For research use only.
Catalog No.S4056 Synonyms: SB-275833
CAS No. 224452-66-8
Retapamulin (SB-275833) is a topical antibiotic, which binds to both E. coli and S. aureus ribosomes with similar potencies with Kd of 3 nM.
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|Description||Retapamulin (SB-275833) is a topical antibiotic, which binds to both E. coli and S. aureus ribosomes with similar potencies with Kd of 3 nM.|
|Features||Retapamulin is insoluble in water but is soluble in dimethyl sulfoxide and methanol.|
Retapamulin is a potent inhibitor of protein synthesis with an IC50 of 0.33 μM in lysates prepared from erythromycin-susceptible E. coli cells. Retapamulin (100 μM) is ineffective in inhibiting eukaryotic translation when tested in a rabbit reticulocyte lysate system with the cellular components necessary for mammalian protein synthesis. Retapamulin binds to Erys ribosomes and fully displaces the labeled ligand with an IC50 of 26.1 nM. Retapamulin partially inhibits the ability of charged, N-blocked tRNA to bind to the P-site of E. coli ribosomes, with an IC50 of 17.4 nM (maximum inhibition of 80%).  Retapamulin inhibits Staphylococcus aureus and Streptococcus pyogenes with MIC90 of 0.12 μg/mL and ≤0.03 μg/mL, respectively. Retapamulin inhibits S. aureus subset with MIC50/90 values of 0.06/0.12 μg/mL. Retapamulin shows excellent activity against these isolates, with only two requiring a MIC of 0.06 μg/mL.  Retapamulin is very active against the S. pyogenes isolates tested with MIC90 of 0.016 μg/mL, and based on MIC90s, is 32- and >1,024-fold more active than mupirocin and fusidic acid, respectively. Retapamulin binds to a unique site on the bacterial ribosome, and by virtue of its novel mode of action.  Retapamulin (<2 mg/L) inhibits 37/52 (71%) strains of the B. fragilis group and 85/87 (98%) of the other Gram-negative bacilli. Retapamulin is more active than clindamycin, metronidazole and ceftriaxone against Propionibacterium acnes and anaerobic Gram-positive cocci.  Retapamulin inhibits total viable cells (TVC), Protein synthesis and 50S subunit synthesis in both wild-type (wt) Staphylococcus aureus strain RN1786 with IC50 of 12 ng/mL, 5 ng/mL and 27 ng/mL, respectively. 
-  Yan K, et al. Antimicrob Agents Chemother, 2006, 50(11), 3875-3881.
-  Jones RN, et al. Antimicrob Agents Chemother, 2006, 50(7), 2583-2586.
-  Rittenhouse S, et al. Antimicrob Agents Chemother, 2006, 50(11), 3882-3885.
|In vitro||DMSO||104 mg/mL (200.86 mM)|
* Please note that Selleck tests the solubility of all compounds in-house, and the actual solubility may differ slightly from published values. This is normal and is due to slight batch-to-batch variations.
In vivo Formulation Calculator (Clear solution)
|Step 1: Enter information below (Recommended: An additional animal making an allowance for loss during the experiment)|
|Dosage||mg/kg||Average weight of animals||g||Dosing volume per animal||ul||Number of animals|
|Step 2: Enter the in vivo formulation ()|
|% DMSO % % Tween 80 % ddH2O|
Working concentration： mg/ml；
Method for preparing DMSO master liquid: ： mg drug pre-dissolved in μL DMSO (Master liquid concentration mg/mL，)
Method for preparing in vivo formulation：Take μL DMSO master liquid, next addμL PEG300， mix and clarify, next addμL Tween 80，mix and clarify, next add μL ddH2O，mix and clarify.
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Clinical Trial Information
|NCT Number||Recruitment||interventions||Conditions||Sponsor/Collaborators||Start Date||Phases|
|NCT03304873||Completed||Drug: Retapamulin|Drug: Placebo Ointment||MRSA||NYU Langone Health||December 1 2017||Phase 3|
|NCT01812382||Completed||Drug: Retapamulin Microdialysis||Skin Infections Bacterial||GlaxoSmithKline||April 2 2014||Phase 1|
|NCT01445600||Completed||Drug: ALTARGO(retapamulin)||Skin Infections Bacterial||GlaxoSmithKline||November 2012||--|
|NCT00903279||Withdrawn||Drug: Placebo|Drug: Altabax (retapamulin)||Orthopedic Procedures|Methicillin-resistant Staphylococcus Aureus||Bay Pines VA Healthcare System||August 2009||Phase 2|
Answers to questions you may have can be found in the inhibitor handling instructions. Topics include how to prepare stock solutions, how to store inhibitors, and issues that need special attention for cell-based assays and animal experiments.
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