Novel PEG-grafted nanostructured lipid carrier for systematic delivery of a poorly soluble anti-leukemia agent Tamibarotene: characterization and evaluation

Abstract

Tamibarotene (Am80), a poorly water-soluble drug for the treatment of acute promyelocytic leukemia (APL), loaded nanostructured lipid carrier (Am80-NLC) was developed and characterized previously. The purpose of the present work was to develop PEGylated nanostructured lipid carrier (PEG-NLC) for intravenous delivery of Am80, with the aim to further extend the circulation in blood and decrease the adverse events. Am80-loaded PEG-NLC (Am80-PEG-NLC) modified with PEG-40 stearate (PEG40-SA, molecular weight 2000?Da) was formulated by the method of melt-emulsification and low temperature-solidification technique. Am80-NLC was developed as well as control. Based on the optimized results of single-factor screening experiment, the average drug entrapment efficiency, the mean particle size, and zeta potential of Am80-NLC and Am80-PEG-NLC were found to be 89.8–94.3%, 178.9–201.6?nm, and ?37.74 to ?20.1?mV, respectively. In vitro drug release of Am80-NLC and Am80-PEG-NLC possessed a sustained release characteristic and their release behavior was in accordance with the Ritger–Peppas equation. In vivo, after intravenous (i.v.) injection to rats, the mean residence time (MRT) of Am80-PEG-NLC group was significantly prolonged and the AUC value was improved as well compared with the Am80-NLC group. Furthermore, the biodistribution in mice showed that Am80-PEG-NLC preferentially decreased the accumulation of Am80 in kidney and increased the drug concentration in brain after i.v. injection. In conclusion, Am80-PEG-NLC may be a potential delivery system for Am80 in the treatment of APL.     

Tamibarotene Improves Hippocampus Injury Induced by Focal Cerebral Ischemia-Reperfusion via Modulating PI3K/Akt Pathway in Rats

Goal: The present study aimed to examine whether Am80 (tamibarotene) protects the hippocampus against cerebral ischemia-reperfusion (I/R) injury and whether phosphoinositide-3-kinase/Akt (PI3K/Akt) pathway mediates this effect. Materials and methods: Rats were subjected to 90 minutes of middle cerebral artery occlusion followed by 24 hours of reperfusion. The animals were randomly divided into 7 groups: sham-operated group; I/R group; groups pretreated with 2 mg/kg, 6 mg/kg, and 10 mg/kg of Am80; Am80 (6 mg/kg) combined with the selective PI3K inhibitor wortmannin (0.6 mg/kg), and wortmannin (0.6 mg/kg) only group. After 24 hours of reperfusion, neurological deficits and infarct volume were measured. Pathological changes in hippocampal neurons were analyzed by transmission electron microscopy. Neuronal survival was examined by TUNEL staining. The expression of Bcl-2, Bax, and Akt, and Akt phosphorylation (p-Akt) were measured by Western blotting and quantitative real-time polymerase chain reaction. Findings: The pretreatment with Am80 improved the neurologic deficit score, reduced infarct volume, and decreased the number of TUNEL-positive cells in the hippocampus. Moreover, Am80 pretreatment downregulated the expression of Bax, upregulated the expression of Bcl-2, and increased the level of p-Akt. Wortmannin abolished in part the increase in p-Act and the neuroprotective effect exerted on the ischemic by Am80 pretreatment. Conclusions: Our results documented that Am80 pretreatment protects ischemic hippocampus after cerebral I/R by regulating the expression of apoptosis-related proteins through the activation of the PI3K/Akt signaling pathway.     

Preparation and Antitumor Activity of a Tamibarotene-Furoxan Derivative

Multi-target drug design, in which drugs are designed as single molecules to simultaneously modulate multiple physiological targets, is an important strategy in the field of drug discovery. QT-011, a tamibarotene-furoxan derivative, was here prepared and proposed to exert synergistic effects on antileukemia by releasing nitric oxide and tamibarotene. Compared with tamibarotene itself, QT-011 displayed stronger antiproliferative effects on U937 and HL-60 cells and was more effective evaluated in a nude mice U937 xenograft model in vivo. In addition, QT-011 could release nitric oxide which might contribute to the antiproliferative ctivity. Autodocking assays showed that QT-011 fits well with the hydrophobic pocket of retinoic acid receptors. Taken together, these results suggest that QT-011 might be a highly effective derivative of tamibarotene and a potential candidate compound as antileukemia agent.     

他米巴罗汀药理学研究进展

本文对他米巴罗汀的药理学进行综述。他米巴罗汀是一个新的维甲酸受体α（RARα）促进剂，在体外可诱导急性早幼粒细胞性白血病基因（PML）分化和成熟，抑制PML增殖。在临床试验中，他米巴罗汀显示了明显的抗肿瘤活性和较好的耐受性。     

他米巴罗汀对牙龈卟啉单胞菌抗原刺激RAW264.7细胞的影响

目的 探讨他米巴罗汀（Tamibarotene,Am80）对经牙龈卟啉单胞菌（Porphyromonas gingivalis,P.gingivalis）抗原刺激后的小鼠单核巨噬细胞RAW264.7的影响。方法 采用P.gingivalis抗原刺激RAW264.7细胞,分别用不同浓度的Am80进行干预;相差显微镜下观察各组细胞生长情况;MTS法检测不同浓度Am80对抗原刺激RAW264.7细胞的增殖情况;酶联免疫吸附法（ELISA）检测细胞培养上清中抗炎因子IL-10的含量。结果 10 nmol/L Am80能够显著抑制P.gingivalis抗原刺激RAW264.7细胞的增殖分化（P<0.001）;Am80（10 nmol/L）致抗原刺激的细胞IL-10的分泌量显著增加（P<0.05）;倒置相差显微镜下观察显示Am80抑制抗原刺激细胞的增殖分化。结论 Am80（10 nmol/L）时可显著促进P.gingivalis抗原诱导小鼠巨噬细胞分泌抗炎因子IL-10,并可能由此抑制P.gingivalis抗原诱导的炎症反应。     

他米巴罗汀原料药的稳定性考察

目的考察他米巴罗汀原料药的稳定性。方法依据2010年版《中国药典（二部）》附录“原料药与药物制剂稳定性试验指导原则”的有关技术要求,进行稳定性试验,包括影响因素试验、加速试验、长期试验。结果两年考察结果显示,3批样品的熔点、含量、有关物质均无显著变化,外观上稍有吸湿性。结论他米巴罗汀原料药应密闭于阴凉干燥处贮藏,有效期暂定两年。