Preparation of Budesonide-Loaded Polycaprolactone Nanobeads by Electrospraying for Controlled Drug Release

Corticosteroids such as budesonide are the drugs of choice for the treatment of inflammatory disorders with an inherent limitation, viz., rapid elimination. To overcome this constraint and attain sustained release, budesonide was encapsulated in a biodegradable polymer, polycaprolactone (PCL), by DC electrospraying. By varying the experimental parameters involved in electrospraying such as applied voltage, flow rate, viscosity as well as conductivity of the polymer solution, the dimensionality of nanostructures was tuned from 1-D nanofibers to spherical nanoparticles. By adopting this rapid and viable method of DC electrospraying, we successfully prepared aqueous suspensions of nearly monodispersed, nano-sized drug encapsulated PCL. Drug encapsulation efficiency, in vitro drug release as well as biocompatibility studies of budesonide-loaded PCL nanobeads were carried out. The cytocompatible nanobeads prepared by electrospraying exhibited good encapsulation efficiency (approx. 75%), with controlled drug release enabled by the dissolution of the polymer. Our results demonstrate the potential of this novel technique of electrospraying in developing efficient drug encapsulated polymeric nanocarriers possessing sustained drug release profile.     

The Effects of Lactidyl/Glycolidyl Ratio and Molecular Weight of Poly(D,L -Lactide-co-Glycolide) on the Tetracycline Entrapment and Release Kinetics of Drug-Loaded Nanofibers

Electrospun tetracycline (Tet)-loaded poly(D,L-lactide-co-glycolide) (PLGA) nanofibers are considered to have great potential as local drug-delivery systems. This study was designed to explore the effects of the lactidyl/glycolidyl (LA/GA) unit ratio and molecular weight of PLGA on Tet entrapment efficiency and in vitro release kinetics. Three kinds of PLGA (PLGA75/25, M _w = 100 000 or 50 000; PLGA50/50, M _w = 50 000) were examined in this study. Electrospun nanofibers were fabricated containing 3, 5, 10 wt% Tet. The results showed that PLGA50/50 entrapped more Tet than both PLGA75/25 co-polymers, and the PLGA75/25 of M _w = 100 000 entrapped the least amount of Tet, suggesting that the lower the molecular weight of PLGA was, the higher the GA content in PLGA was and the higher the resulting Tet entrapment. Tet loading played an important role in Tet release. Nanofibers with 3 and 5 wt% Tet loading exhibited a sustained release for more than 28 days, whereas 10 wt% Tet only lasted 14 days. Loading of 3 wt% Tet resulted in approx. 35% release in the initial 12 h, 5 wt% Tet released approx. 70% and 10 wt% Tet resulted in approx. 85% release. The integrity of Tet incorporated into electrospun PLGA nanofibers was identified by FT-IR spectrum examination and the bacterial inhibition test. The modified Kirby–Bauer test showed dose-dependent inhibition of Staphylococcus aureus growth by Tet, confirming Tet structural stability throughout the electrospinning procedure. MG-63 cells demonstrated good adhesion and proliferation on all PLGA/Tet fibrous membranes. These results indicate that Tet entrapment and release kinetics of PLGA/Tet composite fibrous scaffolds can be tailored by the LA/GA ratios, molecular weights and drug loadings. Tet-loaded fibrous scaffolds show great potential for local drug delivery and bone defect repair.     

In Vitro and In Vivo Release of Basic Fibroblast Growth Factor Using a Silk Fibroin Scaffold as Delivery Carrier

Two different solvents were used to prepare two types of silk fibroin scaffolds via the salt-leaching technique, i.e., hexafluoroisopropanol (HFIP) and water. The in vitro release study suggests that the opposite charge between the silk fibroin and basic fibroblast growth factor (bFGF) at physiological pH rendered them to form a complex, and the difference in the solvents used to produce the silk fibroin scaffold did not affect the affinity of silk fibroin to bFGF. However, a higher degradation rate of the aqueous-derived silk fibroin scaffolds provided faster in vitro release kinetics of the bFGF, as compared to the HFIP-derived scaffolds. From the in vivo studies, the use of silk fibroin scaffolds as the carrier matrix enabled the control of the in vivo release of bFGF in a sustained fashion over two weeks, while the majority of the bFGF disappeared within one day after the injection of the bFGF in soluble form. In addition, the in vivo release of bFGF from the silk fibroin scaffolds was not affected by the mode of processing due to their similar degradation behavior in vivo.     

Role of Thermo-responsiveness and Poly(ethylene glycol) Diacrylate Cross-link Density on Protein Release from Poly(N-isopropylacrylamide) Hydrogels

Thermo-responsive hydrogels have shown promise as injectable materials for local drug delivery. However, the phase-induced changes in polymer properties of N-isopropylacrylamide (NIPAAm) can pose additional challenges for achieving controlled protein release. In this work, thermo-responsive hydrogels derived from NIPAAm and cross-linked with poly(ethylene glycol) diacrylate (PEG-DA) were synthesized via free radical polymerization. The volume phase transition temperature (VPTT) of the hydrogels ranged from 32.9°C to 35.9°C. Below the VPTT, swelling ratios of the hydrogels decreased with cross-linker concentration, and showed a sharp drop (at least 4-fold) upon phase change. Protein encapsulation efficiency was high (84–90%) and decreased with cross-linker concentration. Release of bovine serum albumin, a model protein, at body temperature was significantly higher than at room temperature (67% at 37°C compared to 44% at 23°C after 48 h). The release kinetics of proteins from the hydrogels were initially expected to be a function of cross-link density. However, at the hydrogel compositions explored in this work, protein release did not change significantly with cross-linker mol fraction. The thermo-responsive hydrogels offer a promising platform for the localized delivery of proteins.     

Preparation of a Magnetic-Field-Sensitive Hydrogel and Preliminary Study of Its Drug Release Behavior

The study describes the in situ formation of magnetite nanoparticles within a swollen polyacrylamide hydrogel. The average diameter of nanoparticles, as determined by TEM analysis, was found to be nearly 12.5 nm. In XRD analysis the characteristic peaks, observed at d = 3.07, 2.78, 2.64, 2.53, 2.32 and 2.03, also confirmed the formation of magnetite within the polymer network. The percent swelling of magnetite-loaded gel in physiological fluid was observed to decrease with increasing amount of magnetite in the gel. Moreover, the percent swelling increased from 140 to 254% as the strength of the applied magnetic field increased from 500 to 2500 Oe. Finally, the model drug, vitamin B₂, loaded magnetic gels showed relatively slower release in the presence of an applied magnetic field.     

Effect of Polymer Type on the Dynamics of Phase Inversion and Drug Release in Injectable In Situ Gelling Systems

The objective of this study was to evaluate the effect of the nature of the polymer on the dynamics of phase inversion and drug release in an in situ forming gel drug-delivery system composed of a biodegradable polymer and the solvent N-methyl-2-pyrrolidone (NMP), with metoclopramide monohydrochloride (metosalt) used as a low-molecular-weight model drug. Injection of this solution into an aqueous medium leads to the formation of a solid gel due to the rapid solvent/water exchange, followed by sustained release of the incorporated drug. The release of solvent from the injectable gel into phosphate buffer, which influences the polymer precipitation rate, was investigated as a function of the type of polymer using UV-Vis spectrophotometry. The cross-sectional gel morphology and its water uptake were characterized to relate the initial burst release (and thus the dynamics of phase inversion) to the polymer lactide/glycolide ratio and to the end-group characteristics. The results show that the phase inversion of hydrophobic polymers (e.g., PdlLA) occurs faster than the phase inversion of relatively more hydrophilic polymers (e.g., PLGA75/25, RG502 and RG502H). Three of the four polymers exhibit a four-phase profile, with the characteristics of each phase dependent on the hydrophobicity and degradation kinetics of the individual polymer.     

吗氯贝胺单次口服后药代动力学与脑电功率谱的关系

探讨健康人吗氯贝胺药代动力学参数与定量脑电图改变之间的关系。１２例受试单次口服吗氯贝胺３００ｍｇ，分次取血测定血浆浓度。同时测定服药前后定量脑电图改变。吗氯贝胺的消除半衰期１．８５±０．５５ｈｒ；达峰时间（Ｔｐｅａｋ）１．３５±１．１０ｈｒ；峰浓度（Ｃｍａｘ）２８４０±６８５μｇ／Ｌ；血浆清除率（ＣＬ／Ｆ）３０．７８±９．１７Ｌ／ｈｒ。服药后定量脑电图的Ａｌｐｈａｌ频段相对功率谱增加，而Ｂｅｔａ２频段，Ｄｅｌｔａ频段某些导联相对功率谱下降。药物达峰时间与峰浓度与脑电图改变有一定关联。     

大学生体育锻炼态度与心理健康的关系研究

目的探讨大学生体育锻炼态度与心理健康的关系。方法采用体育锻炼态度量表、中国人心理健康量表对230名大学生进行调查。结果大学生体育锻炼态度得分与心理健康得分在专业因素上存在显著差异;大学生的体育锻炼态度与心理健康总均分之间存在显著负相关。结论大学生的心理健康水平可能受到体育锻炼态度的影响。     

高血压病患者血浆神经肽Y的释放特点及其与血脂代谢的关系

应用放射免疫法测定５０例不同期高血压病患者血浆神经肽Ｙ（ＮＰＹ）释放变化特点并比较其与吸烟、血脂代谢之间的关系。结果发现：高血压病患者血浆ＮＰＹ含量为１４０．３±７３．８ｐｇ／ｍｌ,与对照组比较（７１．１±２１．８ｐｇ／ｍｌ）有显著性差异（Ｐ＜０．０１）;Ⅲ期高血压病患者血浆ＮＰＹ含量明显高于Ⅰ、Ⅱ期高血压病患者（Ｐ＜０．０１）;既往有吸烟史或血糖（ＢＧ）、血甘油三酯（ＴＧ）异常的高血压病患者血浆ＮＰＹ含量较无吸烟史及ＢＧ、ＴＧ正常者明显增高（Ｐ＜０．０１）。提示：高血压病患者血浆ＮＰＹ水平明显升高,而它的升高与吸烟、血甘油三酯及血糖增高有一定关系,它们的共同作用进一步使动脉血管弹性减退,导致微循环障碍,参予了高血压病、冠心病的发病机制与病理生理过程。     

身心因素与肠易激综合征患者生活质量的相关研究

目的调查肠易激综合征(IBS)患者生活质量状况并评估躯体及心理因素对它的影响。方法采用肠易激综合征生活质量量表(IBS-QOL)、临床症状问卷、艾森克人格问卷简式(EPQ-RSC)、简明心境问卷简式(POMS-SF)、医学应对问卷(MCMQ)对120例IBS患者进行测查,将IBS患者的心理健康水平(人格、情绪、应对)及躯体症状(肠道症状、肠外症状、睡眠障碍)与IBS患者生活质量进行相关分析。结果IBS患者IBS-QOL的8个因子和总分均显著降低(P<0.05),其中健康忧虑和饮食限制降低最为明显,除IBS症状外,肠外症状、睡眠障碍、精神心理异常在IBS患者中也很常见。心理因素中EPQ-RSC神经质(N)分、POMS中焦虑、抑郁等多项因子分及总分、MCMQ屈服积分与IBS-QOL总分呈负相关;躯体因素中IBS症状、肠外症状、睡眠障碍积分与IBS-QOL总分呈负相关。结论肠易激综合征患者的生活质量明显降低,除躯体症状外,心理功能失调也是决定患者生活质量的重要因素。     

青少年下颌第三磨牙生长发育与下颌骨相关变量的分析

目的分析青少年第三磨牙的生长发育与下颌骨相关变量的关系,为临床和基础研究提供参考依据。方法随机抽取全景片1177张,通过相关指标的测量分析,研究下颌骨第三磨牙的生长发育规律。结果牙齿先天缺失率为12.02%;第二磨牙后间隙BX和第三磨牙牙冠宽度比值与磨牙后间隙长度(MD/BX)12岁组、13岁组、14岁组和20岁组都与下一年龄组有显著性差异;下颌第三磨牙倾斜角男女之间,各年龄组之间均无统计学差异。结论青少年下颌骨第二磨牙后间隙会不断地增长,其中12~14岁生长显著。第三磨牙倾斜角随着年龄的增长由正态分布变为一部分倾向直立,另一部分更加倾斜的偏态分布。