Department of Pharmacy, School of Chemical Sciences and Pharmacy , Central University of Rajasthan , Bandarsindri, Ajmer , Rajasthan 305817 , India.
Division of Cyclotron And Radiopharmaceutical sciences , Institute of Nuclear Medicine and Allied Sciences , New Delhi 110054 , India.
Mol Pharm. 2018 Jun 4;15(6):2084-2097. doi: 10.1021/acs.molpharmaceut.7b00625. Epub 2018 Apr 30.
Successful delivery of a chemotherapeutic agent like bendamustine still remains a challenge in clinical conditions like chronic lymphatic leukemia (CLL), non-Hodgkin lymphoma (NHL), and multiple myeloma. We have conjugated bendamustine to polyamidoamine (PAMAM) dendrimers after conjugating with N-(hydroxyethyl)maleimide (spacer) via an ester bond. The particle size of PAMAM-bendamustine conjugate was 49.8 ± 2.5 nm. In vitro drug release resulted in sustained release with improved solution stability of drug up to 72 h. In a 24 h cytotoxicity study by MTT assay against human monoblastic leukemia cells (THP-1), the IC50 value for PAMAM-bendamustine was 32.1 ± 4.8 μM compared to 50.42 ± 3.4 μM and 2303 ± 106.5 μM for bendamustine and PAMAM dendrimer, respectively. Significantly higher cell uptake and apoptosis were observed in THP-1 cells by PAMAM-bendamustine conjugate which was confirmed by flow cytometry and confocal laser scanning microscopy. Preliminary in vivo studies undertaken included pharmacokinetics studies, organ distribution studies, and tumor inhibition studies. In healthy Wistar rat model (1CBM IV push model), the pharmacokinetic studies revealed that bioavailability and t increased significantly, i.e., almost 8.5-fold (193.8 ± 1.116 vs 22.8 ± 0.158 μg mL/h) and 5.1-fold (0.75 ± 0.005 vs 3.85 ± 0.015 h), respectively, for PAMAM-bendamustine conjugate compared to pure bendamustine ( p < 0.05), however, clearance and volume of distribution were found to be decreased compared to those of free drug. The study suggests that PAMAM-bendamustine conjugate was not only stable for the longer period but also least toxic and highly taken up by THP-1 cells to exert an anticancer effect at the reduced dose. Tumor inhibition and biodistribution studies in tumor-bearing BALB/c mice revealed that PAMAM-bendamustine conjugate was more effective than the pure drug and showed higher accumulation in the tumor.
在慢性淋巴细胞白血病（CLL）、非霍奇金淋巴瘤（NHL）和多发性骨髓瘤等临床情况下，成功递送像苯达莫司汀这样的化疗药物仍然是一个挑战。我们通过酯键将苯达莫司汀与 N-（羟乙基）马来酰亚胺（间隔臂）缀合到聚酰胺胺（PAMAM）树状大分子上。PAMAM-苯达莫司汀缀合物的粒径为 49.8±2.5nm。体外药物释放结果表明，药物的释放具有持续性，药物的稳定性得到了改善，可达 72 小时。在针对人单核白血病细胞（THP-1）的 MTT 细胞毒性研究中，24 小时时，PAMAM-苯达莫司汀的 IC50 值为 32.1±4.8μM，而苯达莫司汀和 PAMAM 树状大分子的 IC50 值分别为 50.42±3.4μM 和 2303±106.5μM。通过流式细胞术和共聚焦激光扫描显微镜证实，THP-1 细胞中观察到 PAMAM-苯达莫司汀缀合物的细胞摄取和细胞凋亡显著增加。初步的体内研究包括药代动力学研究、器官分布研究和肿瘤抑制研究。在健康的 Wistar 大鼠模型（1CBM IV 推注模型）中，药代动力学研究表明，生物利用度和 t1/2 显著增加，即 PAMAM-苯达莫司汀缀合物的生物利用度和 t1/2 分别增加了近 8.5 倍（193.8±1.116 vs 22.8±0.158μg·mL-1·h-1）和 5.1 倍（0.75±0.005 vs 3.85±0.015h），而与游离药物相比，清除率和分布容积则有所降低。研究表明，PAMAM-苯达莫司汀缀合物不仅在较长时间内稳定，而且毒性最小，能够被 THP-1 细胞大量摄取，以较低剂量发挥抗癌作用。荷瘤 BALB/c 小鼠的肿瘤抑制和生物分布研究表明，PAMAM-苯达莫司汀缀合物比纯药物更有效，在肿瘤中积累更高。
