Kianinejad Nazanin, Kwon Young Min
Department of Pharmaceutical Sciences, College of Pharmacy, Health Professions Division, Nova Southeastern University, Fort Lauderdale, FL, USA.
Bioimpacts. 2023;13(1):1-3. doi: 10.34172/bi.2022.26321. Epub 2022 Dec 31.
The delivery of chemotherapies to brain tumors faces the difficult task of crossing the blood-brain barrier (BBB). The brain capillary endothelial cells (BCECs) along with other cell lines, such as astrocytes and pericytes, form the BBB. This highly selective semipermeable barrier separates the blood from the brain parenchyma. The BBB controls the movement of drug molecules in a selective manner and maintains central nervous system (CNS) homeostasis. Depending on the properties of drugs such as their hydrophilic-lipophilic balance (HLB), some can cross the BBB through passive diffusion. However, this approach alone has not led to successful drug developments due to low net diffusion rates and systemic toxicity. Although the use of nanomedicine has been proposed to overcome these drawbacks, many recent studies still rely on the so-called 'enhanced permeability and retention (EPR)' effect though there is a realization in the field of drug delivery that EPR effect may not be sufficient for successful drug delivery to brain tumors. Since, compared to many other solid tumors, brain tumors pose additional challenges such as more restrictive blood-tumor barrier as well as the well-developed lymphatic drainage, the selection of functional moieties on the nanocarriers under consideration must be carried out with care to propose better solutions to this challenge.
向脑肿瘤递送化疗药物面临着跨越血脑屏障（BBB）这一艰巨任务。脑毛细血管内皮细胞（BCEC）与其他细胞系，如星形胶质细胞和周细胞，共同构成了血脑屏障。这种高度选择性的半透性屏障将血液与脑实质分隔开来。血脑屏障以选择性方式控制药物分子的移动，并维持中枢神经系统（CNS）的稳态。根据药物的性质，如它们的亲水-亲脂平衡（HLB），一些药物可以通过被动扩散穿过血脑屏障。然而，由于净扩散速率低和全身毒性，仅靠这种方法尚未成功开发出药物。尽管有人提出使用纳米药物来克服这些缺点，但最近许多研究仍然依赖所谓的“增强渗透与滞留（EPR）”效应，尽管药物递送领域已经认识到EPR效应可能不足以成功地将药物递送至脑肿瘤。由于与许多其他实体瘤相比，脑肿瘤带来了额外的挑战，如血瘤屏障更具限制性以及淋巴引流发达，因此在考虑纳米载体上功能部分的选择时必须谨慎，以便为这一挑战提出更好的解决方案。
