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PEPT1-mediated prodrug strategy for oral delivery of peramivir 被引量:5
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作者 Yongbing Sun Wei Gan +7 位作者 Mingdao Lei Wei Jiang Meng Cheng junwei he Qi Sun Wan Liu Lvjiang Hu Yi Jin 《Asian Journal of Pharmaceutical Sciences》 SCIE CAS 2018年第6期555-565,共11页
Peramivir was a novel and highly potent neuraminidase(NA) inhibitor for the treatment of influenza A and B. However, it exhibited a very low oral bioavailability(only 3%) due to the high polarity(log P of-1.4) and the... Peramivir was a novel and highly potent neuraminidase(NA) inhibitor for the treatment of influenza A and B. However, it exhibited a very low oral bioavailability(only 3%) due to the high polarity(log P of-1.4) and the low membrane permeability across the intestine. To utilize the PEPT1-mediated prodrug strategy to improve the oral absorption and develop the oral alternative, seven amino acid ester prodrugs and seven amino acid amide prodrugs have been synthesized. The permeability of these prodrugs across Caco-2 cells were screened. Peramivr-(CH_2)_2-l-Val and Peramivir-l-Ile were of the highest permeability in ester prodrugs and amide prodrugs, respectively, and then they were selected for further studies. Glycylsarcosine(gly-sar) uptake by Caco-2 could be inbihited by Peramivir-(CH_2)_2-l-Val and Peramivir-l-Ile in a concentration-dependent manner, and the IC 50 was 1.34 ± 0.31 m M and 1.78 ± 0.48 m M, respectively. The direct uptake of Peramivir-(CH_2)_2-l-Val and Peramivirl-Ile in MDCK-PEPT1 cells were significantly higher than in MDCK mock cells, and could be markedly inhibited by gly-sar. The uptake of Peramivir-(CH_2)_2-l-Val and Peramivir-l-Ile(0.01 to 50 m M) in MDCK-hPEPT1 cells conformed to Michaelis–Menten Equation. The oral bioavailability of peramivir was 65.3% and 37.3% after the oral administration of Peramivir-(CH_2)_2-l-Val and Peramivir-l-Ile to rats, respectively. The oral absorption and bioactivation of Peramivir-(CH_2)_2-l-Val was rapid and extensive, and no Peramivir-(CH_2)_2-l-Val was found in plasma. Because the amide bond was relatively stable, Peramivir-l-Ile could not be totally converted to the parent drug in vivo. Peramivir-(CH_2)_2-l-Val with good oral profiles and rapid bioactivation might be a promising prodrug for the further clinic development. The present study also corroborated the idea that the PEPT1-mediated prodrug approach has enormous promise for improving the oral absorption of poorly absorbed drug. 展开更多
关键词 PERAMIVIR PRODRUG Peptide TRANSPORTER 1 PHARMACOKINETICS ORAL BIOAVAILABILITY
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轧制温度对耐候热轧H型钢力学性能的影响 被引量:1
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作者 夏勐 陈辉 +4 位作者 汪杰 彭林 何军委 邢军 彦井成 《钢结构(中英文)》 2021年第3期46-51,共6页
根据热轧H型钢翼缘厚度方向变形集中在万能轧制阶段的特点,将万能阶段开轧温度设定在800~1000℃,其余主要工艺参数不变。通过对热轧H型钢进行力学性能检验及显微组织对比分析,发现铁素体晶粒尺寸及外形对产品力学性能有至关重要的影响,... 根据热轧H型钢翼缘厚度方向变形集中在万能轧制阶段的特点,将万能阶段开轧温度设定在800~1000℃,其余主要工艺参数不变。通过对热轧H型钢进行力学性能检验及显微组织对比分析,发现铁素体晶粒尺寸及外形对产品力学性能有至关重要的影响,而万能阶段开轧温度对铁素体晶粒尺寸及外形存在显著影响。当开轧温度在1000~950℃时,虽然能够实现奥氏体动态再结晶,但在轧后分别从900和850℃空冷时,再结晶晶粒长大迅速,也易出现反常长大。当开轧温度为1000℃时,铁素晶粒尺寸不一,存在明显的混晶,当温度降低至950℃时,虽然混晶情况有所改善,但依然无法消除。在温度降低至900℃时,不仅能够完成奥氏体动态再结晶,而且轧后空冷起始温度降低至800℃,再结晶晶粒长大被抑制,形成了细小且均匀的初始奥氏体组织,此时的铁素体晶粒为10~30μm的等轴状。当温度进一步降低至850~800℃时,因无法达到促进奥氏体动态再结晶的热激活能需求,仅在未再结晶区进行了变形,最终形成扁平状铁素体晶粒,长轴与短轴尺寸比例接近2∶1,长轴尺寸减小不明显,短轴尺寸进一步减小。正因为如此,随着开轧温度从1000℃降低至900℃,铁素体晶粒尺寸减小,从而增加了晶界面积,降低了应力集中程度,增大了瞬时变形的均匀分配能力,使得产品屈服强度从369 MPa升高至415 MPa,抗拉强度从508 MPa升高至546 MPa,断后伸长率从30.0%升高至31.5%,低温冲击功均值从36 J提升至99 J;当温度降低至850~800℃时,扁平状铁素体晶粒进一步增大了晶界面积,使得产品屈服强度和抗拉强度分布进一步升高至468 MPa和567 MPa,但由于长、短轴差距增大,导致塑性变形时需要协调转动而产生畸变能,断后伸长率降低至27.5%,低温冲击功均值提升至109 J,此时屈强比已达到0.83。鉴于降低开轧温度影响生产节奏,同时考虑万能轧机负荷、能耗及辊耗等经济因素,900~850℃是较为理想的开轧温度区间,此时产品不仅强度及塑性指标均保持在较高的水平,而且韧性指标大幅提升,耐候热轧H型钢的综合力学性能得到明显改善。 展开更多
关键词 耐候热轧H型钢 轧制温度 力学性能 铁素体晶粒
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前列腺小细胞癌三例诊疗分析并文献复习
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作者 蔡蓝蝶 何君伟 +3 位作者 胡萍 潘俊 汤桂兴 白遵光 《中华腔镜泌尿外科杂志(电子版)》 2023年第4期397-402,共6页
目的探讨前列腺小细胞癌患者的诊断、治疗和预后情况,提高对前列腺小细胞癌的认识。方法对3例广东省中医院收治的前列腺小细胞癌进行病例报告,并收集国内已报道的112例前列腺小细胞癌患者的资料进行综合分析。结果本研究共115例患者,63... 目的探讨前列腺小细胞癌患者的诊断、治疗和预后情况,提高对前列腺小细胞癌的认识。方法对3例广东省中医院收治的前列腺小细胞癌进行病例报告,并收集国内已报道的112例前列腺小细胞癌患者的资料进行综合分析。结果本研究共115例患者,63例单纯前列腺小细胞癌患者的中位PSA为2.68 ng/ml,22例混合型前列腺小细胞癌患者的中位PSA为19.46 ng/ml,余无PSA值或病理类型不明确。临床分期以T3、T4为主,远处转移以骨转移多见,其次是肺、肝转移。115例患者中92例有随访资料,中位生存期8个月,其3个月、1年、2年生存率分别为85.7%、26.5%、17.0%。无远处转移患者中,接受化疗的中位生存期为12个月,未接受化疗的中位生存期为8个月,差异有统计学意义(P<0.05);接受局部治疗的中位生存期为15个月,未接受局部治疗的中位生存期为7个月,差异有统计学意义(P<0.05)。远处转移患者中,接受化疗的中位生存期为8个月,未接受化疗的中位生存期为5个月,差异有统计学意义(P<0.05);接受局部治疗与未接受局部治疗的患者生存时间差异无统计学意义(P>0.05)。结论前列腺小细胞癌恶性程度高,其侵袭性强、进展快、预后差,多数病例临床确诊时已是晚期,远处转移以骨转移多见。化疗能改善患者生存期,局部治疗能显著延长无远处转移患者的中位生存期。 展开更多
关键词 前列腺肿瘤 小细胞神经内分泌癌 小细胞癌 前列腺神经内分泌癌 前列腺小细胞癌
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