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 negligible biotransformation after parenteral administration.
Route of Elimination: The small absorbed fraction is rapidly distributed in the tissues and is excreted by the kidney in keeping with the degree of kidney function.
Half Life: 2 to 3 hours

Toxicity Summary
Aminoglycosides like neomycin "irreversibly" bind to specific 30S-subunit proteins and 16S rRNA. Specifically neomycin binds to four nucleotides of 16S rRNA and a single amino acid of protein S12. This interferes with decoding site in the vicinity of nucleotide 1400 in 16S rRNA of 30S subunit. This region interacts with the wobble base in the anticodon of tRNA. This leads to interference with the initiation complex, misreading of mRNA so incorrect amino acids are inserted into the polypeptide leading to nonfunctional or toxic peptides and the breakup of polysomes into nonfunctional monosomes.

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Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
Although no information exists on the excretion of neomycin into milk, other aminoglycoside antibiotics are poorly excreted into breastmilk. Newborn infants apparently absorb small amounts of aminoglycosides, but serum levels are far below those attained when treating newborn infections and systemic effects of neomycin are unlikely. Older infants would be expected to absorb even less neomycin. Monitor the infant for possible effects on the gastrointestinal flora, such as diarrhea, candidiasis (e.g., thrush, diaper rash) or rarely, blood in the stool indicating possible antibiotic-associated colitis.
Oral, topical, ophthalmic or otic neomycin should result in very low levels in breastmilk and present negligible risk to the infant, although topical application to the nipple may increase the risk of diarrhea in the infant. Only water-miscible cream or gel products should be applied to the breast because ointments may expose the infant to high levels of mineral paraffins via licking.
◉ 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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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, being a glycoside ester of neamine and neobiosamine B. It has a role as an antibacterial drug, an allergen and an Escherichia coli metabolite. It is a conjugate base of a framycetin(6+).
A component of neomycin that is produced by Streptomyces fradiae. On hydrolysis it yields neamine and neobiosamine B. (From Merck Index, 11th ed)
Neomycin has been reported in Glycine max, Streptomyces albus, and other organisms with data available.
Framycetin is an aminoglycoside antibiotic isolated from Streptomyces lavendulae (decaris), mainly containing neomycin B, with broad-spectrum antibacterial activity. Framycetin is used mostly as a topical preparation and is poorly absorbed. Upon parenteral administration, this agent can cause nephrotoxicity and ototoxicity.
A component of neomycin that is produced by Streptomyces fradiae. On hydrolysis it yields neamine and neobiosamine B. (From Merck Index, 11th ed). Neomycin is a bactericidal aminoglycoside antibiotic that binds to the 30S ribosome of susceptible organisms. Binding interferes with mRNA binding and acceptor tRNA sites and results in the production of non-functional or toxic peptides.
A component of NEOMYCIN that is produced by Streptomyces fradiae. On hydrolysis it yields neamine and neobiosamine B. (From Merck Index, 11th ed)
See also: Neomycin (annotation moved to); Neomycin Sulfate (annotation moved to).

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Drug Indication
For the treatment of bacterial blepharitis, bacterial bonjunctivitis, corneal injuries, corneal ulcers and meibomianitis. For the prophylaxis of ocular infections following foreign body removal

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Mechanism of Action
Framycetin binds to specific 30S-subunit proteins and 16S rRNA, four nucleotides of 16S rRNA and a single amino acid of protein S12. This interferes with decoding site in the vicinity of nucleotide 1400 in 16S rRNA of 30S subunit. This region interacts with the wobble base in the anticodon of tRNA. This leads to interference with the initiation complex, misreading of mRNA so incorrect amino acids are inserted into the polypeptide leading to nonfunctional or toxic peptides and the breakup of polysomes into nonfunctional monosomes.

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Pharmacodynamics
Framycetin is used for the treatment of bacterial eye infections such as conjunctivitis. Framycetin is an antibiotic. It is not active against fungi, viruses and most kinds of anaerobic bacteria. Framycetin works by binding to the bacterial 30S ribosomal subunit, causing misreading of t-RNA, leaving the bacterium unable to synthesize proteins vital to its growth. Framycetin is useful primarily in infections involving aerobic bacteria bacteria.

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.)