Telithromycin

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Cat Number

API0231586

CAS Number

191114-48-4

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Product Detail Description Scientific Support Customer Q&A

CAS Number

191114-48-4

EINECS

682-750-4

Storage

Store at 2-8℃

Synonyms

HMR3647; Levviax; RU-66647; telithromycine; telitromicina; KI8H7H19WL; DTXSID3046455; NSC-758940; DTXCID1026455

Molecular Formula

C43H65N5O10

Molecular Weight

812

Smiles

CC[C@@H]1[C@@]2([C@@H]([C@H](C(=O)[C@@H](C[C@@]([C@@H]([C@H](C(=O)[C@H](C(=O)O1)C)C)O[C@H]3[C@@H]([C@H](C[C@H](O3)C)N(C)C)O)(C)OC)C)C)N(C(=O)O2)CCCCN4C=C(N=C4)C5=CN=CC=C5)C

Appearance

White to off-white crystalline powder

Melting Point

176-188℃

Boiling Point

966℃ at 760 mmHg

Relative Density

1.26±0.1 (Predicted)

General Description

Telithromycin is a first-in-class ketolide antibiotic, a semisynthetic derivative of erythromycin designed to overcome macrolide resistance. It is structurally characterized by a 3-keto group replacing the cladinose sugar found in traditional macrolides. The drug demonstrates enhanced binding to bacterial ribosomes and activity against resistant respiratory pathogens.

Mechanism of Action

Telithromycin binds to two distinct sites on the bacterial 50S ribosomal subunit, inhibiting protein synthesis at the peptidyl transferase center. This dual binding prevents the exit of nascent polypeptide chains and disrupts ribosome assembly. The drug maintains activity against macrolide-resistant strains due to its high affinity for the ribosome, even in the presence of erm-encoded methylases that alter the typical macrolide binding site.

Application

Telithromycin was approved for the treatment of community-acquired pneumonia, acute exacerbations of chronic bronchitis, and acute bacterial sinusitis.

Telithromycin demonstrated potent activity against 280 Enterococcus faecalis and 122 E. faecium clinical isolates from Chinese inpatients, with MIC50 values of 2 and 4 µg/mL, respectively, among strains carrying erm resistance genes. Multilocus sequence typing identified predominant sequence types: ST16, ST30, and ST179 for E. faecalis; ST18, ST78, and ST80 for E. faecium. Subinhibitory concentrations (1/4–1/8 × MIC) reduced biofilm formation by ~35%. At 8 × MIC, telithromycin or ampicillin reduced established biofilms by ~40%, whereas vancomycin or linezolid had minimal effect. Combining telithromycin with ampicillin achieved ~70% reduction. The authors conclude that telithromycin warrants consideration as a candidate for treating enterococcal infections, including those involving biofilms.

Fig. 1 Telithromycin inhibiting biofilm formation of 16 E. faecalis isolates. (Xiong Y, et al., 2021)

References

Xiong Y, et al. The Antibacterial and Antibiofilm Activity of Telithromycin Against Enterococcus spp. Isolated From Patients in China. Front Microbiol. 2021;11:616797

Does Telithromycin require refrigerated storage as a ketolide antibiotic?

Yes, it must be stored at 2-8°C. At room temperature, the macrolactone ring is susceptible to hydrolysis, leading to rapid loss of antibacterial activity.

Is Telithromycin sensitive to moisture, and how is this prevented?

It is highly hygroscopic. Our packaging includes moisture-barrier aluminum foil bags with desiccant, and the material should be opened only in low-humidity environments.

What is the stability of Telithromycin in tablet formulations?

It shows good stability when formulated with standard excipients and packaged in moisture-protective blisters. We provide long-term stability data at 2-8°C and 25°C.

How is the impurity telithromycin pseudoaglycone monitored during stability?

This key degradation product (from cladinose hydrolysis) is specifically quantified using a stability-indicating HPLC method, ensuring it remains within ICH limits.