Methyldopa: centrally acting antihypertensive (alpha-methyl amino acid).
Methyldopa testing at Vanguard Laboratory: identity, purity and quantity $250 per sample, with results in 3 to 5 business days.
Methyldopa: 2D structure drawn from the PubChem record (CID 18530292).
41372-08-1
C10H13NO4 · 1½H2O
238.24 g/mol
Centrally acting antihypertensive (alpha-methyl amino acid)
Identity: Methyldopa (sesquihydrate)
IUPAC name: (2S)-2-amino-3-(3,4-dihydroxyphenyl)-2-methylpropanoic acid;hydrate
Method for the $250 identity, purity and quantity test: HPLC-UV purity and assay, LC-MS identity, against a reference standard, with results in 3 to 5 business days.
The USP monograph covers identity by infrared spectroscopy and HPLC retention time, assay by HPLC, organic impurities by HPLC, residue on ignition, optical rotation, acidity by titration, and water content. Full testing to the USP Methyldopa monograph is available and quoted.
Chromatographic purity and mg per unit by the method matched to the compound, identity against a reference standard. 1 unit.
| Add-on test | Price |
|---|---|
| Identity and impurities | |
| FTIR identity | $90 |
| CHNS elemental analysis (carbon, hydrogen, nitrogen, sulfur) | $125 |
| Chiral purity (where a chiral method exists; new methods quoted) | $250 |
| Water, solvents and salt form | |
| Water content by Karl Fischer | $60 |
| Residual solvents | $150 |
| Counterions: chloride, acetate and TFA | $70 |
| Assay | |
| Assay, % w/w (with raw powder purity; $250 together) | +$50 |
| Metals and conformity | |
| Heavy metals: arsenic, cadmium, chromium, mercury and lead | $150 |
| Conformity: purity and quantity on more units from the same lot | $100 per extra unit |
| Microbiology (injectables) | |
| Endotoxin | $210 |
| Sterility or bioburden | $150 |
| Container closure integrity (CCI) | $50 |
| Screening | |
| Fentanyl screen | $50 |
10% off for 10 or more samples.
Need something else? Other tests are available on request.
Purity and quantity is $250 per sample (1 unit) and raw powder purity is $200 for 50 mg, with results in 3 to 5 business days. Send the material sealed and labeled, with the label claim and the form it contains.
No. The $250 test covers identity, purity and quantity by HPLC-UV for purity and quantity and LC-MS for identity. Full testing to the USP Methyldopa monograph is available and quoted.
USP methyldopa is the sesquihydrate, which carries about 11 percent water by weight. Results can be reported on the as-is or anhydrous basis, and the basis changes the assay number, so it should be stated on the report.
Yes. Methyldopa is a catechol and darkens as it oxidizes, especially in solution or when exposed to air and light. Oxidation products show up as extra peaks in the HPLC purity profile.
Yes. Methyldopa carries an extra methyl group, so it differs from levodopa in both HPLC retention time and mass by LC-MS.
https://pubchem.ncbi.nlm.nih.gov/compound/18530292
Identity facts from the USP monograph header for this compound.
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