The pH value has an impact on the inhibitory action of framycetin (also known as neomycin B or fradiomycin B) on RNase P RNA, and an increase in pH will counteract the inhibitory effect of other systems [1]. Human and cellular ribosome translation is inhibited by framycetin. 5"-Its nitrogen-based Framycetin Fold B and Framycetin B selectively inhibit the production of mature miRNAs, enhance transcription factors, and inhibit the right side of HCC cell lines [2]. Framycetin has major homology with the structural motif sequence motif of RNA. The target is the 16S rRNA decoding site, but it also binds to the HIV-1 hammerhead ribozyme, the Rev response element, and group I intron, inhibiting their biological functions [3]. This process results in misreading the genetic code and inhibits various ribozymes. The ribosome target site is the 1400 to 1500 region of 16 S rRNA [4].

Metabolism / Metabolites
Neomycin undergoes minimal biotransformation after parenteral administration. Elimination Pathway: The small amount of absorbed drug is rapidly distributed in tissues and excreted via the kidneys, depending on renal function. Half-life: 2 to 3 hours

Toxicity Summary
Aminoglycoside antibiotics such as neomycin can bind "irreversibly" to specific 30S subunit proteins and 16S rRNA. Specifically, neomycin binds to four nucleotides of the 16S rRNA and one amino acid of the S12 protein. This interferes with the decoding site near nucleotide 1400 in the 30S subunit 16S rRNA. This region interacts with the wobble base in the tRNA anticodon. This leads to interference with the initiation complex, mRNA misreading, resulting in the insertion of incorrect amino acids into the polypeptide chain, leading to the production of nonfunctional or toxic peptides, and the breakdown of polyribosomes into nonfunctional monomeric ribosomes. Pregnancy and Lactation Effects ◉ Overview of Lactation Use While there is currently no information regarding the secretion of neomycin into breast milk, the amount of other aminoglycoside antibiotics secreted into breast milk is minimal. Newborns appear to absorb small amounts of aminoglycoside antibiotics, but their serum concentrations are far lower than those achieved when treating neonatal infections, making systemic effects of neomycin unlikely. Older infants are expected to absorb less neomycin. Closely monitor the infant's gut microbiota for potential effects such as diarrhea, candidiasis (e.g., thrush, diaper rash), or rare hematochezia, which may indicate antibiotic-associated colitis. Oral, topical, ophthalmic, or otopathic neomycin concentrations in breast milk should be extremely low, posing negligible risk to the infant; however, nipple application may increase the risk of diarrhea in the infant. Only water-soluble creams or gels should be applied to the breast, as ointments may expose the infant to high concentrations of mineral oil through licking. ◉ Effects on breastfed infants: No published information found as of the revision date. ◉ Effects on lactation and breast milk: No published information found as of the revision date.

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Toxicity Data
LD50: 200 mg/kg (rat) (A308)

[1]. Inhibition of RNase P RNA Cleavage by Aminoglycosides. Proc Natl Acad Sci U S A. 1999 May 25;96(11):6155-60.

[2]. Small Molecule Targeting of a MicroRNA Associated with Hepatocellular Carcinoma. ACS Chem Biol. 2016 Feb 19;11(2):375-80.

[3]. Monovalent ion dependence of neomycin B binding to an RNA aptamer characterized by spectroscopic methods. Chembiochem. 2007 Jul 9;8(10):1137-45.

[4]. Antibiotic inhibition of RNA catalysis: neomycin B binds to the catalytic core of the td group I intron displacing essential metal ions. J Mol Biol. 1998 Sep 25;282(3):557-69.

Framycetin is a tetracyclic antibacterial agent derived from neomycin, and is a glycoside ester of neomycin amine and neomycin B. It possesses multiple functions, including antibacterial activity, allergen status, and being a metabolite of E. coli. It is the conjugate base of Framycetin (6+). Neomycin is produced by Streptomyces fradiae. Hydrolysis yields neomycin amine and neomycin B. (From Merck Index, 11th edition) Neomycin has also been reported in soybean (Glycine max), Streptomyces albus, and other microorganisms with relevant data. Framycetin is an aminoglycoside antibiotic isolated from Streptomyces lavendulae (decaris), with neomycin B as its main component, exhibiting broad-spectrum antibacterial activity. Framycetin is primarily used as a topical preparation, with low absorption. Parenteral administration can cause nephrotoxicity and ototoxicity. Neomycin is a component of Streptomyces fradiae. Hydrolysis yields neomycin amine and neomycin B. (From Merck Index, 11th edition). Neomycin is a bactericidal aminoglycoside antibiotic that binds to the 30S ribosomes of susceptible bacteria. This binding interferes with both the mRNA binding site and the receptor tRNA site, resulting in the production of nonfunctional or toxic peptides. See also: Neomycin (note moved to) Neomycin sulfate (note moved to).

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Indications
For the treatment of bacterial blepharitis, bacterial conjunctivitis, corneal injury, corneal ulceration, and meibomianitis. For the prevention of ocular infection after foreign body removal. Mechanism of Action Flamexetine binds to specific 30S subunit proteins and 16S rRNA, binding four nucleotides of the 16S rRNA and one amino acid of the S12 protein. This interferes with the decoding site near nucleotide 1400 in the 30S subunit 16S rRNA. This region interacts with the wobble base in the tRNA anticodon. This leads to interference with the initiation complex, misreading of the mRNA, inserting incorrect amino acids into the polypeptide chain, producing nonfunctional or toxic peptides, and causing polyribosomes to break down into nonfunctional monomeric ribosomes. Pharmacodynamics Flamexetine is used to treat bacterial eye infections, such as conjunctivitis. Flamexetine is an antibiotic. It is ineffective against fungi, viruses, and most anaerobes. Flamexetine's mechanism of action is to bind to the bacterial 30S ribosomal subunit, causing tRNA misreading and preventing the bacteria from synthesizing proteins essential for their growth. Flamexetine is primarily used to treat aerobic bacterial infections.

C23H46N6O13

614.64374

614.312

119-04-0

Framycetin sulfate;4146-30-9;Neomycin sulfate;1405-10-3

8378

Colorless to light yellow liquid

1.61 g/cm3

927.1ºC at 760 mmHg

6 °C (sulfate form)

514.5ºC

1.6000 (estimate)

-9

13

19

9

42

872

19

C1[C@H]([C@@H]([C@H]([C@@H]([C@H]1N)O[C@@H]2[C@@H]([C@H]([C@@H]([C@H](O2)CN)O)O)N)O[C@H]3[C@@H]([C@@H]([C@H](O3)CO)O[C@@H]4[C@@H]([C@H]([C@@H]([C@@H](O4)CN)O)O)N)O)O)N

PGBHMTALBVVCIT-KNSIFCLBSA-N InChi Code

InChI=1S/C23H46N6O13/c24-2-7-13(32)15(34)10(28)21(37-7)40-18-6(27)1-5(26)12(31)20(18)42-23-17(36)19(9(4-30)39-23)41-22-11(29)16(35)14(33)8(3-25)38-22/h5-23,30-36H,1-4,24-29H2/t5-,6+,7-,8+,9-,10-,11-,12+,13-,14-,15-,16-,17-,18-,19-,20-,21-,22-,23+/m1/s1

(2S,3S,4R,5R,6R)-5-amino-2-(aminomethyl)-6-(((2R,3S,4R,5S)-5-(((1R,2R,3S,5R,6S)-3,5-diamino-2-(((2R,3R,4R,5R,6R)-3-amino-6-(aminomethyl)-4,5-dihydroxytetrahydro-2H-pyran-2-yl)oxy)-6-hydroxycyclohexyl)oxy)-4-hydroxy-2-(hydroxymethyl)tetrahydrofuran-3-yl)oxy)tetrahydro-2H-pyran-3,4-diol

Neomycin B Fradiomycin B Actilin Soframycin

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)

H2O : ~100 mg/mL (~162.70 mM)
DMSO : ~50 mg/mL (~81.35 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (4.07 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (4.07 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
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.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (4.07 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: 120 mg/mL (195.24 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication.

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