Omadacycline tosylate
[CAS# 1075240-43-5]

Identification

• Classification: API >> Other chemicals
• Name: Omadacycline tosylate
• Synonyms: PTK 0796 tosylate
• Molecular Formula: C₂₉H₄₀N₄O₇^.C₇H₈O₃S
• Molecular Weight: 728.85
• CAS Registry Number: 1075240-43-5
• EC Number: 966-277-3
• SMILES: CC1=CC=C(C=C1)S(=O)(=O)O.CC(C)(C)CNCC1=CC(=C2C[C@H]3C[C@H]4[C@@H](C(=O)C(=C([C@]4(C(=O)C3=C(C2=C1O)O)O)O)C(=O)N)N(C)C)N(C)C

Properties

• Solubility: 10 mM (DMSO), 2 mg/mL (H2O) (Expl.)

Safety Data

• Hazard Symbols: GHS07;GHS08 Warning
• Hazard Statements: H302-H361
• Precautionary Statements: P203-P264-P270-P280-P301+P317-P318-P330-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Reproductive toxicity	Repr.	2	H361d

Discovory and Applicatios

Omadacycline tosylate is a salt form of omadacycline, a modern aminomethylcycline antibiotic developed to combat bacterial resistance. It is derived from the tetracycline class and has been structurally modified to retain activity against bacteria that have developed resistance to earlier tetracyclines. The tosylate salt is used to improve the compound’s solubility, stability, and ease of formulation for pharmaceutical applications.

Omadacycline was discovered through chemical modification of minocycline by adding a bulky aminomethyl group at the C9 position on the D-ring of the tetracycline core. This structural modification prevents the efflux of the antibiotic from bacterial cells and avoids ribosomal protection mechanisms that usually confer resistance to conventional tetracyclines. These improvements allow omadacycline to maintain broad-spectrum activity against both Gram-positive and Gram-negative pathogens, as well as atypical and anaerobic bacteria.

The tosylate (p-toluenesulfonate) form of omadacycline was developed during pharmaceutical formulation efforts to enhance the drug’s pharmacokinetic properties. Tosylate salts are commonly used in drug development for their favorable crystallinity and stability profiles, which aid in drug manufacturing and shelf-life. Omadacycline tosylate is particularly valuable for preparing oral or intravenous dosage forms that require precise solubility and bioavailability characteristics.

Omadacycline tosylate exhibits potent in vitro and in vivo activity against multidrug-resistant organisms, including Streptococcus pneumoniae, Staphylococcus aureus (including methicillin-resistant strains), Enterococcus faecalis, Escherichia col and Klebsiella pneumoniae. Its mechanism of action involves inhibition of protein synthesis by binding to the 30S ribosomal subunit of bacteria, a typical mechanism for tetracyclines, but its structural alterations make it less susceptible to common resistance mechanisms.

The application of omadacycline tosylate in clinical medicine is focused on the treatment of community-acquired bacterial pneumonia (CABP) and acute bacterial skin and skin structure infections (ABSSSI). These infections, which have increasingly become difficult to treat due to rising antibiotic resistance, can now be more effectively managed with omadacycline as either a first-line or step-down therapy. It has been approved for clinical use in several countries based on multiple Phase III clinical trials demonstrating non-inferiority to linezolid and moxifloxacin in the respective indications.

Pharmacologically, omadacycline tosylate displays favorable absorption, with good oral bioavailability and a long half-life allowing once-daily dosing. It does not require dose adjustment in patients with renal or hepatic impairment, enhancing its usability in diverse patient populations. It has a broad tissue distribution and low potential for drug–drug interactions, making it suitable for monotherapy in complex infections.

The development and utilization of omadacycline tosylate reflect a broader trend in antibiotic innovation, where chemical modifications of known scaffolds are employed to overcome resistance and extend the useful life of antibiotic classes. It is also part of a response to the global need for new antimicrobial agents capable of addressing urgent public health threats posed by resistant bacteria.

Omadacycline tosylate continues to be studied for potential use in other infections, such as urinary tract infections and infections caused by biothreat pathogens. Its oral and IV formulations provide flexibility for both inpatient and outpatient care, supporting antimicrobial stewardship efforts by facilitating early hospital discharge and reducing healthcare-associated complications.

References

2009. Deal watch: Novartis acquires marketing rights for novel broad-spectrum antibiotic. Nature Reviews Drug Discovery, 8(12).
DOI: 10.1038/nrd3064

2016. Discovery, pharmacology, and clinical profile of omadacycline, a novel aminomethylcycline antibiotic. Bioorganic & Medicinal Chemistry, 24(24).
DOI: 10.1016/j.bmc.2016.07.029

2018. Omadacycline: A New Tetracycline Antibiotic. The Annals of Pharmacotherapy, 53(5).
DOI: 10.1177/1060028018818094