多孔淀粉负载青蒿素微球的抗肿瘤活性研究

探讨多孔淀粉负载青蒿素微球(ART-PS)与青蒿素原药(ART)在不同浓度下的抗肿瘤活性,以及分别联合全铁转铁蛋白后对肿瘤细胞的生长抑制作用。在体外实验中,取对数生长期的人肝癌细胞和正常肝细胞接种于96孔板中,不同浓度(0、50、100、150、200μmol·L^-1)给药处理24h后,用MTT法分别检测多孔淀粉负载青蒿素微球与青蒿素原药对细胞的生长抑制作用。MTT结果显示,同等处理浓度下,多孔淀粉负载青蒿素微球对肿瘤细胞Hep G2和SMMC-7721的抑制效果都高于青蒿素原药,但与盐酸阿霉素相比,都具有较低的细胞毒性,对正常细胞HL7702的毒副作用非常低,结果与分别联合全铁转铁蛋白后对肿瘤细胞的生长抑制作用一致。多孔淀粉负载青蒿素微球对人肝癌细胞的增殖有明显的抑制作用,效果优于青蒿素原药,并对正常肝细胞的毒副作用非常低,为青蒿素在治疗癌症的应用与研究提供了重要的参考依据。     

辅酶Q10/两亲性木聚糖纳米悬浮剂的制备以及生物利用度

研究一种新型共聚物负载辅酶Q10形成纳米悬浮剂能够增加CoQ10的水溶性,并且提高其口服生物利用度。本研究以槲皮素—木聚糖（QT-Xylan）共聚物偶联为基础进行合成,采用高剪切均质法进一步包载辅酶Q10,形成了一种新型载药纳米悬浮剂。采用单因素实验设计,并以粒径大小作为单因素实验的考察条件,影响其粒径大小的因素包括高压均质压力、高压均质次数、共聚物浓度、共聚物与CoQ10的质量比4个因素,并进行一系列体外实验评价。当均质压力为60 MPa,均质次数为7次,共聚物浓度为1 mg·mL^-1,共聚物与CoQ10的质量比为1∶1,是纳米悬浮剂的最佳制备工艺,此时粒径大小为166.7 nm。在最佳工艺条件下,在体外溶出实验中,包载CoQ10纳米悬浮剂的体外溶出率在人工胃液（SGF）和人工肠液（SIF）中分别是CoQ10原药的1.89和1.48倍。在体内生物利用度实验中,分别对大鼠灌胃CoQ10原药与载药纳米悬浮剂后,检测不同时间点的血药浓度,考察药物在大鼠体内的吸收和代谢情况,负载CoQ10的纳米悬浮剂在大鼠体内的血药浓度明显高于CoQ10原药,生物利用度提高为CoQ10原药的2.64倍。     

0710合生元结肠靶向微生态调节剂体外释放及定位作用研究

目的将益生菌双歧杆菌与枸杞多糖提取物设计为口服结肠定位给药系统(OCDDS),制备0710合生元结肠靶向微生态调节剂,考查其体外释放行为及体内定位作用。方法以枸杞中多糖为指标,对制剂进行体外溶出实验,并利用X-射线跟踪技术验证0710合生元结肠靶向微生态调节剂在人体内的靶向性。结果该制剂在人工胃液2 h、人工小肠液4 h,几乎不释药,而在人工结肠液中6 h释药达到100%,符合中国药典2005年版对缓释制剂的规定,且体内实验在结肠中黏附性较好。结论0710合生元结肠靶向微生态调节剂在体外结肠液中释放良好,在体内结肠具有靶向性,达到制剂设计要求。     

仿生提取ICP-MS法测定冬虫夏草8种重金属含量及健康风险评价

目的：建立冬虫夏草中铅（Pb）、镉（Cd）、汞（Hg）、砷（As）、铜（Cu）、银（Ag）、锡（Sn）和锑（Sb）8种重金属的仿生提取含量测定方法,并对其健康风险进行评价。方法：采用人工胃液、人工肠液仿生提取冬虫夏草中可溶性重金属,ICP-MS法测定重金属含量,靶标危害系数（THQ）法评价健康风险。结果：8种重金属在各自质量浓度范围内线性关系良好（R2> 0.997 0）,平均回收率84.05%～114.71%(RSD 2.9%～4.9%)。冬虫夏草中As、Hg、Cu、Cd、Sb、Pb、Ag总量均值依次为12.122、0.644、15.828、0.095、0.027、0.636、0.075 mg·kg-1,未检出Sn。As、Hg、Cu、Cd、Pb、Ag在人工胃液溶出率大于人工肠液,其在人工胃液中的溶出率均值为19.69%～52.62%,在人工肠液中的溶出率均值为0%～16.05%;Sb在人工肠液的溶出率25.54%大于人工胃液的溶出率14.68%。健康风险评价结果显示,As、Hg、Cu、Cd、Pb、Ag、Sb的THQ均<1,表明冬虫夏草中上述8种重金属不会对人体造成明显的健...     

几株饲用益生菌对体外模拟胃肠道环境的抗逆性评估

目的研究几株益生菌胃肠道环境下的抗逆能力。方法体外模拟正常猪的胃肠道环境,配制人工肠液和人工胃液,将实验室几株饲用益生菌在人工胃液和人工肠液中分别作用4、6 h,每2 h测一次活菌量。结果实验菌株对模拟胃液的耐受性都较强;除乳酸菌A外,其他菌株对模拟肠液的耐受性也较强。结论除乳酸菌A外的几株实验菌种作为饲用益生菌在抵御猪胃肠道的不良环境方面有很大优势。     

不同类型益生菌制剂在胃肠道中耐受程度的对比

目的对市场销售的几种不同类型益生菌制剂进行胃、肠液耐受程度比较,评价各益生菌制剂活菌数量,为临床选择益生菌制剂提供参考。方法选择7种菌粉及某颗粒益生菌、国产某晶球、日本产某晶球、某胶囊益生菌、圣邦步步佳肠释益生菌共12种口服益生菌产品,在崩解时限仪中加入人工胃液进行崩解试验,在0.0 h、0.5 h、1.0 h、1.5 h和2.0 h时吸取上述样品并进行浓度梯度稀释,并在MRS固体培养基上培养后进行活菌计数。在上述5个时间点吸取部分益生菌-胃液混合物(针对益生菌粉末)或取出益生菌产品(针对晶球、肠溶胶囊、肠释益生菌)换人工肠液再进行40 min崩解,在MRS固体培养基上培养后进行活菌计数。结果粉末状益生菌制剂对人工胃液的耐受能力普遍较差。某颗粒益生菌、国产某晶球、日本产某晶球、某胶囊益生菌、圣邦步步佳肠释益生菌在人工胃液中不崩解。圣邦步步佳肠释益生菌在人工肠液中40 min完全崩解且活菌数峰值较高。结论圣邦步步佳肠释益生菌对人工胃、肠液耐受能力较强,且活菌数较高。     

基于固体分散技术的阿司匹林肠溶微丸的制备

目的:制备阿司匹林固体分散体肠溶微丸。方法:以Eudragit L(EL)作为载体,采用固体分散技术制备阿司匹林肠溶微丸。运用X射线衍射法,扫描电镜法等分析方法研究其晶体性质,并考察其体外释放性能。结果:阿司匹林以无定形分散于固体分散体肠溶微丸中,药物体外释放曲线在胃液中符合零级动力学方程,在肠液中符合一级动力学方程。结论:阿司匹林固体分散体肠溶微丸可以较好地在肠道吸收,从而减少对胃部的刺激。     

氯雷他定固体自乳化制剂的体外溶出及体内药动学研究

目的:研究氯雷他定固体自乳化制剂的体外溶出行为及其在比格犬体内的药物动力学。方法:采用HPLC方法测定氯雷他定固体自乳化制剂与市售片剂的体外溶出曲线;采用LC-MS/MS测定市售片剂和氯雷他定固体自乳化制剂在比格犬体内的血药浓度,考察氯雷他定固体自乳化制剂的相对生物利用度。结果:以0.1 mol·L-1盐酸溶液为溶出介质的体外溶出结果表明,氯雷他定固体自乳化胶囊与市售片剂30 min时均可以溶出80%以上;比格犬体内药物动力学研究结果表明,固体自乳化制剂比市售片剂最高血药浓度显著性增加(P0.05),Cmax=1.79μg·L-1,而市售片剂Cmax=0.67μg·L-1;AUC(0~t)提高了149%(P0.05)。结论:固体自乳化制剂可以显著提高氯雷他定的体内吸收。     

两种荧光探针标记鹿茸提取物的稳定性和生物活性比较研究

比较两种荧光探针异硫氰酸荧光素FITC和Cy5标记鹿茸提取物PAEs的最佳方法。用FITC和Cy5分别标记PAEs得到标记物FITC-PAEs和Cy5-PAEs;用SDS-PAGE凝胶电泳检测并比较两种荧光染料标记蛋白分子量的差异;用酶标仪检测在特定波长处OD值计算其标记率;用PC12细胞验证两种荧光染料的生物安全性;将荧光标记物分别与人工胃液和人工肠液共孵育,观察它们在其中的稳定性。结果表明,两种荧光染料标记PAEs蛋白分子量并无明显差异,但FITC-PAEs荧光强度稍强。通过计算标记率表明两种荧光染料均可充分标记PAEs,但Cy5价格昂贵。相比于FITC-PAEs,Cy5-PAEs在人工胃液和人工肠液中稳定性较差。因此,我们选择标记率高,在人工胃液和人工肠液中较为稳定且对机体无毒副作用,价格合理的FITC荧光染料标记PAEs并用于后续实验研究。这为建立蛋白类中药大分子的活性示踪方法,开发口服蛋白类药物奠定基础。     

模拟人体胃肠道环境筛选益生乳杆菌

【目的】筛选具有益生特性的乳杆菌作为保健型酸奶的候选菌株。【方法】从健康人肠道和奶豆腐中分离筛选出耐受人工胃液的乳杆菌,对其进行体外益生特性(人工胃肠液耐受性、胆盐耐受性、抑菌活性及胆固醇降解能力)研究。【结果】从在乳杆菌分离培养基上有溶钙圈的41株菌株中筛选出5株耐酸、耐人工胃液较强的菌株,经16S rR NA基因测序鉴定,其中3株为乳杆菌,分别命名为植物乳杆菌Lp MT-3、植物乳杆菌Lp MT-5和唾液乳杆菌LsA F-7。在人工胃液中3株菌的耐受力均强于商品化的对照菌株LGG(鼠李糖乳杆菌GG);转入肠液4 h后直至26 h,Lp MT-5存活率基本稳定在45%左右,仅次于LGG。胆盐浓度为0.10%时,3株乳杆菌的耐胆盐能力均强于LGG;胆盐浓度为0.20%时,Lp MT-3和LsA F-7仍能存活。3株乳杆菌均具有抑菌活性,对粪肠球菌的抑制最明显,其次是金黄色葡萄球菌,对大肠杆菌、沙门氏菌的抑制作用较差。3株乳杆菌对胆固醇的清除效力依次为Lp MT-3LpM T-5Ls AF-7;清除率依次为Ls AF-7Lp MT-3LpM T-5。【结论】筛选出3株适应人体胃肠液环境、耐胆盐、抑菌及降胆固醇活力强的乳杆菌,可作为进一步开发新的益生菌产品和保健型酸奶的菌株。     

Agglomerated Oral Dosage Forms of Artemisinin/β-Cyclodextrin Spray-Dried Primary Microparticles Showing Increased Dissolution Rate and Bioavailability

Artemisinin, a poorly water-soluble antimalarial drug, presents a low and erratic bioavailability upon oral administration. The aim of this work was to study an agglomerated powder dosage form for oral administration of artemisinin based on the artemisinin/β-cyclodextrin primary microparticles. These primary microparticles were prepared by spray-drying a water–methanol solution of artemisinin/β-cyclodextrin. β-Cyclodextrin in spray-dried microparticles increased artemisinin water apparent solubility approximately sixfold. The thermal analysis evidenced a reduction in the enthalpy value associated with drug melting, due to the decrease in drug crystallinity. The latter was also evidenced by powder X-ray diffraction analysis, while ¹³C-NMR analysis indicated the partial complexation with β-cyclodextrin. Agglomerates obtained by sieve vibration of spray-dried artemisinin/β-cyclodextrin primary microparticles exhibited free flowing and close packing properties compared with the non-flowing microparticulate powder. The in vitro dissolution rate determination of artemisinin from the agglomerates showed that in 10 min about 70% of drug was released from the agglomerates, whereas less than 10% of artemisinin was dissolved from raw material powder. Oral administration of agglomerates in rats yielded higher artemisinin plasma levels compared to those of pure drug. In the case of the agglomerated powder, a 3.2-fold increase in drug fraction absorbed was obtained.     

Conventional and long-circulating liposomes of artemisinin: preparation, characterization, and pharmacokinetic profile in mice

Artemisinin (qinghaosu), a unique endoperoxide sesquiterpene lactone isolated from Artemisia annua L., is a very active antimalarial drug, including severe and cerebral malaria. However, its therapeutical efficacy is limited due to its scarce bioavailability. In this article, artemisinin-loaded conventional and polyethylene glycol (PEGylated) liposomes were proposed as carriers to increase biopharmaceutical properties of the drug. Encapsulation efficacy was determined by high-performance liquid chromatography/diode array detection/electrospray ionization-mass spectrometry, dimensional analysis was performed by dynamic light scattering, and morphology was performed by trasmission electron microscopy. After dialysis, both liposomal formulations showed an encapsulation efficacy of more than 70%; mean diameter of all the artemisinin-loaded vesicles was approximately 130-140?nm. The polydispersity index of the formulations ranged from 0.2 to 0.3 and resulted as suitable for intraperitoneal (i.p.) administration. Pharmacokinetic profile and the main pharmacokinetic parameters of the carriers were evaluated in healthy mice i.p. Free artemisinin was rapidly cleared from plasma and hardly detected 1 hour after administration. Conversely, both liposomal formulations showed much longer blood-circulation time than free artemisinin; artemisinin was still detectable after 3 and 24 hours of administration, respectively, for conventional and PEGylated liposomes. AUC(0-24 h) values were increased by approximately 6 times in both of the liposomal formulations, in comparison with free artemisinin. A strong effect of formulation on the half-life of artemisinin was enhanced by more than 5-fold by the incorporation of PEG into liposomes. Liposomes loaded with artemisinin, especially the long-circulating vesicles, could really represent a new strategy for developing smart, well-tolerated, and efficacious therapeutic nanocarriers to treat tumors, but could also be very useful to treat parasitic disease.     

Preparation and characterization of poly(D,L-lactide-co-glycolide) microspheres for controlled release of human growth hormone

The purpose of this research was to assess the physicochemical properties of a controlled release formulation of recombinant human growth hormone (rHGH) encapsulated in poly(D,L-lactide-co-glycolide) (PLGA) composite microspheres. rHGH was loaded in poly(acryloyl hydroxyethyl) starch (acHES) microparticles, and then the protein-containing microparticles were encapsulated in the PLGA matrix by a solvent extraction/evaporation method. rHGH-loaded PLGA microspheres were also prepared using mannitol without the starch hydrogel microparticle microspheres for comparison. The detection of secondary structure changes in protein was investigated by using a Fourier Transfer Infrared (FTIR) technique. The composite microspheres were spherical in shape (44.6±2.47 μm), and the PLGA-mannitol microspheres were 39.7±2.50 μm. Drug-loading efficiency varied from 93.2% to 104%. The composite microspheres showed higher overall drug release than the PLGA/mannitol microspheres. FTIR analyses indicated good stability and structural integrity of HGH localized in the microspheres. The PLGA-acHES composite microsphere system could be useful for the controlled delivery of protein drugs.     

Sustained release of the antitumor drug paclitaxel from poly(3-hydroxybutyrate)-based microspheres

The development of sustained release formulations based on biodegradable polymers is a promising trend in modern pharmacology. Polyhydroxyalkanoates (PHA) attract increasing attention due to their biodegradability and high biocompatibility, which make them suitable for the development of novel drug dosage forms. We have produced poly(3-hydroxybutyrate) (PHB)-based microspheres loaded with the antitumor drug paclitaxel and investigated morphology, drug release kinetics and the effect of these microspheres on tumor cells in vitro. The data on the kinetics of drug release, biocompatibility and biological activity of the biopolymer microspheres in vitro have demonstrated that the studied system of prolonged drug release had lower toxicity and higher efficiency compared to the traditional dosage forms of paclitaxel.     

Two-stage optimization process for formulation of chitosan microspheres

The objective of the present study was to optimize the concentration of a chitosan solution, stirring speed, and concentration of drugs having different aqueous solubility for the formulation of chitosan microspheres. Chitosan microspheres (unloaded and drug loaded) were prepared by the chemical denaturation method and were subjected to measurement of morphology, mean particle size, particle size distribution, percentage drug entrapment (PDE), drug loading, and drug release (in vitro). Morphology of the microspheres was dependent on the level of independent process parameters. While mean particle size of unloaded microspheres was found to undergo significant change with each increase in concentration of chitosan solution, the stirring rate was found to have a significant effect only at the lower level (ie, 2000 to 3000 rpm). Of importance, spherical unloaded microspheres were also obtained with a chitosan solution of concentration less than 1 mg/mL. Segregated unloaded microspheres with particle size in the range of 7 to 15 microm and mean particle size of 12.68 microm were obtained in the batch prepared by using a chitosan solution of 2 mg/mL concentration and stirring speed of 3000 rpm. The highest drug load ( microg drug/mg microspheres) was 50.63 and 13.84 for microspheres containing 5-fluorouracil and methotrexate, respectively. While the release of 5-fluorouracil followed Higuchi's square-root model, methotrexate released more slowly with a combination of first-order kinetics and Higuchi's square-root model. The formation of chitosan microspheres is helped by the use of differential stirring. While an increase in the concentration of water-soluble drug may help to increase PDE and drug load over a large concentration range, the effect is limited in case of water-insoluble drugs.     

Controlled Release of Dutasteride from Biodegradable Microspheres: In Vitro and In Vivo Studies

The aim of the present work was to study the in vitro/in vivo characteristics of dutasteride loaded biodegradable microspheres designed for sustained release of dutasteride over four weeks. An O/W emulsion-solvent evaporation method was used to incorporate dutasteride, which is of interest in the treatment of benign prostatic hyperplasia (BPH), into poly(lactide-co-glycolide) (PLGA). A response surface method (RSM) with central composite design (CCD) was employed to optimize the formulation variables. A prolonged in vitro drug release profile was observed, with a complete release of the entrapped drug within 28 days. The pharmacokinetics study showed sustained plasma drug concentration-time profile of dutasteride loaded microspheres after subcutaneous injection into rats. The in vitro drug release in rats correlated well with the in vivo pharmacokinetics profile. The pharmacodynamics evaluated by determination of the BPH inhibition in the rat models also showed a prolonged pharmacological response. These results suggest the potential use of dutasteride loaded biodegradable microspheres for the management of BPH over long periods.     

Porous bioactive glass scaffolds for local drug delivery in osteomyelitis: development and in vitro characterization

A new bioactive glass-based scaffold was developed for local delivery of drugs in case of osteomyelitis. Bioactive glass having a new composition was prepared and converted into porous scaffold. The bioactivity of the resulting scaffold was examined by in vitro acellular method. The scaffolds were loaded with two different drugs, an antibacterial or antifungal drug. The effects of the size of the scaffold, drug concentration, and dissolution medium on drug release were studied. The scaffolds were further coated with a degradable natural polymer, chitosan, to further control the drug release. Both the glass and scaffold were bioactive. The scaffolds released both the drugs for 6 weeks, in vitro. The results indicated that the bigger the size and the higher the drug concentration, the better was the release profile. The scaffolds appeared to be suitable for local delivery of the drugs in cases of osteomyelitis.     

Artemisinin, an endoperoxide antimalarial, disrupts the hemoglobin catabolism and heme detoxification systems in malarial parasite.

Endoperoxide antimalarials based on the ancient Chinese drug Qinghaosu (artemisinin) are currently our major hope in the fight against drug-resistant malaria. Rational drug design based on artemisinin and its analogues is slow as the mechanism of action of these antimalarials is not clear. Here we report that these drugs, at least in part, exert their effect by interfering with the plasmodial hemoglobin catabolic pathway and inhibition of heme polymerization. In an in vitro experiment we observed inhibition of digestive vacuole proteolytic activity of malarial parasite by artemisinin. These observations were further confirmed by ex vivo experiments showing accumulation of hemoglobin in the parasites treated with artemisinin, suggesting inhibition of hemoglobin degradation. We found artemisinin to be a potent inhibitor of heme polymerization activity mediated by Plasmodium yoelii lysates as well as Plasmodium falciparum histidine-rich protein II. Interaction of artemisinin with the purified malarial hemozoin in vitro resulted in the concentration-dependent breakdown of the malaria pigment. Our results presented here may explain the selective and rapid toxicity of these drugs on mature, hemozoin-containing, stages of malarial parasite. Since artemisinin and its analogues appear to have similar molecular targets as chloroquine despite having different structures, they can potentially bypass the quinoline resistance machinery of the malarial parasite, which causes sublethal accumulation of these drugs in resistant strains.