Convection-enhanced delivery for brain malignancies: Technical parameters, formulation strategies and clinical perspectives

The blood-brain barrier's protective nature greatly restricts the entrance of active pharmaceutical ingredients (APIs), presenting a significant challenge for effective drug delivery into the brain. Convection-enhanced delivery (CED) is emerging as a promising strategy to overcome this barrier by enabling the direct infusion of APIs at therapeutic concentrations into brain tissue, thereby expanding potential treatment options for brain tumours and neurological conditions. This review provides a current and comprehensive update on the field of CED, highlighting recent advances and ongoing challenges. In addition, various formulation strategies, including nanoparticles, cyclodextrins, and hydrogels, are considered, with an emphasis on identifying optimal formulation properties required to enhance CED administration. With insights from clinical trials, device engineering and pharmaceutical perspectives, this review highlights the critical factors that influence the success of CED and outlines future directions for its effective clinical translation.