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Impurities

SynThink is a trusted producer and supplier of Pharmaceutical Reference Standards, including Impurity Standards. These materials are essential for pharmaceutical companies conducting research into the quality, stability, and biological safety of drug products. We maintain a robust inventory of API impurities, ready to support your development and regulatory needs.

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Impurities, Molnupiravir

((3aR,4R,6R,6aR)-6-(2,4-Dioxo-3,4-dihydropyrimidin-1(2H)-yl)-2,2-dimethyl-tetrahydrofuro[3,4-d][1,3]dioxol-4-yl)methyl isobutyrate

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CAS No.

: 2346620-53-7

Mol F.

: C16H22N2O7

Mol W.

: 354.36

Cat No.

: SA46204

Impurities, Topiramate

((3aR,6S,7S,7aR)-6,7-Dihydroxy-2,2-dimethyltetrahydro-3aH-[1,3]dioxolo[4,5-b]pyran-3a-yl)methyl Sulfamate

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CAS No.

: 152192-21-7

Mol F.

: C9H17NO8S

Mol W.

: 299.3

Cat No.

: SA45512

Impurities, Ketoconazole

(+)-Ketoconazole

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CAS No.

: 142128-59-4

Mol F.

: C26H28Cl2N4O4

Mol W.

: 531.4

Cat No.

: SA54913

Impurities, Tetrabenazine

(+/-) Tetrabenazine

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CAS No.

: 58-46-8

Mol F.

: C19H27NO3

Mol W.

: 317.4

Cat No.

: SA53900

Impurities, Rosuvastatin

(+/-)-tert-Butyl 6-Chloro-5-hydroxy-3-oxohexanoate

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CAS No.

: 319924-73-7

Mol F.

: C10H17ClO4

Mol W.

: 236.69

Cat No.

: SA12154

Ethinylestradiol, Impurities

(±)-6-Hydroxy Ethinylestradiol

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CAS No.

: 108646-70-4

Mol F.

: C20H24O3

Mol W.

: 312.41

Cat No.

: SA13115

Fosaprepitant, Impurities

(1’S,2S,3R)-Fosaprepitant Dimeglumine

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CAS No.

: NA

Mol F.

: C37H56F7N6O16P

Mol W.

: 1004.83

Cat No.

: SA45417

Ethinylestradiol, Impurities

(13S,14R, 17R)-Ethinyl Estradiol

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CAS No.

Mol F.

: C20H20O2

Mol W.

: 292.37

Cat No.

: SA13131

Impurities, Mometasone

(16α)-21-Chloro-17-hydroxy-16-methylpregna-1,4,9(11)-triene-3,20-dione

$595.00 25 mg

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CAS No.

: 151265-36-0

Mol F.

: C22H27ClO3

Mol W.

: 374.9

Cat No.

: SA28715

Impurities, Norethindrone

(17α)-17-Hydroxy-19-norpregn-5-en-20-yn-3-one Cyclic 1,2-Ethanediyl Acetal

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CAS No.

: 22170-58-7

Mol F.

: C22H30O3

Mol W.

: 342.47

Cat No.

: SA13435

Estradiol, Impurities

(17β)-3,17-Bis[(1-oxopentyl)oxy]-estra-1,3,5(10)-trien-6-one

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CAS No.

: 1350468-78-8

Mol F.

: C₂₈H₃₈O₅

Mol W.

: 454.6

Cat No.

: SA13208

Estradiol, Impurities

(17β)-3,17-Bis[(tetrahydro-2H-pyran-2-yl)oxy]-estra-1,3,5(10)-trien-6-one

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CAS No.

: 53573-82-3

Mol F.

: C₂₈H₃₈O₅

Mol W.

: 454.6

Cat No.

: SA13207

Impurities, Levomilnacipran

(1R-cis)-Milnacipran

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CAS No.

: 175131-61-0

Mol F.

: C₁₅H₂₃ClN₂O

Mol W.

: 282.81

Cat No.

: SA29203

Impurities, Tadalafil

(1R, 3R) N-Methyl Amide Tadalafil Impurity

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CAS No.

: NA

Mol F.

: C20H19N3O3

Mol W.

: 349.38

Cat No.

: SA20910

Edoxaban, Impurities

(1R,2R,4S)-2-((tert-Butoxycarbonyl)amino)-4-(dimethylcarbamoyl)cyclohexyl Methanesulfonate

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CAS No.

: 929693-31-2

Mol F.

: C15H28N2O6S

Mol W.

: 364.46

Cat No.

: SA33037

Impurities, Tramadol

(1R,2R)-Tramadol EP Impurity D (HCl)

$1,555.00 100 mg

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CAS No.

: 148262-77-5

Mol F.

: C15H23NO2. HCl

Mol W.

: 249.36 : 36.46

Cat No.

: SA49707

Impurities, Nirmatrelvir

(1R,2S,5S)-N-((2S)-1-Amino-1-oxo-3-(2-oxopyrrolidin-3-yl)propan-2-yl)-3-((S)-3,3-dimethyl-2-(2,2,2-trifluoroacetamido)butanoyl)-6,6-dimethy

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CAS No.

: NA

Mol F.

: C23H34F3N5O5

Mol W.

: 517.6

Cat No.

: SA46913

Impurities, Sapropterin

(1R,2S)-1-(2-amino-4-oxo-3,4-dihydropteridin-6-yl)-2-hydroxypropyl acetate

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CAS No.

: NA

Mol F.

: C11H13N5O4

Mol W.

: 279.26

Cat No.

: SA45212

Impurities, Ticagrelor

(1R,2S)-2-(3,4-Difluorophenyl)cyclopropanamine Hydrochloride

$195.00 100 mg

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CAS No.

: 1402222-66-5

Mol F.

: C9H9F2N

Mol W.

: 205.63

Cat No.

: SA32518

Aprepitant, Impurities

(1S,2R,3R) Aprepitant Isomer

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CAS No.

: 1242175-34-3

Mol F.

: C23H21F7N4O3

Mol W.

: 534.4

Cat No.

: SA43713

Aprepitant, Impurities

(1S,2R,3S) Aprepitant Isomer

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CAS No.

: 170902-81-5

Mol F.

: C23H21F7N4O3

Mol W.

: 534.4

Cat No.

: SA43714

Impurities, Nirmatrelvir

(1S,2R,5R)-N-((S)-1-Cyano-2-((S)-2-oxopyrrolidin-3-yl)ethyl)-3-((S)-3,3-dimethyl-2-(2,2,2-trifluoroacetamido)butanoyl)-6,6-dimethyl-3-azabi

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CAS No.

: NA

Mol F.

: C23H32F3N5O4

Mol W.

: 499.5

Cat No.

: SA46904

Aprepitant, Impurities

(1S,2S,3S) Aprepitant Isomer

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CAS No.

: 1242175-40-1

Mol F.

: C23H21F7N4O3

Mol W.

: 534.4

Cat No.

: SA43715

Impurities, Tramadol

(1S,2S)-Tramadol EP Impurity D (HCl)

$1,555.00 100 mg

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CAS No.

: 148218-19-3

Mol F.

: C15H23NO2. HCl

Mol W.

: 249.36 : 36.46

Cat No.

: SA49704

Impurities, Saxagliptin

(1S,3S,5S)-2-azabicyclo[3.1.0]hexane-3-carbonitrile

$2,555.00 1 g

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CAS No.

: 866083-42-3

Mol F.

: C6H8N2

Mol W.

: 108.14

Cat No.

: SA27419

Impurities, Sertraline

(1S,4R) Sertraline Hydrochloride

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CAS No.

: 79896-31-4

Mol F.

: C17H17Cl2N.HCl

Mol W.

: 342.69

Cat No.

: SA36520

Abacavir, Impurities

(1S,4R)-4-(2-Amino-6-chloro-9H-purin-9-yl)-2-cyclopentene-1-carboxylate

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CAS No.

: 1246819-78-2

Mol F.

: C11H10ClN5O2

Mol W.

: 279.68

Cat No.

: SA18115

Abacavir, Impurities

(1S,4R)-4-Amino-2-cyclopentene-1-methanol

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CAS No.

: 136522-35-5

Mol F.

: C6H11NO

Mol W.

: 113.16

Cat No.

: SA18118

Impurities, Ribociclib

(2-Chloro-7-cyclopentyl-7H-pyrrolo[2,3-d]pyrimidin-6-yl)methanol

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CAS No.

: 1374639-77-6

Mol F.

: C12H14ClN3O

Mol W.

: 251.71

Cat No.

: SA47124

Apremilast, Impurities

(2’S)-2′-[(1S)-1-(3-Ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethyl]-4-acetylamino-2,4′-biisoindole-1,1′,3,3′-tetrone

$295.00 25 mg

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CAS No.

Mol F.

: C30H27N3O9S

Mol W.

: 605.62

Cat No.

: SA30012

Impurities, Rosuvastatin

(2E,5R,6E)-3-Dehydroxy Rosuvastatin

$1,250.00 25 mg

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CAS No.

Mol F.

: C22H26FN3O5S

Mol W.

: 463.52

Cat No.

: SA12135

Impurities, Nebivolol

(2R, 2’S)-6-Fluoro-2-(2′-oxiranyl)chromane

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CAS No.

: 129050-26-6

Mol F.

: C11H11FO2

Mol W.

: 194.2

Cat No.

: SA14702

Canagliflozin, Impurities

(2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(3-((5-(4-fluorophenyl)thiophen-2-yl)methyl)-2-methylphenyl)tetrahydro-2H-pyran-3,4,5-triyl triacetate

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CAS No.

Mol F.

: C32H33FO9S

Mol W.

: 612.66

Cat No.

: SA14930

Efinaconazole, Impurities

(2R,3S)-2-(2,4-Difluorophenyl)-1-(1H-1,2,4-triazol-1-yl)-2,3-butanediol

$695.00 25 mg

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CAS No.

: 135270-11-0

Mol F.

: C12H13F2N3O2

Mol W.

: 269.25

Cat No.

: SA23607

Argatroban, Impurities

(2R,4R)-1-[N8-amino-N2-(3-methylquinoline-8-sulfonyl)-L-arginyl]-4-methylpiperidine-2carboxylic acid

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CAS No.

: NA

Mol F.

: C23H37N7O5S

Mol W.

: 523.65

Cat No.

: SA48407

Argatroban, Impurities

(2R,4R)-Benzyl 1-((S)-2-(tert-butoxycarbonyl)-5-(3-nitroguanidino)pentanoyl)-4-methylpiperidine-2-carboxylate

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CAS No.

: 367952-82-7

Mol F.

: C25H38N6O7

Mol W.

: 534.61

Cat No.

: SA48410

Argatroban, Impurities

(2R,4R)-Ethyl 1-((S)-5-guanidino-2-(6-hydroxy-3-methyl-1,2,3,4-tetrahydroquinoline-8-sulfonamido)pentanoyl)-4-methylpiperidine-2-carboxylat

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CAS No.

: NA

Mol F.

: C25H40N6O6S

Mol W.

: 552.69000000000005

Cat No.

: SA48416

Impurities, Sacubitril

(2R,4R)-Sacubitril Isomer

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CAS No.

: 766480-48-2

Mol F.

: C24H29NO5

Mol W.

: 411.49

Cat No.

: SA40903

Argatroban, Impurities

(2R,4R)1-[(2S)2-Amino-5-[[imino(nitroamino)methyl]amino]-1-oxopentyl]-4-methyl-2-piperidinecarboxylic Acid Ethyl Ester Hydrochloride

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CAS No.

: 74874-08-1 (HCl)

Mol F.

: C15H28N6O5

Mol W.

: 408.88

Cat No.

: SA48406

Argatroban, Impurities

(2R,4S)-Ethyl 4-methyl-1-((S)-1-phenylethyl)piperidine-2-carboxylate

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CAS No.

: 1350815-39-2

Mol F.

: C17H25NO2

Mol W.

: 275.39

Cat No.

: SA48413

Impurities, Sacubitril

(2R,4S)-Sacubitril

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CAS No.

: 149709-62-6

Mol F.

: C24H29NO5

Mol W.

: 411.49

Cat No.

: SA40900

Cobicistat, Impurities

(2R,5R)-1,6-Diphenylhexane-2,5-diamine dihydrochloride

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CAS No.

: 1247119-31-8

Mol F.

: C18H26Cl2N2

Mol W.

: 341.32

Cat No.

: SA48602

Avibactam, Impurities

(2R,5R)-Avibactam

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CAS No.

: 1797510-56-5

Mol F.

: C7H10N3O6S

Mol W.

: 264.2

Cat No.

: SA57601

Emtricitabine, Impurities

(2R,5R)-L-Menthol-5-(acetyloxy)-1,3-oxathiolane-2-carboxylate

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CAS No.

: 147027-09-6

Mol F.

: C₁₆H₂₆O₅S

Mol W.

: 330.44

Cat No.

: SA22912

Argatroban, Impurities

(2R)-Ethyl 4-methyl-1-((S)-1-phenylethyl)piperidine-2-carboxylate

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CAS No.

: 139334-63-7

Mol F.

: C17H25NO2

Mol W.

: 275.39

Cat No.

: SA48412

Impurities, Lamivudine

(2S-cis)-5-Fluoro-1-[2-(hydroxymethyl)-1,3-oxathiolan-5-yl]-2,4(1H,3H)-pyrimidinedione

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CAS No.

: 145281-92-1

Mol F.

: C8H9FN2O4S

Mol W.

: 248.23

Cat No.

: SA22315

Impurities, Nebivolol

(2S, 2’S)-6-Fluoro-2-(2′-oxiranyl)chromane

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CAS No.

: 129050-23-3

Mol F.

: C11H11FO2

Mol W.

: 194.2

Cat No.

: SA14703

Ethambutol, Impurities

(2S,13S)-2,13-diethyl-6,9-bis((S)-1-hydroxybutan-2-yl)-3,6,9,12-tetraazatetradecane-1,14-diol

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CAS No.

Mol F.

: C22H50N4O4

Mol W.

: 434.66

Cat No.

: SA43801

Ethambutol, Impurities

(2S,2’S)-2,2′-(2,2′-((S)-1-hydroxybutan-2-ylazanediyl)bis(ethane-2,1-diyl))bis(azanediyl)dibutan-1-ol hydrochloride salt

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CAS No.

Mol F.

: C16H37N3O3

Mol W.

: 319.48

Cat No.

: SA43800

Impurities, Timolol

(2S,2’S)-3,3’-((1,2,5-Thiadiazole-3,4-diyl)bis(oxy))bis(1-(tert-butylamino)propan-2-ol)

$1,995.00 100 mg

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CAS No.

Mol F.

: C16H32N4O4S

Mol W.

: 376.51

Cat No.

: SA23211