Biopolymer-hydrophobic drug fibers and the delivery mechanisms for sustained release applications

Forthcoming drug delivery devices are systems designed to have delivery profiles significantly changed by an external stimuli or conditions. The translation of stimuli-responsive drug-delivery systems from the lab to the bedside is not straightforward, mainly by their usually sophisticated designs. Herein, we propose and detail a simple drug delivery design approach, exploiting the water uptake and diffusion phenomena in fibers containing hydrophilic antibacterial agents, to achieve a sustained and complete release. The manufactured delivery systems were evaluated assessing both, antibiofilm potential and delivery mechanisms. Our analysis, let us to distinctly separate the release profiles in two regions, each one dominated by a different mechanism. Within the first period of delivery, the release is dominated by a limited diffusion mechanism that cannot be described by a Fickian model, only after the ratio of mass delivered reach about 70%, the release behavior change and diffusion becomes the dominant mechanism. For the last range, the diffusion coefficients have been estimated, showing independency from initial concentrations. The switch and the mechanisms dominance are explained through a fiber mesh-like behavior activated by the water-uptake.