solution having a pH of about 2.0 to 3.0, the aqueous solution comprising an alkyl sulfonic acid and a phosphate buffer,
- about 1% to about 8% by volume of acetonitrile, and
- about 5% to about 20% by volume of methanol;
- and
- the second mobile phase comprises:
- about 5% to about 30% by volume of an aqueous solution having a pH of about 2.0 to 3.0, the aqueous solution comprising an alkyl sulfonic acid and a phosphate buffer,
- about 8% to about 30% by volume of acetonitrile, and
- about 50% to about 85% by volume of methanol.
11 more elements
A method of analyzing purity of enteric-coated cysteamine beads comprising:
- (i) grinding enteric-coated cysteamine beads;
- (ii) dissolving the ground beads in a solvent having an acidic pH to form a sample solution comprising cysteamine;
- (iii) injecting the sample solution onto a reverse-phase HPLC column;
- (iv) eluting the sample from the column using a mobile phase comprising an alkyl sulfonic acid, a buffer, acetonitrile, and methanol;
- and
- (v) measuring the eluted sample using a UV detector at a wavelength of about 170 nm to about 250 nm;
- wherein the sample is eluted using a gradient elution, the elution comprising gradient eluting the sample using first and second mobile phases,
- wherein the first mobile phase comprises:
- about 75% to about 95% by volume of an aqueous solution having a pH of about 2.0 to 3.0, the aqueous solution comprising an alkyl sulfonic acid and a phosphate buffer,
- about 1% to about 8% by volume of acetonitrile, and
- about 5% to about 20% by volume of methanol;
- and
- the second mobile phase comprises:
- about 5% to about 30% by volume of an aqueous solution having a pH of about 2.0 to 3.0, the aqueous solution comprising an alkyl sulfonic acid and a phosphate buffer,
- about 8% to about 30% by volume of acetonitrile, and
- about 50% to about 85% by volume of methanol.
13 more elements
A method of analyzing purity of compositions comprising cysteamine comprising:
- (i) dissolving a cysteamine sample in a solvent having an acidic pH to form a sample solution comprising cysteamine;
- (ii) injecting the sample solution onto a C18 reverse-phase HPLC column;
- (iii) gradient eluting the sample from the column using first and second mobile phases,
- wherein the first mobile phase comprises:
- about 85% by volume of an aqueous solution having a pH of about 2.6, the aqueous solution comprising about 23.6 mM 1-octanesulfonic acid sodium and about 29 mM sodium phosphate;
- about 3% by volume of acetonitrile;
- and about 12% by volume of methanol, and
- the second mobile phase comprises:
- about 10% by volume of an aqueous solution having a pH of about 2.6, the aqueous solution comprising about 0.2 M 1-octanesulfonic acid sodium and about 0.1 M sodium phosphate;
- about 18% by volume of acetonitrile;
- and about 72% by volume of methanol;
- and
- (iv) measuring the eluted sample using a UV detector at a wavelength of about 210 nm or less.
10 more elements
Dependencies are inferred from the claim text.