The blood-prostate barrier: an obstacle to drug delivery into the prostate

The blood-prostate barrier (BPB), a non-static physical barrier, stands as an obstacle between the prostate stroma and the lumen of the prostate gland tube. The barrier has the ability to dynamically regulate and strictly control the mass exchange between the blood and the prostate, thereby limiting drug penetration into the prostate. The basement membrane, fibrous stromal layer, capillary endothelial cell, prostatic ductal epithelial cell, lipid layer, etc., have been confirmed to be involved in the composition of the barrier structure and altered membrane permeability mainly by regulating the size of paracellular ion pores. Various studies have been conducted to improve the efficiency of drug therapy for prostate diseases by changing the administration approaches, improving barrier permeability and increasing drug penetration. To gain a full understanding of BPB, the composition of BPB, the methodology for evaluating the permeability of BPB and alterations in barrier function under pathological conditions are summarized in this review. To find a shortcut for drug delivery across BPB, the biodistribution of drugs in the prostate and different methods of improving drug penetration across BPB are outlined. This review offers an applied perspective on recent advances in drug delivery across BPB.