Hexadimethrine bromide (commercial brand name Polybrene) is a
cationic
An ion () is an atom or molecule with a net electrical charge.
The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...
polymer
A polymer (; Greek '' poly-'', "many" + ''-mer'', "part")
is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic a ...
with several uses. Currently, it is primarily used to increase the efficiency of
transduction of certain cells with
retrovirus in
cell culture. Hexadimethrine bromide acts by neutralizing the charge repulsion between
virion
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea.
Since Dmitri Ivanovsky's ...
s and
sialic acid on the
cell surface. Use of Polybrene can improve transduction efficiency 100-1000 fold
although it can be toxic to some cell types. Polybrene in combination with DMSO shock is used to transfect some cell types such as NIH-3T3 and CHO.
It has other uses, including a role in
protein sequencing
Protein sequencing is the practical process of determining the amino acid sequence of all or part of a protein or peptide. This may serve to identify the protein or characterize its post-translational modifications. Typically, partial sequencing o ...
.
Hexadimethrine bromide also reverses heparin anticoagulation during
open-heart surgery, and it was the original reversal agents used in the 1950s and 1960s.
It was replaced by
protamine sulfate in 1969, after it was shown that hexadimethrine bromide could potentially cause
kidney failure
Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney failure is classified as eit ...
in dogs when used in doses in excess of its therapeutic range.
It is still used as an alternative to protamine sulfate for patients who are sensitive to protamine, and at least one surgical center has gone back to using it as their standard reversal agent, since protamine sulfate causes at least a mild hypotensive reaction in most or all patients
Hexadimethrine bromide is also used in enzyme kinetic assays in order to reduce spontaneous activation of zymogens that are prone to auto activation.
References
Organic polymers
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