A COMPARATIVE STUDY OF DRUG TRANSPORT BETWEEN THE HOMOGENEOUS AND VASCULATURE SOLID TUMOR

Nowadays, cancer is regarded as one of the main reasons for morbidity and mortality among people worldwide. One of the classic therapeutic regimens is chemotherapy, which is used with radiotherapy and sometimes before tumor surgery. In chemotherapy, drug agents are injected intravenously or locally into the body. The two main barriers in drug delivery to solid tumors are the high amount of interstitial fluid pressure in the tumor region and the heterogeneity of the tumor's microvasculatures which prevent the drug's macromolecules from reaching the tumor cells. To find a solution, a better understanding of these phenomena is needed. In order to find and prognosticate the tumor behavior, a mathematical model was developed to solve intravascular blood pressure, interstitial fluid pressure, and interstitial fluid velocity. The values were implemented in the drug transport equation, which is coupled with pharmacokinetics equations in both bolus and continuous infusion. Doxorubicin is used as a chemotherapy drug and functional for eliminating tumor cells. A numerical method is used to solve these equations in order to reach a reasonable solution for interstitial drug concentration. In this study, the tissue is assumed as a porous medium. Continuity equation, Darcy's law, Starling's equation, drug transport, and pharmacokinetic equations are employed in two different same-dimension geometries, one with explicit vasculature and the other with a homogeneous domain. A general semicircular model of the tumor with surrounding tissue and random microvessels is utilized. The results from the vasculature domain are compared with a simple geometry for both the continuous and the bolus injections. The interstitial fluid velocity is more significant than the interstitial fluid pressure because the rate of drug infusion in both bolus and continuous infusion is increased in vasculature geometry. Drug distribution is faced with the heterogeneity of microvasculature in the domain, so for a better drug infusion in the tumor, it needs a longer clinical time for drug infusion.