Five decades of doxycycline: Does nanotechnology improve its properties?

Doxycycline (DX) is a well-established antimicrobial drug that has been used since 1967 to treat several diseases. This drug has a wide therapeutic range, acting as antibacterial, antiviral, antiparasitic, and anticancer agent, including its neuroprotective, anti-inflammatory, and wound healing effects. However, DX is unstable in the physiological environment, presenting poor cellular penetration and adverse effects related to gastrointestinal irritation. As for practically all antibiotics, bacteria can develop resistance to this drug. Pharmaceutical nanotechnology proved to be a promising strategy to overcome these drawbacks. Thus, this review addresses scientific studies regarding formulations of DX-loaded nanoparticles (DX-NPs) for therapy use. Formulations with different materials, manufacturing methods, and biomedical applications are described and discussed to understand NPs contribution for in vitro and in vivo DX performance.