A Case of Hydrophilic Polymer Embolism after TEVAR / 日本心臓血管外科学会雑誌

Hydrophilic polymer embolism (HPE) associated with endovascular therapy has steadily gained attention. We report a case of a 70-year-old man who had undergone one-debranched TEVAR. He had a history of distal arch replacement for dissecting aortic aneurysm 14 years earlier. Pseudoaneurysm at the proximal site of graft anastomosis was found on computed tomography (CT) angiogram during the follow-up. 1 debranching TEVAR was performed using the pull-through technique. Fourth days after the procedure, a skin rash appeared in the right lower extremity around the access site. Skin biopsy with pathological examination revealed HPE. We decided to observe a patient because there was no symptom of limb ischemia. Skin lesions improved and he was discharged on the 27th postoperative day. Hydrophilic polymers are widely used in the endovascular devices and there is an urgent need to better understand the complication of HPE.

Size Control of 99mTc-tin Colloid Using PVP and Buffer Solution for Sentinel Lymph Node Detection

Colloidal particle size is an important characteristic that allows mapping sentinel nodes in lymphoscintigraphy. This investigation aimed to introduce different ways of making a 99mTc-tin colloid with a size of tens of nanometers. All agents, tin fluoride, sodium fluoride, poloxamer-188, and polyvinylpyrrolidone (PVP), were mixed and labeled with 99mTc. Either phosphate or sodium bicarbonate buffers were used to adjust the pH levels. When the buffers were added, the size of the colloids increased. However, as the PVP continued to increase, the size of the colloids was controlled to within tens of nanometers. In all samples, phosphate buffer added PVP (30 mg) stabilized tin colloid (99mTc-PPTC-30) and sodium bicarbonate solution added PVP (50 mg) stabilized tin colloid (99mTc-BPTC-50) were chosen for in vitro and in vivo studies. 99mTc-BPTC-50 (100 nm) mainly accumulated in the liver. When a rabbit was given a toe injection, the node uptake of 99mTc-PPTC-30 decreased over time, while 99mTc-BPTC-50 increased. Therefore, 99mTc-BPTC-50 could be a good candidate radiopharmaceutical for sentinel node detection. The significance of this study is that nano-sized tin colloid can be made very easily and quickly by PVP.

Molecular dynamics simulation on mechanical properties of PVP/PVA / 医用生物力学

Objective To study the mechanical properties of PVP/PVA composite hydrogel and its interaction principle based on the molecular dynamics (MD) theory. Methods MD simulation was applied to investigate mechanical properties and radial distribution functions of PVP, PVA and their mixed system PVP/PVA. Results Compared with the pure PVP, mechanical properties of PVP/PVA were significantly improved, and not affected by temperature. The interaction between PVA and PVP was expected to occur through the interchain hydrogen bonding between the oxygen atom of PVP and the hydroxyl group of PVA. Conclusions MD method revealed the interaction mechanism of PVP/PVA hydrogel at molecular microscopic level and proved it better than pure PVP. Meanwhile, its mechanical properties were stable at different environment temperatures. These results provide a reliable theoretical research method for studying the fabrication process of hydrogel prosthesis in clinic and its mechanical properties.

Hydroxypropylcellulose controlled release tablet matrix prepared by wet granulation: effect of powder properties and polymer composition

The aim of this study was to attain 100 percent drug release of caffeine after 24 h from hydroxypropylcellulose (HPC) tablet matrices and to investigate the effect of co-excipient. Physical properties of the powders were evaluated and suggested for a wet granulation process. The tablet containing caffeine was formulated by different weight ratios of hydrophilic polymers. The results of polymer evaluation confirmed that the increase of HPC level with the same drug content significantly decreased the rate of drug release. The presence of co-polymer excipients carboxymethylcellulose (CMC) and polyvinylpyrrolidone (PVP) in the tablet matrix was also investigated. The release rate was also controlled by low levels of CMC (<10 percent) while PVP did not show any considerably effect. The best fit release rate 100 percent at 24 h was obtained when 10 percent of α-lactose monohydrate was added to the formulation.

O objetivo deste estudo é desenvolver a liberação 100 por cento da droga cafeína em 24 horas em comprimidos matrizes e investigar o uso de hidroxipropilcelulose (HPC) mais os efeitos de co-excipiente. As propriedades físicas dos pós foram avaliadas assim como seu uso no processo de granulação úmida. O comprimido contendo a cafeína foi formulado por diferentes relações de peso dos polímeros hidrofílicos. Os resultados da avaliação do polímero confirmaram que o aumento do nível de HPC com o mesmo índice da droga diminuiu significativamente a taxa de liberação da droga. A presença do co-polímero excipiente carboximetilcelulose (CMC) e do polivinilpirrolidona (PVP) na matriz do comprimido foi também investigado. A taxa de liberação foi controlada principalmente por baixos níveis de CMC (< 10 por cento) enquanto PVP não mostrou efeito diferente considerável. A melhor taxa de liberação de cafeína 100 por cento em 24 horas foi obtida quando 10 por cento da lactose monoidrato foi adicionado na formulação.

Preparation and dissolution of solid dispersion of Fructus Schisandrae Chinensis extracts / 中草药

Objective To prepare Wurenchun solid dispersion of alcohol extracts of Fructus Schisandrae Chinensis so as to improve the dissolution of its active compound in vitro.Methods The Wurenchun solid dispersions were prepared with various carriers and drug/carrier ratios by mixing the carrier in alcohol extractive solution of FSC directly,and the apparent solubility and dissolution of deoxyschisandrin in them were tested and compared.Results The apparent solubility and dissolution of deoxyschisandrin of Wurenchun solid dispersion(extracts: polyvinylpyrrolidone(PVP) K30=1∶3) were increased remarkably to 5.06 ?g/mL and 43.2% in water individually,including dispersed and dissolved drug whose particle size is below 0.22 ?m,compared with that of the self-prepared Wurenchun capsules.Conclusion Wurenchun solid dispersion made of PVP K30 can remarkably enhance apparent solubility and dissolution of the active compound in vitro.

Study on Optimization of Nano-silver Prepared by Method of Liquid Reduction / 环境与健康杂志

Objective The various influencing factors in the process of nano-silver preparation were studied in order to prepare nano-silver that has uniformity particle size distribution and good crystallinity. Methods Through the method of liquid reduction at room temperature,the nano-silver powders were prepared directly using silver nitrate as raw material,water as the reactive medium,polyvinylpyrrolidone(PVP) as protecting agent and ammonium formate as reducing agent. By means of EDS and TEM(transmission electron microscopy),the prepared silver particles were characterized. The various influencing factors in the process of preparation were also discussed. Results With the increasing concentration of AgNO3,the particle diameter of nano-silver changed obviously. When the concentration of silver nitrate was 0.25-0.30 mol/L,the size of product is the smallest. With the increasing concentration of reductant,the diameter of nano-silver decreased gradually. While at the concentration of 0.70 mol/L HCOOH,the average diameter of nano-silver is not more than 10 nm. Smaller and more well-distributed silver powder could be prepared at ratio of concentration of PVP to AgNO3 with the value of 1.5-1.0,at which PVP presented effective protection. Conclusions This method can prepare particle of nano-silver which revealed well dispersed and uniform size. The process is stable and reliable,easy to operate,high yields and suitable for industrial production.