# US 9,435,785 B2 · Methods for analyzing cysteamine compositions > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,435,785 B2 - Document ID: US9435785B2 - Status: Granted - Kind: B2 - Application number: 14/306,820 - Filed: 2014-06-17 - Published: 2015-02-26 - Granted: 2016-09-06 - Earliest claimed: 2013-06-17 - Assignees: Raptor Pharmaceuticals Inc. - Applicants: Raptor Pharmaceuticals Inc. - Inventors: Kathlene Powell; Ramesh Muttavarapu - Web page: https://patentgrep.com/patent/US9435785B2 ## CPC - G01N 30/74: Optical detectors {(measurement of intensity, velocity, spectral content, polarisation, or phase of infrared, visible or ultraviolet light G01J)} - B01D 15/325: {Reversed phase} - G01N 21/33: using ultraviolet light (G01N21/39 takes precedence) - G01N 30/02: Column chromatography - G01N 30/06: Preparation - G01N 30/16: Injection (G01N30/24 takes precedence) - G01N 30/88: Integrated analysis systems specially adapted therefor, not covered by a single one of the groups G01N30/04 - G01N30/86 - G01N 33/15: Medicinal preparations {; Physical properties thereof, e.g. dissolubility} - G01N 30/34: of fluid composition, e.g. gradient (G01N30/36 takes precedence) - G01N 2030/027: {Liquid chromatography} - G01N 2030/8818: {involving amino acids} - Y10T 436/173845: Amine and quaternary ammonium - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract Methods of analyzing purity of compositions comprising cysteamine and detecting impurities in cysteamine compositions are described. ## Claims ### Claim 1 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. ### Claim 2 (depends on 1) The method of claim 1, further comprising dissolving a cysteamine sample in a solvent having an acidic pH to form the sample solution comprising cysteamine. ### Claim 3 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. ### Claim 4 (depends on 2, 3) The method of claim 2 or 3, wherein the solvent comprises an alkyl sulfonic acid, a buffer, acetonitrile, and methanol. ### Claim 5 (depends on 1, 3) The method of claim 1 or 3, wherein the HPLC column has a packing material particle size of about 1 μm to about 10 μm in diameter. ### Claim 6 (depends on 1, 3) The method of claim 1 or 3, wherein the HPLC column has an internal diameter of about 0.1 mm to about 10 mm. ### Claim 7 (depends on 1, 3) The method of claim 1 or 3, wherein the eluted sample is measured using a UV detector at a wavelength of about 180 nm to about 230 nm. ### Claim 8 (depends on 1, 3) The method of claim 1 or 3, wherein the aqueous solution of the first mobile phase comprises: about 15 mM to about 50 mM of an alkyl sulfonic acid, and about 15 mM to about 100 mM phosphate buffer. ### Claim 9 (depends on 1, 3) The method of claim 1 or 3, wherein the aqueous solution of the second mobile phase comprises: about 100 mM to about 300 mM of an alkyl sulfonic acid, and about 100 mM to about 200 mM phosphate buffer. ### Claim 10 (depends on 1, 3) The method of claim 1 or 3, wherein the sample is eluted using a flow rate of about 0.001 mL/min to about 2 mL/min. ### Claim 11 (depends on 1, 3) The method of claim 1 or 3, wherein the sample solution comprises cysteamine bitartrate. ### Claim 12 (depends on 3) The method of claim 3, wherein the beads are ground to form a powder. ### Claim 13 (depends on 3) The method of claim 3, wherein the beads are ground to form a paste. ### Claim 14 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. ### Claim 15 (depends on 14) The method of claim 14, comprising gradient eluting at a flow rate of about 1.0 mL/min according to the following profile: HPLC Gradient Time (min) First Mobile Phase (%) Second Mobile Phase (%) 0.0 100 0 2.0 100 0 20.0 60 40 25.0 60 40 25.1 100 0 40.0 100 0 ### Claim 16 (depends on 14) The method of claim 14, wherein the HPLC column has a packing material particle size of about 3.5 μm in diameter. ### Claim 17 (depends on 14) The method of claim 14, wherein the HPLC column has a length of about 150 mm and an internal diameter of about 4.6 mm. ### Claim 18 (depends on 1, 3) The method of any one of claim 1, 3, or 14, comprising injecting at least 30 μg of cysteamine onto the column.