Antibacterial Activity of Polymyxins Encapsulated in Nanocarriers Against Gram-Negative Bacteria

Bacterial infections have become a global public health problem in recent decades, mainly due to infections caused by Gram-negative bacteria with antibiotic resistance profiles, which were responsible for over 3 million deaths in 2019. Polymyxin B (PMB) and polymyxin E (PME or colistin) are cyclic cationic polypeptide antimicrobials that have re-emerged in clinical practice due to the high rates of morbidity and mortality in infections caused by Gram-negative multidrug-resistant or extensively drug-resistant. Although polymyxins have antibacterial potential, they still have low stability and adverse effects, thus limiting their administration. To overcome these limitations, the use of controlled release systems such as liposomes, nanoparticles, and nanotubes is a viable strategy. Therefore, the objective of this review article is to present recent studies that address the antibacterial activity of PMB and PME encapsulated in nanocarriers against Gram-negative bacteria and to highlight the advantages of these nanocarriers and how they can overcome polymyxin limitations and bacterial resistance to polymyxin, as well as increasing drugs efficacy and safety. The preparation of this narrative review was based on the following steps: identification of the theme, establishment of inclusion and exclusion criteria, analysis and selection of articles, interpretation of data and results, and the writing of this article. Nanoparticles, electrostatic nanocomplexes, nanostructured lipid carriers, liposomes, and halloysite nanotubes can enhance bacterial activity from both PMB and PME, reducing minimum inhibitory concentration, inhibiting and eradicating biofilm, as well as prolonging polymyxins activity, reducing toxicity, and improving bioavailability. The strategy of encapsulation of polymyxin in nanocarriers has demonstrated a significant enhancement in polymyxin activity and pharmacokinetics, resulting in elevated therapeutic efficacy. Therefore, nanocarriers containing polymyxin emerge as a promising and innovative strategy to address this global challenge in public health.