Ademetionine Disulfate Tosylate
S-(Adenosyl)-l-methionine disulfate tosylate. (3S)-5¢-[(3-Amino-3-carboxypropyl)methylsulfonio]-5¢-deoxyadenosine, disulfate-methylbenzenesulfonate ![]() ![]() ![]() » Ademetionine Disulfate Tosylate is the disulfatetosylate mixed salt of a mixture of diastereoisomers of the ademetionine ions. It contains not less than 95.0 percent and not more than 105.0 percent of ademetionine (C15H23N6O5S+), calculated on the anhydrous basis.
Packaging and storage
Preserve in tight, light-resistant containers, and store in a refrigerator.
USP Reference standards
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Labeling
Label it to indicate the minimum content, in percentage, of S,S-isomer.
Identification
A:
Infrared Absorption
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B:
The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of ademetionine in the System suitability solution, as obtained in the Assay.
pH
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Water, Method Ia
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Heavy metals, Method I
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Isomeric ratio
Buffer A
Transfer 4.2 g of citric acid monohydrate and 2.03 g of sodium dihydrogen phosphate dihydrate to a 1-L volumetric flask, dissolve in and dilute with water to volume, and mix.
Mobile phase
Transfer 4.0 g of sodium dodecyl sulfate and 440 mL of acetonitrile to a 1-L volumetric flask, dilute with Buffer A to volume, and mix.
Standard solution
Dissolve an accurately weighed quantity of USP Ademetionine Disulfate Tosylate RS in water to obtain a solution having a known concentration of 1.0 mg per mL.
Test solution
Transfer about 100 mg of Ademetionine Disulfate Tosylate, accurately weighed, to a 100-mL volumetric flask, dissolve in and dilute with water to volume, and mix.
Chromatographic system (see Chromatography
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Procedure
Separately inject equal volumes (about 20 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the peak responses. Identify the peaks of the S,S- and R,S-isomers in the chromatogram of the Test solution by comparison with the chromatogram of the Standard solution, and calculate the percentage of the S,S-isomer by the formula:
100[rSS / (rSS + rRS)]
in which rSS and rRS are the areas of the peaks corresponding to the S,S-isomer and the R,S-isomer, respectively, in the Test solution. Not less than 60% and not less than the labeled amount of the S,S-isomer is found.
Content of sulfate
Mobile phase
Prepare a solution of 8.0 mM sodium carbonate and 1.0 mM sodium bicarbonate in water.
Standard solution
Dissolve an accurately weighed quantity of potassium sulfate in water to obtain a solution having a known sulfate concentration of about 0.18 mg per mL.
Test solution
Transfer about 50 mg of Ademetionine Disulfate Tosylate, accurately weighed, to a 100-mL volumetric flask, dissolve in and dilute with water to volume, and mix.
Chromatographic system (see Chromatography
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Procedure
Separately inject equal volumes (about 25 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the area of the sulfate peak. Calculate the percentage of sulfate in the portion of Ademetionine Disulfate Tosylate taken by the formula:
10,000(C/W)(rU / rS)
in which C is the concentration, in mg per mL, of the Standard solution; W is the weight, in mg, of Ademetionine Disulfate Tosylate taken to prepare the Test solution; and rU and rS are the peak responses obtained for sulfate in the chromatograms of the Test solution and the Standard solution, respectively. The content of sulfate is not less than 23.5% and not more than 26.5%.
Assay
Buffer
Transfer 10 mL of glacial acetic acid to a 1-L volumetric flask, add 500 mL of water, and mix. To the flask add 2.06 g of sodium 1-hexanesulfonate, dilute with water to volume, and mix.
Mobile phase
Prepare a filtered and degassed solution of Buffer and acetronitrile (85:15).
System suitability solution
Dissolve accurately weighed quantities of USP Ademetionine Disulfate Tosylate RS and USP S-Adenosyl-l-Homocysteine RS in water to obtain a solution having concentrations of about 400 µg of each per mL.
Standard preparations
Dissolve an accurately weighed quantity of USP S-Adenosyl-l-Homocysteine RS in water to obtain Standard preparation A, having a known concentration of about 400 µg per mL. Dilute portions of Standard preparation A to obtain Standard preparation B and Standard preparation C, having known concentrations of about 200 µg per mL and 80 µg per mL, respectively.
Assay preparation
Transfer about 20 mg of Ademetionine Disulfate Tosylate, accurately weighed, to a 50-mL volumetric flask, add 40 mL of water, and stir for 30 minutes; then dilute with water to volume, and mix. Transfer 1.0 mL of the solution to a 1.5-mL microcentrifuge tube, and centrifuge for 1 minute. Use a portion of the supernatant as the Assay preparation.
Chromatographic system
(see Chromatography
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Procedure
Separately inject equal volumes (about 10 µL) of the Standard preparations and the Assay preparation into the chromatograph, record the chromatograms, and measure the area of the S-adenosyl-l-homocysteine peak in all three solutions and the ademetionine disulfate tosylate peak in the Assay preparation. Plot a calibration curve of the peak area of the Standard preparations versus the corresponding S-adenosyl-l-homocysteine concentration, in mg per mL, and draw the straight line best fitting the three points. From the calibration curve, and using the peak area of ademetionine from the chromatogram obtained with the Assay preparation, determine the concentration, C, in mg per mL, of ademetionine as S-adenosyl-l-homocysteine in the Assay preparation. Calculate the quantity, in mg, of ademetionine (C15H23N6O5S+) in the portion of Ademetionine Disulfate Tosylate taken by the formula:
50C(399.44/384.41)
in which 399.44 and 384.41 are the molecular weights of ademetionine and S-adenosyl-l-homocysteine, respectively.
Auxiliary Information
Please check for your question in the FAQs before contacting USP.
Chromatographic Column
USP32NF27 Page 961
Pharmacopeial Forum: Volume No. 31(2) Page 469
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.
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