bFGF-PLGA缓释微球及其体外释药性能研究

目的以bFGF为缓释药物、PLGA为药物载体制备bFGF-PLGA缓释微球,观察微球表面形态,检测微球物理性能和体外释药行为。方法采用W1/O/W2复乳溶剂挥发法制作微球;通过扫描电镜观察微球的表面形态结构;利用ELISA法测试微球中药物的载药量和包封率,并对微球中药物的体外释放行为进行研究。结果微球表面圆滑均匀,平均粒径(0.75±0.08)μm,载药量[(59.9±1.9)×10-3]%,包封率为(79.9±2.8)%;在为期45 d的体外释放试验中,bFGF累积释放率达到80%。结论bFGF-PLGA微球能够稳定地在较长时间释放药物bFGF,验证了PL-GA微球作为bFGF控制释放载体的可行性。     

羟基喜树碱微球的制备及其小鼠体内分布研究

目的:制备肺靶向性羟基喜树碱(HCPT)微球,评价其体外释药特性及其在小鼠体内的肺靶向性。方法:以聚乳酸为主要辅料,采用溶剂挥发法制备微球,考察其粒径、包封率、载药量,比较微球及原料药的体外释药性;取12只小鼠分别尾静脉注射HCPT微球及原料药,30min后分别测定血浆及各组织的药物浓度并计算相对分布率。结果:所制微球粒径在7～30μm者达81.6%,平均粒径为(14.2±3.1)μm,包封率为72.36%,载药量为(40.6±3.6)%,微球及原料药体外释药参数T50分别为85、18min。微球给药组在肺中的药物浓度最高(32.2±2.48)μg.mL-1,相对分布率58.1%;原料药给药组在血浆中的药物浓度最高(13.52±2.58)μg.mL-1,相对分布率25.24%。结论:所制HCPT微球具有明显的缓释性及肺靶向性。     

低分子肝素聚乳酸-羟基乙酸缓释微球的研制

目的制备低分子肝素聚乳酸-羟基乙酸(LWMH-PLGA)缓释微球,观察微球表面形态,检测微球物理性能和体外释药行为。方法采用W1/O/W2复乳溶剂挥发法制作微球;通过扫描电镜观察微球的表面形态结构;利用天青A比色法测试微球中药物的载药量和包封率,并对微球中药物的体外释放行为进行研究。结果微球表面显现较多的孔隙,平均粒径为(2.55±0.94)μm,载药量为(14.79±1.03)%,包封率为(55.7±2.21)%;48 h的体外释放试验表明,LWMH累积释放率达到40%。结论 LWMH-PLGA微球能够稳定地释放药物LWMH,验证了PLGA微球作为LWMH控制释放载体的可行性。     

雷公藤内酯醇缓释微球的制备及体内外释放规律研究

目的:制备雷公藤内酯醇缓释微球,并考察其体内外释放规律。方法:采用液中干燥法制备雷公藤内酯醇缓释微球,以静止法研究其体外释放规律,以大鼠药动学实验研究其体内释药规律。结果:制备的缓释微球外观呈规则的球形,粒径分布均匀((38.2±1.7)μm),包封率为(74.7±3.2)%。雷公藤内酯醇缓释微球在体外恒速释放;在大鼠体内的Cmax为(114.7±31.90)ng.mL-1,tmax为(8.32±4.43)h,AUC为(1774282±1046152)ng.h.mL-1,MRT为(596±165)h;在体内外的相关系数为0.9553(P<0.01)。结论:本制备工艺可行;雷公藤内酯醇有制备成缓释注射微球的可行性。     

玻璃体内注射用地塞米松微球的制备

目的为治疗增殖性玻璃体视网膜病变,制备玻璃体内注射用地塞米松微球。方法以生物可降解乙交酯和丙交酯的无规共聚物(PLGA)为载体材料,采用W/O型乳化-溶剂挥发方法制备地塞米松微微球。研究影响微球制备的工艺条件,考察了微球的粒径大小与分布、载药量和包封率,评价载药微球的体外释放行为。结果微球形态完整,表面光滑,微球的粒径范围为4.70±1.6μm,载药量为(15.5±0.32)%,包封率为(78.8±1.3)%。体外释药13d约90%,属扩散-溶蚀机制。结论制备方法可行,地塞米松PLGA微球具有药物缓释作用。可以作为玻璃体内注射用地塞米松的给药载体。     

牛血清白蛋白阳离子微球的制备及体外评价

目的 制备牛血清白蛋白(BSA)口服阳离子微球,考察天然阳离子物质壳聚糖(CHS)的加入对蛋白微球的粒径、电动电势、包封率、载药量及体外释放情况的影响。方法 以乳酸/羟基乙酸共聚物(PLGA)和壳聚糖(CHS)为载体材料,采用W/O/W复乳-溶剂挥发法制备牛血清白蛋白乳酸/羟基乙酸共聚物-壳聚糖(PLGA/CHS)阳离子微球。通过正交设计优化制备工艺,确定最佳处方。建立准确而简便的蛋白含量测定方法,并对微球进行体外评价。结果 最佳处方为：BSA浓度为150 g·L^-1、PLGA浓度为8%、外水相体积为80 mL、壳聚糖浓度为0.2%。制得的微球形态圆整,平均粒径为(6.9±5.5)μm,为表面荷正电的阳离子微球[ζ电势=(10.0±0.6)mV],包封率为(75.4±4.6)%,载药量为(9.3±0.2)%。体外释放结果表明,在模拟胃液和模拟肠液中,壳聚糖的加入均能减少突释,延缓药物的释放。结论 与PLGA微球相比,制得的PLGA/CHS阳离子微球表面带正电,具有较高的包封率和载药量,可以延缓药物释放,同时减少突释现象。     

灯盏花素羧甲基壳聚糖鼻黏膜微球的研制

摘要：目的:对灯盏花素（BRE）鼻黏膜微球的制备工艺进行优化,并对其体外质量进行考察,为进一步体内实验奠定基础。方法:以羧甲基壳聚糖（CMCS）为载体,采用喷雾干燥法制备BRE微球。以包封率及载药量的综合评分为评价指标,采用正交试验优化其处方及制备工艺,并对其形态、粒径及体外释药特性进行考察。结果:优选出的BRE微球最佳制备条件为:CMCS浓度为0.8 g·ml-1,BRE∶CMCS为1∶5（g∶g）,CMCS∶三聚磷酸钠（TPP）为15∶1（g∶g）,蠕动泵速度为20 ml·min-1。BRE微球外形圆整光滑,粒径均匀,体外释药呈明显缓释性,包封率和载药量分别为（68.33±0.35）%和（16.26±0.42）%。结论:BRE-CMCS微球制备简单,体外质量理想,值得进一步研究。     

吸附和包埋法制备洛美沙星淀粉微球及其体外释放比较研究

目的 制备盐酸洛美沙星淀粉微球,并对其体外释药模式进行研究。方法 以盐酸洛美沙星为模型药物,采用吸附载药法和包埋载药法制备了载药淀粉微球,通过测定微球载药量、包封率和在不同的释放介质中的体外释放情况,对上述2种方法制备的载药微球进行质量评价。结果 吸附法制备的载药微球的平均载药量为14.54 µg·mg^-1,药物包封率为39.72%;而包埋载药法制备的淀粉微球的平均载药量为19.32 µg·mg^-1,药物包封率为48.95%。体外释药特性研究表明它们具有缓释特性,其中包埋载药法制备的淀粉微球比吸附载药法制备的淀粉微球有更好的缓释能力,在不同的释放介质中释药曲线也有所不同,在模拟胃液中累计释药量只能得到70%;而在模拟肠液中累计释药量能达到80%以上。结论 吸附载药法和包埋载药法制备的载药淀粉微球都具有缓释作用,但后者体外释药具有更明显的缓释效果。     

长春西汀聚乳酸-聚乙醇酸缓释微球的研制

目的:制备长春西汀聚乳酸-聚乙醇酸(PLGA)缓释微球,并研究其药剂学性质。方法:采用改良O/W乳化-溶剂挥发法制备微球,以PLGA浓度、理论载药量、有机相与分散介质的比例和分散介质中明胶的浓度为4因素,每个因素选定3个水平,按L9(34)的正交设计方案,以载药量、包封率和粒径分布为指标,优化处方。用扫描电镜观察微球的形态,用光学显微镜观察并计算微球的粒径分布,用差示扫描量热(DSC)法研究药物在载体中的分散状态,用紫外分光光度法检测微球中长春西汀含量并计算载药量和包封率,用动态透析释药法进行微球的体外释放研究。结果:最佳处方为PLGA浓度16%,理论载药量20%,有机相与分散介质的比例1:10,分散介质中明胶的浓度1%;制备的长春西汀PLGA缓释微球的形态圆整、光滑,粒径分布均匀,平均粒径为(10.0±0.18)μm(n=500),DSC法分析药物确已被包裹于微球中,载药量为(18.46±0.26)%,包封率为(91.30±0.98)%(n=3),24h累积释药率约为18%。结论:长春西汀PLGA缓释微球制备工艺稳定,质量符合药剂学要求,缓释性好。     

吸附和包埋法制备洛美沙星淀粉微球及其体外释放比较研究

目的制备盐酸洛美沙星淀粉微球,并对其体外释药模式进行研究。方法以盐酸洛美沙星为模型药物,采用吸附载药法和包埋载药法制备了载药淀粉微球,通过测定微球载药量、包封率和在不同的释放介质中的体外释放情况,对上述2种方法制备的载药微球进行质量评价。结果吸附法制备的载药微球的平均载药量为14.54μg·mg^-1,药物包封率为39.72%;而包埋载药法制备的淀粉微球的平均载药量为19.32μg·mg^-1,药物包封率为48.95%。体外释药特性研究表明它们具有缓释特性,其中包埋载药法制备的淀粉微球比吸附载药法制备的淀粉微球有更好的缓释能力,在不同的释放介质中释药曲线也有所不同,在模拟胃液中累计释药量只能得到70%;而在模拟肠液中累计释药量能达到80%以上。结论吸附载药法和包埋载药法制备的载药淀粉微球都具有缓释作用,但后者体外释药具有更明显的缓释效果。     

Interaction of estrone and estradiol with DNA and protein of liver and kidney in rat and hamster in vivo and in vitro

[6,7-³H] Estrone (E) and [6,7-³H]estradiol-17 (E₂) have been synthesized by reduction of 6-dehydroestrone and 6-dehydroestradiol with tritium gas. Tritiated E and E₂ were administered by oral gavage to female rats and to male and female hamsters on a dose level of about 300 g/kg (54 mCi/kg). After 8 h, the liver was excised from the rats; liver and kidneys were taken from the hamsters. DNA was purified either directly from an organ homogenate or via chromatin. The radioactivity in the DNA was expressed in the units of the Covalent Binding Index, CBI = (mol chemical bound per mol DNA-P)/(mmol chemical administered per kg b.w.). Rat liver DNA isolated via chromatin exhibited the very low values of 0.08 and 0.09 for E and E₂, respectively. The respective figures in hamster liver were 0.08 and 0.11 in females and 0.21 and 0.18 in the males. DNA isolated from the kidney revealed a detectable radioactivity only in the female, with values of 0.03 and 0.05 for E and E₂, respectively. The values for male hamster kidney were < 0.01 for both hormones. The minute radioactivity detectable in the DNA samples does not represent covalent binding to DNA, however, as indicated by two sets of control experiments. (A) Analysis by HPLC of the nucleosides prepared by enzyme digest of liver DNA isolated directly or via chromatin did not reveal any consistent peak which could have been attributed to a nucleoside-steroid adduct. (B) All DNA radioactivity could be due to protein contaminations, because the specific activity of chromatin protein was determined to be more than 3,000 times higher than of DNA. The high affinity of the hormone to protein was also demonstrated by in vitro incubations, where it could be shown that the specific activity of DNA and protein was essentially proportional to the concentration of radiolabelled hormone in the organ homogenate, regardless of whether the animal was treated or whether the hormone was added in vitro to the homogenate.Carcinogens acting by covalent DNA binding can be classified according to potency on the basis of the Covalent Binding Index. Values of 10³–10⁴ have been found for potent, 10² for moderate, and 1–10 for weak carcinogens. Since estrone is moderately carcinogenic for the kidney of the male hamster, a CBI of about 100 would be expected. The actually measured limit of detection of 0.01 places covalent DNA binding among the highly unlikely mechanisms of action. Similar considerations can be made for the liver where any true covalent DNA binding must be below a level of 0.01. It is concluded that an observable tumor induction by estrone or estradiol is unlikely to be due to DNA binding.Paper presented at the Satellite Symposium of the European Society of Toxicology, Rome, March 29, 1983     

Arsenic induced changes in growth development and apoptosis in neonatal and adult brain cells in vivo and in tissue culture

Arsenic at a nonlethal level in drinking water consumed over a period of time has been reported to produce chronic toxicity and various types of health problems ranging from skin cancer to disturbance in memory. Neurotoxic effects have been reported in clinical cases with chronic exposure to arsenic. Physiological detoxication of arsenic occurs partially through methylation. Arsenic and its methylated derivatives are distributed in different organs and systems. The present study examined the possible interference in the neuronal development and differentiation due to the exposure to arsenic during gestation. The experiments were carried out to examine short and long term effects of arsenic on brain explants and cells grown and maintained in tissue culture system. The effects of arsenic exposure showed changes in brain cell membrane function indicated by generation and release of reactive oxygen-nitrogen intermediates. On the morphological aspect the explants' growth was reduced, ground matrix was lost and neural networking was inhibited. Cells showed signs of apoptotic changes. Arsenic toxicity may induce damage to brain cells prior to more visible clinical conditions. The deleterious effects also pass from the maternal to fetal tissue across the transplacental barrier.     

Nicotine metabolism and urinary elimination in mouse: in vitro and in vivo

This study aimed at elucidating the in vivo metabolism of nicotine both with and without inhibitors of nicotine metabolism. Second, the role of mouse CYP2A5 in nicotine oxidation in vitro was studied as such information is needed to assess whether the mouse is a suitable model for studying chemical inhibitors of the human CYP2A6. The oxidation of nicotine to cotinine was measured and the ability of various inhibitors to modify this reaction was determined. Nicotine and various inhibitors were co-administered to CD2F1 mice, and nicotine and urinary levels of nicotine and four metabolites were determined. In mouse liver microsomes anti-CYP2A5 antibody and known chemical inhibitors of the CYP2A5 enzyme blocked cotinine formation by 85–100%, depending on the pre-treatment of the mice. The amount of trans-3-hydroxycotine was five times higher than cotinine N-oxide, and ten times higher than nicotine N-1-oxide and cotinine. Methoxsalen, an irreversible inhibitor of CYP2A5, significantly reduced the metabolic elimination of nicotine in vivo, but the reversible inhibitors had no effect. It is concluded that the metabolism of nicotine in mouse is very similar to that in man and, therefore, that the mouse is a suitable model for testing novel chemical inhibitors of human CYP2A6.     

Circulating nucleic acids in plasma and serum: roles in diagnosis and prognosis in diabetes and cancer

The presence of DNA and RNA circulating in human plasma and serum is described. The possible sources of the DNA/RNA in blood, their ability to enter other cells and to express in the recipient cells are discussed and the relationship with metastases considered. The possible role(s) of the DNA/RNA in clinical diagnosis, in monitoring treatment and in prognosis are considered for diabetes and oncology.     

SalB stimulates neurogenesis and angiogenesis in vitro and in vivo

Aims： Previous studies suggested that Salvianolic acid B （SalB） has strong protective effect against cerebral ischemia. Recently, Sal B has been reported to enhance angiogenesis in vitro. Based on the information above, in this study we are interested in the effect of SalB on neurogenesis and angiogenesis. Methods：In vitro study, we used embryonic mouse （El6） primary cortical neural cultures. Neuron was recognized by anti-MAP2 with immunocytochemistry. Neurogenesis was tested with BrdU incorporation by ELSA method. SalB（ 10 -6 -10 -8M） or vehicle was added to the culture medium 24 hrs before BrdU addition. In vivo, middle cerebral artery occlusion （MCAO） rats were used as focal cerebral ischemia model.     

Metabolic interaction between imipramine and carbamazepine in vivo and in vitro in rats

Summary The pharmacokinetic consequences of the combination of carbamazepine with imipramine in male Wistar rats have been investigated. It was found that a 2-week treatment with the combination resulted in the increase of the concentrations of the parent compounds and a simultaneous decrease in their metabolites in blood plasma i.e. carbamazepine inhibited imipramine demethylation in the side chain while imipramine inhibited carbamazepine 10,11-epoxidation. The velocity of imipramine 2-hydroxylation and 10,11-epoxy-carbamazepine hydration did not seem to be changed by the combination. On the basis of studies in vitro it is concluded that the observed metabolic interaction between carbamazepine and imipramine is due to the competition of the drugs for the active centre of cytochrome P 450 and to a certain qualitative alteration of the enzyme by imipramine as can be deducted from the decrease of carbamazepine binding to the cytochrome. Send offprint requests to K. J. Netter     

Nicotine metabolism and urinary elimination in mouse: in vitro and in vivo

This study aimed at elucidating the in vivo metabolism of nicotine both with and without inhibitors of nicotine metabolism. Second, the role of mouse CYP2A5 in nicotine oxidation in vitro was studied as such information is needed to assess whether the mouse is a suitable model for studying chemical inhibitors of the human CYP2A6. The oxidation of nicotine to cotinine was measured and the ability of various inhibitors to modify this reaction was determined. Nicotine and various inhibitors were co-administered to CD2F1 mice, and nicotine and urinary levels of nicotine and four metabolites were determined. In mouse liver microsomes anti-CYP2A5 antibody and known chemical inhibitors of the CYP2A5 enzyme blocked cotinine formation by 85-100%, depending on the pre-treatment of the mice. The amount of trans-3-hydroxycotine was five times higher than cotinine N-oxide, and ten times higher than nicotine N-1-oxide and cotinine. Methoxsalen, an irreversible inhibitor of CYP2A5, significantly reduced the metabolic elimination of nicotine in vivo, but the reversible inhibitors had no effect. It is concluded that the metabolism of nicotine in mouse is very similar to that in man and, therefore, that the mouse is a suitable model for testing novel chemical inhibitors of human CYP2A6.     

Pharmacokinetic and pharmacogenetic determinants and considerations in chemotherapy selection and dosing in infants

INTRODUCTION: There is a lack of high-quality data regarding optimal chemotherapy dosage regimens among infants. Dosing regimens for chemotherapy during the first year of life are commonly based on empiric recommendations extrapolated from older children; however, balancing efficacy and toxicity is critical as severe adverse drug reactions may lead to treatment failure or reduced adherence to needed medications. AREAS COVERED: This review describes pharmacokinetic and pharmacogenetic considerations when administering chemotherapeutic agents to infants. Examples of commonly used agents are provided with practical recommendations for dosing adjustments. EXPERT OPINION: Optimal chemotherapy for children and infants in particular has lagged behind the remarkable progress in cancer treatment and it is clear that far more basic and clinical research are needed with respect to the mechanistic basis of age-dependent differences in pharmacokinetic parameters. More recent studies which have combined pharmacokinetic data with clinical toxicity and outcome data have resulted in a number of more evidence-based guidelines at least for the initial chemotherapy dosing; however, at present, the dosing of chemotherapy drugs in neonates and infants remains largely empiric.     

Consistency in catecholamine and cortisol excretion in males and females

Data from a series of experiments performed on 24 female and 24 male subjects were used to evaluate the consistency in urinary catecholamine and cortisol excretion. Data were available from 8 laboratory situations of varying activity level and content, spaced at intervals of maximum 3 months. Correlational analyses showed that for cortisol, interindividual consistency was higher for measures obtained on the same day than for measures obtained on different days. Interindividual consistency was generally high in catecholamine and cortisol excretion during non-stressful situations in both sexes. During experimental stress, however, consistency was as high as during nonstress for males, while it was lower for females. Analysis of variance components confirmed these results and showed that in males variation due to interindividual differences was high during both baseline and experimental-stress situations, while in females it was high during baseline situations only. During experimental stress, variation for females was due primarily to interaction. It is suggested that the males showed a more generalized stress response over situations than the females.     

Penetration and action of edoxudine in vitro and in vivo

The penetration of 5-ethyl-2'-deoxyuridine (edoxudine, Aedurid) from gel base with and without the addition of urea and other adjuvant has been studied in an in vitro model using guinea pig skin. The formulation of 3% edoxudine gel with 5% urea showed the best results. In vivo experiments on hairless mice infected intracutaneously with herpes simplex virus type 1 also showed this formulation's good efficacy as compared to other formulations.