Bacterial 50S ribosomal subunit. Tulathromycin B, like tulathromycin A, binds to domain V of the 23S rRNA of the 50S ribosomal subunit. This binding inhibits bacterial protein synthesis by blocking the translocation step of translation. It is bacteriostatic but can also exert concentration-dependent bactericidal activity against susceptible respiratory pathogens in cattle and swine.

Tulathromycin B exhibits antibacterial activity against a broad spectrum of Gram-positive and Gram-negative bacteria, particularly respiratory pathogens. It is more potent against Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni. While specific MIC values for tulathromycin B are less extensively reported than for tulathromycin A, both isomers contribute to the overall antibacterial activity.

In bovine models of respiratory disease, tulathromycin (as a mixture of tulathromycin A and B isomers) administered as a single subcutaneous injection at 2.5 mg/kg body weight provides effective treatment and control of BRD, with efficacy comparable to or better than other macrolides such as tilmicosin or florfenicol. It persists in lung tissue for extended periods, enabling single-dose therapy.

Not applicable as a drug target assay. Tulathromycin B is tested for ribosomal binding. For binding studies, purified 50S ribosomal subunits from susceptible bacteria (e.g., E. coli or M. haemolytica) are incubated with radiolabeled tulathromycin B (e.g., 14C or 3H-labeled) at various concentrations (1 nM-10 uM) in binding buffer (10 mM Tris-HCl, pH 7.4, 10 mM MgCl2, 100 mM NH4Cl) at 37degC for 30 minutes. Bound antibiotic is separated from unbound by filtration through nitrocellulose filters, and radioactivity is measured by liquid scintillation counting. Specific binding is determined by subtracting non-specific binding measured in the presence of excess unlabeled tulathromycin (100 uM). The dissociation constant (Kd) is calculated from saturation binding curves.

For in vitro antibacterial assays, clinical isolates of M. haemolytica, P. multocida, and H. somni are cultured on blood agar plates. Bacterial colonies are suspended in Mueller-Hinton broth to a density of 10⁵-10⁶ CFU/mL. Tulathromycin B is serially diluted (0.001-100 ug/mL) in 96-well plates. Bacteria are added and plates are incubated at 37degC for 18-24 hours. Minimum inhibitory concentration (MIC) is determined as the lowest concentration that inhibits visible bacterial growth. MIC90 values for tulathromycin against these pathogens are typically ≤0.5 ug/mL. For time-kill assays, bacterial cultures are treated with tulathromycin B at 1×, 2×, and 4× MIC, and bacterial counts are determined by plating at 0, 2, 4, 8, 12, and 24 hours.

In a typical bovine respiratory disease model, male Holstein calves (3-4 months old, 100-150 kg) are challenged intratracheally with 5 × 10⁹ CFU of M. haemolytica or P. multocida. Clinical signs (fever, depression, respiratory rate) are monitored for 24 hours. At 24 hours post-challenge, animals are treated with a single subcutaneous injection of tulathromycin B (2.5 mg/kg). Blood samples are collected for pharmacokinetic analysis. Rectal temperatures and clinical scores are recorded daily for 7-10 days. At study termination, bronchoalveolar lavage fluid and lung tissue are collected for bacterial quantification. Efficacy is determined by reduction of clinical signs, fever, and bacterial counts compared to untreated controls.

Tulathromycin B is a macrolide antibiotic with a long elimination half-life in target species. In cattle, following a single subcutaneous injection at 2.5 mg/kg, maximum plasma concentration (Cmax) is reached at 0.5-1 hour (approximately 0.5-1.0 ug/mL). The terminal half-life is approximately 90 hours, enabling once-daily or single-dose treatment. Tulathromycin exhibits extensive tissue distribution, particularly to lung tissue, where concentrations exceed plasma levels by >100-fold. It is metabolized slowly, primarily in the liver. Tulathromycin B, being an isomer, shares similar PK properties with tulathromycin A.

Tulathromycin B is generally safe in cattle and swine at the recommended dose of 2.5 mg/kg. The most common adverse reactions include injection site reactions (swelling, pain). At higher doses, gastrointestinal disturbances (diarrhea, reduced feed intake) and mild transient salivation may occur. In toxicity studies, the no-observable-effect level (NOEL) in cattle was approximately 5 mg/kg. It has low toxicity in humans and is considered a veterinary-only antibiotic.

[1]. Ana BERGANT SIMONCIC, et al. Process for preparation of tulathromycin. Patent. WO2015014907.

Tulathromycin A is an aminoglycoside antibiotic. See also: Ketoprofen; Tulathromycin (ingredients); Tulathromycin A (note moved to). Indications: Cattle: For the treatment and prevention of bovine respiratory disease (BRD) caused by Tulathromycin-sensitive hemolytic Mansonia, Pasteurella multocida, Haemophilus influenzae, and Mycoplasma bovis. The presence of the disease in the herd should be determined before prophylactic treatment. For the treatment of infectious bovine keratoconjunctivitis (IBK) caused by Tulathromycin-sensitive Moraxella bovis. Pigs: For the treatment and prevention of swine respiratory disease (SRD) caused by Actinobacillus pleuropneumoniae, Pasteurella multocida, Mycoplasma hyopneumoniae, Haemophilus parasuis, and Tulathromycin-sensitive Bordetella bronchiseptica. The presence of the disease in the herd should be determined before prophylactic treatment. This product is only indicated if pigs are expected to develop the disease within 2-3 days. Sheep: Used to treat early-stage infectious plantar dermatitis (hoof rot) caused by highly virulent Clostridium nodosus, a disease requiring systemic treatment. Cattle: Used to treat and prevent bovine respiratory disease (BRD) caused by Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, and Mycoplasma bovis susceptible to Tulathromycin. The presence of the disease in the herd should be determined before administering preventative treatment. Used to treat infectious bovine keratoconjunctivitis (IBK) caused by Moraxella bovis susceptible to Tulathromycin. Pigs: Used for the treatment and prevention of swine respiratory disease (SRD) caused by Actinobacillus pleuropneumoniae, Pasteurella multocida, Mycoplasma hyopneumoniae, Haemophilus parasuis, and Bordetella. Also for bronchial septicemia sensitive to Tulathromycin. Before administering prophylactic treatment, the presence of the disease in the herd should be determined. This product is only applicable when pigs are expected to develop the disease within 2-3 days. Sheep: Used to treat the early stages of infectious plantar dermatitis (hoof rot) caused by highly virulent Clostridium nodosa, which requires systemic treatment. Cattle: Used for the treatment and prevention of bovine respiratory disease (BRD) caused by hemolytic Mannsella, Pasteurella multocida, Haemophilus, and Mycoplasma bovis sensitive to Tulathromycin. Before administering prophylactic treatment, the presence of the disease in the herd should be determined. For the treatment of infectious bovine keratoconjunctivitis (IBK) caused by Morella bovis susceptible to Tulathromycin. For pigs: Treatment and prevention of porcine respiratory disease (SRD) caused by Actinomyces pleuropneumoniae, Pasteurella multocida, Mycoplasma hyopneumoniae, Haemophilus parasuis, and Bordezoella bronchiseptica susceptible to Tulathromycin. Before administering preventative treatment, the presence of the disease in the herd should be determined. This product is only applicable when pigs are expected to develop symptoms within 2-3 days. For sheep: Treatment of early infectious plantar dermatitis (hoof rot) caused by highly virulent Clostridium nodosus, which requires systemic treatment. For cattle: Treatment and prevention of bovine respiratory disease (BRD) caused by Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, and Mycoplasma bovis susceptible to Tulathromycin. Before administering preventative treatment, the presence of the disease in the herd should be determined. Used to treat infectious bovine keratoconjunctivitis (IBK) caused by Moraxella bovis, which is susceptible to Tulathromycin. Pigs: Used to treat and prevent swine respiratory disease (SRD) caused by Actinobacillus pleuropneumoniae, Pasteurella multocida, Mycoplasma hyopneumoniae, Haemophilus parasuis, and Bordetella. Also used for bronchial septicemia susceptible to Tulathromycin. Before administering preventative treatment, the presence of the disease in the herd should be determined. This product is only applicable when pigs are expected to develop the disease within 2-3 days. Sheep: Used to treat the early stages of infectious plantar dermatitis (hoof rot) caused by highly virulent Clostridium nodosa, a disease requiring systemic treatment. Cattle: For the treatment and prevention of bovine respiratory disease (BRD) caused by hemolytic Mansonia solani, Pasteurella multocida, Haemophilus influenzae, and Mycoplasma bovis susceptible to Tulathromycin. The presence of the disease in the herd should be determined before prophylactic treatment. Also for the treatment of infectious bovine keratoconjunctivitis (IBK) caused by Moraxella bovis susceptible to Tulathromycin. Pigs: For the treatment and prevention of swine respiratory disease (SRD) caused by Actinobacillus pleuropneumoniae, Pasteurella multocida, Mycoplasma hyopneumoniae, Haemophilus parasuis, and Bordetella bronchiseptica susceptible to Tulathromycin. The presence of the disease in the herd should be determined before prophylactic treatment. This product is only applicable when pigs are expected to develop symptoms within 2-3 days. Sheep: For the treatment of early infectious plantar dermatitis (hoof rot) caused by highly virulent Clostridium dichotomum, which requires systemic treatment. Cattle: Used for the treatment and prevention of bovine respiratory disease (BRD) caused by Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, and Mycoplasma bovis susceptible to Tulathromycin. The presence of the disease in the herd should be determined before prophylactic treatment. Also used to treat infectious bovine keratoconjunctivitis (IBK) caused by Moraxella bovis susceptible to Tulathromycin. Pigs: Used for the treatment and prevention of swine respiratory disease (SRD) caused by Actinobacillus pleuropneumoniae, Pasteurella multocida, Mycoplasma hyopneumoniae, Haemophilus parasuis, and Bordetella. For bronchial septicemia sensitive to Tulathromycin. Before administering prophylactic treatment, the presence of the disease in the herd should be confirmed. Draxxin should only be used if pigs are expected to develop symptoms within 2-3 days. Sheep: For the treatment of early stages of infectious plantar dermatitis (hoof rot) associated with highly virulent Clostridium nodosa, requiring systemic treatment. Cattle: For the treatment and prevention of bovine respiratory disease (BRD) associated with hemolytic Mansonia, Pasteurella multocida, Haemophilus influenzae, and Mycoplasma bovis sensitive to Tulathromycin. Before administering prophylactic treatment, the presence of the disease in the herd should be confirmed. For the treatment of infectious bovine keratoconjunctivitis (IBK) associated with Moraxella bovis sensitive to Tulathromycin. Pigs: For the treatment and prevention of swine respiratory disease (SRD) caused by Actinobacillus pleuropneumoniae, Pasteurella multocida, Mycoplasma hyopneumoniae, Haemophilus parasuis, and Bordetella bronchiseptica sensitive to Tulathromycin. Before administering preventative treatment, it should be determined whether the disease is present in the herd. This product is only applicable if the pigs are expected to develop the disease within 2-3 days. Sheep: Used to treat early infectious hoof dermatitis (hoof rot) caused by highly virulent Clostridium nodosa, which requires systemic treatment.

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Tulathromycin B is also known as CP 547272. It is one of two regioisomers (tulathromycin A and tulathromycin B) that constitute the active pharmaceutical ingredient in the veterinary product Draxxin® (Zoetis). Tulathromycin B (CAS 280755-12-6) is supplied as a solid powder with purity ≥98%. It is a macrolide antibiotic belonging to the triamilide subclass. It is a prescription veterinary drug and is not approved for human use. Molecular formula: C41H79N3O12; molecular weight: 806.08. IUPAC name: (2S,3S,6R,8R,9R,10S,11S,12R)-2-[(2R,3R)-2,3-dihydroxypentan-2-yl]-9-[(2S,3R,4S,6R)-4-(dimethylamino)-3-hydroxy-6-methyloxan-2-yl]oxy-8-hydroxy-11-[(2R,4R,5S,6S)-5-hydroxy-4-methoxy-4,6-dimethyl-5-(propylaminomethyl)oxan-2-yl]oxy-3,6,8,10,12-pentamethyl-1-oxa-4-azacyclotridecan-13-one.

C41H79N3O12

806.08

805.566

280755-12-6

9832301

Typically exists as solid at room temperature

1.2±0.1 g/cm3

870.5±65.0 °C at 760 mmHg

480.3±34.3 °C

0.0±0.6 mmHg at 25°C

1.536

3.17

7

15

11

56

1240

18

CCCNCC1(C(C)OC(OC2C(C)C(=O)OC(C(C(CC)O)(C)O)C(C)NCC(C)CC(C)(O)C(OC3OC(C)CC(N(C)C)C3O)C2C)CC1(C)OC)O

GUARTUJKFNAVIK-QPTWMBCESA-N

InChI=1S/C41H79N3O12/c1-15-17-42-22-41(50)28(8)53-31(20-39(41,10)51-14)55-33-25(5)35(56-37-32(45)29(44(12)13)18-24(4)52-37)38(9,48)19-23(3)21-43-27(7)34(46)40(11,49)30(16-2)54-36(47)26(33)6/h23-35,37,42-43,45-46,48-50H,15-22H2,1-14H3/t23-,24-,25+,26-,27-,28+,29+,30-,31+,32-,33+,34-,35-,37+,38-,39-,40-,41+/m1/s1

(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-11-[(2S,3R,4S,6R)-4-(dimethylamino)-3-hydroxy-6-methyloxan-2-yl]oxy-2-ethyl-3,4,10-trihydroxy-13-[(2R,4R,5S,6S)-5-hydroxy-4-methoxy-4,6-dimethyl-5-(propylaminomethyl)oxan-2-yl]oxy-3,5,8,10,12,14-hexamethyl-1-oxa-6-azacyclopentadecan-15-one

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)