Document Abstract
Delivering drugs effectively to the brain remains a formidable challenge in modern medicine
due to the selective nature of the blood–brain barrier (BBB). Lipophilic nanoparticles, with
their strong affinity for lipid-rich membranes, have emerged as promising candidates to
enhance drug transport across this barrier. In this study, a theoretical model is developed to
describe the mechanisms of nanoparticle movement through the BBB using diffusion and
active transport concepts. The approach integrates Fick’s law of diffusion with the Stokes
Einstein relation to predict nanoparticle flux as a function of concentration gradients, particle
size, and medium viscosity. Analytical derivations and comparative analysis indicate that
increased lipophilicity enhances both permeability and residence time within the membrane,
but an optimal range is required to achieve balanced drug release. The insights derived from
this study may serve as a quantitative foundation for designing nanocarriers capable of
overcoming the BBB for neurological applications.