Tacrolimus Impurity Standards

Tacrolimus impurity reference standards are used by pharmaceutical quality-control laboratories, contract research organisations, and generic drug manufacturers to identify, quantify, and control Tacrolimus-related impurities during analytical method development, method validation, and regulatory filing. As a calcineurin inhibitor immunosuppressant, Tacrolimus 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 Tacrolimus 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

N-NITROSO TACROLIMUS 21-CARBOXYLIC ACID IMPURITY

Chemical Name: N-NITROSO TACROLIMUS 21-CARBOXYLIC ACI...

CAS No:
N.A.

Molecular Formula: C44H70N2O14

Molecular Weight: 851.03

CAT No:
ALL-T08220

Keywords: N-NITROSO Tacrolimus 21-Carboxylic Acid ...

Inventory Status:Delivery 2-3 Weeks

COA MSDS

TACROLIMUS REGIOISOMER

Chemical Name: (1R,9S,12S,13R,14S,17S,18E,21S,23S,24R,2...

CAS No:
131944-48-4

Molecular Formula: C44H69NO12

Molecular Weight: 804.02

CAT No:
ALL-TRC-2098

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

Inventory Status:IN STOCK

COA MSDS

13-O-DESMETHYL TACROLIMUS IMPURITY

Chemical Name: 15,19-Epoxy-3H-pyrido[2,1-c][1,4]oxaazac...

CAS No:
139958-51-3

Molecular Formula: C43H67NO12

Molecular Weight: 789.99

CAT No:
ALL-T06874

Keywords: SMILES string - CO[C@@H]1[C@@]2([H])O[C@...

Inventory Status:IN STOCK-02-580

COA MSDS

ASCOMYCIN

Chemical Name: (1R,9S,12S,13R,14S,17R,18E,21S,23S,24R,2...

CAS No:
104987-12-4

Molecular Formula: C43H69NO12

Molecular Weight: 792.01

CAT No:
ALL- A03368

Keywords: SMILES string - CCC1\C=C(C)\C[C@H](C)C[...

Inventory Status:In Stock

COA MSDS

DESMETHYL TACROLIMUS IMPURITY

Chemical Name: (1R,9S,12S,13R,14S,17R,18E,21S,23S,24R,2...

CAS No:
132172-14-6

Molecular Formula: C43H67NO12

Molecular Weight: 789.99

CAT No:
ALL-T03931

Keywords: SMILES string - CC1CC(C(C2CC(C(O2)(C(=O)...

Inventory Status:IN STOCK-02-804

COA MSDS

TACROLIMUS

Chemical Name: (1R,9S,12S,13R,14S,17R,18E,21S,23S,24R,2...

CAS No:
104987-11-3

Molecular Formula: C44H69NO12

Molecular Weight: 804.02

CAT No:
ALL-T03369

Keywords: SMILES string - CC1CC(C2C(CC(C(O2)(C(=O)...

Inventory Status:IN STOCK-02-805

COA MSDS

TACROLIMUS 20 ETHOXY ACETAL IMPURITY

Chemical Name: 3S,4R,5S,8R,12S,14S,15R,16S,18R,19S,26aS...

CAS No:
N.A.

Molecular Formula: C46H75NO13

Molecular Weight: 850.10

CAT No:
ALL-T08449

Keywords: SMILES string - O=C([C@@](CCCC1)([H])N1...

Inventory Status:In Stock

COA MSDS

TACROLIMUS 21-CARBOXYLIC ACID IMPURITY

Chemical Name: 2-((2R,3R,5S)-6-((1S,3S,5Z,7R,10S,11R,1...

CAS No:
N.A

Molecular Formula: C44H71NO13

Molecular Weight: 822.1

CAT No:
ALL-T08686

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

Inventory Status:IN STOCK-02-230

COA MSDS

TACROLIMUS C4-EPIMER DIENE IMPURITY

Chemical Name: 15,19-Epoxy(5E,9E)-3H-pyrido[2,1-c][1,4]...

CAS No:
N.A

Molecular Formula: C44H67NO11

Molecular Weight: 786.0

CAT No:
ALL-T03326

Keywords: TACROLIMUS C4-EPIMER DIENE

Inventory Status:IN STOCK-02-238

COA MSDS

TACROLIMUS DEHYDRO IMPURITY

Chemical Name: 15,19-Epoxy-3H-pyrido[2,1...

CAS No:
129212-37-9

Molecular Formula: C44H67NO11

Molecular Weight: 786.0

CAT No:
ALL-T03184

Keywords: SMILES string - C[C@@H]1C[C@@H]([C@@H]2[...

Inventory Status:IN STOCK-02-236

COA MSDS

TACROLIMUS DELTA LACTONE IMPURITY

Chemical Name: TACROLIMUS DELTA LACTONE

CAS No:
1026775-21-2

Molecular Formula: C44H69NO12

Molecular Weight: 804.0

CAT No:
ALL-T06793

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

Inventory Status:IN STOCK-02-237

COA MSDS

TACROLIMUS EP IMPURITY C

Chemical Name: (1R,9S,12S,13R,14S,17R,18E,21S,23S,24R,2...

CAS No:
N.A

Molecular Formula: C43H67NO12

Molecular Weight: 789.99

CAT No:
ALL-T08426

Keywords: SMILES string - CC1CC=CC(C(=O)CC(C(C(OC(...

Inventory Status:IN STOCK-02-232

COA MSDS

TACROLIMUS EP IMPURITY D

Chemical Name: (1R,9S,12S,13R,14S,17S,18E,21S,23S,24R,2...

CAS No:
129212-35-7

Molecular Formula: C44H69NO12

Molecular Weight: 804.02

CAT No:
ALL-TRC-2090

Keywords: SMILES string - (1R,9S,12S,13R,14S,17S,1...

Inventory Status:IN STOCK-02-119

COA MSDS

TACROLIMUS EP IMPURITY E

Chemical Name: (1R,9S,12S,13R,14S,17R,18E,21S,23S,24R,2...

CAS No:
104987-30-6

Molecular Formula: C44H71NO12

Molecular Weight: 806.05

CAT No:
ALL-TRC-2091

Keywords: SMILES string -CCCC1C=C(CC(CC(C2C(CC(C(O...

Inventory Status:IN STOCK-02-118

COA MSDS

TACROLIMUS EP IMPURITY F

Chemical Name: (3S,4R,5S,8R,9E,12S,14S,15R,16S,18R,19R,...

CAS No:
N.A

Molecular Formula: C44H69NO12

Molecular Weight: 804.02

CAT No:
ALL-T07091

Keywords: SMILES string - CC1CC(C(C(CC(C(=O)C(=O)C...

Inventory Status:IN STOCK-02-233

COA MSDS

TACROLIMUS EP IMPURITY G

Chemical Name: (1S,9S,12S,13R,14S,17R,18E,21S,23S,24R,2...

CAS No:
144490-63-1

Molecular Formula: C44H69NO12

Molecular Weight: 804.03

CAT No:
ALL-TRC-2088

Keywords: SMILES string - CC1CC(C2C(CC(C(O2)(C(=O)...

Inventory Status:IN STOCK-02-120

COA MSDS

TACROLIMUS EP IMPURITY H

Chemical Name: (1E,3S,4R,5S,8R,9E,12S,14S)-5-Hydroxy-1-...

CAS No:
143210-33-7

Molecular Formula: C43H69NO11

Molecular Weight: 776.0

CAT No:
ALL-TR03018

Keywords: SMILES string - CC1CC(C(OC1=O)C(CC(C)CC(...

Inventory Status:IN STOCK-02-234

COA MSDS

TACROLIMUS EP IMPURITY I

Chemical Name: (1R,9S,12S,13R,14E,17R,18E,21S,23S,24R,2...

CAS No:
104987-16-8

Molecular Formula: C44H67NO11

Molecular Weight: 786.02

CAT No:
ALL-TRC-2092

Keywords: Store at - CC1CC(C2C(CC(C(O2)(C(=O)C(=O)...

Inventory Status:IN STOCK-02-117

COA MSDS

TACROLIMUS HYDROXY ACID IMPURITY

Chemical Name: (3S,4R,5S,8R,12S,14S,15R,16S,18R,25aS,E)...

CAS No:
1700657-83-5

Molecular Formula: C44H71NO13

Molecular Weight: 822.03

CAT No:
ALL-TRC-2093

Keywords: SMILES string - O=C(O)C1(O)C(=O)N2CCCCC2...

Inventory Status:IN STOCK-02-116

COA MSDS

TACROLIMUS IMPURITY 1

Chemical Name: [3S-[3R*[E(1S*,3S*,4S*)],4S*,5R*,8S*,9E,...

CAS No:
123719-19-7

Molecular Formula: C43H69NO11

Molecular Weight: 776.01

CAT No:
ALL-T03470

Keywords: SMILES string - O=C([C@@](CCCC1)([H])N1C...

Inventory Status:IN STOCK-02-231

COA MSDS

TACROLIMUS LACTONE ISOMER

Chemical Name: (1R,9S,12S,15R,16E,19S,21S,22R,23S,25R)-...

CAS No:
134590-88-8

Molecular Formula: C44H69NO12

Molecular Weight: 804.02

CAT No:
ALL-T03089

Keywords: SMILES string - CC1CC(C2C(CC(C(O2)(C(=O)...

Inventory Status:IN STOCK-02-122

COA MSDS

TACROLIMUS METHYL ACRYL ALDEHYDE IMPURITY

Chemical Name: (E)-3-[(1R,3R,4R)-4-hydroxy-3-methoxycyc...

CAS No:
109466-74-2

Molecular Formula: C11H18O3

Molecular Weight: 198.26

CAT No:
ALL-TAC-ALD

Keywords: SMILES string - CC(=CC1CCC(C(C1)OC)O)C=O

Inventory Status:IN STOCK-02-115

COA MSDS

TACROLIMUS METHYL ETHER

Chemical Name: TACROLIMUS METHYL ETHER

CAS No:
124554-16-1

Molecular Formula: C45H71NO12

Molecular Weight: 818.04

CAT No:
ALL-T07178

Keywords: TACROLIMUS METHYL ETHER/124554-16-1

Inventory Status:IN STOCK-02-229

COA MSDS

TACROLIMUS O ETHYL OPEN RING (PEAK 1) - USP

Chemical Name: (3S,4R,5S,8R,12S,14S,15R,16S,18R,26aS,E)...

CAS No:
N.A.

Molecular Formula: C46H78NO13

Molecular Weight: 853.11

CAT No:
ALL-T08447

Keywords: SMILES string - O=C([C@@](CCCC1)([H])N1C...

Inventory Status:In Stock

COA MSDS

TACROLIMUS O ETHYL OPEN RING (PEAK 2) - USP

Chemical Name: (3S,4R,5S,8R,12S,14S,15R,16S,18R,26aS,E)...

CAS No:
N.A.

Molecular Formula: C46H75NO13

Molecular Weight: 850.1

CAT No:
ALL-T08448

Keywords: TACROLIMUS O ETHYL OPEN RING (PEAK 2)

Inventory Status:In Stock

COA MSDS

TACROLIMUS OPEN RING IMPURITY

Chemical Name: (5R,7S,8R,9S,11S,13E,15R,18S,19R,20S,23S...

CAS No:
144432-23-5

Molecular Formula: C44H71NO13

Molecular Weight: 822.03

CAT No:
ALL-TRC-2097

Keywords: SMILES string – CC1CC(C(C(CC(C(=O)C(C...

Inventory Status:IN STOCK-02-114

COA MSDS

TACROLIMUS RING-OPENING IMPURITY

Chemical Name: (5R,7S,8R,9S,11S,13E,15R,18S,19R,20S,23S...

CAS No:
1393890-33-9

Molecular Formula: C44H69NO12

Molecular Weight: 804.0

CAT No:
ALL-TO3017

Keywords: TACROLIMUS RING-OPENING IMPURITY/1393890...

Inventory Status:IN STOCK-02-111

COA MSDS

TACROLIMUS USP RELATED COMPOUND A

Chemical Name: (18E)-17-ethyl-1,14-dihydroxy-12-[(E)-1-...

CAS No:
135635-46-0

Molecular Formula: C43H69NO12

Molecular Weight: 792.01

CAT No:
ALL-TRC-2099

Keywords: SMILES string – CCC1C=C(CC(CC(C2C(CC(...

Inventory Status:IN STOCK-02-112

COA MSDS

TACROLIMUS-13C D2

Chemical Name: TACROLIMUS-13C D2

CAS No:
�1356841-89-8

Molecular Formula: C4313CH67D2NO12

Molecular Weight: 807.02

CAT No:
ALL-D01898

Keywords: O=C(O[C@@H]([C@@H]([C@H](CC1=O)O)C)/C(C)...

Inventory Status:NA

COA MSDS

TACROLIMUS-13C, D2 (MAJOR)

Chemical Name: FK-506-13C,D2 (Major) (Tacrolimus)

CAS No:
1356841-89-8

Molecular Formula: C4313CH67D2NO12

Molecular Weight: 807.0

CAT No:
ALL-T08450

Keywords: SMILES string - CO[C@@H]1[C@]([C@H](C[C@...

Inventory Status:DELIVERY 3-4 WEEKS

COA MSDS

TACROLIMUSE EP IMPURITY B

Chemical Name: (1S,9S,12S,13R,14S,17R,18E,21S,23S,24R,2...

CAS No:
N.A

Molecular Formula: C43H69NO12

Molecular Weight: 792.01

CAT No:
ALL-T03412

Keywords: SMILES string - CCC1C=C(CC(CC(C2C(CC(C(O...

Inventory Status:IN STOCK-02-121

COA MSDS

Key Tacrolimus Impurity Variants Available

N — Nitroso Tacrolimus 21-Carboxylic Acid Impurity
Tacrolimus EP Impurity A (13 — epi-Tacrolimus / related epimeric form)
Tacrolimus EP Impurity B (secomacrolide — type degradation product)
Tacrolimus EP Impurity C (dihydro/oxidative degradation variant)
Tacrolimus 21 — Carboxylic Acid Impurity (non-nitrosated precursor)

Allmpus Capability for the Tacrolimus Impurity Family

Allmpus Laboratories maintains dedicated synthetic and analytical chemistry capability for complex macrolide impurities, including nitrosamine-class substances that require specialized handling and containment during synthesis. Our analytical chemistry division supports full structural characterization using NMR, mass spectrometry, and HPLC purity assessment, allowing each impurity lot to be supplied with a certificate of analysis referencing spectral data and chromatographic purity. Batches are produced in accordance with our internal quality practices at our Amravati manufacturing facility, with process documentation available to support customer method validation and regulatory submission packages. For laboratories working on ANDA filings, EP/USP compliance testing, or stability studies involving tacrolimus formulations, Allmpus can also evaluate custom synthesis requests for related impurities not currently listed in the catalogue.

Frequently Asked Questions

Are these tacrolimus impurity standards suitable for regulatory filing support?

Yes. Standards are supplied with analytical characterization data (NMR, MS, HPLC) intended to support method validation and regulatory documentation; customers should confirm specific data package requirements with our technical team prior to ordering.

Can Allmpus synthesize a tacrolimus impurity not listed in the current catalogue?

Custom synthesis requests are evaluated on a case-by-case basis through our synthetic chemistry service. Structural information or a target specification should be provided for feasibility assessment.

What quantities are available for tacrolimus impurity standards?

Quantities are typically supplied at analytical reference scale for QC and method development use; larger quantities for extended studies can be discussed directly with our team via the enquiry form.