Omadacycline tosylate (PTK 0796 tosylate) is an orally administered aminocyclitol antibacterial agent and tetracycline antibiotic exhibiting broad-spectrum antimicrobial activity against Gram-positive, Gram-negative, anaerobic, and atypical pathogens. Omadacycline tosylate binds to the 30S ribosomal subunit of bacteria to inhibit protein synthesis and may be employed in studies of pneumonia and cutaneous infections.

The 90% minimum inhibitory concentrations (MIC₉₀) of omadacycline tosylate against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and beta-hemolytic streptococci are 1.0 μg/ml, 0.25 μg/ml, and 0.5 μg/ml, respectively; its MIC₉₀ against penicillin-resistant Streptococcus pneumoniae (PRSP) and Haemophilus influenzae (H. influenzae) are 0.25 μg/ml and 2.0 μg/ml, respectively [2].
Omadacycline tosylate (10 μM, equivalent to 5.57 μg/ml) inhibits the ligand-binding activity of the M2 subtype of muscarinic acetylcholine receptors (M2 receptors) by 82%. At the same time, it exerts no substantial effect on the M3 subtype of muscarinic receptors (M3 receptors) or nicotinic acetylcholine receptors [5].

In the mouse abdominal infection model, a single intravenous injection of Omadacycline tosylate (0.11-18 mg/kg) demonstrated therapeutic effects against Streptococcus pneumoniae, Escherichia coli, and Staphylococcus vitis vinifera. The 50% effective dose (ED₅₀) for Streptococcus pneumoniae ranged from 0.45 mg/kg to 3.39 mg/kg, while the ED₅₀ for Staphylococcus vitis vinifera ranged from 0.30 mg/kg to 1.74 mg/kg. The ED₅₀ for Escherichia coli was 2.02 mg/kg[2].