洛索洛芬钠缓释微球的制备及体外释药特性考察

目的延缓洛索洛芬钠在局部的作用时间,了解洛索洛芬钠缓释微球的体外释药特性。方法采用乳化-化学交联法制备明胶微球,采用正交试验优化明胶微球的处方和制备工艺;采用流化床包衣技术制备缓释微球;采用透析法考察体外释药特性。结果制备明胶微球最优处方和工艺为:洛索洛芬钠5.0 g,质量分数为20%的明胶溶液100 mL作为水相,含质量分数0.5%Span 80的液体石蜡混合液400 mL作为油相,55℃搅拌下将水相缓缓加入至油相中,500 r.min-1乳化20 min,冰水浴20 min,加入戊二醛使体积分数为50%,交联90 min,4000 r.min-1离心分离10 min,用丙酮、乙醚交替洗涤3次,40℃真空干燥12 h;制备的明胶微球平均粒径为18.25μm,载药量为19.37%,包封率为87.72%,包衣后质量增加25%;洛索洛芬钠缓释微球体外释药过程符合Higuchi方程。结论制备的洛索洛芬钠缓释微球具有明显的缓释作用。     

关节腔内注射用氟比洛芬明胶微球

目的:制备关节腔注射用氟比洛芬明胶微球。方法:按均匀设计法筛选乳化冻凝法制备氟比洛芬明胶微球(FP GMS)的最佳制备工艺。结果:微球粒径范围为2.5～12.3μm,平均粒径为7.53μm,氟比洛芬含量为5.02%(w/w)。其体外释药符合Higuchi方程,稳定性实验表明,FP-GMS的稳定性良好,兔关节腔内注射后,与溶液剂对照组相比氟比洛芬体内平均驻留时间(MRT)显著延长(P<0.01),峰时比对照组延长2.03倍,峰浓度比对照组减小5.57倍。体内外相关性研究表明,FP-GMS体外累积溶出百分率与兔体内药物吸收分数呈显著相关(P<0.01)。结论:本法制备的氟比洛芬明胶微球粒径分布集中,粒径大小符合设计要求,体内外释药结果表明氟比洛芬明胶微球具有明显的缓释作用。     

肺靶向贝母素甲明胶微球的制备

目的制备肺靶向贝母素甲明胶微球,并对其理化性质进行考察。方法采用乳化—化学交联法制备贝母素甲明胶微球;采用光学显微镜对微球形态、粒度分布等进行考察;利用柱前衍生HPLC方法测微球的包封率和载药量;利用透析法考察微球体外释药特性。结果在光学显微镜下观察,微球呈球形,表面光滑,很少黏连,平均粒径10.72μm,粒径在5～25μm范围内的微球占总数的85.8%,载药量为5.128%,包封率为66.35%,体外释药具有缓释特征。结论微球的粒径、形态、载药量和包封率、体外释药性能等基本符合肺部靶向的要求。     

双氯芬酸钠壳聚糖明胶复合微球的释药机制研究

目的制备双氯芬酸钠壳聚糖明胶复合微球(DS-CGMs),探讨其体外释药机制。方法建立DS-CGMs体外释放度的测定方法;研究药物从微球中释放的影响因素;分别考查双氯芬酸钠明胶微球(DS-GMs)、双氯芬酸钠壳聚糖微球(DS-CMs)及DS-CGMs的体外释药情况,并通过数学原理和相关模型探讨其释放行为和机制。结果DS-GMs、DS-CMs以扩散和骨架溶蚀作用释放,而DS-CGMs呈骨架溶蚀作用机制,具有更好的缓释效果。结论获得较为满意的DS-CGMs,其体外释药具有一定的缓释性。     

丹皮酚明胶微球的制备及质量评价

目的 制备丹皮酚明胶微球并进行药剂学性质考察.方法 以丹皮酚为芯材,明胶为载体,采用交联固化法制备丹皮酚明胶微球;采用正交试验优选制备工艺,并对制得的明胶微球进行体外释药性能考察.结果 影响明胶微球包封率的主要因素为明胶浓度和搅拌速度.制得的明胶微球平均粒径100 μm,载药量和包封率分别为8.49%和86.4%,体外释药试验表明所得微球具有明显的缓释作用.结论 所选工艺可用于制备丹皮酚明胶微球,可为缓释药物传递系统提供参考.     

双氯芬酸钠/海藻酸钠微球的制备与体外释药行为考察

目的以海藻酸钠为载体材料,双氯芬酸钠为模型药物,制备载药微球并考察其性质及体外释放行为。方法本文采用海藻酸钠为药物载体,采用喷雾干燥法制备双氯芬酸钠/海藻酸钠微球。考察于双氯芬酸钠/海藻酸钠投料比对载药微球理化性质的影响。采用扫描电镜对所得到的微球进行形貌观察。同时考察其体外药物释放行为。结果所得到的载药微球形态呈不规则的扁平状,粒径分布较为均匀。通过控制投料比,可以得到不同粒径(5.64～9.58μm),载药量(5.76～18.43%)和包封率(35.45～43.92%)的载药微球。体外药物释放行为结果显示微球在含有0.5%氯化钙的PBS(pH=7.4)溶液的药物释放时间可以持续96h,具有一定的缓释效果。结论通过喷雾干燥法制备的双氯芬酸钠/海藻酸钠载药微球具有较高载药量和一定的药物缓释效果。     

胸腺肽明胶微球的制备和体外释药的特性

目的:为提高胸腺肽的生物利用度,增强疗效,制备胸腺肽的明胶微球.方法:用乳化交联法制备胸腺肽明胶微球,正交设计法筛选其最佳制备工艺,Lowry法测定药物的含量,计算微球的载药量、包封率及体外释药量.结果:微球粒径范围为1.0～30.2 μm,平均粒径为14.64 μm,平均载药量为20.20%(w/w),平均包封率为80.82%,其体外释药符合Higuchi方程,稳定性考察实验结果表明其稳定性较好.结论:本法制备的胸腺肽明胶微球粒径分布集中,粒径大小符合设计要求,体外释药有明显的缓释作用,具有良好应用前景.     

醋酸戈舍瑞林缓释微球的制备及体外释药研究

目的制备醋酸戈舍瑞林缓释微球,考察其一般性质和体外释药特性。方法采用复乳-液中干燥法制备醋酸戈舍瑞林微球,测定微球的外观形态、粒度分布和体外释药曲线。结果微球形态规则,粒径约为85.6μm,微球体外释药规律符合Higuchi方程：Q=16.202t1/2＋1.550 3,r=0.991 0。结论制备的醋酸戈舍瑞林微球具有长时间的缓释作用。     

紫杉醇肺靶向微球的制备及体内外评价

目的用生物可降解材料聚乳酸-聚羟基乙酸共聚物(PLGA)制备肺靶向紫杉醇缓释微球。方法在单因素考察的基础上进行正交试验设计,筛选出肺靶向紫杉醇PLGA微球的最佳制备工艺条件;利用桨板法研究了微球的体外释药规律;用小鼠为实验对象,研究了紫杉醇聚乳酸微球的体内组织药物分布。结果制得的微球形态圆整,粒径在5~15μm范围内的占总体积的87.18%,微球平均粒径为9.65μm;包封率为83.8%;载药量为19.7%;体外释药符合Higuchi方程Q=-2.193 7 22.009t0.5,r=0.990 4;体内实验表明紫杉醇微球混悬剂较普通注射剂更趋于聚集在肺组织。结论微球制备工艺稳定,具有明显的缓释作用和肺靶向性。     

格列吡嗪缓释微球的制备及释药特性考察

目的采用球晶造粒技术制备格列吡嗪缓释微球并考察体外释药特性。方法以乙基纤维素和水溶性高分子材料聚乙二醇6000为载体,采用球晶造粒技术制备格列吡嗪缓释微球,对微球的形状、粒径分布、载药量、包封率和体外释药等进行了考察。结果该法所制微球外观圆整、流动性好,粒度分布在40～190μm内的微球占总数的99%,载药量为35.6%,包封率为89.5%,体外释药行为符合Higuchi方程,24h累计释药量96%。结论该法可用于制备格列吡嗪缓释微球。     

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     

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.     

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.     

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     

Buprenorphine and naloxone alone and in combination in opioid-dependent humans

Subjective, physiological and behavioral effects of subcutaneously administered hydromorphone (6 mg), naloxone (0.2 mg), buprenorphine (0.2 and 0.3 mg), and two buprenorphine-naloxone combinations (buprenorphine 0.2 mg plus naloxone 0.2 mg and buprenorphine 0.3 mg plus naloxone 0.2 mg) were assessed under double-blind conditions in six opioid-dependent volunteers. Physiologic measures and subject- and observer-rated behavioral responses were measured before dosing and for 120 min after drug administration. Hydromorphone decreased pupil diameter and respiration, increased blood pressure and increased scores on subjective measures indicating opioid-like effects. Buprenorphine given alone had no significant effect on any variable measured. Naloxone given alone produced opioid abstinence-like effects which were measurable on subject- and observer-rated behavioral measures and physiological measures. Buprenorphine in combination with naloxone somewhat attenuated the naloxone-precipitated withdrawal response. Overall, the naloxone-buprenorphine combinations produced effects which were qualitatively similar to the effects of naloxone alone, suggesting a low potential for abuse of the combination product by opioid-dependent individuals.Supported by a grant from Reckitt and Colman Pharmaceutical Division and USPHS Grants DA-00050 and DA-04089 from the National Institute on Drug Abuse     

Strain-dependency in motor activity and in concentration and turnover of catecholamines in synchronized rats

Circadian rhythm in motor activity was studied with an Animex motimeter in six strains of rats (ACI, BH, BS, DA, LEW, TNO) synchronized by a 12 hr light: 12 hr dark cycle. ANOVA revealed significant interstrain differences in motor activity as well as in the concentration and turnover of central noradrenaline and dopamine. Strain-dependent differences were also found with regard to tyrosine hydroxylase inhibition on motor activity. However, no significant interstrain correlations were found between endogenous concentration and/or turnover rates of the catecholamines and motor activity in normal and drug-treated rats.     

氯胺酮复合丙泊酚及氯胺酮复合咪达唑仑在小儿麻醉中的麻醉效果对比

目的研究氯胺酮分别复合丙泊酚和咪迟唑仑在小儿麻醉术中及术后的麻醉效果。方法 40例2⁸岁拟在全身麻醉下行择期下腹部手术患儿,不拘性别。随机数字表法分为氯胺酮复合丙泊酚组(A组),氯胺酮复合咪达唑仑组(B组),每组备20例(n=20),比较两组镇痛、镇静效果及躁动、恶心呕吐、呼吸抑制等并发症的发生率。结果两组镇痛及镇静效果均满意,但B组躁动、恶心呕吐的发生率明显高于A组,且A组比B组苏醒时间明显缩短。结论氯胺酮复合丙泊酚用于小儿麻醉效果更加安全圾效。     

Pharmacokinetics and tolerability of artesunate and amodiaquine alone and in combination in healthy volunteers

Objectives  The WHO recommends artemisinin-based combination therapies for treatment of uncomplicated falciparum malaria. At least 15 African countries have adopted artesunate plus amodiaquine as treatment policy. As no pharmacokinetic data on this combination have been published to date, we investigated its pharmacokinetic interactions and tolerability in healthy volunteers in Africa. Methods  In a randomized, three-phase, cross-over study, amodiaquine (10 mg/kg) and artesunate (4 mg/kg) were given as single oral doses to 15 healthy volunteers. Artesunate was given to all volunteers on day 0. On day 7 they received either amodiaquine or amodiaquine plus artesunate and the alternative regimen on day 28. The pharmacokinetics of artesunate and amodiaquine and their main active metabolites dihydroartemisinin and desethylamodiaquine were compared following monotherapy and combination therapy using analysis of variance. Results  Thirteen volunteers completed the study, and pharmacokinetic parameters could be determined for twelve volunteers. When given in combination, the mean AUC was lower for dihydroartemisinin [ratio 67% (95% CI 51–88%); P = 0.008] and desethylamodiaquine [ratio 65% (95% CI 46–90%); P = 0.015] when compared with monotherapy. Adverse events of concern occurred in four volunteers (27%): grade 3 transaminitis (n = 1), neutropaenia (n = 2), and hypersensitivity (n = 1). Conclusion  The total drug exposure to both drugs was reduced significantly when they were given in combination. The clinical significance of these interactions is unclear and must be studied in malaria patients. The frequency and nature of adverse events among the healthy volunteers were of concern, and suggest laboratory monitoring would be needed in malaria patients treated with artesunate plus amodiaquine.     

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.     

Evaluation of pharmacokinetic interactions between bicyclol and co-administered drugs in rat and human liver microsomes in vitro and in rats in vivo

1. Bicyclol is a new synthetic anti-hepatitic drug and primarily metabolized by CYP3A. The aim of this study was to evaluate the pharmacokinetic interactions between bicyclol and co-administered drugs including metformin, pioglitazone, atorvastatin, fenofibrate, Cyclosporin A (CsA), and tacrolimus in rat and human liver microsomes (RLMs/HLMs) in vitro and in rats in vivo.

2. The depletion rate of bicyclol in RLMs was significantly inhibited by 44.8% and 35.5% after preincubation with pioglitazone and fenofibrate while the metabolite formation rate of bicyclol in HLMs was inhibited by 26.1% and 23.9% after preincubation and coincubation with tacrolimus, and by 20.2% after preincubation with CsA. Conversely, preincubation and coincubation with bicyclol significantly inhibited the depletion rate of pioglitazone in RLMs by 34.1% and 27.1%, respectively, and the formation rate of para- and ortho-hydroxy atorvastatin in RLMs and HLMs by 20.6–36.2%. There were no significant pharmacokinetic interactions between bicyclol and pioglitazone in rats after a single or multiple oral treatment.

3. As the selected inhibitory drug concentrations in vitro were significantly higher than those in clinical settings and the maximum inhibition rate did not exceed 50%, the clinically significant interaction between bicyclol and these co-administered drugs in humans is predicted less likely to happen.