Lipid-based Nanosized Delivery Systems for Fluoroquinolones: A Review

Background: The class of fluoroquinolone antibiotics, due to its core chemical modifications, is considered as wide-spectrum antibacterial drugs with useful pharmacokinetic and pharmacodynamic properties. However, because of their poor solubility in water, they are used as salts (lactates or hydrochlorides). Fluoroquinolones, bacterial membranes and eukaryotic cell membranes interactions are well known and their permeation properties are well investigated. In fact, they are concentrated inside the cells and intracellular compartments. Nanotechnology in Drug Delivery has developed many supra-molecular structures that have been used to improve both pharmacokinetic and pharmacodynamic properties. The main results of the published papers showed reduction of toxicity, higher intracellular concentrations (both bacteria and eukaryotic), enhancement of antimicrobial activity, prolonged drug release, decreased mortality in animal model studies, improved water solubility and improved in vitro efficacy against intracellular pathogens. Methods: a literature search was performed in the NCBI-PUBMED database, with no time range, using the keywords "solid lipid nanoparticles" and 'quinolones' or the name of single antibiotics. Results: the most important aspects of lipid-based nanocarrier technology used for fluoroquinolones have been highlighted, with a focus on the latest formulation developments that have led to significant improvements of pharmacokinetics and pharmacodynamics. Both technological and microbiological aspects of published papers have been discussed. Conclusion: the potentiality of using lipid nanoparticles to improve the efficacy and potency of quinolone antibiotics has been supported by recent scientific publications, although some criticism appeared due to the microbiological investigative methods used and because of lack of systematic evaluation about the influence of technological approaches to the in vitro and in vivo drug activity.