Purposes to estimate parameters for gadolium-diethylenetriaminepentaacetic acid (Gd-DTPA) diffusion and distribution after drug delivery in the rat brain extracellular space (ECS). Methods An isotropic diffusion pattern in the homogeneous media was presumed for Gd-DTPA diffusion in the rat brain ECS, and a mathematical model was established to describe the pharmacokinetics of Gd-DTPA. Results the analytical solution of the diffusion equation was obtained by Laplace transform, and the least square method was utilized to calculate the diffusion coefficient (D) and the clearance rate (k) of drugs in the sphere coordinates. Animal experimental data of Gd-DTPA-related intensity was acquired by magnetic resonance imaging (MRI). D and k were computed as 0.0129 mm2/h and 0.0957 /h, respectively. Conclusions By the proposed method, drug diffusion, distribution, and clearance in the rat brain can be quantitatively analyzed, which will enhance our understanding of drug delivery in the central nervous system.
Clinical Implications of Exosomes: Targeted Drug Delivery for Cancer Treatment