University of São Paulo: USP researchers study new nanoparticles to treat bacterial eye infections


Bacterial infections are a serious global health problem: they affect from life expectancy to food production, according to a report by the World Health Organization (WHO) . Thinking about more effective therapeutic solutions for bacterial eye infections, researchers from the Faculty of Pharmaceutical Sciences (FCF) at USP are developing studies with nanoparticles based on lipids (fats) loaded with antibiotics (LBNs). These tiny particles – smaller than 500 nanometers (the equivalent of 5 centimeters divided by 100,000) – are capable of carrying a drug through the body to the site of infection.

Currently, there are several types of nanoparticles widespread on the market, used in drugs with different routes of administration, such as oral and ophthalmic, to treat infectious, bacterial and cardiovascular diseases, chronic inflammation, neurological disorders and even cancer. The aim of the USP scientists is to improve the action of these drugs through the advantages provided by the use of LBNs, such as the faster absorption of the drug by the body, with the aim of treating eye infections caused by bacteria.

Researcher Mirla Bazan Henostroza, a doctoral student at the FCF Drugs and Medicines Program, explains to Jornal da USP that there are several types of nanoparticles: they can be dispersed in an organic aqueous medium (as in the case of lipid systems — LBNs — and polymers), inorganic (as in metallic nanoparticles) or hybrids.

Before starting her doctoral research, Mirla carried out a survey of studies published in the last six years that show the improvement of the antimicrobial activity of these nanocarriers in in vitro and in vivo tests. The objective was to understand the latest advances in the use of this technology before starting his thesis.

“The survey showed that nanostructured antibiotics in lipid systems were at least twice as effective when compared to free antibiotics,” says Mirla. “In the most surprising results, there was up to a 12-fold improvement in antimicrobial activity.”

The data were published in the article Antibiotic-loaded lipid-based nanocarrier: A promising strategy to overcome bacterial infection , available since April of this year in the international journal Journal of Pharmaceutics.

Among the advantages of LBNs, Mirla highlights the greater speed of absorption by the body, protection of the drug against chemical or enzymatic degradation, greater carrying capacity and less toxicity. According to the researcher, nanoparticles can be considered as a supplement to drugs that potentiate their effects and a promising alternative for the therapeutic use of antibiotics due to their superior characteristics compared to conventional treatments.

In addition to preventing or reducing toxicity related to most antibiotics available today, “nanocarriers contribute to increased solubility, which allows a greater amount of the drug to be available in therapeutic concentrations suitable to act against bacteria”, explains the researcher. . With the greater efficiency of these particles in transporting the medication, it is possible to reduce even the number of medication doses, which contributes to greater patient adherence to treatment.

Eye drops with lipid-based nanoparticles
In her master ‘s degree , the researcher studied a nanoemulsion containing rifampicin for the treatment of ocular tuberculosis. Currently, Mirla is developing her doctoral thesis at FCF, under the guidance of Professor Nádia Araci Bou Chacra. The studies are focused on the preparation and characterization of innovative nanocarriers for the treatment of ophthalmic (eye) infections through eye drops. The next steps of the thesis, which is due to be defended in mid-2023, aim to evaluate the antimicrobial efficacy of these antibiotic-containing lipid nanoparticles produced in the laboratory in in vitro and in vivo tests .

According to Mirla, the expectation is that, in the future, these products can be approved by regulatory agencies and reach the market for use by the population.

A strategy against superbugs
According to the World Health Organization (WHO), bacterial resistance has grown worldwide and has become an increasingly worrying global health problem. Overuse and erroneous prescription of drugs contribute to bacteria mutating and becoming more resistant to the action of these antibiotics, which makes infectious diseases such as pneumonia, tuberculosis and gonorrhea increasingly difficult to treat.

According to Mirla, the use of nanoparticles can help fight the creation of superbugs. “Nanocarriers represent one of the most viable strategies in the short and medium term for the control of bacterial resistance due to the complex mechanism of action of the antibiotic-nanoparticle junction, which can generate an increase in the effectiveness of currently existing antibiotics and which, in its free, would not be able to kill resistant bacteria”, he concludes.

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