Development and evaluation of lafutidine solid dispersion via hot melt extrusion:Investigating drug-polymer miscibility with advanced characterisation

In current study,immediate release solid dispersion(SD)formulation of antiulcer drug lafutidine(LAFT)was developed using hot melt extrusion(HME)technique.Amphiphilic Soluplus
used as a primary solubilizing agent,with different concentrations of selected surfactants like PEG 400,Lutrol F127(LF127),Lutrol F68(LF68)were used to investigate their influence on formulations processing via HME.Prepared amorphous glassy solid dispersion was found to be thermodynamically and physicochemically stable.On the contrary,traces of crystalline LAFT not observed in the extrudates according to differential scanning calorimetry(DSC),X-ray diffraction(XRD),scanning electron microscopy(SEM)and Raman spectroscopy.Raman micro spectrometry had the lowest detection limit of LAFT crystals compared with XRD and DSC.Atomic Force microscopy(AFM)studies revealed drugpolymer molecular miscibility and surface interaction at micro level.1HeCOSY NMR spectroscopy confirmed miscibility and interaction between LAFT and Soluplus
,with chemical shift drifting and line broadening.MD simulation studies using computational modelling showed intermolecular interaction between molecules.Dissolution rate and solubility of LAFT was enhanced remarkably in developed SD systems.Optimized ratio of polymer and surfactants played crucial role in dissolution rate enhancement of LAFT SD.The obtained results suggested that developed LAFT has promising potential for oral delivery and might be an efficacious approach for enhancing the therapeutic potential of LAFT.

Sustainable Raw Materials in Hot Melt Adhesives: A Review

Hot-melt (HM) adhesives offer advantages over their contemporary water-based and solvent-based adhesives like low volatile organic compounds (VOCs), 100% solid, fast drying, setting etc. In recent years, to reduce their dependence on dwindling petroleum resources and due to the enormous use of HM adhesives in packaging areas that demand 100% recyclability, efforts have been devoted to making these formulations completely bio-based, sustainable and biodegradable. In this attempt, research and developments have been focused on using starch, modified starch, soy protein, polylactides, polyamides, lignin and vegetable oils as a partial/fully replacement to the petrochemical-based polymers. The huge amount of research going on in the field of bio-based polymers has still not reached its complete potential in the field of HM adhesives. In this review paper, HM adhesives based on sustainable raw materials namely starch, modified starch, polyamides, poly (lactic acid), soy protein and lignin are discussed.

Lactic Acid-Sustainable Raw Material for Biodegradable Hot Melt Adhesive: Review

Currently, due to scarcity of hydrocarbon resources and the extensive use of water based, solvent based and hot melt adhesives in wood bonding in furniture industries and packaging industries that demand recyclability, compostability and bio-degradability, recently attention has been concentrated to making these formulations completely bio-based, sustainable and biodegradable. Biodegradable hot melt adhesives (HMAs) prepared from natural sources have a potential for use in furniture and packaging industries because of an increase in awareness of environmental issues, the replacement of conventional petroleum-derived hydrocarbon raw materials by renewable, biodegradable and sustainable materials has developed. In terms of environmental issues, such as climate crisis due to an increase of carbon dioxide emission, attempts have been made to produce HMAs using non-hydrocarbon resins, such as polylactic acid (PLA)-based resins, containing no petroleum as a raw material. Polylactic acid was prepared by self-condensation reactions of lactic acid or by lactide ring opening polymerisation, and used for packaging materials, sanitary pads, diapers etc., especially adhesives owing to its excellent processability and the excellent mechanical properties of its HMAs products. Therefore, recently the use of PLA materials as a substitute for non-biodegradable hydrocarbon-based polymers can be considered to be environmentally favourable. Here, we discussed the various uses of PLA as a sustainable and bio-degradable and sustainable hot melt adhesive.

Application of hot melt extrusion to enhance the dissolution and oral bioavailability of oleanolic acid

The aim of this study was to improve the in vitro dissolution rate and oral bioavailability of oleanolic acid(OA), a water insoluble drug belonging to BCS class IV. Hot melt extrusion(HME) was applied to develop OA amorphous solid dispersions. The characterizations of the optimal formulation were performed by differential scanning calorimetry, X-ray powder diffraction, Fourier transform infrared spectroscopy and in vitro dissolution test.The in vivo pharmacokinetic study was conducted in rats. As a result, OA solid dispersion based on PVP VA 64(OA-PVP) was successfully prepared. In the dissolution medium containing 0.3% SDS, OA-PVP dramatically increased the releasing rate of OA compared with the physical mixture(PM-PVP) and commercial tablet. Furthermore, OA-PVP exhibited higher AUC(P < 0.05) and Cmax(P < 0.05) than PM-PVP and commercial tablet. The superior dissolution property and bioavailability of OA-PVP mainly attributed to the amorphous state of OA in PVP VA64 and the well dispersion caused by thermal melting and shearing. Overall, hot melt extrusion was an efficient strategy to enhance the dissolution rate and oral bioavailability of OA.

PPC-based Reactive Hot Melt Polyurethane Adhesive(RHMPA)--Efficient Glues for Multiple Types of Substrates

Tens of billion metric tons of anthropogenic CO_2 discharged from the burning of fossil fuels lead to an enormous environmental and resource burden. It is charming to transform CO_2 to desirable, economical chemicals and materials. Poly（propylene carbonate）（PPC） is an emerging CO_2-based material. Herein, we report the design, synthesis and characterization of the reactive hot melt polyurethane adhesive（RHMPA） based on PPC polyol. The resultant RHMPAs exhibit good adhesion properties to multiple substrates including plastics（PC, PMMA, ABS） and metals（aluminium, steel）, which is comparable to or even better than conventional RHMPAs prepared from petro-based polyol. Furthermore, the PPC-based RHMPAs have tunable mechanical properties, and are thermally stable in the typical working range of bonding process（up to 270 °C）. The study is expected to expand the applications of PPC and provide a new type of CO_2-based renewable and eco-friendly materials.

Strong,Removable,and Photoluminescent Hyperbranched Polyamide-amine Hot Melt Adhesive

The development of adhesive technology is gaining increasing attention in machinery,electronics,aviation,and other fields.However,traditional adhesives are difficult to be peeled and removed after cross-linking and curing due to the limited solubility in common solvents,which causes pollution and damage to the surface of the adherend.In this work,we synthesized random hyperbranched polyamide-amine hot melt adhesives through Michael addition of 1,8-octanediamine and N,N’-methylene diacrylamide(ODA-RHP HMA).Owing to the presence of various polar groups,ODA-RHP HMA exhibited robust lap shear strength to different substrates,including glass(6.6 MPa),ceramics(10.3 MPa),steel(11.5 MPa),and aluminum(11.8 MPa).Due to the hydrogen bonds in ODA-RHP,the HMA demonstrated intrinsic self-healing ability,which can be used repeatedly when being subjected to cyclic heating and cooling.Since ODA-RHP HMA can be swollen or dissolved in ethanol,the adhesives can be easily removed through erasing.In addition,ODA-RHP exhibited aggregation-induced luminescence due to the tertiary amine structure in the molecular structure of ODA-RHP,which can be used in the field of cultural relics restoration.

Development and Characterisation of Natamycin Mini-Matrices Prepared by Hot-Melt Extrusion for Vaginal Delivery

In this study, bioadhesive mini-matrices of natamycin were prepared for vaginal application by hot-melt extrusion. In addition, melt viscosity measurements, thermogravimetric analysis, in vitro drug release studies and in vitro mucoadhesion test were performed. High molecular weight grades of KlucelTM hydroxypropylcellulose were used as a thermoplastic polymer. TEC and PEG 400 were chosen as plasticizer. According to the obtained results of melt viscosity measurements, the maximum torque of extrudates prepared using PEG 400 increased with increasing drug loading. The thermo-gravimetric analyses showed that natamycin is stable up to 198℃ and this result gives the opportunity to hot melt extrussion process at 90℃. In vitro drug release results showed that the release was extended up to 72 hours and drug release rate increased with increasing drug loading. In respect to the in vitro mucoadhesion test results, the values of work of mucoadhesion were found high as 771,977 mN.mm, 753,199 mN.mm, 686,356 mN.mm for the prepared hot melt extruded mini-matrices. Our results showed that the developed formulations were found worthy of further studies.

Influence of melt-treatment on material constants of aluminum sheet used for easy-open can during hot deformation

The isothermal compression test at elevated temperature was carried out for aluminum sheets prepared by different melt-treatment methods with aid of dynamic hot/mechanical simulation experimental technology. The material constants of hot deformation have been solved by multivariate regression directly. Influence of metallurgy factors on the constants was analyzed. The results show that at some strain, the relationship of sheets’ flow stress with deformation temperature and strain rate can be expressed more suitably with Arrhenius equation modified by hyperbolic sine function. Structure factor A1, stress-level coefficient α, strain rate sensibility exponent m and deformation activation energy Q all increase with increment of strain, while stress exponent n decreases gradually. The bigger α value or the smaller n value is, the more obvious the dynamic softening is, but the α value will increase for the metallurgy defects existing in the sheets. Influence of melt-treatment on Q depends upon the synthesis effect of all kinds of metallurgy defects. The Q and n values of the sheet prepared by high-efficient melt-treatment are the least, while the m value is the biggest, and the sheet can deform easily and evenly.

Basic Study on the Evaluation of Thermoplastic Polymers as Hot-Melt Adhesives for Mixed-Substrate Joining

A selection of 22 low-melting polymers was thermally and rheologically evaluated to be used as hot-melt adhesives in mixed-substrate joining samples. The choice of polymers was based on the published melting point. It was required to include a broad variety of different polymers backbones to study the influence of the different polymers comprehensively. A tool-box of widely applicable tests was developed to judge if a thermoplastic polymer is suitable for a hot-melt adhesive application. Melting temperature (onset, peak and offset temperature) and melting enthalpy were determined using standardized methods. Rheological methods were used to characterize the shear rate dependence and the flow behavior at the application temperature. The wetting behavior of the polymers was evaluated with contact angle measurements. The adhesive strength of the most promising candidates was analyzed using the Lumi Frac-adhesion method including the failure pattern.

Hot-melt sub-and outercoating combined with enteric aqueous coating to improve the stability of aspirin tablets

Aspirin is apt to hydrolyze. In order to improve its stability, a new method has been developed involving the application of hot-melt sub-and outercoating combined with enteric aqueous coating. The main aim was to investigate the influence of these factors on the stability of ASA and understand how they work. Satisfactory storage stability were obtained when the aspirin tablet core coated with Eudragit L30D55 film was combined with glycerin monostearate(GMS) as an outercoat. Hygroscopicity testing indicated that the moisture penetrating into the tablet may result in a significant change in the physical properties of the coating film observed by scanning electron microscopy. Investigation of the compatibility between the drug and film excipients shows that the talc and methacrylic acid had a significant catalytic effect on ASA. A hypothesis was proposed that the hydrolysis of ASA enteric coated tablets(ASA-ECT) was mostly concentrated in the internal film and the interfaces between the film and tablet core. In conclusion, hot-melt coating technology is an alternative to subcoating or outercoating. Also, GMS sub-coating was a better choice for forming a stable barrier between the tablet core and the polymer coating layer, and increases the structure and chemical stability.

Ni60-SiC Coating Prepared by Plasma Spraying, Plasma Re-melting and Plasma Spray Welding on Surface of Hot Forging Die

In order to produce the hear-resistant inner layer of hot-forging die, plasma spraying and plasma re-melting and plasma spray welding were adopted. Substrate material was W6Mo5Cr4V2, including 10%, 20%, 30% SiC ceramic powder used as coating material to obtain different Ni-based SiC alloys coating. Micro-structure and micro-hardness analysis of the coating layer were followed, as well as thermophysical properties for the coating layer were measured. The experimental results show that the coating prepared with 70% Ni60, 30% SiC powder has best properties with plasma spray welding, in which the micro-hardness can achieve 1100 HV, meanwhile can improve the thermal property of hot-forging die dramatically.

Preparation of Ni60-WC Coating by Plasma Spraying, Plasma Re-melting and Plasma Spray Welding on Surface of Hot Forging Die

In order to produce the hear-resistant inner layer of hot-forging die, the plasma spraying and plasma re-melting and plasma spray welding were adopted. Substrate material was W6Mo5Cr4V2, including 10%, 20%, 30% tungsten carbide （WC） ceramic powder used as coating material to obtain different Nickel-based WC alloys coating. Micro-structure and micro-hardness analysis of the coating layer are conducted, as well as thermophysical properties for the coating layer were measured. The experimental results show that the coating prepared with 70%Ni60, 30%WC powder has the best properties with plasma spray welding, in which the micro-hardness can achieve 900HV, meanwhile it can improve the thermal property of hot-forging die dramatically.

聚氨酯热熔胶用预聚体的合成

以二异氰酸酯和聚醚多元醇为原料,通过定时测定—NCO的含量,确定了合适的预聚反应时间和温度,制备了聚氨酯热熔胶用预聚体。对影响预聚体合成的因素:异氰酸酯的种类、—NCO的含量、水分的含量以及预聚体的贮存稳定性等进行了探讨。结果表明,最佳预聚反应条件为80℃、2 h,—NCO含量控制在9%~10%,物料中水分质量分数低于0.05%,制备的产物性能稳定。

体育用品合成革用水性聚氨酯热熔胶研究

为顺应绿色环保理念,保障体育运动装备综合性能,优化体育用品用水性聚氨酯合成革的力学性能与粘接性能,制备环保型水性聚氨酯热熔胶以粘接、修补合成革具有非常重要的现实意义。据此,本文以甲苯二异氰酸酯、聚己二酸-1,4-丁二醇酯二醇等为原料制备了水性聚氨酯乳液,并以接枝剂甲基丙烯酸羟乙酯改性制备了体育合成革用水性聚氨酯热熔胶,同时对其性能进行了测试表征。结果发现,随着接枝剂甲基丙烯酸羟乙酯用量的增加,体育用品合成革用水性聚氨酯热熔胶拉伸强度与断裂伸长率随之增大,剥离强度与剪切强度逐步增大,水接触角逐渐增大,而吸水率明显下降,表明接枝剂甲基丙烯酸羟乙酯的掺入,可有效改善水性聚氨酯热熔胶的机械性能、粘接性能,以及耐水性与疏水性。

高强中模碳纤维增强高耐热双马树脂复合材料性能

研究了一种耐高温改性双马来酰亚胺树脂(805)的工艺特性、流变特性和耐热性能,在此基础上制备了TG800/805国产高强中模碳纤维复合材料,并对高温及室温的力学性能和断裂微观形貌进行了表征。结果表明:805树脂的最低黏度为1.6 Pa·s,具有良好的工艺性;TG800/805复合材料具有优异的力学性能,经280℃热处理后,其弯曲强度和层间剪切强度在280℃的保持率分别为68%和52%,其玻璃化转变温度(Tg)为356℃,说明研制的TG800/805材料体系可以在280℃高温下较长时间使用。

超吸水织物的制备及性能研究

以丙烯酸为单体,过硫酸钾、亚硫酸氢钠为氧化还原引发剂,与聚乙烯醇共混,采用溶液聚合法制备了丙烯酸高聚物溶液,浸轧丙纶热熔无纺布织物,经烘干得到超吸水织物,通过傅里叶变换红外光谱仪、场发射扫描电子显微镜、同步热分析仪对超吸水织物的结构、形貌和热性能进行分析,考察了聚合反应水浴温度、丙烯酸中和度、聚乙烯醇添加量、带液率对吸水倍率的影响,并对吸水机理进行探讨。结果表明:在聚合反应水浴温度为75℃,丙烯酸中和度75%,聚乙烯醇添加量(对单体)为5%(质量分数),带液率为500%,烘干温度为120℃条件下,制备的超吸水织物吸蒸馏水倍率为109.82g/g。

热熔压敏胶研究进展

本研究综述了国内外SIS基热熔压敏胶和聚氨酯热熔压敏胶的研究进展,阐述了二者的优缺点、改性方法(如聚合改性、物理共混改性、化学改性)以及研究应用领域(如金属粘接、物流标签、建筑防水材料和医用胶粘剂等)进展,并对SIS基热熔压敏胶和聚氨酯热熔压敏胶的未来发展方向做了展望。

热加工过程中M50轴承钢一次碳化物的形成与演化

针对M50轴承套圈生产过程中的真空感应熔炼、真空自耗重熔、锻造、轧制、辗环五个环节,利用OM、SEM、EDS及X射线三维成像技术分析了一次碳化物在整个生产流程中的演化。结果表明:真空感应熔炼后粗大的一次碳化物M2C和MC沿晶间呈网状析出,真空自耗重熔可减少一次碳化物的析出,自耗锭边缘处析出的一次碳化物尺寸较小,体积分数最少,为2.614%。锻造过程中网状一次碳化物被部分破碎,轧制和辗环可进一步破碎一次碳化物并使其沿加工流线分布,但并不能完全改变一次碳化物分布不均匀的情况。热变形在破碎细化碳化物的同时也会在一次碳化物内部及周围形成孔洞。

一种双胎基弹性体改性沥青防水卷材的产品设计及T型缝搭接性能研究

介绍了一种双胎基弹性体改性沥青防水卷材,该产品采用SBS热塑性弹性体作为改性剂,结合优质聚酯胎基布形成7层结构。为解决双胎基设计导致的卷材过厚问题,本产品引入超薄胎基,增强了搭接边的伏贴性,并提升了改性沥青涂盖料的设计用量。研究表明,在T型搭接部位,通过单独热熔施工和采用沥青涂料进行细部增强,可以显著提高搭接部位的粘结性能,进而提升防水系统的可靠性。

固体分散体制备技术及质量控制研究进展

【目的】从固体分散体(solid dispersions,SDs)制备技术和质量控制角度出发,揭示SDs技术在药物制剂领域的发展现状与挑战,旨在为SDs技术的进一步推广应用提供参考。【研究现状】总结熔融法、溶剂法、溶剂-熔融法、机械分散法等SDs制备技术,其中熔融法又包括传统熔融法、热熔挤出法、熔融凝聚、KinetiSol~?Dispersing、3D打印技术等,溶剂法又包括喷雾干燥、冷冻干燥、流化床干燥、超临界流体法、共沉淀法和静电纺丝法等;目前SDs制备技术存在需要使用有毒溶剂,可能导致药物热降解以及扩展性较差的问题。并归纳总结溶出度、药物和聚合物之间的相互作用、固态等SDs质量控制因素,重点强调一直被研究人员忽视的SDs粉体学性质。【展望】认为今后的研究重点应在开发或引入更多高效、无毒、稳定和扩展性好的SDs制备技术方面,并且要不断完善SDs的质量控制体系。