Polymyxin B

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Polymyxin B
Systematic (IUPAC) name
N-[4-amino-1-[[1-[[4-amino-1-oxo-1-[[6,9,18-tris(2-aminoethyl)-15-benzyl-3-(1-hydroxyethyl)- 12-(2-methylpropyl)-2,5,8,11,14,17,20-heptaoxo-1,4,7,10,13,16,19-heptazacyclotricos-21-yl]amino]butan-2-yl]amino]- 3-hydroxy-1-oxobutan-2-yl]amino]-1-oxobutan-2-yl]-6-methyloctanamide
Identifiers
CAS number	1405-20-5
ATC code	A07AA05 J01XB02, S01AA18, S02AA11, S03AA03
PubChem	5702105
DrugBank	APRD01190
Chemical data
Formula	C56H100N16O17S
Mol. mass	1301.56 g/mol
Pharmacokinetic data
Bioavailability	?
Metabolism	?
Half life	?
Excretion	?
Therapeutic considerations
Pregnancy cat.	?
Legal status
Routes	?

Polymyxin B is an antibiotic primarily used for resistant gram negative infections. Polymyxins bind to the cell membrane and alters its structure making it more permeable. The resulting water uptake leads to cell death. They are cationic, basic proteins that act like detergents. Side effects include neurotoxicity and acute renal tubular necrosis.

1. Family of polypeptides with attached fatty acid; cationic detergent at physiological pH, both hydrophilic and hydrophobic properties
2. Bactericidal for gram-negative; little to no effect on gram-positive since cell wall is too thick to permit access to membrane

[edit] Mechanism of action

1. Alters cytoplasmic membrane permeability by binding to a negatively charged site in the lipopolysaccharide layer which has an electrostatic attraction for the positively charged amino groups in the cyclic peptide portion
2. Fatty acid portion dissolves in hydrophobic region of membrane and disrupts membrane integrity
3. Leakage of cellular molecules, inhibition of cellular respiration
4. Binds and inactivates endotoxin
5. Relative absence of selective toxicity: nonspecific for cell membranes of any type, highly toxic

v • d • e Antidiarrheals, intestinal anti-inflammatory/anti-infective agents (A07) Intestinal anti-infectives Antibiotics (Neomycin, Nystatin, Natamycin, Streptomycin, Polymyxin B, Paromomycin, Amphotericin B, Kanamycin, Vancomycin, Colistin, Rifaximin) Sulfonamides (Phthalylsulfathiazole, Sulfaguanidine, Succinylsulfathiazole) other (Miconazole, Broxyquinoline, Acetarsol, Nifuroxazide, Nifurzide) Intestinal adsorbents Charcoal - Bismuth - Pectin - Kaolin - Crospovidone - Attapulgite - Diosmectite Antipropulsives Diphenoxylate - Opium - Loperamide - Difenoxin - Paregoric - Laudanum - Codeine - Morphine Intestinal anti-inflammatory agents corticosteroids acting locally (Prednisolone, Hydrocortisone, Prednisone, Betamethasone, Tixocortol, Budesonide, Beclometasone) antiallergic agents, excluding corticosteroids (Cromoglicic acid) aminosalicylic acid and similar agents (Sulfasalazine, Mesalazine, Olsalazine, Balsalazide) Antidiarrheal micro-organisms Saccharomyces boulardii Other antidiarrheals Albumin tannate - Ceratonia - Racecadotril

v • d • e Antibacterials for systemic use: others (J01X) Glycopeptide Vancomycin (Oritavancin, Telavancin) - Teicoplanin (Dalbavancin) Polymyxins Colistin - Polymyxin B Steroid antibacterials Fusidic acid Imidazole derivatives Metronidazole - Tinidazole - Ornidazole Nitrofuran derivatives Nitrofurantoin - Nifurtoinol Other -mycin (Fosfomycin, Spectinomycin, Daptomycin, Hitachimycin) Xibornol - Clofoctol - Methenamine - Iclaprim - Mandelic acid - Nitroxoline - Linezolid

v • d • e Otologicals (S02) Anti-infectives Chloramphenicol - Nitrofural - Boric acid - Aluminium acetotartrate - Clioquinol - Hydrogen peroxide - Neomycin - Tetracycline - Chlorhexidine - Acetic acid - Polymyxin B - Rifamycin - Miconazole - Gentamicin Corticosteroids Hydrocortisone - Prednisolone - Dexamethasone - Betamethasone Other otologicals Lidocaine - Cocaine