Glycopeptide; macrolides antibiotic/bactericidal; cell wall synthesis

Oritavancin, a semisynthetic lipoglycopeptide with activity against gram-positive bacteria, has multiple mechanisms of action, including the inhibition of cell wall synthesis and the perturbation of the membrane potential. [1]

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Both oritavancin and vancomycin achieved 99.9% (3-log) kill, with oritavancin achieving the limit of detection (10(2) CFU/ml) within 1 h and vancomycin achieving this limit at 24 h for both isolates. Detection of resistance was not observed for oritavancin or vancomycin during the 48-h experiments. The key pharmacodynamic parameter for oritavancin has not been well defined. In our experiment, the ratios of the area under the curve from 0 to 24 h to the MIC of oritavancin, oritavancin plus albumin, and vancomycin for both isolates were greater than 944.5, and the ratios of the maximum concentration of drug in serum to the MIC ranged from 73.7 to 7188.5. T>MIC was 100% for oritavancin and vancomycin for both isolates. Oritavancin is a unique and potent antimicrobial that warrants further investigation against multidrug-resistant S. pneumoniae[2].

In postexposure prophylaxis dose-ranging studies, a single intravenous (i.v.) dose of oritavancin of 5, 15, or 50 mg/kg 24 h after a challenge with 50 to 75 times the median lethal dose of Ames strain spores provided 40, 70, and 100% proportional survival, respectively, at 30 days postchallenge. Untreated animals died within 4 days of challenge, whereas 90% of control animals receiving ciprofloxacin at 30 mg/kg intraperitoneally twice daily for 14 days starting 24 h after challenge survived. Oritavancin demonstrated significant activity post symptom development; a single i.v. dose of 50 mg/kg administered 42 h after challenge provided 56% proportional survival at 30 days. In a preexposure prophylaxis study, a single i.v. oritavancin dose of 50 mg/kg administered 1, 7, 14, or 28 days before lethal challenge protected 90, 100, 100, and 20% of mice at 30 days; mice treated with ciprofloxacin 24 h or 24 and 12 h before challenge all died within 5 days. Efficacy in pre- and postexposure models of inhalation anthrax, together with a demonstrated low propensity to engender resistance, promotes further study of oritavancin pharmacokinetics and efficacy in nonhuman primate models[3].

Susceptibility of B. anthracis strains to oritavancin as measured by broth microdilution. [3]
Oritavancin MICs were determined by broth microdilution in 96-well plates according to guidelines of the Clinical and Laboratory Standards Institute. As recommended in guideline M100-S18, polysorbate 80 was included at a final concentration of 0.002% throughout drug dissolution and all steps of the assay to minimize oritavancin binding to surfaces. To determine the impact, if any, of polysorbate 80 upon oritavancin MICs for B. anthracis, a parallel broth microdilution assay was conducted in which oritavancin was dissolved in water and drug dilutions were prepared without polysorbate 80. Quality control of oritavancin dilutions was established by using S. aureus ATCC 29213 with polysorbate 80 at 0.002% throughout; an acceptable range of oritavancin MICs against this strain is 0.015 to 0.12 μg/ml.

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Titration of polysorbate 80 in oritavancin MIC test. [1]
To determine the polysorbate 80 concentration dependence of the oritavancin MICs, broth microdilution susceptibility tests with S. aureus ATCC 29213 as an indicator strain were performed according to the CLSI M7-A7 methodology, except that various test concentrations of polysorbate 80 were included at the drug dissolution step and were maintained at the test concentration onwards.[1]

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Order of addition of polysorbate 80 in oritavancin MIC test. [1]
To determine whether the order of addition of polysorbate 80 affected the oritavancin MICs, broth microdilution susceptibility tests were performed with S. aureus ATCC 29213 as an indicator strain, in which oritavancin was either dissolved in 0.002% polysorbate 80 and diluted and assayed by maintaining polysorbate 80 at 0.002% or dissolved and diluted in water and then assayed by adding inoculum with or without polysorbate 80. When polysorbate 80 was present, it was added at a final concentration of 0.002%, as described in the CLSI guidelines for dalbavancin.

In vitro pharmacodynamic model. [2] The in vitro pharmacodynamic model consists of a 250-ml one-compartment glass chamber with ports for the addition and removal of the THB with 0.5% yeast extract with or without albumin, injection of antibiotics, and removal of samples. Prior to each experiment, colonies from an overnight growth of bacteria on TSA plates with 5% SB were added to THB with 0.5% yeast extract to obtain a concentration of 106 CFU/ml. Fresh stock solutions of oritavancin and vancomycin were prepared daily and were stored at 2 to 8°C between dose administration times. Experimental regimens simulated antibiotic concentrations achieved in human plasma. Vancomycin was administered at a dose of 1 g every 12 h (four doses given) to achieve a peak concentration in serum (Cmax) of 30 μg/ml and a trough concentration of 7.5 μg/ml. To achieve targeted concentrations of oritavancin in plasma during the first 48 h of dosing in humans, oritavancin was administered at a loading dose of 5 mg/kg of body weight at 0 h, followed by 4 mg/kg at 24 h, to achieve a peak concentration of 100 μg/ml and 24-h trough concentration of 15 μg/ml. Each antibiotic was administered as a bolus into the models over 30 s using a hypodermic syringe. Fresh medium (SMHB) was continuously supplied and removed from the model along with the drug via a peristaltic pump set to simulate the half-lives (t1/2s) of vancomycin (6.5 h) and oritavancin (t1/2 at α phase [t1/2α] = 2 h); the pump ran in this manner for 8 h after dosing and then was changed to simulate a t1/2 of 12.3 h for the remaining 16 h of the 24 h dosing period. Each model apparatus was placed in a water bath and maintained at 37°C for the entire 48 h study period. The pharmacodynamic model experiments were performed in duplicate, simultaneously, in order to ensure reproducibility.

Absorption, Distribution and Excretion
Pharmacokinetic analysis of oritavancin revealed a Cmax of 138 and μg/mL and an AUC0-∞ of 2800 μg•h/mL. The AUC0-t in a study of healthy volunteers after an 800 mg dose 1,1111 μg•h/mL. was also be Another pharmacokinetic study reported a Cmax of 4.7-7.6 micrograms/mL, generally achieved within 24 hours of administration.
Oritavancin is excreted as unchanged drug in both the urine and feces. Less than 5% has been recovered in the urine, and 1% has been recovered in the feces.
The volume of distribution of oritavancin is estimated at 87.6 L, suggesting extensive tissue distribution.
The clearance of oritavancin is approximately 0.445 L/h. One study revealed a renal clearance of 0.457 mL/min.

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Metabolism / Metabolites
In vitro studies on human hepatocytes suggest that oritavancin is not metabolized, and is excreted unchanged.

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Biological Half-Life
The average terminal half-life of oritavancin is about 245 hours. A pharmacokinetic study revealed a terminal half-life ranging from 135.8-273.8 hours.

Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
Because oritavancin is poorly absorbed orally, it is not likely to reach the bloodstream of the infant or cause any adverse effects in breastfed infants. Monitor the infant for possible effects on the gastrointestinal tract, such as diarrhea, vomiting, and candidiasis (e.g., thrush, diaper rash). However, because there is no published experience with oritavancin during breastfeeding, an alternate drug may be preferred, especially while nursing a newborn or preterm infant.
◉ Effects in Breastfed Infants
Relevant published information was not found as of the revision date.
◉ Effects on Lactation and Breastmilk
Relevant published information was not found as of the revision date.

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Protein Binding
Oritavancin is about 85% bound to plasma proteins.

[1]. Effect of polysorbate 80 on oritavancin binding to plastic surfaces: implications for susceptibility testing. Antimicrob Agents Chemother. 2008 May;52(5):1597-1603. [2]. Activity of oritavancin (LY333328), an investigational glycopeptide, compared to that of vancomycin against multidrug-resistant Streptococcus pneumoniae in an in vitro pharmacodynamic model. Antimicrob Agents Chemother. 2001 Mar;45(3):706-9. [3]. Efficacy of oritavancin in a murine model of Bacillus anthracis spore inhalation anthrax. Antimicrob Agents Chemother. 2008 Sep;52(9):3350-7.
[4]. Oritavancin for the treatment of acute bacterial skin and skin structure infections: an evidence-based review. Core Evid. 2015 Feb 11;10:39-47.

Oritavancin is a semisynthetic glycopeptide used (as its bisphosphate salt) for the treatment of acute bacterial skin and skin structure infections caused or suspected to be caused by susceptible isolates of designated Gram-positive microorganisms including MRSA. It has a role as an antibacterial drug and an antimicrobial agent. It is a disaccharide derivative, a glycopeptide and a semisynthetic derivative. It is functionally related to a vancomycin aglycone.
Oritavancin is a glycopeptide antibiotic used for the treatment of skin infections. It was developed by The Medicines Company (acquired by Novartis). Oritavancin was initially approved by the FDA in 2014 and formulated to combat susceptible gram-positive bacteria that cause skin and skin structure infections. It boasts the option of single-dose administration and has been proven as non-inferior to a full course of [vancomycin] therapy. On March 12, 2021 the FDA approved Kimyrsa, a complete course of therapy in a single, 1 hour 1200 mg infusion. Orbactiv, the other FDA approved oritavancin product, is administered over a 3 hour infusion and contains a lower dose of 400 mg. Marketed by Melinta Therapeutics, Kimyrsa offers effective and time-efficient treatment for skin and skin structure infections.
Oritavancin is a Lipoglycopeptide Antibacterial. The mechanism of action of oritavancin is as a Cytochrome P450 2C19 Inhibitor, and Cytochrome P450 2C9 Inhibitor, and Cytochrome P450 3A4 Inducer, and Cytochrome P450 2D6 Inducer.
See also: Oritavancin Diphosphate (active moiety of).

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Drug Indication
Oritavancin is indicated for the treatment of adult patients with acute bacterial skin and skin structure (including subcutaneous) infection. It is used for confirmed/suspected infections with designated and susceptible gram-positive organisms. There are two preparations of oritavancin; the 400 mg dose that is administered over 3 hours, and the 1200 mg dose administered over 1 hour. Both are indicated for susceptible gram-positive skin and skin structure infections in adults. As antimicrobial susceptibility patterns are geographically distinct, local antibiograms should be consulted to ensure adequate coverage of relevant pathogens prior to use.
FDA Label
Tenkasi is indicated for the treatment of acute bacterial skin and skin structure infections (ABSSSI) in adults and paediatric patients aged 3 months and older (see sections 4. 2, 4. 4 and 5. 1). Consideration should be given to official guidance on the appropriate use of antibacterial agents.

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Mechanism of Action
The cell wall is vital for the survival and replication of bacteria, making it a primary target for antibiotic therapy. Oritavancin works against susceptible gram-positive organisms via three separate mechanisms. Firstly, it binds to the stem peptide of peptidoglycan precursors, inhibiting transglycosylation (polymerization). This process normally occurs during cell wall synthesis. Secondly, oritavancin inhibits crosslinking during bacterial cell wall biosynthesis via binding to cell wall pentaglycyl peptide bridging segments. Finally, this drug also acts by disrupting the bacterial cell membrane, interfering with its integrity, which eventually leads to cell death by various mechanisms.

C86H97N10O26CL3

1793.10078

1790.56

C, 57.61; H, 5.45; Cl, 5.93; N, 7.81; O, 23.20

171099-57-3

Oritavancin diphosphate;192564-14-0

16136912

Solid powder

8.57

20

29

19

125

3700

22

CC(C[C@H](C(N[C@H]1C(=O)N[C@@H](CC(=O)N)C(=O)N[C@H]2C(N[C@H]3C(=O)N[C@@H]([C@@H](C4C=CC(OC5C=C2C=C(C=5O[C@@H]2O[C@H](CO)[C@@H](O)[C@H](O)[C@H]2O[C@@H]2O[C@@H](C)[C@H](O)[C@@](C)(NCC5C=CC(C6C=CC(Cl)=CC=6)=CC=5)C2)OC2C=CC(=CC=2Cl)[C@H]1O)=C(Cl)C=4)O[C@@H]1O[C@@H](C)[C@H](O)[C@@](C)(N)C1)C(=O)N[C@H](C(=O)O)C1=CC(=CC(O)=C1C1=C(C=CC3=C1)O)O)=O)=O)NC)C

PWTROOMOPLCZHB-BHYQHFGMSA-N

InChI=1S/C86H97Cl3N10O26.2H3O4P/c1-35(2)22-51(92-7)77(110)98-67-69(105)42-15-20-55(49(88)24-42)120-57-26-44-27-58(73(57)125-84-74(71(107)70(106)59(34-100)122-84)124-62-32-86(6,76(109)37(4)119-62)93-33-38-8-10-39(11-9-38)40-12-17-45(87)18-13-40)121-56-21-16-43(25-50(56)89)72(123-61-31-85(5,91)75(108)36(3)118-61)68-82(115)97-66(83(116)117)48-28-46(101)29-54(103)63(48)47-23-41(14-19-53(47)102)64(79(112)99-68)96-80(113)65(44)95-78(111)52(30-60(90)104)94-81(67)1142*1-5(2,3)4/h8-21,23-29,35-37,51-52,59,61-62,64-72,74-76,84,92-93,100-103,105-109H,22,30-34,91H2,1-7H3,(H2,90,104)(H,94,114)(H,95,111)(H,96,113)(H,97,115)(H,98,110)(H,99,112)(H,116,117)2*(H3,1,2,3,4)/t36-,37-,51+,52-,59+,61-,62-,64+,65+,66-,67+,68-,69+,70+,71-,72+,74+,75-,76-,84-,85-,86-/m0../s1

(4R)-22-O-(3-Amino-2,3,6-trideoxy-3-C-methyl-α-L-arabinohexopyranosyl)-N3-(p-(p-chlorophenyl)benzyl)vancomycin diphosphate

Oritavancin Free Base; LY333328; LY 333328; 171099-57-3; LY333328; Chlorobiphenyl-chloroeremomycin; Oritavancin [INN]; LY-333328; UNII-PUG62FRZ2E; PUG62FRZ2E; LY-333328

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.)