Gentamicin release from photopolymerized PEG diacrylate and pHEMA hydrogel discs and their in vitro antimicrobial activities

Hydrogels based on poly(ethylene glycol)-diacrylate (PEG-DA) and 2-hydroxyethyl methacrylate (HEMA) were polymerized with cross-linking agent ethylene glycol diacrylate (EGDMA) under mild photoinitiating conditions. PEG-DA and HEMA concentrations of disks with 1 ± 0.3 mm thickness were 30% and 50% w/w and 40% and 60% w/w, respectively. Gentamicin sulphate was incorporated into the hydrogel during photopolymerization and its release kinetics were tested by spectrophotometric method at 255 nm wavelength in phosphate buffer (pH 7.4) and citrate buffer (pH 2.2). The drug release in citrate buffer was faster compared with to phosphate buffer. The release of drug from 40% HEMA containing hydrogel showed Fickian diffusion mechanisms in phosphate buffer (pH 7.4). Antimicrobial efficiency of the samples was tested by agar diffusion method in two different bacterial cultures (Pseudomonas aeruginosa [ATCC 10145], Staphylococcus aureus [ATCC 25923]). Inhibition zone diameter (mm) surrounding each sample was measured after 24 hr incubation of drug loaded disks onto agar plates at 37°C. Inhibition zone formation also confirms that gentamicin sulphate preserves its antimicrobial activity after subjected to photopolymerization conditions.     

Gentamicin Release from Photopolymerized PEG Diacrylate and pHEMA Hydrogel Discs and Their In Vitro Antimicrobial Activities

Hydrogels based on poly(ethylene glycol)-diacrylate (PEG-DA) and 2-hydroxyethyl methacrylate (HEMA) were polymerized with cross-linking agent ethylene glycol diacrylate (EGDMA) under mild photoinitiating conditions. PEG-DA and HEMA concentrations of disks with 1 ± 0.3 mm thickness were 30% and 50% w/w and 40% and 60% w/w, respectively. Gentamicin sulphate was incorporated into the hydrogel during photopolymerization and its release kinetics were tested by spectrophotometric method at 255 nm wavelength in phosphate buffer (pH 7.4) and citrate buffer (pH 2.2). The drug release in citrate buffer was faster compared with to phosphate buffer. The release of drug from 40% HEMA containing hydrogel showed Fickian diffusion mechanisms in phosphate buffer (pH 7.4). Antimicrobial efficiency of the samples was tested by agar diffusion method in two different bacterial cultures (Pseudomonas aeruginosa [ATCC 10145], Staphylococcus aureus [ATCC 25923]). Inhibition zone diameter (mm) surrounding each sample was measured after 24 hr incubation of drug loaded disks onto agar plates at 37°C. Inhibition zone formation also confirms that gentamicin sulphate preserves its antimicrobial activity after subjected to photopolymerization conditions.     

Hydrogel Containing Silica Shell Cross-Linked Micelles for Ocular Drug Delivery

Poly(2-hydroxyethyl methacrylate–methacrylic acid–ethylene glycol dimethacrylate) hydrogels loaded with silica shell cross-linked methoxy(polyethylene glycol)-block-polycaprolactone (MePEG-b-PCL) micelles with rod-like morphology were prepared as a potential soft contact lens material for the sustained release of ocular drugs. The silica shell cross-linked methoxy micelles (SSCMs) comprising a polycaprolactone core surrounded by a silica shell were synthesized and their size, morphology, stability, and drug release kinetics were evaluated. The relationships between the composition of the SSCM-loaded poly(2-hydroxyethyl methacrylate) (pHEMA)-based hydrogels and their transparency, surface wettability, and equilibrium water content were determined. Scanning electron microscopy (SEM) images of SSCM–hydrogel systems showed the presence of intact SSCMs within the hydrogel matrix. Dexamethasone acetate (DMSA), a hydrophobic ophthalmic drug, was loaded into the SSCMs prior to their incorporation into the hydrogels. In vitro release of DMSA from the SSCM–hydrogels, with varying drug loading levels, was observed for up to 30 days. Overall, the incorporation of rod-like SSCMs within pHEMA-based hydrogels provided sustained release over prolonged periods while maintaining optical transparency. This delivery system may be suitable for use as a therapeutic soft contact lens material.     

Radiolabeling of new generation magnetic poly(HEMA–MAPA) nanoparticles with 131I and preliminary investigation of its radiopharmaceutical potential using albino Wistar rats

In this study, N ‐methacryloyl‐l ‐phenylalanine (MAPA) containing poly(2‐hydroxyethylmethacrylate) (HEMA)‐based magnetic poly(HEMA–MAPA) nanobeads [mag‐poly(HEMA–MAPA)] were radiolabeled with ¹³¹I [¹³¹I‐mag‐poly(HEMA–MAPA)], and the radiopharmaceutical potential of ¹³¹I‐mag‐poly(HEMA–MAPA) was investigated. Quality control studies were carried out by radiochromatographic method to be sure that ¹³¹I binded to mag‐poly(HEMA–MAPA) efficiently. In this sense, binding yield of ¹³¹I‐mag‐poly(HEMA–MAPA) was found to be about 95–100%. In addition to this, optimum radiodination conditions for ¹³¹I‐mag‐poly(HEMA–MAPA) were determined by thin‐layer radiochromatography studies. In addition to thin‐layer radiochromatography studies, lipophilicity (partition coefficient) and stability studies for ¹³¹I‐mag‐poly(HEMA–MAPA) were realized. It was determined that lipophilicities of mag‐poly(HEMA–MAPA) and ¹³¹I‐mag‐poly(HEMA–MAPA) were 0.12 ± 0.01 and 1.79 ± 0.76 according to ACD/logP algorithm program, respectively. Stability of the radiolabeled compound was investigated in time intervals given as 0, 30, 60, 180, and 1440 min. It was found that ¹³¹I‐mag‐poly(HEMA–MAPA) existed as a stable complex in rat serum within 60 min. After that, biodistribution and scintigraphy studies were carried out by using albino Wistar rats. It was determined that the most important ¹³¹I activity uptake was observed in the breast, the ovary, and the pancreas. Scintigraphy studies well supported biodistribution results. Copyright © 2013 John Wiley & Sons, Ltd.     

角膜基质内植入改性聚羟乙基丙烯酸甲脂材料的生物学反应

目的评价角膜层间植入改性聚羟乙基丙烯酸甲酯(Poly(2-hydroxyethyl methacrylate,PHEMA)孔隙性材料的生物学反应。方法选用20只新西兰白兔,将PHEMA材料植入角膜基质内,定期观察。结果植入后PHEMA材料全部稳定存留于角膜内,角膜组织呈穿通性长入PHEMA材料孔隙内,现最长达12个月以上。未见PHEMA材料排出,也未发生白内障、视网膜脱离、角膜后膜等并发症。术后并发症包括睑缘红肿、畏光、流泪等刺激症状,均于术后1周内消失；组织学提示PHEMA材料孔隙内有多量的成纤维细胞并有胶原等细胞外基质沉积。电镜检查PHEMA材料周围角膜细胞功能活跃,分泌胶原,类似组织愈合过程。结论PHEMA孔隙材料是人工角膜支架的理想材料；由于该材料还可以制作成光学性能良好的光学部,故可望制成一体式人工角膜。     

Correlations between the properties and effects of clinical therapy using textile material with antipsoriatic action]

The aim of the study was to design a textile material as a carrier for dermatological drugs. Cotton fabric was chosen for experimentation to be a fibrous support for the system. Additional components were a drug carrier in form of synthetic hydrogel impregnation (partially crosslinked poly(acrylic acid) and a bioactive agent dithranol) dispersed within the gel. The rate of release of the drug from the fibrous system was measured in aqueous media and depended on the concentration of dithranol. The structure and physical properties of the material were designed and controlled in order to ensure the optimal contact with the skin. Clinical studies were carried out with psoriatic patients. The results of the treatment with the textile material containing dithranol were presented using a computer optimalization method. In conclusion it was asserted that this type of textile-based medical device is effective and in many respects more convenient and less troublesome alternative in the treatment of psoriasis as compared to conventional treatments with dithranol suspended in ointments and creams.     

Soft contact lenses capable of sustained delivery of timolol

The aim of this work was to evaluate the influence of the composition and the application of an imprinting technique on the loading capability of weakly crosslinked hydroxyethyl methacrylate (HEMA) hydrogels, with a view to their use as reloadable soft contact lenses for administration of timolol. Hydrogels were prepared by dissolution of ethylene glycol dimethacrylate (EGDMA, 10 mM) in HEMA with or without methacrylic acid (MAA) or methyl methacrylate (MMA; 100-400 mM) and with or without timolol maleate (10 mg/mL), initiation of polymerization by addition of 2,2'-azo-bis(isobutyronitrile) (AIBN, 10 mM), injection in molds, and curing in an oven at 50-70 degrees C. Unreacted reagents were removed by boiling. The dry hydrogels were clear and fully polymerized with smooth, poreless surfaces and presented optimal mechanical properties. The hydrogels were then characterized by determination of their swelling and timolol release kinetics in 0.9% NaCl, phosphate buffer (pH 7.4) and artificial lacrimal fluid, and of the timolol loading capacity of both nonimprinted hydrogels and de-timololized imprinted hydrogels at various pHs. Both water uptake and timolol release exhibited Fickian kinetics, except in the case of hydrogels made with 400 mM MAA. Timolol diffusion into 0.9% NaCl from HEMA or HEMA/MMA was slow; release from HEMA/MAA into phosphate buffer or lacrimal fluid was faster and increased with the MAA content of the polymer. Timolol loading was significant for HEMA/MAA hydrogels (imprinted or not) at pH 5.5-7.5, and specially for imprinted hydrogels containing 100 mM MAA, which absorb 12 mg timolol/g dry hydrogel. The results indicate that the incorporation of MAA as comonomer increases the timolol loading capacity to therapeutically useful levels while retaining appropriate release characteristics.     

Sustained prevention of biofilm formation on a novel silicone matrix suitable for medical devices

Bacterial colonization and biofilm formation on medical devices constitute major challenges in clinical long-term use of e.g. catheters due to the risk of (re)infection of patients, which would result in additional use of antibiotics risking bacterial resistance development. The aim of the present project was to introduce a novel antibacterial approach involving an advanced composite material applicable for medical devices. The polymeric composites investigated consisted of a hydrogel network of cross-linked poly(2-hydroxyethyl methacrylate) (PHEMA) embedded in a poly(dimethylsiloxane) (PDMS) silicone elastomer produced using supercritical carbon dioxide (scCO₂). In these materials, the hydrogel may contain an active pharmaceutical ingredient while the silicone elastomer provides the sufficient mechanical stability of the material. In these conceptual studies, the antimicrobial agent ciprofloxacin was loaded into the polymer matrix by a post-polymerization loading procedure. Sustained release of ciprofloxacin was demonstrated, and the release could be controlled by varying the hydrogel content in the range 13–38% (w/w) and by changing the concentration of ciprofloxacin during loading in the range of 1–20 mg/mL. Devices containing 25% (w/w) hydrogel and loaded with ciprofloxacin displayed a strong antibacterial effect against Staphylococcus aureus bacterial colonization and subsequent biofilm formation on the device material was inhibited for 29 days. In conclusion, the hydrogel/silicone composite represents a promising candidate material for medical devices that prevent bacterial colonization during long-term use.     

Development of cisplatin-loaded hydrogels for trans-portal vein chemoembolization in an orthotopic liver cancer mouse model

Transarterial chemoembolization is a standard treatment for intermediate-stage hepatocellular carcinoma (HCC). This study evaluated the anti-tumor effect of the semi-interpenetrating network (IPN) hydrogel as a novel embolic material for trans-portal vein chemoembolization (TPVE) in vivo. A nude mice orthotopic HCC model was established, followed by TPVE using IPN hydrogel loaded with or without cisplatin. Portal vein blockade was visualized by MRI and the development of tumor was monitored by IVIS Spectrum Imaging. Tumor proliferation and angiogenesis were evaluated by Ki67 and CD34 staining respectively. Intra-tumor caspase 3, Akt, ERK1/2, and VEGF activation were detected by Western Blot. ¹⁸F-FMISO uptake was evaluated by microPET-MRI scanning. IPN hydrogel first embolized the left branch of portal vein within 24 hours and further integrated into the intra-tumor vessels during 2 weeks after the treatment. Mice treated with cisplatin-loaded hydrogels exhibited a significant decrease in tumor growth, along with lower plasma AFP levels as compared to hydrogel-treated and untreated tumor-bearing mice. By Ki67 and CD34 staining, the TPVE with IPN hydrogel suppressed tumor proliferation and angiogenesis. In addition, increased tumor apoptosis shown by up-regulation of caspase 3 with decreased expressions of tumor cell survival indicators Akt and ERK1/2 were observed in the treatment groups. Consistent with the decreased expression of VEGF after TPVE, hypoxia level in the tumor was also reduced as indicated by ¹⁸F-FMISO uptake level. IPN hydrogel-based TPVE significantly suppressed the tumor development by regulating intra-tumor angiogenesis and cell survival in an orthotopic HCC mouse model, suggesting a viable embolic agent for transarterial chemoembolization.     

Synthesis and characterization of cyclic acetal based degradable hydrogels.

While many synthetic, hydrolytically degradable hydrogels have been developed for biomedical applications, there are only a few examples whose polymer backbone does not form acidic products upon degradation. In order to address this concern, we proposed to develop a hydrogel based on a cyclic acetal unit that produces diols and propanals upon hydrolytic degradation. In particular, we proposed the fabrication of hydrogels formed by the free radical polymerization of two diacrylate monomers, 5-ethyl-5-(hydroxymethyl)-beta,beta-dimethyl-1,3-dioxane-2-ethanol diacrylate (EHD), a cyclic acetal having two acryl groups, and poly(ethylene glycol)diacrylate (PEGDA). However, the hydrophobicity of the EHD monomer inhibits hydrogel fabrication. Therefore this work develops a strategy to form hydrogels with a co-monomer system, one of which is hydrophobic, and subsequently describes the properties of the resulting hydrogel. Using benzoyl peroxide as an initiator and N,N-dimethyl-p-toluidine as an accelerator, the EHD and PEGDA monomers were reacted in an acetone/water co-solvent system. The chemical structure of the resulting EH-PEG [5-ethyl-5-(hydroxymethyl)-beta,beta-dimethyl-1,3-dioxane-2-ethanol-co-PEG] hydrogel was then characterized by FT-IR. Physicochemical properties of the EH-PEG hydrogel, including swelling degree, sol fraction, and contact angle, were determined so as to characterize the properties of these materials and ultimately investigate their use in drug delivery and tissue engineering applications. Results showed that EH-PEG hydrogel may be formed using the co-solvent system. Further results indicated that swelling degree is dependent upon initiator concentration, monomer concentration, and molar ratios of monomers, while sol fraction significantly depended on initiator concentration and monomer concentration, only. These results demonstrate the ability to fabricate hydrogels using EHD and PEGDA system as well as to control the properties of the resulting hydrophilic networks.     

急性缺血性卒中患者血管内治疗疗效的相关因素分析

随着2015年5项随机对照临床试验陆续发表,血管内治疗已成为大动脉闭塞所致急性脑梗死患者优选治疗方案。有一部分患者尽管血管已经再通,但是其预后不良。笔者通过查阅相关资料,发现有很多因素可能会影响到血管再通的效果及预后。该文就从时间窗、高血糖、侧支循环、血压、取栓次数、美国国立卫生研究院卒中量表（NIHSS）评分等部分影响血管内治疗疗效的可能因素作一综述。     

Poly(acrylic acid) microspheres loaded with lidocaine: Preparation and characterization for arterial embolization

A new embolic agent, poly(acrylic acid) microspheres (PMs), was synthesized and the cytocompatibility was proved by mouse L929 fibroblast cells. An analgesic drug, lidocaine, was loaded on the PMs to relief pain caused by embolization. PMs and lidocaine loaded microspheres (LMs) were characterized by investigating infrared spectrum, morphology, particle size, and equilibrium water contents (EWC). A series of tests were employed to evaluate the elasticity of PMs, LMs and Embosphere?, including once compression, twice compression, and stress relaxation test. The pressures of PMs and LMs passing through a catheter were measured on line by our new designed device. Drug release was studied with T-cell apparatus. The properties of PMs and LMs were proved to be suitable for embolization. Both PMs and LMs in this study might be potential embolic agents in the future.     

血管内治疗小脑后下动脉瘤24例临床经验

目的 探讨血管内治疗小脑后下动脉（PICA）瘤的治疗策略、安全性及临床疗效。方法 回顾性分析安徽医科大学第一附属医院2017年7月至2022年1月行血管内治疗的24例PICA动脉瘤病人的临床资料（其中,PICA近端13例、过渡段1例、远端10例;以蛛网膜下腔出血首诊的21例、未破裂动脉瘤3例）,单纯栓塞12例、动脉瘤及载瘤动脉闭塞7例（闭塞材料使用弹簧圈3例、Onyx胶4例）、支架辅助弹簧圈栓塞5例。术后随访3～24个月。结果 24例PICA动脉瘤病人术中动脉瘤均栓塞顺利。23例病人无近期并发症,1例出血病人合并严重脑血管痉挛自动出院（临床预估死亡）。随访结果：19病人远期随访无复发;4例复发,其中2例二期行支架辅助栓塞,后期随访良好、未再复发;1例首次支架辅助栓塞病人再次行穿支架网孔弹簧圈单纯栓塞,后期随访良好、未再复发;1例首次单纯栓塞病人再次行弹簧圈栓塞,后期随访良好、未再复发。结论 血管内治疗PICA动脉瘤安全、可行,疗效可靠。根据动脉瘤血管解剖位置,对于破裂出血的PICA动脉瘤首次治疗倾向单纯栓塞或载瘤动脉闭塞术。首次单栓病例术后复发,可二期行支架辅助栓塞能取得满意效果。对于...     

Glypican-3免疫组化在肝穿刺活检肝细胞癌诊断的价值

目的磷脂酰肌醇蛋白聚糖-3（GPC3）是一种硫酸乙酰肝素蛋白聚糖,仅在肝细胞癌（hepatocellular carcinoma,HCC）患者的血清中升高,而在正常人和良陆肝脏疾病患者无升高。此文探讨GPC3免疫组化在肝穿刺活检中诊断HCC的价值。方法采用免疫组化检测41例HCC、7例肝局竈结节增生或局竈肝细胞异型增生、4例肝硬化、4例病毒性肝炎或未见病变肝组织、4例赡管癌、21例转移癌GPC3（1G12克隆）表达,并设阳性和阴性对照。结果80．5％的HCC（33／41例）GPC3呈阳性反应。相反,40例非HCC肝穿刺病例,包括肝局竈结节增生或局竈肝细胞异型增生、肝硬化、病毒性肝炎或未见病变肝组织、胆管癌和转移癌GPC3均为阴性。GPC3免疫组化检测在肝穿刺活检HCC诊断的敏感性和特异性分别为80.5％和100％。结论GPC3免疫组化是肝穿刺活检诊断HCC的良好指针,也是区别其它肝脏良陆疾病和转移癌的鉴别诊断指针。     

Supramolecular hydrogels as a universal scaffold for stepwise delivering Dox and Dox/cisplatin loaded block copolymer micelles

A general and simple method was presented for preparing supramolecular hydrogels to deliver anticancer drugs. In this system, hydrophobic anticancer drug doxorubicin (Dox) was loaded into poly(ethylene glycol)-b-poly(?-caprolactone) (PEG-b-PCL) amphiphilic block copolymer micelles by hydrophobic interaction. The drug loaded micelles were then mixed with α-cyclodextrin (α-CD) solution to generate the hydrogel. The α-CDs were threaded onto the PEG coronae of the micelles, and formed physical crosslinks of the molecular necklaces. Moreover, by mixing solutions of cisplatin complexed poly(ethylene glycol)-b-poly(acrylic acid) (PEG-b-PAA) micelles, Dox loaded PEG-b-PCL micelles and α-CDs together, a dual-drug loaded supramolecular hydrogel was generated. The gelation properties could be tuned by changing concentrations and polymerization degree of the polymers, and by adding PEG homopolymers or Pluronic copolymers as additives. Structures and properties of the drug loaded hydrogels were studied by wide-angle X-ray diffraction (XRD) and rheology measurement, respectively. In vitro drug release in PBS with different pH values was quantified. The erosion of hydrogels produced discrete micelles, from which the free drugs were released. In vitro cytotoxicity studies showed that the Dox loaded hydrogel inhibited the growth of human bladder carcinoma EJ cells, and the dual-drug loaded hydrogel showed even higher cytotoxicity.     

Synthesis and characterisation of inulin-azo hydrogels designed for colon targeting

The present paper describes the synthesis and characterisation of new hydrogel systems designed for colon targeting. The gels were composed of methacrylated inulin (MA-IN), copolymerized with the aromatic azo agent bis(methacryloylamino)azobenzene (BMAAB) and 2-hydroxyethyl methacrylate (HEMA) or methacrylic acid (MA). The gels were assessed by studying the influence of various parameters on the dynamic and equilibrium degree of swelling. It was shown that the uptake of water in the gels was inversely proportional to the MA-IN feed concentration, the degree of substitution of the inulin backbone, and the concentration of BMAAB. The latter can probably be explained by the hydrophobic nature and rigidity of the aromatic azo agent. Incorporation of the hydrophilic monomers HEMA or MA also reduced the equilibrium degree of swelling. An increasing network density and hydrogen bonding propensity, can suggested to be responsible for this observation. It was shown that water uptake in the hydrogels was controlled by both relaxation and diffusion mechanisms (anomalous behaviour). When the release of the model drug prednisolone was studied in phosphate buffer, it was shown that >80% of the drug was released during the first 3 h from hydrogels of MA-IN:HEMA. Although drug release decreased significantly from MA-IN:HEMA:BMAAB hydrogels, it remained too high: approximately 50% of the drug was released after 5 h. The same observation was made for hydrogels containing MA instead of HEMA. These results clearly point out the difficulty in finding the optimal balance between swelling to allow degradation in the colon (high swelling of the gels) and low premature drug release before the colonic environment is reached (low swelling properties).     

Calcein Release from Polymeric Vesicles in Blood Plasma and PVA Hydrogel

Purpose  The main goal of this study was to show the long-term stability of vesicles from poly(2-methyl oxazoline-block-polydimethylsiloxane-block poly(2-methyl oxazoline) (PMOXA-PDMS-PMOXA) in PBS, blood plasma and the feasibility to use these vesicles for drug release from PVA hydrogels. Methods  The vesicle formation properties and loading efficiency was evaluated using fluorescent dyes. The stability of the vesicles was evaluated in buffer at pH 7 at room temperature and in 50% blood plasma at 37°C. The calcein loaded vesicles were dispersed in a UV crosslinked PVA hydrogel. The stability of the vesicles in the hydrogel was observed over one week, before the vesicles were ruptured with Triton X-100. Results  The vesicles are very stable in buffer, blood plasma, and the PVA hydrogel. In plasma 50% of the calcein is released in 48 h in the presence of sodium azide. The vesicles can be evenly dispersed in PVA and are stable. The release can be triggered and the calcein diffuses afterwards quickly throughout the gel. Conclusion  Polymeric vesicles can be used as diffusion barrier in hydrogels for the controlled release of water soluble drugs. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Modeling of swelling and drug release behavior of spontaneously forming hydrogels composed of phospholipid polymers

Physically cross-linked hydrogel had been investigated in order to make use of oral polypeptide drug delivery carrier. By using 2-methacryloyloxyethyl phosphorylcholine (MPC) copolymer, we had prepared a spontaneously forming hydrogel showing controllable dissociation via pH changes. In this study, the dissociation and release of polypeptide drugs from the MPC polymer hydrogel loaded with polypeptide drugs, which had been prepared from aqueous solutions containing water-soluble poly[MPC-co-methacrylic acid (MA)] (PMA) and poly[MPC-co-n-butyl methacrylate (BMA)] (PMB) had been executed. The polymer concentration was 10 wt.% and PMA/PMB feed ratio (A/B feed ratio) was 5/5. Insulin labeled with fluorescein-4-isothiocyanate (FITC) and cytochrome c had been loaded for the examination of the release behavior. The hydrogel in pH 1.8 aqueous solution would be swelling, for the hydrogel would absorb outside water. However, during this process, the polymer is dissoluting out from the hydrogel due to the widening of the polymer network. The cytochrome c followed anomalous transport while insulin depended on the swelling and dissolution of the polymer chains. The hydrogel showed surface erosion in neutral condition, although the hydrogel is composed of two different polymer possessing divergent physical properties. The release followed anomalous transport, but the erosion rate slightly changed with as the hydrophobicity of the loaded drugs. The total amount of the drugs released in neutral condition was larger compared to the acidic condition. When the eroded percentage and the release percentage were compared with each other, it showed that release was slightly slower than erosion, indicating that the erosion was controlling the release phenomenon.     

聚甲基丙烯酸-2-羟乙酯软骨膜的制备及性能研究

目的制备缓、控释性能优异的依诺沙星-聚甲基丙烯酸-2-羟乙酯水凝胶膜,在体外研究其性能。方法以过硫酸铵（〔（NH4）2S2O8〕）作为引发剂,KH570（γ-甲基丙稀酰氧基丙基三甲基硅烷）为交联剂,2-甲基丙烯酸-2-羟乙酯（HEMA）为原料聚合成水凝胶膜。选用依诺沙星为模型药物水相聚合,通过分步法和同步法导入药物,并测定其体外释药情况。结果水凝胶膜表面形态理想,导入药物后的载药膜具有良好的膨胀性能和更优秀的缓、控释特征。结论以甲基丙烯酸-2-羟乙酯（25%）为单体、KH570（γ-甲基丙稀酰氧基丙基三甲基硅烷）为交联剂通过溶液聚合开发出一类性能优异的载药水凝胶膜。     

Chlordecone-induced hepatic dysfunction

Chlordecone (Kepone) is a decachloroketone analog of the dodecachlorohydrocarbon mirex and is used as a stomach poison insecticide. Despite the structural similarity to mirex, chlordecone is unlike mirex in general organ-specific toxic properties. Chlordecone is primarily accumulated in the liver, where it causes a variety of morphological and biochemical alterations. Although less effective than mirex as a hepatotoxin, it causes liver enlargement, focal necrosis, mitochondrial changes, fatty infiltration of hepatocytes, and proliferation of endoplasmic reticulum. Chlordecone accumulation and morphological alterations in the liver were also observed in occupationally exposed human patients. Induction of hepatic microsomal mixed-function oxidases (MFOs) and impaired production and utilization of hepatocellular energy are the principal biochemical aberrations produced by chlordecone. Chronic exposure causes carcinogenesis in mice and rats. Hyperplastic nodules, which progress to hepatocellular carcinomas, are the principal pathological lesions. Acute and chronic exposures to chlordecone result in hepatobiliary dysfunction manifested as impaired excretion of anionic compounds accompanied by choleresis. Exposure to chlordecone results of greatly potentiated haloalkane hepatotoxicity, representing a most potent toxic interaction at otherwise individually nontoxic levels. In view of the demonstrated carcinogenic effect of chlordecone, such interactions at very low levels assume extraordinary significance in terms of chronic toxicological and pathological manifestations induced by combinations of toxic chemicals.