Cyrene™ as an Alternative Sustainable Solvent for the Preparation of Poly(lactic-co-glycolic acid) Nanoparticles

Toxic and environmental harmful organic solvents are widely applied to prepare poly(lactic-co-glycolic acid) (PLGA)-based nanoparticles (NP) in standard preparation methods. Alternative non-toxic solvents suffer from disadvantages like high viscosity and plasticizing effects. To overcome these hurdles, Cyrene? as a new sustainable, non-toxic and low viscous solvent was used to formulate PLGA NPs. A new preparation method was developed and optimized. Small sized blank NPs around 220 nm with a narrow size distribution and highly negative charge (<?23 mV) were obtained. To test the application for drug delivery, the lipophilic model drug atorvastatin was encapsulated in high drug loads with comparable physicochemical characteristics as the blank NPs, and a total drug release within 24 h. No changes of the crystallinity or plasticizing effects could be observed. Highly purified NPs were obtained with a residual Cyrene? content <2.5%. Finally, the biocompatibility of Cyrene? itself and of the NPs formed in the presence of Cyrene? was demonstrated in a hen's egg test. Conclusively, the use of Cyrene? as solvent offers a simple, fast and non-toxic procedure for preparation of PLGA NPs as drug delivery systems circumventing the downsides of standard methods.     

Effect of end-grafted PEG conformation on the hemocompatibility of poly(styrene-b-(ethylene-co-butylene)-b-styrene)

Abstract

Polyethylene glycol (PEG) with one and two ends are grafted onto poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) via polydopamine (PDA) as a spacer to fabricate a hemocompatible surface. Linear and looped conformational PEGs modified SEBS are obtained, and the structures and compositions are confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The hemocompatibility of SEBS are improved by the modification of PDA and PEG, and the proteins resistances of the looped PEG are superior to that of the linear PEG with the same grafting length and mass. Quartz crystal microbalance with dissipation illustrates that the protein resistance mechanism of looped PEG is because of the huge viscoelasticity and deformation. Furthermore, looped and linear PEGs with the same grafting density are grafted onto SEBS surface to clarify the superiority of the looped conformation. Protein adsorption of looped PEG with twice length of linear PEG shows lower adsorbed amount than the others. Therefore, immobilizing the looped conformation of PEG on SEBS surface is a versatile and efficient way to improve the hemocompatibility of SEBS.     

Conductive Polymer for Elevated Temperature Applications Based on Sodium Sulfosuccinate Coupled Poly(ethylene glycol)s

Sodium sulfosuccinate coupled poly(ethylene glycol) (PEG) (S–PEG–SS) conductive polymers for hot melt adhesives are synthesized from PEG, maleic anhydride, and sodium hydrogen sulphite using a one‐pot three‐step reaction. Infrared spectroscopy and ¹H NMR spectroscopy are used to characterize the molecular structure and to determine the yield of esterification. S–PEG150–SS has the highest yield of esterification, whereas S–PEG2000–SS provides the lowest yield of esterification. Gel permeation chromatography and shear viscosity measurements are applied to characterize multiple condensation products and to describe the viscoelastic properties. The results reveal that the viscoelastic properties and the conductivity depend on molar mass of esterified PEG, on the degree of condensation, and on the concentration of ions.     

多次不同剂量PEG 400对大鼠体内细胞色素P450 3A活性的影响

目的：研究多次不同剂量PEG400对大鼠体内细胞色素P4503A活性的影响。方法：以咪哒唑仑为探针，HPLC法测定咪哒唑仑及其代谢物1′－羟基咪哒唑仑在大鼠体内的血药浓度并计算其药动学参数，以多次不同剂量PEG400处理组与阴性对照组的AU0.4h比值为指标，研究它们对大鼠体内细胞色素P4503A药酶活性的影响。结果：与生理盐水组相比，PEG400（5mg&#183;kg^-1，tid，3d）、PEG400（20mg&#183;kg，tid，3d）分别增加咪哒唑仑AUC0-4h（1．9&#177;0．5）（P〈0．05）、（1．14&#177;0．21）倍，显著降低1′-羟基咪哒唑仑与咪哒唑仑AUC0-4h的比值，分别从（1．09&#177;0．22）降至（0．27&#177;0．11）和（0．58&#177;0．14）（P〈0．05）。结论：2种剂量PEG400对CYP3A均有明显的抑制作用，PEG400（5mg&#183;kg^-1，tid，3d）显著增加咪哒唑仑的生物利用度。     

用PEG6000从新鲜猪血中分离提取猪血红蛋白

目的从新鲜猪血中分离提取猪血红蛋白。方法将猪血离心过滤处理后过阴离子交换柱,用PEG6000沉淀猪血红蛋白;以蛋白浓度、PEG6000浓度、pH考察最适沉淀条件。结果与结论当猪血红蛋白浓度为7.8 mg.ml-1、PEG6000为15%时,沉淀效果最好,pH对实验结果影响不大。所得猪血红蛋白可达电泳纯。     

Formulation Development and Release Studies of Indomethacin Suppositories

Indomethacin suppositories were prepared by using water-soluble and oil soluble suppository bases, and evaluated for in vitro release by USP I and modified continuous flow through bead bed apparatus. Effect of the Tween 80 (1% and 5%) was further studied on in vitro release of the medicament. Release rate was good in water-soluble suppositories bases in comparison to oil soluble suppositories bases. Release was found to be greater in modified continuous flow through bead bed apparatus. When surfactant was used in low concentration then release rate was much greater, as compared to high concentration. When stability studies were performed on the prepared indomethacin suppositories it was found that suppositories made by water-soluble base had no significant changes while suppositories prepared by oil soluble bases, had some signs of instability.     

Amine-reactive pyridylhydrazone-based PEG reagents for pH-reversible PEI polyplex shielding

PEGylation which is reversed after the therapeutic agent reaches the target cell presents an attractive feature for drug, protein or nucleic acid delivery. Amine-reactive, endosomal pH cleavable polyethylene glycol aldehyde-carboxypyridylhydrazone, N-hydroxysuccinimide esters (PEG-HZN-NHS) were synthesized and applied for bioreversible surface shielding of DNA polyplexes. Monofunctional mPEG-HZN-NHS was synthesized by reacting succinimidyl hydraziniumnicotinate with mPEG-butyraldehyde (20 kDa). Bifunctional OPSS-PEG-HZN-NHS was synthesized analogously via a omega-2-pyridyldithio-PEG (10 kDa) propionaldehyde intermediate. Polyethylenimine (PEI) polyplexes were reacted with the pH-sensitive (mPEG-HZN-NHS) or the corresponding stable (mPEG-NHS) reagent. Both types of polyplexes remained shielded at pH 7.4 as demonstrated by particle size and zeta potential measurements after 4h of incubation at 37 degrees C. Polyplex deshielding at endosomal pH 5 was observed only with the mPEG-HZN-NHS shielded particles. This was confirmed by fluorescence correlation spectroscopy using the analogous Alexa-488 fluorescently labeled bifunctional PEGylation reagents. Luciferase gene transfections with epidermal growth factor (EGF) containing polyplexes using EGF-receptor overexpressing hepatoma HUH7 cells showed an up to 16-fold enhancement in gene expression with the reversibly shielded polyplexes as compared to stably shielded polyplexes. Consistently, the reversibly shielded polyplexes mediated also an enhanced tumor specific in vivo transgene expression after intravenous administration in a subcutaneous HUH7 tumor model in SCID mice.     

PEG 6000处理对黄芩种子萌发和幼苗生长的影响

目的 以PEG 6000溶液模拟干旱胁迫条件,研究黄芩种子的萌发和幼苗生长对干旱胁迫的响应.方法 分别用10%和20%PEG 6000处理黄芩种子,对种子的含水量、萌发率、萌发势、萌发指数、幼苗鲜质量及各器官的长度进行测量.结果 PEG 6000处理对黄芩种子的含水量、萌发率和幼苗的生长均产生影响.结论 10%PEG6000浸种4 h、20%PEG 6000浸种1 h可以提高黄芩种子的萌发率,可以选择20%PEG 6000处理黄芩种子8 h作为模拟干旱条件,用于幼苗黄芩抗旱材料的选育工作.