Reducing Antibiotic Side Effects with the Help of Chromatography

Antibiotics were a significant development in the history of medicine. Before antibiotics diseases like tuberculosis killed thousands – a bacterial infection easily spread by coughing and sneezing whose treatment was fresh air and confinement to a sanitorium far from everyone else. Before antibiotics even a paper cut could kill if it got infected. But that’s not to say we’re safe forever as indiscriminate and excessive antibiotic use leads to ever more powerful germs that we cannot fight.

And antibiotics can also cause harm as they help to cure us. Like many drugs we use, they can have side effects. But researchers are seeking ways to reduce the side effects while leaving the potency of antibiotics against bacterial infections intact. Researchers at Stanford University School of Medicine have investigated how reformulating an antibiotic known as gentamicin could reduce the harm it causes to patients hearing, and chromatography helped to play a role.

Gentamicin – potent at saving lives

Gentamicin is widely used to treat a variety of bacterial infections. Eye infections, diabetic foot infections and infections in patients with cystic fibrosis are among the bacterial infections that a doctor might prescribe gentamicin as a treatment. It is also a popular drug in developing countries as it is a very effective drug that is inexpensive to buy and is simple to transport and store as it doesn’t need any refrigeration. But like many drugs there are potential side effects to its use.

Researchers estimate that up to 20% of patients treated using gentamicin experience some degree of hearing loss, in some cases it can cause deafness – the drug has some ototoxic properties. Now the researchers have used chromatography to reformulate gentamicin to make it safer to use for patients. Research published in the paper Dissociating antibacterial from ototoxic effects of gentamicin C-subtypes in the Proceedings of the National Academy of Sciences of the United States of America.

Subtypes as good as whole

The researchers from Stanford University have found a simple way to reformulate gentamicin that reduces the risk of patients suffering from any hearing loss. Gentamicin is a mixture of five different subtypes of the antibiotic that are all grown together. The resultant medicine also contains impurities. The team used high-performance liquid chromatography to separate the subtypes and then tested the isolated types on ear tissue from rats. The separation of biological samples is discussed in the article, µ-Pillar Array Column – an Innovative Approach for the Separation and Characterisation of Complex Biological Samples.

The researchers identified the most and least toxic subtypes and showed that the sub types were as effective as standard gentamicin. In a press release, Anthony Ricci one of the authors stated, “This discovery lays the groundwork for the discovery of safer antibiotic alternatives and future drug development."