Monitoring the hydrolyzation of aspirin during the dissolution testing for aspirin delayed-release tablets with a fiber-optic dissolution system

The purpose of this study was to investigate the hydrolyzation of aspirin during the process of dissolution testing for aspirin delayed-release tablets. Hydrolysis product of salicylic acid can result in adverse effects and affect the determination of dissolution rate assaying. In this study, the technique of differential spectra was employed, which made it possible to monitor the dissolution testing in situ. The results showed that the hydrolyzation of aspirin made the percentage of salicylic acid exceed the limit of free salicylic acid （4.0）, and the hydrolyzation may affect the quality detection of aspirin delayed-release tablets.

Optimization of the Extraction Process of Astaxanthin from Haematococcus pluvialis with Oil Dissolution Method

[ Objective ] This study aimed to optimize the extraction process of astaxanthin from Haematococcus pluvialis with oil dissolution method. [ Method ] Small amounts of acetone or ethanol were separately added into soybean oil for astaxanthin extraction. The extraction efficiency of astaxanthin from H. pluvialis with different methods was compared. [ Result] The extraction efficiency of astaxanthin from H. pluvialis with acetone, acetone ＋ soybean oil, ethanol ＋ soybean oil, soybean oil was 20.46, 21.65, 20.85 mg/g and 13.05 mg/g, respectively. According to the results, acetone ＋ soybean oil led to the highest extraction rate, which was approximately twice that of soybean oil and higher than that of acetone. [ Conclusion ] This study laid the foundation for large-scale production of astaxanthin.

The space time CE/SE method for solving one-dimensional batch crystallization model with fines dissolution

This article is concerned with the numerical investigation of one-dimensional population balance models for batch crystallization process with fines dissolution.In batch crystallization,dissolution of smaller unwanted nuclei below some critical size is of vital importance as it improves the quality of product.The crystal growth rates for both size-independent and size-dependent cases are considered.A delay in recycle pipe is also included in the model.The space–time conservation element and solution element method,originally derived for non-reacting flows,is used to solve the model.This scheme has already been applied to a range of PDEs,mainly in the area of fluid mechanics.The numerical results are compared with those obtained from the Koren scheme,showing that the proposed scheme is more efficient.

A feedback control method for phase signal demodulation in fber-optic hydrophones

In the realm of acoustic signal detection,the identification of weak signals,particularly in the presence of negative signal-to-noise ratios,poses a significant challenge.This challenge is further heightened when signals are acquired through fiber-optic hydrophones,as these signals often lack physical significance and resist clear systematic modeling.Conventional processing methods,e.g.,low-pass filter(LPF),require a thorough understanding of the effective signal bandwidth for noise reduction,and may introduce undesirable time lags.This paper introduces an innovative feedback control method with dual Kalman filters for the demodulation of phase signals with noises in fiber-optic hydrophones.A mathematical model of the closed-loop system is established to guide the design of the feedback control,aiming to achieve a balance with the input phase signal.The dual Kalman filters are instrumental in mitigating the effects of signal noise,observation noise,and control execution noise,thereby enabling precise estimation for the input phase signals.The effectiveness of this feedback control method is demonstrated through examples,showcasing the restoration of low-noise signals,negative signal-to-noise ratio signals,and multi-frequency signals.This research contributes to the technical advancement of high-performance devices,including fiber-optic hydrophones and phase-locked amplifiers.

A Method for Rapid Determination of Polymer Dissolution Time

In view of the limited space of offshore platform and the large amount of polymer injection, the dissolution time method, solution viscosity method, conductivity method, undissolved filtration method and falling ball method are used as the rapid detection methods of polymer dissolution. The results show that the error of conductivity method is the largest, and that of dissolution time method is the second, and both methods are time-consuming. Solution viscosity method and insolubles filtration method have small error, but they are time-consuming, especially for offshore platforms, which makes detection inconvenient. The drop ball method is simple in operation and has a small error, so it is a promising method for rapid determination of polymer dissolution time.

Analysis and modeling of alumina dissolution based on heat and mass transfer

A comprehensive heat and mass transfer model of dissolution process of non-agglomerated and agglomerated alumina particles was established in an aluminum reduction cell. An appropriate finite difference method was used to calculate the size dissolution rate, dissolution time and mass of alumina dissolved employing commercial software and custom algorithm based on the shrinking sphere assumption. The effects of some convection and thermal condition parameters on the dissolution process were studied. The calculated results show that the decrease of alumina content or the increase of alumina diffusion coefficient is beneficial for the increase of size dissolution rate and the decrease of dissolution time of non-agglomerated particles. The increase of bath superheat or alumina preheating temperature results in the increase of size dissolution rate and the decrease of dissolution time of agglomerated particles. The calculated dissolution curve of alumina（mass fraction of alumina dissolved） for a 300 k A aluminum reduction cell is in well accordance with the experimental results. The analysis shows that the dissolution process of alumina can be divided into two distinct stages： the fast dissolution stage of non-agglomerated particles and the slow dissolution stage of agglomerated particles, with the dissolution time in the order of 10 and 100 s, respectively. The agglomerated particles were identified to be the most important factor limiting the dissolution process.

Dissolution Characteristics of Hydrophobically Associating Polyacrylamide in Stirred Tanks

Enhanced oil recovery(EOR)by means of polymer flooding is an important technology for the strategic development of offshore oilfields in China.Hydrophobically associating polyacrylamide(HAPAM)has been recently proposed as a new flooding agent.The solubility of HAPAM is low,which is the bottleneck for further improving the oil recovery through polymer flooding in offshore oilfield.Stirred tanks have been used on offshore platforms to enhance HAPAM dissolving.But there is little literature on the study of HAPAM dissolving characteristics in stirred tanks.In this paper,effects of temperature,salinity,stirring speed,impeller type and stirring method on the dissolution of HAPAM are reported.The experimental results manifest that the dissolving rate of HAPAM increases with temperature and stirring speed,but the viscosity of the polymer solution decreases.There is an optimal range of salinity for polymer dissolving.Combining the operation mode of up-pumping with varying stirring speed,hydrofoil impeller can accelerate the dissolution of HAPAM and maintain a high solution viscosity.

Dissolution improvement of fenofibrate by melting inclusion in mesoporous silica

In this study,using mesoporous silica for the solubility enhancement of poorly watersoluble drug was investigated.Although the incorporating drug into mesoporous silica is generally performed through the solvent method,the new melting method was proposed in the present study.Fenofibrate,a poorly water-soluble drug,was incorporated into mesoporous silica by solvent method and melting method.The obtained samples were observed by SEM and their physicochemical properties were evaluated by PXRD and DSC measurement.The dissolution and supersaturated property were also investigated.The results from SEM,PXRD and DSC measurement showed that drug could be loaded into pore via the melting method as well as by the solvent method.The drug loaded quantity depended on the pore volume.Drug up to 33%could be incorporated into mesoporous silica and existed in amorphous state.When drug was overloaded or difficulty in incorporation into pore was found,recrystallization of drug occurred at the outer surface of mesoporous silica.From the dissolution test,samples prepared by solvent method and melting method gave the supersaturated drug concentration which sample from melting method showed superior dissolution to the one from solvent method.From this study,drug was efficiently incorporated into mesoporous silica by the melting method which is a simple and solvent-free process,and the aqueous solubility enhancement of poorly watersoluble drug was achieved.

Comparative dissolution study on counterfeit medicines of PDE-5 inhibitors

Counterfeit medicines are a growing problem in both developing and industrialised countries. In general the evaluation of these medicines is limited to the identification and the dosage of the active ingredients. In this study in vitro dissolution tests were conducted on two sets of counterfeit medicines containing PDE-5 inhibitors （sildenafil citrate and tadalafil）. The dissolution profiles were statistically compared to the ones of the genuine products using the f2-method and a comparison at each time point using the Cochran test. The results showed low equivalences between counterfeit and genuine products as well as higher variations around the mean dissolution value at the different time points for the counterfeit products.

吡罗昔康贴剂溶出度的测定及不同测定方法结果的评估

目的:采用桨碟法、转筒法、扩散池法测定吡罗昔康贴剂的溶出度,并对溶出结果进行评价,以期选择能更加准确反映吡罗昔康贴剂释药过程的测定方法,为科学准确评价药品质量提供参考。方法:建立检测吡罗昔康的液相色谱测定方法,分别使用桨碟法、转筒法、扩散池法考察吡罗昔康贴剂的24 h溶出曲线,分别使用f 1差异因子法、f 2相似因子法、Weibull模型拟合对溶出曲线进行比较,评估不同测定方法的结果。结果:吡罗昔康在1~150μg·mL^(-1)范围内线性关系良好(r=1.000),准确度100.9%(n=9),精密度1.7%(n=9),样品溶液在72 h内稳定。溶出曲线比较结果表明,吡罗昔康贴剂的溶出曲线更符合Weibull模型。在相同溶出介质和温度的条件下,桨碟法和转筒法差异不大,存在相互替代的可能性,扩散池法与其他2种方法均存在显著性差异。结论:扩散池法的装置更加符合吡罗昔康贴剂在实际使用中的溶出过程,为该药物的质量评价提供更多的参考。

四川盆地中部地区震旦系大型碳酸盐岩气藏开发技术新进展

四川盆地中部地区(以下简称川中地区)震旦系灯影组气藏为大型古老深层岩溶风化壳型碳酸盐岩气藏,气藏整体表现为低孔隙度低渗透率,储集空间小尺度缝洞发育,储层非均质性强特征,气藏开发面临储层表征难、井位部署和效益开发难度大等系列挑战。为此,以川中地区安岳气田灯影组气藏为对象,通过地质工程一体技术化攻关,深化了对储层发育特征和成因机理的认识,提出了气藏开发新模式,创建形成了气藏高效开发的关键技术。研究结果表明:①灯影组储层主要为岩溶成因储层,具有“叠合岩溶差异控储”的发育特征;②岩溶储层非均质性强,“溶蚀相成因控储”可精细刻画储层的非均质性;③灯影组气藏宜采用“单井指标叠加论证气藏规模”的开发新模式;④创新形成了“双界面”岩溶古地貌恢复及定量刻画方法,并指导平面选区,其中Ⅰ+Ⅱ类井比例由评价期的40%提高到方案建设期的100%;⑤创建了小尺度缝洞识别、刻画及表征技术,并指导钻井轨迹设计,测试百万立方米气井比例由开发评价期的41.6%提高到建产期的60%;⑥配套完善了分段酸压工艺技术,高效动用了优质储层,并解放了低品位储层,储层渗透率由改造前的0.62 mD提高到酸压改造后的6.77 mD。结论认为,“十四五”期间,在上述开发技术的支持下,安岳气田由台缘带灯四段高效开发转向长期稳产和台内地区多层系效益开发,蓬莱含气区由单井高产转向区块高产和气藏规模建产,将强力支撑中国石油西南油气田公司“十四五”末天然气上产500×10^(8)m^(3)。

融入探究和思政特色的新胶体电泳实验

本案例以解决传统Fe(OH)_(3)胶体电泳实验中存在的胶体废液浪费、缺乏探究性以及思政育人难融入等局限为出发点,通过发展胶溶法、引入表面带不同电荷AgI胶体制备及其带电性质自主判断环节,守正创新,赋予该实验项目以资源节约、绿色环保、富有探究性等特色。尤其重要的是,本案例通过综合采用任务驱动自主学习、翻转课堂、研讨启发等多种教学模式,将经典基础物理化学实验与提高我国数量巨大但来之不易的钢铁资源的循环利用率和改变学生对胶体带电性质的固有认识有机结合起来,在潜移默化中弘扬/培育了学生“绿色”化学理念、可持续发展责任担当、科学辩证思维素养以及创新精神等。本案例已初步推广应用于本校的胶体电泳实验教学中,教学反响热烈,达到了专业知识、技能传授与课程思政育人相济相长的教学效果;为提升传统实验的专业育人和思政育人效果提供有益借鉴。

胶囊壳变更对头孢氨苄胶囊溶出曲线的影响研究

目的评价胶囊壳变更对头孢氨苄胶囊溶出曲线的相似性是否有影响。方法按照《中国药典》2020年版四部通则0931第二法(浆法)测定变更胶囊后头孢氨胶囊与参比制剂在不同pH溶出介质中的溶解度,采用非模型依赖法中相似因子法(f^(2)),比较头孢氨苄胶囊与参比制剂溶出曲线的相似性。结果使用3个不同厂家胶囊壳制备的头孢氨苄胶囊,对比头孢氨苄胶囊与参比制剂溶出曲线,其中2个批次头孢氨苄胶囊与参比制剂曲线相似,另外1个批次头孢氨苄胶囊在pH 6.8磷酸介质中溶出曲线与参比制剂溶出曲线不相似。结论头孢氨苄胶囊的胶囊壳变更对产品溶出曲线的相似性产生影响。

基于体外溶出评价方法对硝苯地平缓释片(Ι)一致性评价研究

建立硝苯地平缓释片(Ⅰ)体外溶出评价方法,以原研制剂为参比,评价本公司一致性研究前后的自研制剂(以下简称自制1、自制2),为质量一致性提供依据。选取0.3%吐温80的不同pH值(pH值1.0,pH值4.0,pH值6.8,水)溶液为溶出介质,采用高效液相色谱法考察0.25,0.5,1,2,3,10,12 h的释放度,从而建立体外溶出曲线方法,并进行了方法学验证,最后采用相似因子法(f_(2))将自研制剂与参比进行比较。结果表明,建立的本品体外溶出曲线方法的专属性、线性、精密度、准确度、滤膜吸附、溶液稳定性各项指标均符合要求;自制1与参比溶出行为不一致且f_(2)小于50,调整处方工艺后,自制2与参比体外溶出行为一致,且f_(2)均大于50。本品建立的体外溶出评价方法准确可靠,自制1与参比体外溶出不一致;自制2与参比溶出曲线相似,体外溶出一致。

依鲁替尼纳米晶的制备工艺研究

为改善依鲁替尼(IBR)的水溶性和溶出度,采用湿法介质研磨法制备了依鲁替尼纳米晶(IBR-NC),采用单因素实验优化了IBR-NC的制备工艺,并通过粒径分析、扫描电镜(SEM)、X-射线粉末衍射(XRPD)分析、差示扫描量热(DSC)分析及溶出度实验对IBR-NC的质量进行了评价。结果表明,以PVP-K30-SDS为稳定剂,在物料比(IBR、PVP-K30、SDS的质量比)为10∶4∶1、IBR用量为120 mg、氧化锆珠规格为0.3 mm、氧化锆珠用量为40 g、研磨转速为150 r·min^(-1)、研磨时间为2.0 h的最优条件下,制备的IBR-NC的粒径为(224.7±5.7)nm、PDI为0.151±0.017,累积溶出率在10 min能达到99.49%,溶出效果良好,且放置90 d后依然具有良好的溶出性质。

克唑替尼固体分散体的制备及体外溶出度研究

为了提高克唑替尼的溶解度进而改善其生物利用度,采用冷冻干燥法制备了克唑替尼固体分散体,以体外累积溶出度为评价指标,对其制备工艺进行了优化;并通过傅立叶变换红外光谱仪(FTIR)、X-射线衍射仪(XRD)、扫描电子显微镜(SEM)和差示扫描量热仪(DSC)对克唑替尼固体分散体进行了表征。结果表明,在克唑替尼与载体羟丙基甲基纤维素(HPMC)的质量比为1∶3、反应溶剂为叔丁醇、反应温度为50℃、反应时间为30 min的最佳条件下,克唑替尼固体分散体的溶出效果最佳,60 min体外累积溶出度达到93.98%,远高于克唑替尼原料药(10.96%);克唑替尼以无定形态高度分散于载体HPMC中。

穿越溶洞桥梁桩基嵌岩深度计算方法研究

为准确计算岩溶区桥梁桩基嵌岩深度,依托莆炎高速公路岩溶区桥梁桩基工程,分别考虑桩基竖向极限承载力、桩身稳定性和桥梁全寿命周期内溶洞溶蚀量,提出3种穿越溶洞桥梁桩基嵌岩深度计算方法,并验证3种方法的可靠性。选取34根代表性桩基对比嵌岩深度设计值与所提方法计算值,并选取1根试桩对比规范值与所提方法计算值。结果表明:34根代表性桩基中,1根桩基的嵌岩深度设计值小于考虑全寿命周期内溶洞溶蚀量的嵌岩深度计算值,占比2.9%;10根桩基的嵌岩深度设计值同时满足竖向极限承载力、桩身稳定性和桥梁全寿命周期内溶洞溶蚀量要求,且安全储备合理,占比29.5%;23根桩基存在安全储备较高问题,占比67.6%,其中14.7%的桩基嵌岩深度设计安全储备高达5倍。各规范关于桩基嵌岩深度的取值差异较大,为确保桥梁桩基承载安全,同时降低施工难度和成本,建议设计穿越溶洞桥梁桩基的合理嵌岩深度时,充分考虑桥梁全寿命周期内溶洞溶蚀量。

基质全溶解-固相萃取-UPLC-MS/MS法分析聚酯纤维中阻燃剂

目的探索聚酯纤维中常见有机磷酸酯阻燃剂(磷酸三苯酯和三苯基氧化膦)的分析方法。方法通过完全溶解法将样品基质溶解,再采用商品化固相萃取柱PEP-2对提取的样品溶液进行进一步净化,结合UPLC-MS/MS技术测定5种聚酯纤维样品中的两种有机磷酸酯阻燃剂。结果在最优的条件下,建立的分析方法线性关系良好(r≥0.9958),灵敏度高,磷酸三苯酯和三苯基氧化膦方法检测限分别为0.08 ng·g^(-1)和0.014 ng·g^(-1),加标回收率范围为80.2%~104.6%,方法精密度RSD值低于8.8%。结论建立的分析方法准确度高、精密度好、无基质干扰、稳定可靠,为该类基质中痕量污染物的分析提供了新的策略。

四嗪二甲酰胺环糊精包合物制备研究

目的:制备四嗪二甲酰胺(ZGDHu-1)环糊精包合物,对其质量进行表征。方法:采用饱和水溶液法制备四嗪二甲酰胺的甲基-β-环糊精包合物体系,通过高效液相色谱法检测药物含量,通过扫描电镜、差示扫描量热分析、包合率和溶出度对包合物质量进行考察。结果:四嗪二甲酰胺含量检测在1.078~107.9μg·mL^(-1)范围内线性关系良好,扫描电镜观察和差示扫描量热分析表明四嗪二甲酰胺以无定型状态被包埋在辅料空腔内,包合物中四嗪二甲酰胺的平均包合率为87.19%,包合物体系显著提高了四嗪二甲酰胺的溶出度,80 min累积溶出度为82.60%。结论:四嗪二甲酰胺环糊精包合物制备方法简便,包合率高,对体外溶出具有良好的改善效果。

仿制药盐酸达拉他韦片与原研药DAKLINZA^(®)体外溶出一致性评价研究

目的建立盐酸达拉他韦片溶出方法,考察自制制剂与原研药DAKLINZA®在多种溶出介质中的溶出相似性,为该品种的仿制药研发提供参考。方法采用桨法,分别以pH1.0盐酸、pH4.5醋酸盐、pH6.8磷酸盐缓冲液(含0.15%苄泽35)为溶出介质,采用高效液相色谱法检测盐酸达拉他韦片,应用系统的方法学,对自制制剂与参比制剂溶出曲线相似性进行验证。结果所建立的溶出方法线性、准确度良好,自制制剂与参比制剂在pH1.0盐酸介质中15min时,溶出度均大于85%;在pH4.5醋酸盐、pH6.8磷酸盐缓冲液(含0.15%苄泽35)介质中,溶出曲线f2值均大于50,说明二者溶出具有相似性。结论自制制剂与参比制剂在多种溶出介质中溶出相似,说明二者体外溶出一致。