A novel design for stable self-assembly cubosome precursor-microparticles enhancing dissolution of insoluble drugs

Cubosomes have been presented to enhance dissolution of insoluble drugs, but their applications are limited by the practical hurdles associated with both preparation and storage instability, resulting in drug delivery failure. In the present study, an innovative cubosome precursor-microparticles (CPMs) spray dried from an aqua-free precursor solution was developed to improve cubosome stability during both preparation and storage as well as to enhance the dissolution of insoluble drugs. These CPMs spontaneously self-assembled in situ forming homogeneous cubosome dispersion by hydration and disintegration after exposure to the aqueous medium. The stable cubosome dispersion was obtained from self-assembly (SA) of CPMs after administration instead of fragmentation of bulk cubic phase gel into cubosomes, which settled the preparation instability due to avoidance of high energy fragmentation (e.g. ultrasonic effect, high speed shear and high pressure homogenization). Also, the subsequent storage instability issue can be excluded as the CPMs were stored in a solid stable form. The CPMs disintegration and cubosome SA were demonstrated by the notable morphology variation and the distinct microparticle size decrease from CPMs (10–20?μm) to SA-cubosomes (150–200?nm). The cumulative release of docetaxel (DTX, model insoluble drug) incorporated in CPMs increased to 96.4% within 120?minutes compared with only 75.2% for blank CPMs and DTX physical mixture, demonstrating that CPMs significantly enhanced the dissolution extent of insoluble drug. The SA-cubosomes possessed quite high drug entrapment efficiency (>95%) and an integrated drug dissolution content, which significantly increased the drug utilization rate.     

Atmospheric Photopolymerization of Acrylamide Enabled by Aqueous Glycerol Mixtures: Characterization and Application for Surface‐Based Microfluidics

Polyacrylamide usually is the material of choice for electrophoretic separation in slab gels, capillaries, and microfluidic devices. So far its polymerization requires anaerobic environments because oxygen impurities inhibit or even terminate the polymerization reaction of acrylamide. Here, it is demonstrated that gel precursor solutions with glycerol contents above 20 vol% enable direct atmospheric photopolymerization of acrylamide with no need for sealing or degassing the solution in advance. The positive effect of glycerol on the polymerization reaction is proven by simulation‐validated electron paramagnetic resonance measurements. Nuclear magnetic resonance reveals that glycerol does not interfere with the reaction indicating that the observed enhancement in polymerization is owed to the low oxygen solubility of aqueous glycerol mixtures. Glycerol concentrations of >60 vol% in the gel precursor solution enable complete polymerization of volumes down to 5 nL within less than 5 s. This enables using liquid handling robots to fabricate channel‐free open microfluidic structures of solid polyacrylamide hydrogel in a low‐cost automated manner in a standard lab environment.     

Hydrogen production through anaerobic co-digestion of food waste and crude glycerol at mesophilic conditions

Hydrogen production from mesophilic anaerobic co-digestion of food waste (FW) and crude glycerol (GLC) was investigated in this study. Batch experiments were carried out at 35 °C for 36 h to assess the effect of supplementation of different glycerol concentrations (1%, 3% and 5% (v/v)) on dark fermentation of FW. The maximum hydrogen yield (180 mLH₂/gVS) was obtained at 5% GLC while the maximum specific production rate (around 13 mLH₂/(gVS.h)) was similar for all experiments with glycerol addition. Besides contributing to increase H₂ productivity, the presence of glycerol reduced the microorganisms acclimation time (Lag phase) in comparison to the control tests conducted without this co-substrate. In addition, the increment of glycerol concentration also enhanced volatile fatty acids generation and favoured the production of 1,3-propanediol (1,3-PDO). In the experimental conditions studied (i.e., 1–5% (v/v) of GLC), the results revealed that co-digestion of FW and GLC is promising and can be potentially used to maximize energy production while contributing to the management and treatment of these wastes.     

Synthesis, properties and biomedical applications of poly(glycerol sebacate) (PGS): A review

Poly(glycerol sebacate) (PGS) is a biodegradable polymer increasingly used in a variety of biomedical applications. This polyester is prepared by polycondensation of glycerol and sebacic acid. PGS exhibits biocompatibility and biodegradability, both highly relevant properties in biomedical applications. PGS also involves cost effective production with the possibility of up scaling to industrial production. In addition, the mechanical properties and degradation kinetics of PGS can be tailored to match the requirements of intended applications by controlling curing time, curing temperature, reactants concentration and the degree of acrylation in acrylated PGS. Because of the flexible and elastomeric nature of PGS, its biomedical applications have mainly targeted soft tissue replacement and the engineering of soft tissues, such as cardiac muscle, blood, nerve, cartilage and retina. However, applications of PGS are being expanded to include drug delivery, tissue adhesive and hard tissue (i.e., bone) regeneration. The design and fabrication of PGS based devices for applications that mimic native physiological conditions are also being pursued. Novel designs range from accordion-like honeycomb structures for cardiac patches, gecko-like surfaces for tissue adhesives to PGS (nano) fibers for extra cellular matrix (ECM) like constructs; new design avenues are being investigated to meet the ever growing demand for replacement tissues and organs. In less than a decade PGS has become a material of great scrutiny and interest by the biomedical research community. In this review we consolidate the valuable existing knowledge in the fields of synthesis, properties and biomedical applications of PGS and PGS-related biomaterials and devices.     

Application of a two‐stage temperature control strategy to enhance 1,3‐propanediol productivity by Clostridium butyricum

BACKGROUND: The purpose of the present work was to enhance 1,3‐propanediol productivity during the batch cultivation on a type of raw glycerol by application of a two‐stage temperature control strategy. RESULTS: First, the effect of the raw glycerol on microbial growth and 1,3‐propanediol production was investigated. The highest 1,3‐propanediol productivity, 1.93 g L^?1 h^?1, was achieved when the initial raw glycerol concentration was 6% (v/v). Second, the effect of temperature on microbial growth and 1,3‐propanediol production was investigated and kinetic analysis was carried out. The results indicated that 37 °C favored microbial growth while 35 °C was best for 1,3‐propanediol production. Finally, a two‐stage temperature control strategy was applied in 1,3‐propanediol production. The incubation temperature was kept at 37 °C from inoculation to 2 h and then switched to 35 °C. Compared with batch cultivations at 35 and 37 °C, the fermentation time was shortened from 10 to 9.2 h, resulting in an increase in 1,3‐propanediol productivity of around 11%. CONCLUSION: 1,3‐propanediol productivity was enhanced effectively by application of a two‐stage temperature control strategy. © 2012 Society of Chemical Industry     

用PLC+PC实现的甘油脂自动输送控制系统

本文通过对卷烟厂的过滤嘴棒生产线的现场条件分析。介绍了用PLC PC实现对生产过滤嘴棒的甘油脂自动输送系统的数据采集处理、各环节检测控制、系统监控管理等自动化、网络化控制过程。     

小分子溶质-混合溶剂三元体系的优先吸附现象

介绍一种用差减色谱研究小分子溶质对混合溶剂中某种组分优先吸附的方法. 在该方法中,淋洗剂是混合溶剂, 进样试液由溶质溶于混合溶剂制得. 通过测定自由溶剂峰的尺寸, 得到优先吸附参数λ2 (λ2 为周围溶剂化溶剂中某种溶剂组分的超额量与溶质重量之比). 用该方法对由丙三醇与水-乙醇混合溶剂所组成的体系进行研究发现, 当混合溶剂中乙醇的质量浓度低于2%时, 丙三醇对溶剂组分的优先吸附可忽略; 当乙醇质量浓度达到5%时, 丙三醇对乙醇优先吸附; 当乙醇质量浓度在10% ~23%时, 丙三醇对水优先吸附; 当乙醇质量浓度在30% ~60%时, 丙三醇优先吸附的溶剂组分又变成了乙醇.