the blood-brain barrier (BBB) serves to protect and regulate the cnS microenvironment. the development of an in-vitro mimic of the BBB requires recapitulating the correct phenotype of the invivo BBB, particularly for drug permeation studies. However the majority of widely used BBB models demonstrate low transendothelial electrical resistance (TEER) and poor BBB phenotype. The application of shear stress is known to enhance tight junction formation and hence improve the barrier function. We utilised a high teeR primary porcine brain microvascular endothelial cell (pBMec) culture to assess the impact of shear stress on barrier formation using the Kirkstall QuasiVivo 600 (QV600) multi-chamber perfusion system. the application of shear stress resulted in a reorientation and enhancement of tight junction formation on both coverslip and permeable inserts, in addition to enhancing and maintaining TEER for longer, when compared to static conditions. Furthermore, the functional consequences of this was demonstrated with the reduction in flux of mitoxantrone across PBMEC monolayers. The QV600 perfusion system may service as a viable tool to enhance and maintain the high teeR pBMec system for use in in-vitro BBB models. The blood-brain barrier (BBB) represents an insidious barrier for the delivery of therapeutic agents for a wide range of central nervous system (CNS) disorders. Penetration of the restrictive brain microvascular endothelial cell barrier is often hindered by the presence of a network of intra-cellular tight junction proteins, in addition to a network of membrane localised active transporter proteins and enzymatic metabolism processes. The development and maintenance of an appropriate restrictive in-vitro BBB model is critical when assessing the potential for small molecule transport. Despite the rise in the use of in-vivo models for assessing BBB structure and function, in-vitro models are still widely used and have been developed from a range of species. However, a consensus on the most appropriate cellular system has still not been achieved, particularly in the context of assessing drug permeation and inherent barrier properties. For example, the human immortalised hCMEC/D3 cell, when grown in co-culture with astrocytes, yields low TEER values of approximately 140 Ω.cm 2 1 , and those from primary endothelial cells from rodents yield TEER values of approximately 300 Ω.cm 2 2. Higher TEER values have been obtained with stem cell based systems (iPSC-derived endothelial cells) and neuronal progenitor cells, when exposed to chemical treatment, resulting in values of 3000-4000 Ω.cm 2 3 to promote BBB formation, although these often require specialised and costly methods to culture. Although human brain tissue derived in-vitro BBB models are idealised for BBB studies, the lack of appropriate monolayer formation and reproductively, in-vitro, has led to other cellular models being attractive options. The use of a porcine primary cell culture system (PBMEC) reporting high TEER without the need for co-culture with as...