Chapter 2 - Nanoantimicrobials: Activity, Benefits, and Weaknesses
Abstract
Bacterial, mycobacterial, and fungal infections represent an increasing worldwide threat. The increase in the number of infections is caused by general immunosuppression (primarily by tumor treatment and administration of immunosuppressive agents), an increase in the number of HIV-positive patients, and development of resistance not only to commonly used drugs, but also to second- or third-choice drugs. The development of cross-resistant or multidrug-resistant strains constitutes a serious problem as well. This situation can be solved by the discovery of new molecular scaffolds, reengineering/repositioning of some old drug classes, or application of nanotechnology, which may reduce the costs of design and discovery processes. Antimicrobial chemotherapeutics encapsulated in nanoformulations created from biodegradable polymers have great potential to replace the bulk form of these chemotherapeutics. Controlled-release and targeted-delivery nanoformulations protect chemotherapeutics against decomposition or deactivation, enhance bioavailability, decrease toxicity for nontarget tissues, and decrease the “pill burden.” In many cases, nanoencapsulated drugs have restored antibacterial activity against resistant strains. This contribution is focused on methods of incorporation of active ingredients into different types of nanocarriers for targeted biodistribution/controlled release and on the antimicrobial effectiveness of these formulations. In addition, weaknesses in the application of nanoantimicrobials in clinical practice and potential health risks related to the application of nanoformulations are discussed.
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