旱地土壤条件下包膜控释肥料养分释放的试验与数学模拟

采用室内培养方法,测定了不同土壤水分含量条件下指数线性和S线性包膜控释肥料养分释放速率。计算出不同土壤含水量条件下养分释放速率常数(k)。该k值与土壤在最大持水量30%时的k值的比值定义为释放速率系数a,并用土水势(Ψ)的函数表示。分别建立不同旱土水分含量条件下指数线性和S线性包膜控释肥料养分释放数学模型。结果表明,这两个数学模型能够较好地模拟指数线性和S线性包膜控释肥料在自然旱地条件下,任一日变化土温和任一日变化土壤含水量下的氮素释放率,模拟值与实测值基本一致,表明这两个数学模型具有实用性。     

肥料养分释放性能快速测试方法研究

研究了一种肥料养分释放性能的快速测定方法.依据"淋溶法"原理设计了淋溶装置,考察了淋溶液流量对肥料氮、磷、钾与养分累积释放率的关系,并采用此装置测试了3种不同肥料的氮、磷、钾累积释放率,与实际效果完全一致.研究表明,采用"淋溶法",通过改变淋溶液流量可以实现肥料养分释放性能的快速检测.     

原位反应包膜控释复合肥的养分释放

利用静态水中溶出实验和模拟土壤环境的淋溶实验,研究了含生物质油的包膜原料经原位反应制得包膜复合肥的养分释放.用电导率法和吸光度法分别对离子型养分K+、H2PO4-和NH4+和总氮素的释放进行了研究.结果表明,以生物质油为基本原料,在复合肥表面原位反应包膜可以制得符合欧洲标准委员会规定的控释肥;养分的释放速率与包膜材料组成和膜的化学结构等因素有关.     

自制稻谷垫在预防褥疮中的应用

自１９９０年始 ,我们选用自制稻谷垫置于患者受压部位 ,预防褥疮取得了满意的效果 ,现报道如下。１使用方法１.１缝制两个４０ｃｍ×４５ｃｍ大小的软棉质垫布套 ,装入稻谷约５ｋｇ ,制成厚３～４ｃｍ的稻谷垫 ,另制若干个１０ｃｍ×１５ｃｍ的小型稻谷垫 ,或可根据不同部位需要制成形状各异的稻谷垫 ,分别置于躯干及四肢骨隆突处。１.２根据患者躯体受压部位将稻谷垫置于身体的一侧 ,病情允许时 ,侧卧于对侧背对护士 ,将稻谷垫均匀铺平 ,让患者平卧其上 ,护士再到对侧将手稍托起患者局部 ,将手伸入身体下部把稻谷垫边缘拉至所需部位 ,展开…     

6例医源性脾撕裂伤的治疗体会

本文收集了 1994～ 2 0 0 1年在重大手术中出现的 6例脾撕裂伤病例 ,由于术中解剖异常、组织粘连、视野不清、操作不当等 ,致使脾包膜及膜下浅层实质组织撕裂。术中及时给予脾动脉结扎加脾修补术治疗 ,术后效果满意。现将治疗体会报告如下。1　临床资料本组 6例 ,3例为左肾上腺嗜铬细胞瘤 ,2例为胃贲门癌 ,1例为左肾癌。脾撕裂的部位 1～ 2处 ,裂口的大小 1～ 3ｃｍ ,不整齐 ,有裂隙状、三角状及不规则形 ,最深包膜下脾实质内 1 5ｃｍ。在手术中均用 7号丝线距包膜 1～ 4ｃｍ处结扎脾动脉 ,脾撕裂处用粗线交错“ｕ”形缝合 ,部分用止血海绵…     

颅内成熟型畸胎瘤1例

患者男 ,8岁 ,无明显诱因出现轻微头痛 ,呕吐半年 ,呕吐物为胃内容物 ,服药治疗无效 ,头痛加剧 ,频繁呕吐伴双眼眶胀痛 1月入院 ,脑ＣＴ示 :松果体区见一分叶状混杂密度肿块 ,有斑点状钙化灶 ,约 4 5ｃｍ× 4ｃｍ大小 ,考虑为松果体区肿瘤 ,于 1998年 9月 2 9日行右枕小脑幕入路行松果体肿瘤切除术 ,术中见肿瘤位于松果体区 ,大小为 5ｃｍ× 4ｃｍ× 3ｃｍ ,边缘清楚 ,有包膜 ,质韧、实体状呈灰黄色。术中先行瘤内电凝分块切除 ,再分离肿瘤包膜 ,最后全切肿瘤。出院后随访无异常。病理检查　肉眼见肿瘤为灰黄色碎块状组织 ,总体积为 4ｃｍ…     

肾上腺畸胎瘤一例

患者 ,女 ,31岁。因体检Ｂ超偶尔发现右肾上腺巨大占位性病变。无高血压、血尿等其它症状。来我院作内分泌(儿茶酚胺、醛固酮、皮质醇 )等检查均正常。ＩＶＰ示肾功能正常。ＣＴ示右肾上腺区见 12ｃｍ× 9ｃｍ× 8ｃｍ大小的混杂密度区 ,边缘清楚 ,强化后病灶无改变 ,ＣＴ诊断 :右肾上腺肿瘤或畸胎瘤可能。术中发现右肾上腺巨大肿瘤直径 12 5ｃｍ ,包膜完整 ;完整切除肿瘤 ,重 45 0克。病理 :肿瘤直径 12 5ｃｍ ,包膜完整 ,与肾上腺组织易分离 ,切面见多个囊腔直径 0 5～ 4ｃｍ ,囊内见粘冻样分泌物 ,灰褐色、灰白色 ,局部区域较实 ,6ｃ…     

左胸壁类癌1例

患者女 ,4 0岁。无意中发现左乳内上方有一无痛性包块 ,触之质硬。体格检查 :左乳内上象限可触及大小约 3ｃｍ× 4ｃｍ包块 ,质硬 ,边界清楚 ,活动度良好 ,表面光滑 ,无压痛。Ｂ超提示 :左乳纤维腺瘤。手术所见 :肿块有完整包膜 ,可将肿块完整剥离。病理检查 :肉眼可见 :包块 2ｃｍ×1 5ｃｍ ,有包膜 ,质脆。镜下见肿瘤呈巢状分布 ,间质为玻璃样变纤维组织 ,癌巢浸润到横纹肌束间 ,癌细胞大小较一致 ,核圆居中 ,有异型性 ,核分裂象少见 ,胞浆透明 ,未见乳腺腺体组织。免疫组化 :ＮＳＥ ,Ｓ - 10 0 ,Ａｃｔｉｎ ,ＣＫ - ,ＶＩＭ ,ＥＭＡ -…     

胃贲门部腺癌合并胸壁黏液样脂肪肉瘤一例报告

１病例报告患者男 ,７０岁 ,主因前胸部不适近１年 ,进食困难２０ｄ ,于２００１年１２月２９日入院。上消化道造影及食管镜检查示 :贲门小弯侧壁黏膜充血 ,直径约５ｃｍ。胸片示 :左胸壁球形阴影 ,约４ｃｍ×３ｃｍ。临床行胃大部切除及左胸壁肿物切除手术。术中见 :胃小弯肿物 ,约７ｃｍ×５ｃｍ×４ｃｍ ,质硬 ,胃左动脉淋巴结肿大 ;左胸壁有一肿物 ,直径约６ｃｍ ,质软 ,包膜尚完整。新鲜标本病理 :（１）肉眼观察可见①于贲门及胃小弯可触及一鸭蛋大小肿物 ,质坚硬。切面 :贲门部见一约６．２ｃｍ×５．６ｃｍ肿物 ,为灰黄色 ,沿胃小弯…     

纵膈胸腺脂肪瘤一例报告

患者女 ,３９岁 ,持续胸痛４月余。术中见前上纵膈包裹性肿块 ,位于胸骨角两侧各一块 ,分界较清。病理肉眼观察 :淡黄色肿块二个 ,分别为３ｃｍ×２ｃｍ×５ｃｍ、２ｃｍ×２ｃｍ×４ｃｍ ,包膜完整 ,切面均呈实性、质软、淡黄色 ,部分区域灰白色。镜下 :脂肪组织和胸腺组织大量增生 ,分化成熟 ,皮髓质分界清楚 ,髓质中胸腺小体。诊断 :纵膈胸腺脂肪瘤。讨论胸腺脂肪瘤属良性肿瘤 ,非常少见 ,原发于胸腺 ,多位于前纵膈 ,以青少年多见［１］。患者一般无症状 ,肿瘤长大后有胸痛、心悸或呼吸道症状。须与正常复旧的胸腺内富有脂肪组织鉴别 ,故…     

Preparation and Release Characteristics of Protein-Loaded Polyanion/Gelatin Complex

Purpose: This paper describes preparation of polymethacrylic acid/gelatin complex and Myoglobin release characteristics in order to evaluate the polyanion/gelatin complexes as matrices that can release proteins at a near zero-order kinetics over a long period of time. Methods: Mb-loaded PMAA/gelatin complex was prepared by two different titration methods. Mb entrapment efficiency and PMAA/gelatin ratio in the complex were determined by HPLC. The release of Mb and gelatin from the complex was followed by HPLC. Mb conformation was detected by UV-vis spectrophotometer and capillary electrophoresis apparatus. Results: Polyanion/gelatin feed ratio of the polyanion/gelatin/Mb mixed solution has great effects on complex yield and protein entrapment efficiency when “Type I” titration method is adopted, while for the colloid titration method the complex yield and protein entrapment efficiency are hardly influenced by preparative conditions (ca. 100%). Mb release rate could be adjusted by the complex composition (e.g., PMAA MW, hydrophobilization of PMAA, Mb loading and PMAA/gelatin ratio, etc.). Moreover, by coating of high MW PMAA/gelatin complex cylinder in a hydrophobic membrane with one open-end left, the period of protein release can extend to ca. 20 days and the release displays a near zero-order pattern. The protein release profiles can be described by the dissociation/erosion mechanism. The entrapment process has little effect on Mb conformation. Conclusions: The studied polyanion/gelatin complex is promising to be used as protein carriers to release proteins at a near zero-order kinetics over a long period of time by selecting suitable polyanions and designing the device structure.     

Evaluation of a Gastro-Resistant Pulsed Release Delivery System (Pulsincap) in Humans

Using gamma scintigraphy, the behavior of a colon-targeted drug delivery system was followed in nine volunteers to ascertain the time and position in the gastrointestinal tract of a Pulsincap™ device when enteric coat dissolution and plug release occurred. Each subject a single radiolabeled unit with either 50 mL (study 1) or 150 mL water (study 2) after fasting overnight. Anterior, posterior, and lateral views were recorded for up to 12 h after dosing and the images stored for analysis. Dissolution of the enteric coat was observed between 29 and 70 min after gastric emptying with release of the indium label in the small intestine. In the second study, separation of the body and plug of each device was evident in all six subjects after a mean time of 5.34 ± 1.03 h (4.90 ± 1.07 h after gastric emptying). In all cases, plug release occurred in the cecum or ascending colon. In one subject, visualization of separation of plug and body was delayed; at more than 10 h into the study separation was not evident; thereafter, at 10.5 h the separation was 5 cm. The data suggest that the device has excellent potential for positioned delivery of drugs into the gastrointestinal tract.     

肠内营养的临床应用及其并发症

肠内营养（EN）是指通过口服或管饲给予营养液，用于补充机体所需要的全部或部分营养。肠内营养制剂可分为要素型、非要素型和组件型三类。，肠内营养通常采用管饲途径给予，鼻胃管和鼻空肠管属于无创置管，胃造口和空肠造口属于有创置管。肠内营养治疗的适应证包括上消化道、上呼吸道根治性手术；气管插管；食管狭窄；吞咽困难；神经性厌食症；大面积烧伤、创伤等。肠内营养比肠外营养更安全，但也存在并发症，常见的有：（1）机械性并发症，如喂养导管堵塞；（2）胃肠性并发症，表现为腹胀、恶心、呕吐、腹泻，可采用胃肠泵、置鼻肠管、降低营养液输注速度、提高营养液温度、给予胃肠动力药等处理；（3）代谢性并发症，主要为高血糖，可给予外源性胰岛素；（4）感染性并发症，主要是营养液误吸或在胃内潴留反流入气道所致的吸入性肺炎，表现为突发呼吸困难、发热、心率加快等，需注意检查胃潴留情况。     

Osmotic-Driven Release Kinetics of Bioactive Therapeutic Proteins from a Biodegradable Elastomer are Linear, Constant, Similar, and Adjustable

Purpose The aim of the study is to determine whether a biodegradable elastomeric device that uses an osmotic pressure delivery mechanism can release different therapeutic proteins at a nearly constant rate in nanomolar concentrations with high bioactivity, given the same formulation conditions. Vascular endothelial growth factor (VEGF) and interleukin-2 (IL-2) were embedded in the device as sample therapeutic proteins, and their release and bioactivity were compared to that achieved previously with interferon-γ (IFN-γ). Methods A photo-cross-linkable biodegradable macromer consisting of acrylated star(ɛ-caprolactone-co-d,l-lactide) was prepared. VEGF, IL-2, and IFN-γ were co-lyophilized with serum albumin and trehalose at different ratios and were then embedded into the elastomer by photo-cross-linking the lyophilized particles in a macromer solution. The protein mass and the bioactivity in the release supernatant were measured by enzyme-linked immunosorbent and cell-based assays. Results VEGF, IL-2, and IFN-γ were released at the same, nearly constant rate of 25.4 ng/day for over 18 days. Using the optimum elastomer formulation, the release profiles of the proteins were essentially identical, and their rates were linear and constant. Cell-based bioactivity assays showed that 70 and 88% of the released VEGF and IL-2, respectively, were bioactive. The rate of protein release can be adjusted by changing the trehalose loading concentration in the elastomer matrix without altering the linear nature of the protein release kinetics. The elastomeric device degraded in PBS buffer within 85 days. Conclusions The elastomer formulation shows promising potential as a sustained protein drug delivery vehicle for local delivery applications.     

硝苯地平缓释片释放度研究

目的建立硝苯地平缓释片的释放度试验方法，对5个厂家生产的硝苯地平缓释片的含量和释放度进行测定。方法以0．5％吐温-80水溶液（900mL）作为溶出介质，采用桨法测定溶出度，转速为100r／min，温度为（37．0±0．5）℃；用反相高效液相色谱法测定含量，测定波长为333nm。结果用建立的方法可以准确地测定各厂家硝苯地平缓释片的释放度，不同厂家生产的硝苯地平缓释片释放速度差别较大。结论对不同厂家生产的硝苯地平缓释片释放度进行检查，有助于控制产品质量。     

Release of hydrocortisone from a cream matrix: dependency of release on suspension concentration and measurement of solubility and diffusivity

The principal object of the present research was to investigate the sensitivity of drug release from a semisolid system to the manner of its preparation and to the concentration of drug placed within it. Established theory indicated that release should be concentration dependent, with the specific dependency determined by whether the drug in the system is fully in solution or is present substantially as suspended matter. To purposefully explore these relatively untested performance expectations, the total amount of drug in the formula was varied from a low concentration of 0.25% to a high concentration of 3%. Conditions were established such that drug release conformed to release from a semi-infinite medium into a receptor sink. At every concentration, release profiles were well reproduced in replicate samples and, where multiple lots of a kind were employed, from lot to identical lot. In all cases square root of time release kinetics were observed. Moreover and without exception, the square root of time release rate from run to run was directly proportional to the square root of the total concentration of hydrocortisone placed in the formulations. The amount released per square root of time per square root of total concentration was nearly identical from run to run irrespective of total concentration. The overall behavior fit theoretical expectations for suspensions having only a small fraction of the drug they contain in solution. That this condition prevailed even at the lowest 0.25% hydrocortisone strength was proven by independently measuring hydrocortisone's solubility (0.02%). Measurement of solubility permitted estimation of the effective diffusivity of the drug through the cream (2 x 10(-7) cm2/s).     

Enhanced Controlled Release of Loratadine From the Ethylene-vinyl Acetate Matrix Containing Plasticizer

An ethylene-vinyl acetate (EVA) matrix containing plasticizer was prepared as a potential controlled release system for loratadine. The EVA matrix containing loratadine was prepared as the transdermal device using casting methods. The solubility of loratadine according to the volume fraction of PEG 400 was determined. The effects of the drug concentration, temperature, and plasticizers on the release of the drug were determined at 37°C using 40% PEG 400 solution as the receptor medium using the modified Keshary-Chien cell. Some types of plasticizers. such as citrates and phthalates, were used to prepare the pores and increase the flexibility of the EVA matrix. The solubility test according to the PEG 400 volume fraction revealed the highest solubility in the 40% PEG 400 solution. The rate of drug released from the EVA matrix increased with increasing temperature and drug loading. There was a linear relationship between the release rate and the square root of the loading dose. The activation energy for drug release from the EVA matrix with a loading dose of 1%, 2%, 3%, 4%, and 5% was estimated to be 6.83, 6.80, 6.77, 6.71, and 6.65 kcal/mol, respectively Among the plasticizers used, diethyl phthalate showed the highest level of loratadine release. In conclusion, an EVA matrix containing plasticizer could be used to enhance the controlled release of loratadine.     

琥乙红霉素缓释片释放度研究

目的建立琥乙红霉素缓释片体外释放研究分析的硫酸显色法。方法以900 mL经脱气处理的0.1 mol/L盐酸溶液为释放介质,转速为75 r/min,75%的硫酸溶液为显色剂,采用紫外-可见分光光度法于482 nm波长处对琥乙红霉素缓释片的释放度进行测定。结果琥乙红霉素显色后质量浓度在40～72μg/mL范围内与吸收度呈良好线性关系(r=0.999 9);平均回收率为99.75%,RSD为0.76%;12 h内3批样品的释放量均在标示量的90%以上。结论该方法操作简便、准确可靠,可用于琥乙红霉素缓释片释放度的测定,为质量标准的制订提供了依据。     

Partition-controlled progesterone release from waterborne, in situ-gelling materials

The primary goal of this work was to evaluate the long-term constant zero-order release of progesterone from a waterborne, in situ-gelling, injectable material. The motivation for this is to develop an intrafallopian tube embolization system for contraception. Poly(ethylene glycol) diacrylate (PEGDA, 575 g/mol) or poly(propylene glycol) diacrylate (PPODA, 540 g/mol) as a Michael-type addition acceptor was combined with pentaerythritol-tetrakis (3-mercaptopropionate; a Michael-type addition donor) to create a 75 wt.% emulsion solution in 0.1M PBS (pH 7.4 for PEGDA and pH 12 for PPODA) that gels in minutes by the Michael-type reaction to form a hydrophobic solid. Samples, with approximately 5.5 or 25 wt.% progesterone, were formed in Tygon tubing. Samples (1.6 mm x 1.0 cm cylinders) showed constant, partition-controlled release of progesterone for a prolonged period (time dependent on the mass of progesterone). Cylinders with approximately 25 wt.% load of progesterone exhibited constant release (approximately 40 microg per day) for more than 50 days in both the PEGDA and PPODA systems. This type of release is normally associated with preformed hydrophobic matrix systems. In contrast, these in situ-gelling materials reported here can be used to provide zero-order, partition-controlled release of progesterone and enhance the efficiency of an intrafallopian tube embolization system through progesterone release in an injectable, in situ-forming system.     

Production of pH-Responsive Microparticles by Spray Drying: Investigation of Experimental Parameter Effects on Morphological and Release Properties

During spray drying, emphasis is placed on process optimisation to generate favourable particle morphological and flow properties. The effect of the initial feed solution composition on the drug release from the prepared microparticles (MPs) is rarely considered. We investigated the effects of solvent composition, feed solution concentration and drug-loading on sodium salicylate, hydrocortisone and triamcinolone release from spray-dried Eudragit L100 MPs. Eudragit L100 is a pH-responsive polymer whose dissolution threshold is pH 6 so dissolution testing of the prepared MPs at pH 5 and 1.2 illustrated non-polymer controlled burst release. Increasing the water content of the initial ethanolic feed solution significantly reduced hydrocortisone burst release at pH 5, as did reducing the feed solution concentration. These findings caution that changes in feed solution concentration or solvent composition not only affect particles' morphological characteristics but can also negatively alter their drug release properties. This work also illustrate that drug-free MPs can have different morphological properties to drug-loaded MPs. Therefore, process optimisation needs to be carried out using drug-loaded systems. Depending on the physicochemical properties of the encapsulated active pharmaceutical ingredient (API), drug-loading can affect the polymer solubility in the initial feed solution with consequent impact on MPs morphological and release properties.