微囊化吲哚美辛片剂的研讨

以明胶-CAP 为囊材,经复凝聚法制备吲哚美辛微囊,再按所筛选的最佳处方制备微囊化片剂。该片与市售片相比,体外 T_(50)延长约5.6倍,家兔体内达峰时间滞后,能明显减轻对大鼠胃的刺激性。     

静电法制备小微囊包裹成年猪胰岛的实验研究

目的　探索用静电法制备小微囊包裹成年猪胰岛细胞。方法　用自制的静电微囊发生装置、制备海藻酸钠 -多聚赖氨酸 -海藻酸钠 (APA)微囊 (微囊直径 <35 0 μm) ,包裹成年猪胰岛 ,体外检测APA小微囊猪胰岛生物活性及微囊膜的通透性 .结果　静电法制备的APA微囊直径 30 0～ 35 0 μm ,大小相对均一 .小微囊包裹成年猪胰岛后 ,每个微囊内可见 1～ 2个胰岛团 ,表面光滑 .囊内胰岛组织学结构完整 ,体外培养微囊化胰岛素分泌良好 ,葡萄糖刺激释放明显 ,显示了良好的细胞活力及微囊膜通透性 .结论　用我们自制的静电微囊发生装置能制备APA微囊包裹成年猪胰岛细胞 ,微囊直径 30 0～ 35 0 μm ,表面光滑 ,囊内猪胰岛生物活性良好     

Polymeric Microspheres Prepared by Spraying into Compressed Carbon Dioxide

Purpose. The objective was to prepare polymeric microparticles by atomizing organic polymer solutions into a spray chamber containing compressed CO₂ (PCA-process) and to study the influence of various process parameters on their morphological characteristics. Methods. The swelling of various pharmaceutically acceptable polymers [ethyl cellulose, poly(methyl methacrylate), poly(-caprolactone), poly(dl-lactide), poly(l-lactide) and poly(dl-lactide-glycolide) copolymers] in CO₂ was investigated in order to find polymers which did not agglomerate during the spraying process. Poly(l-lactide) (L-PLA) microparticles were prepared by spraying the organic polymer solution into CO₂ in a specially designed spraying apparatus. The effect of various process (pressure and temperature of the CO₂ phase, flow rate) and formulation (polymer concentration) variables on the morphology and particle size of L-PLA-microparticles was investigated. Results. Polymers with low glass transition temperatures agglomerated even at low temperatures. The formation of microparticles was favored at moderate temperatures, low polymer concentrations, high pressures and high flow rates of CO₂. High polymer concentrations and low flow rates resulted in the formation of polymeric fibers. Colloidal L-PLA particles could also be prepared with this technique in a surfactant-free environment. Initial studies on the microencapsulation of drugs resulted in low encapsulation efficiencies. Conclusions. The PCA method is a promising technique for the preparation of drug-containing microparticles. Potential advantages of this method include the flexibility of preparing microparticles of different size and morphology, the elimination of surfactants, the minimization of residual organic solvents, low to moderate processing temperatures and the potential for scale-up.     

含药树脂微囊法制备口服缓释混悬液Ⅰ.右美沙芬口服缓释混悬液

采用含药树脂微囊法制备了右美沙芬口服缓释混悬夜，研究了影响含药树脂药物吸附和释放的因素及体外释药和健康志愿者体内的药动学。结果表明该混悬液在服用12h后，尚有101．9ng／m1的有效血药浓度。     

Preparation of bovine serum albumin loaded poly (D,L-lactic-co-glycolic acid) microspheres by a modified phase separation technique

BSA-loaded mcirospheres were prepared by a modified phase separation method, in which petroleum ether (PE) containing a certain amount of Span 80 rather than poly (dimethylsiloxane) (PDMS) was adopted as coacervating agent. Process parameters such as Span 80 concentration, the volume and addition rate of coacervating agent, polymer concentration, agitation rate during the phase separation process and PE type were evaluated to optimize the protein encapsulation. It was found microspheres with high yield (>80.0%) and entrapment efficiency (>90%) could be obtained using PE containing 5.0% Span 80 as the coacervating agent. Microspheres with small particle size (<10?µm) could be produced successfully with appropriate process parameters. In vitro release study suggested that burst release was significantly influenced by Span 80 concentration, polymer concentration and PE type and the burst release could be reduced to <20% with optimized formulation. A biphasic release behavior in vitro test was observed for the microspheres prepared by this method. GC analysis demonstrated that residual solvent of DCM and petroleum ether was decreased dramatically in comparison with PDMS used as a conventional coacervating agent.     

Insulin encapsulation

Many researchers all over the world are exploring various methods to find better insulin delivery routes for diabetic patients. Microencapsulation in biodegradable polymeric matrices is the source of developing new insulin formulations. This paper will attempt to explain the techniques utilized for insulin microencapsulation, their specifications and the parameters that influence the process. This review takes a closer look at recent researches and methods that have been reported in this decade.     

微囊化嗜铬细胞对癌症病人止痛作用研究

目的寻找行之有效的止痛方法,观察微囊化嗜铬细胞(BCC)对晚期癌症病人的止痛作用.方法用新鲜牛肾上腺分离嗜铬细胞,微囊化处理,经腰穿植入癌症病人脊髓蛛网膜下腔,观察其镇痛效果及不良反应.结果BCC移植后92.30%的病人疼痛完全缓解,不再需任何止痛药;2例疼痛明显减轻,经1周后2次移植完全疼痛缓解;1例疼痛虽有减轻,但仍需服半量止痛药.结论本法止痛作用持续时间长,适用于癌症病人的应用.     

Lyophilised Vegetal BM 297 ATO-Inulin lipid-based synbiotic microparticles containing Bifidobacterium longum LMG 13197: design and characterisation

Abstract

This study aimed at the manufacturing and characterisation of Vegetal BM 297 ATO-inulin-Bifidobacterium longum LMG 13197 microparticles prepared by freeze drying. Emulsions containing 1%, 1.5%, 2%, 3.5% or 5% w/v inulin were prepared, with or without centrifugation before freeze drying. Morphological properties, particle size distribution, encapsulation efficiency of the microparticles and their ability to preserve viability of the enclosed B. longum LMG 13197 cells were evaluated. The microparticles produced from both formulations without a centrifugation step were irregular, porous with concavities and contained high number of bacterial cells. Formulations with or without inulin had average particle sizes of 33.4–81.0?μm with encapsulation efficiencies of 82% and 88%, respectively. Vegetal-inulin microparticles have the morphology and size that will enable their even distribution in final food products, and hence, they have the potential for use as a functional food additive because they are likely to deliver sufficient numbers of viable bacteria.     

Treatment of MPS I mice with microencapsulated cells overexpressing IDUA: effect of the prednisolone administration

Cell encapsulation, although a promising strategy to deliver therapeutic products, is hampered by immune response against biomaterials. The aim of this article is to assess the effect of prednisolone on enzyme release by microencapsulated cells implanted in vivo. Recombinant cells encapsulated were implanted in the peritoneum of wild-type mice and mucopolysaccharidosis (MPS) I mice, with or without prednisolone. Later, microcapsules were recovered for histological and enzyme analysis. Blood was collected from MPS I mice. All animals receiving prednisolone had a smaller inflammatory infiltrate. In vitro, prednisolone increased the amount of enzyme released from the recovered capsules, but this was not accompanied by an increase in the amount of circulating enzyme in vivo after 15 days. However, in 7 days, prednisolone significantly increased the amount of enzyme detected in the serum. Although prednisolone improved enzyme release in vitro and in vivo after 7 days, it was unable to maintain this effect for a longer period.     

The effect of polymer molecular weight and cell seeding density on viability of cells entrapped within PEGDA hydrogel microspheres

Abstract

Cell microencapsulation can be used in tissue engineering as a scaffold or physical barrier that provides immunoisolation for donor cells. When used as a barrier, microencapsulation shields donor cells from the host immune system when implanted for cell therapies. Maximizing therapeutic product delivery per volume of microencapsulated cells necessitates first optimising the viability of entrapped cells. Although cell microencapsulation within alginate is well described, best practices for cell microencapsulation within polyethylene glycol is still being elucidated. In this study we microencapsulate mouse preosteoblast cells within polyethylene glycol diacrylate (PEGDA) hydrogel microspheres of varying molecular weight or seeding densities to assess cell viability in relation to cell density and polymer molecular weight. Diffusion studies revealed molecule size permissible by each molecular weight PEGDA towards correlating viability with polymer mesh size. Results demonstrated higher cell viability in higher molecular weight PEGDA microspheres and when cells were seeded at higher cell densities.