The present investigation is dealt with the effect of interstrut distance on the transport and retention of drug eluted from a well-apposed drug-eluting stent (DES). We consider a two-species model (free and bound), capable of predicting the delivery of drug and its retention in the arterial tissue, in which the specific binding site action is modelled using a reversible chemical reaction. The model also takes into account a time-dependent release kinetics of DES. An axi-symmetric model of drug delivery from a pair of stent struts has been developed in cylindrical polar coordinate system where the transport of free drug is modelled as an unsteady convection–diffusion-reaction process, while the bound drug as an unsteady reaction-diffusion process. An explicit finite-difference scheme has been used to tackle numerically the governing equations of motion together with the physiologically realistic boundary conditions. The effects of quantities of significance such as Peclet number (Pe), equilibrium coefficient (\(K_{eq}\)) and interstrut distance on the transport of free as well as bound drugs are quantitatively investigated graphically. The present results predict a single peak profile of drug concentration when the pair of struts are placed one strut-width apart and also as the interstrut distance increases, discrete peaks form over each strut which is consistent with several existing results in the literature.