Azithromycin Impurity Standards

Azithromycin impurity reference standards are used by pharmaceutical quality-control laboratories, contract research organisations, and generic drug manufacturers to identify, quantify, and control Azithromycin-related impurities during analytical method development, method validation, and regulatory filing. As a macrolide antibiotic, Azithromycin requires precise characterisation of its process impurities, degradation products, and related substances to meet European Pharmacopoeia (EP), United States Pharmacopeia (USP), and British Pharmacopoeia (BP) monograph requirements. Allmpus Laboratories manufactures and supplies a comprehensive library of Azithromycin impurity standards, each provided with a Certificate of Analysis (COA) and Material Safety Data Sheet (MSDS). All products are held in-stock for rapid dispatch and are suitable for use in ANDA and DMF regulatory submissions.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

AZITHROMYCIN IMPURITY P (N-ETHYL IMPURITY)

Chemical Name: 11-((4-(dimethylamino)-3-hydroxy-6-methy...

CAS No:
92594-45-1

Molecular Formula: C39H74N2O12

Molecular Weight: 763.02

CAT No:
ALL-A04111

Keywords: Azithromycin Impurity

Inventory Status:IN STOCK/06-148

COA MSDS

3-HYDROXY AZITHROMYCIN ACID SODIUM SALT

Chemical Name: (2R,3S,4S,5R,8R)-5-(((2S,3R,4S,6R)-4-(di...

CAS No:
N.A

Molecular Formula: C30H59N2O10 : Na

Molecular Weight: 607.81 : 23.0

CAT No:
ALL-AZI-AA

Keywords: 3-HYDROXY AZITHROMYCIN ACID SODIUM SALT

Inventory Status:IN STOCK/06-305

COA MSDS

3-N-DEMETHYL-3-N- (PHENYLSULFONYL) AZITHROMYCIN

Chemical Name: 3’-N-Demethyl-3’-N- (phenylsulfonyl)...

CAS No:
N.A

Molecular Formula: C43H74N2O14S

Molecular Weight: 875.1

CAT No:
ALL-AZI-NP

Keywords: 3-N-DEMETHYL-3-N- (PHENYLSULFONYL) AZITH...

Inventory Status:IN STOCK/06-308

COA MSDS

AZITHROMYCIN 3-DEOXY N-DESMETHYL

Chemical Name: N-DESMETHYL AZITHROMYCIN B

CAS No:
857078-26-3

Molecular Formula: C37H70N2O11

Molecular Weight: 718.95

CAT No:
ALL-AZI-3D

Keywords: AZITHROMYCIN 3-DEOXY N-DESMETHYL/857078-...

Inventory Status:IN STOCK/06-300

COA MSDS

AZITHROMYCIN AGLYCONE

Chemical Name: (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-2-...

CAS No:
117693-42-2

Molecular Formula: C22H43NO7

Molecular Weight: 433.6

CAT No:
ALL-AZI-AG

Keywords: AZITHROMYCIN AGLYCONE/117693-42-2

Inventory Status:IN STOCK/06-306

COA MSDS

AZITHROMYCIN EP IMPURITY A

Chemical Name: N6-Demethylazithromycin; Desmethylazithr...

CAS No:
76801-85-9

Molecular Formula: C37H70N2O12

Molecular Weight: 734.96

CAT No:
ALL-A04095

Keywords: Azithromycin Impurity

Inventory Status:IN STOCK/06-132

COA MSDS

AZITHROMYCIN EP IMPURITY B

Chemical Name: (2R,3R,4S,5R,8R,10R,11R,12S,13S,14R)-13-...

CAS No:
307974-61-4

Molecular Formula: C38H72N2O11

Molecular Weight: 732.99

CAT No:
ALL-A04096

Keywords: SMILES string - C[C@@H]([C@@H]([C@H](C(...

Inventory Status:IN STOCK/06-133

COA MSDS

AZITHROMYCIN EP IMPURITY C

Chemical Name: (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-...

CAS No:
620169-47-3

Molecular Formula: C37H70N2O12

Molecular Weight: 734.98

CAT No:
ALL-A02776

Keywords: SMILES string - C[C@@H]([C@@H]([C@H](C(...

Inventory Status:IN STOCK/06-134

COA MSDS

AZITHROMYCIN EP IMPURITY D

Chemical Name: 14-Demethyl-14-(hydroxymethyl)azithromyc...

CAS No:
612069-26-8

Molecular Formula: C38H72N2O13

Molecular Weight: 765.0

CAT No:
ALL-A04098

Keywords: SMILES string - C[C@H]([C@H]([C@](O)(C[...

Inventory Status:IN STOCK/06-135

COA MSDS

AZITHROMYCIN EP IMPURITY E

Chemical Name: (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-...

CAS No:
612069-27-9

Molecular Formula: C36H68N2O12

Molecular Weight: 720.93

CAT No:
ALL-A04099

Keywords: SMILES string - C[C@@H]([C@@H]([C@H](C(...

Inventory Status:IN STOCK/06-136

COA MSDS

AZITHROMYCIN EP IMPURITY F

Chemical Name: 3-N-Demethyl-3-N-formylazithromycin; (2R...

CAS No:
612069-28-0

Molecular Formula: C38H70N2O13

Molecular Weight: 762.97

CAT No:
ALL-A04100

Keywords: SMILES string - C[C@@H](CN(C)[C@H](C)[C...

Inventory Status:IN STOCK/06-137

COA MSDS

AZITHROMYCIN EP IMPURITY G

Chemical Name: (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-...

CAS No:
612069-31-5

Molecular Formula: C44H76N2O14S

Molecular Weight: 889.14

CAT No:
ALL-A04101

Keywords: SMILES string - C[C@@H]([C@@H]([C@H](C(...

Inventory Status:IN STOCK/06-138

COA MSDS

AZITHROMYCIN EP IMPURITY H

Chemical Name: (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-...

CAS No:
612069-30-4

Molecular Formula: C45H77N3O15S

Molecular Weight: 932.17

CAT No:
ALL-A04102

Keywords: SMILES string - C[C@@H]([C@@H]([C@H](C(...

Inventory Status:IN STOCK/06-139

COA MSDS

AZITHROMYCIN EP IMPURITY I

Chemical Name: (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-2-e...

CAS No:
172617-84-4

Molecular Formula: C37H70N2O12

Molecular Weight: 734.96

CAT No:
ALL-A04103

Keywords: SMILES string - C[C@@]1(O)[C@@H](CC)OC(...

Inventory Status:IN STOCK/06-140

COA MSDS

AZITHROMYCIN EP IMPURITY J

Chemical Name: 13-O-Decladinosylazithromycin

CAS No:
117693-41-1

Molecular Formula: C30H58N2O9

Molecular Weight: 590.79

CAT No:
OLYAZ0010.0J

Keywords: SMILES string - C[C@@H](CN(C)[C@H](C)[C...

Inventory Status:IN STOCK/06-141

COA MSDS

AZITHROMYCIN EP IMPURITY K

Chemical Name: (1R,4R,4'R,5S,5'S,6R,6'S,...

CAS No:
612534-95-9

Molecular Formula: C38H70N2O13

Molecular Weight: 762.97

CAT No:
ALL-A04105

Keywords: SMILES string - CO[C@](C[C@]12O[C@]([C@...

Inventory Status:IN STOCK/06-142

COA MSDS

AZITHROMYCIN EP IMPURITY L

Chemical Name: (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-...

CAS No:
90503-06-3

Molecular Formula: C38H72N2O13

Molecular Weight: 764.98

CAT No:
ALL-A04106

Keywords: SMILES string - C[C@@H]([C@@H]([C@H](C(...

Inventory Status:IN STOCK/06-143

COA MSDS

AZITHROMYCIN EP IMPURITY M

Chemical Name: (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-...

CAS No:
765927-71-7

Molecular Formula: C37H68N2O13

Molecular Weight: 748.94

CAT No:
ALL-A04107

Keywords: SMILES string - C[C@H]([C@H]([C@](O)(C[...

Inventory Status:IN STOCK/06-144

COA MSDS

AZITHROMYCIN EP IMPURITY N

Chemical Name: (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-...

CAS No:
612069-25-7

Molecular Formula: C36H65NO13

Molecular Weight: 719.9

CAT No:
ALL-A04108

Keywords: SMILES string - C[C@@H]([C@@H]([C@H](C(...

Inventory Status:IN STOCK/06-145

COA MSDS

AZITHROMYCIN EP IMPURITY O

Chemical Name: (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-...

CAS No:
763924-54-5

Molecular Formula: C39H74N2O12

Molecular Weight: 763.01

CAT No:
ALL-A04109

Keywords: SMILES string - C[C@@H]([C@@H]([C@H](C(...

Inventory Status:IN STOCK/06-146

COA MSDS

AZITHROMYCIN EP IMPURITY P | AZITHROMYCIN USP RC-P

Chemical Name: Specified Unidentified Impurity

CAS No:
N.A

Molecular Formula: N.A

Molecular Weight: N.A

CAT No:
ALL-A04110

Keywords: Azithromycin Impurity P, Azithromycin Im...

Inventory Status:IN STOCK/06-147

COA MSDS

AZITHROMYCIN EP IMPURITY R

Chemical Name: (1R,2R,3R,6R,7S,8S,9R,10R,12R,15R)-9-(((...

CAS No:
161193-44-8

Molecular Formula: C37H66N2O12

Molecular Weight: 730.93

CAT No:
ALL-E07193

Keywords: SMILES string - C[C@@H]([C@@H]([C@H](C(...

Inventory Status:IN STOCK/06-150

COA MSDS

AZITHROMYCIN EP IMPURITY S

Chemical Name: (1R,2R,3R,6R,7S,8S,9R,10R,12R,15R)-7-[(2...

CAS No:
99290-97-8

Molecular Formula: C37H66N2O12

Molecular Weight: 730.94

CAT No:
ALL-E03110

Keywords: Azithromycin Impurity S, Azithromycin Im...

Inventory Status:IN STOCK/06-151

COA MSDS

AZITHROMYCIN IMPURITY

Chemical Name: (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-...

CAS No:
83905-01-5 (ANHYDROUS) | 117772-70-0 (DIHYDRATE)

Molecular Formula: C38H76N2O14

Molecular Weight: 748.98

CAT No:
ALL-A03469

Keywords: AZITHROMYCIN

Inventory Status:IN STOCK/06-311

COA MSDS

AZITHROMYCIN IMPURITY 2

Chemical Name: methyl ((2S,3R,4S)-2-(((2R,3S,4R,5R,8R,1...

CAS No:
N.A

Molecular Formula: C38H70N2O14

Molecular Weight: 779

CAT No:
ALL-AZI-A2

Keywords: AZITHROMYCIN IMPURITY 2

Inventory Status:IN STOCK/06-309

COA MSDS

AZITHROMYCIN IMPURITY 3 SODIUM SALT

Chemical Name: sodium (2R,3S,4S,5R,6R,8R)-5-(((2S,3R,4S...

CAS No:
N.A

Molecular Formula: C38H73N2O13 : Na

Molecular Weight: 789.01

CAT No:
ALL-AZI-A3

Keywords: AZITHROMYCIN IMPURITY 3 SODIUM SALT

Inventory Status:IN STOCK/06-310

COA MSDS

AZITHROMYCIN IMPURITY Q

Chemical Name: (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-...

CAS No:
2095879-65-3

Molecular Formula: C44H75N3O15S

Molecular Weight: 918.15

CAT No:
ALL-A04114

Keywords: SMILES string - C[C@@H]([C@@H]([C@H](C(...

Inventory Status:IN STOCK/06-149

COA MSDS

AZITHROMYCIN IMPURITY Zy

Chemical Name: 3'N-demethyl-3-'-N-buthyl-2-ol...

CAS No:
N.A

Molecular Formula: C41H78N2O13

Molecular Weight: 807.1

CAT No:
ALL-AZI-AZy

Keywords: AZITHROMYCIN IMPURITY Zy

Inventory Status:IN STOCK/06-307

COA MSDS

AZITHROMYCIN N-DESMETHYL 4-OXIME

Chemical Name: N-Desmethyl 13(4-C,4-O-methylene)-pyrano...

CAS No:
217500-75-9

Molecular Formula: C38H70N2O12

Molecular Weight: 746.97

CAT No:
ALL-AZI-ND

Keywords: AZITHROMYCIN N-DESMETHYL 4-OXIME/217500-...

Inventory Status:IN STOCK/06-301

COA MSDS

Key Azithromycin Impurity Variants Available

Azithromycin EP Impurity A (Desmethyl Azithromycin / Azalide demethylation product) — arises from N-demethylation during synthesis or storage
Azithromycin EP Impurity C (3″ — O-Demethylazithromycin)-a demethylation impurity at the cladinose sugar moiety, listed in both EP and USP
Azithromycin EP Impurity I (N — Desmethyl Azithromycin)-a tertiary amine demethylation product monitored as a related substance
Azithromycin EP Impurity J — a lower-molecular-weight process-related impurity included in the EP related-substances test
N — Nitroso Azithromycin-a nitrosamine-class impurity relevant to ongoing regulatory nitrosamine risk assessments for macrolide and azalide APIs

Allmpus Capability for the Azithromycin/Macrolide Family

Allmpus Laboratories manufactures and isolates Azithromycin impurities alongside related macrolide compounds, applying preparative isolation and forced-degradation methods suited to the multi-ring, multi-substituent structure of azalide antibiotics. Each impurity is supplied with a Certificate of Analysis supported by ¹H NMR, ¹³C NMR, mass spectrometry, HPLC, IR, and TGA data, allowing customers to confirm structural identity and purity before use in method development, method validation, or routine QC testing. Allmpus's portfolio for this family extends to nitroso-impurity variants, including N-Nitroso Azithromycin and related desmethyl nitrosamine analogs, reflecting current regulatory scrutiny of nitrosamine contamination across macrolide APIs, and is manufactured at its Dombivali, Maharashtra facility for supply to pharmaceutical manufacturers and contract testing laboratories.

Frequently Asked Questions

Are Allmpus Azithromycin impurity standards referenced to EP and USP designations?

Yes. Where a pharmacopeial designation exists, the corresponding EP or USP impurity letter is provided along with the chemical name and any commonly used synonym, to support direct use in monograph-based testing.

What analytical data is provided with each impurity standard?

Each standard is issued with a Certificate of Analysis that includes NMR (¹H and ¹³C), mass spectrometry, HPLC purity, IR, and TGA data to support identity and purity confirmation.

Are these standards suitable for human use?

No. Azithromycin impurity standards are supplied strictly for analytical, research, and reference purposes, including method development and quality control testing, and are not intended for human or veterinary administration.