MOLECULAR PHARMACEUTICS
·
2024
·
IF 4.5
Fanfan Fan,Yi Lu,Shuyuan Xu,Minshan Guo,Ting Cai
Metastable polymorphs of active pharmaceutical ingredients can occasionally be used to enhance bioavailability or make processing more convenient. However, the thermodynamic instability of metastable polymorphs poses a severe threat to the quality and performance of the drug products. In this study, we used hot-stage microscopy and powder X-ray diffraction to quantitatively analyze the kinetics of the solid–solid phase transition of piracetam (PCM) polymorphs in the absence and presence of several polymeric excipients. The Forms I and II of PCM are enantiotropically related polymorphs, and the transition point is 75 °C. We found that 1 wt % polymer can strongly affect the transformation rate of Form II to Form I of PCM above 75 °C. PVP K30 has the highest Tg and the strongest inhibitory effect on the transition, whereas PEG has the lowest Tg and the weakest effect on the transition. Below 75 °C, the addition of 1 wt % PEG can decrease the transformation rate from Form I to Form II of PCM by a few orders of magnitude, whereas no phase transition occurs in the presence of the other investigated polymers. The inhibitory effects of the same concentration of polymers on the kinetics of the solid–solid phase transition of piracetam polymorphs are considerably greater than those on the crystallization of PCM from the amorphous phase, especially at low temperatures. We propose that the low segmental mobility of polymers enriched between the crystalline phases can considerably inhibit the nucleation and growth of the stable form at the interface during the phase transition. Our findings deepen the current understanding of the mechanisms underlying the solid-state phase transition of polymorphic drugs in the presence of polymeric excipients, providing a promising formulation approach for stabilizing the metastable pharmaceutical polymorphs.
研究领域:
药剂学
·
材料科学
·
药物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Yi-Bing Zhang,Jin Wang,Jun-Xia Wang,Yi Huang,Ping Luo,Xiao-Feng Liang,Hong-Bin Tan
In order to ascertain the structural relationship of zirconolite and pyrochlore for their potential application in HLW immobilization, the Gd-doped zirconolite-pyrochlore composite ceramics (Ca 1- x Zr 1- x Gd 2 x Ti 2 O 7 ) were systematically synthesized with x = 0.0–1.0 by traditional solid-phase reaction method. The phase evolution and microstructure of the as-prepared samples have been elucidated by XRD and Rietveld refinement , Raman spectroscopy , BSE-EDS and HRTEM analysis. The results showed that zirconolite-2M, zirconolite-4M, perovskite and pyrochlore, four phases were identified in Ca 1- x Zr 1- x Gd 2 x Ti 2 O 7 system and could be coexisted at x = 0.4 composition. With the increase of Gd 3+ substitution, the phase evolution was followed by zirconolite-2M→zirconolite-4M→pyrochlore. It is illustrated that the phase transformation from zirconolite-2M to zirconolite-4M was promoted by the preferential substitution of Gd 3+ for Ca 2+ . And the solubility of Gd 3+ in zirconolite-2M, zirconolite-4M and pyrochlore increased in sequence. The chemical stability test was also measured by the PCT leaching method. The normalized elemental release rates of Ca, Zr, Ti and Gd in Ca 1- x Zr 1- x Gd 2 x Ti 2 O 7 system were fairly low and in the range of 10 −6 −10 −8 g m −2 d −1 , which indicated a potential ceramics composite ensemble of CaZrTi 2 O 7 -Gd 2 Ti 2 O 7 system for nuclear HLW immobilization.
研究领域:
材料科学
·
核能工程
·
化学
✓ 已验证
产品关联
DOI
高影响因子
Advanced Powder Materials
·
2024
·
IF 28.6
Ziming Ye,Yi Zeng,Xiang Xiong,Sen Gao,Chen Shen,Shiyan Chen,Tianxing Jiang,Ge Yang
Multiphase design is a promising approach to achieve superior ablation resistance of multicomponent ultra-high temperature ceramic (UHTC), while understanding the ablation mechanism is the foundation. Here, through investigating a three-phase multicomponent ceramic consisting of Hf-rich carbide, Nb-rich carbide, and Zr-rich silicide phases, we report a newly discovered solid-state reaction process among multiphase multicomponent ceramic during ablation. It was found that this solid-state reaction occurred in the matrix/oxide scale interface region. In this process, metal cations are counter-diffused between the multicomponent phases, thereby resulting in their composition evolution, which allows the multicomponent phases to exist stably under a higher oxygen partial pressure, leading to the improvement of thermodynamic stability of three-phase multicomponent ceramic. Additionally, this solid-state reaction process appears synergistic with the preferential oxidation behavior among the oxide scale in enhancing the ablation performance.
研究领域:
材料科学
·
高温陶瓷研究
✓ 已验证
产品关联
DOI
高影响因子
MOLECULAR PHARMACEUTICS
·
2023
·
IF 4.9
Shuting Li,Binbin Liu,Ziqiao Chen,Xiao Ou,Haowei Rong,Ming Lu
Identification of a thermodynamically stable polymorph is an important step in the early stage of drug development. Ritonavir (RIT) is a well-known case where the most stable polymorph II emerged after being marketed, leading to a loss of $250 million. Herein, we report the findings that routine melt crystallization can reveal the late-appearing polymorph II of RIT at small supercooling, but the probability of nucleation is very low. The addition of 30–50% polyethylene glycol (PEG) promotes the crystallization of Form II as the only phase at low supercooling, making it easier to detect in polymorphism screening. During the course of our research, a new polymorph, denoted Form III, was unexpectedly discovered, crystallizing as the major phase from neat RIT melts. Single crystals of Form III were grown from melt microdroplets. Benefiting from the ability of synchrotron radiation to detect weak diffraction signals that cannot be accessible by a laboratory diffractometer, a reasonable structure of Form III was solved with slight disorder relative to thiazole groups (P1 space group and Z′ = 4). The thermodynamic stability ranking of the three true polymorphs is Form II > Form I > Form III, as opposed to the order of solubility. The capacity to efficiently reveal rich polymorphs, especially the kinetically hindered polymorph, and rapidly grow single crystals of a new phase for structure determination together highlights the necessity of incorporating melt crystallization into routine methods for pharmaceutical polymorphism screening.
研究领域:
药学
·
材料科学
·
晶体学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
VACUUM
·
2023
·
IF 4
Zhaowang Dong,Hanning Liu,Xueyi Guo,Heng Xiong,Bin Yang,Baoqiang Xu
Antimony sulfide can be produced by vacuum distillation of lead antimony sulfide ore. In this paper, the volatilization kinetics of antimony sulfide under vacuum conditions was studied for the first time using a self-made vacuum furnace, and the stability of antimony sulfide was explained through thermodynamic calculations. The results show that under a system pressure of 20 Pa and a temperature range of 873 K–1073 K, the apparent volatilization activation energy of antimony sulfide is 57.6 kJ/mol, and the volatilization control step of antimony sulfide is a gas phase diffusion process. As the temperature increases from 873 K to 1073 K, the volatilization rate of antimony sulfide increases from 0.20 g cm −2 min −1 to 0.88 g cm −2 min −1 by 4.4 times. As the system pressure increases from 20 Pa to 100 Pa, the volatilization rate of antimony sulfide decreases rapidly, decreasing by nearly 11.4 times. Antimony sulfide will not decompose within the range of system pressure above 20 Pa and temperature below 1073 K.
研究领域:
冶金学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2021
·
IF 6.165
Chengzhi Liu,Haoxin Ye,Jian Kuang,Gerui Ren,Qing Shen,Hujun Xie,Qunfang Lei,Wenjun Fang
The interfacial composition and thermodynamic parameters of W/O 14-n-14/alcohol/oil/water microemulsions were investigated by dilution method in terms of the number of linking groups n (n = 3–6), water content, alcohol and oil types. The gemini/alcohol/oil/water microemulsion system formed spontaneously with negative Gibbs free energy at 25 ℃. The long carbon chain of alcohol facilitated the formation of W/O microemulsion. With increasing carbon chain length of the oil phase, the absolute value of the Gibbs free energy initially increased and subsequently decreased. With an increasing number of linking groups in gemini surfactants, the amount of alcohol that was required in the interfacial layer increased, thereby hindering alcohol movement from the continuous phase to the interface layer, and the absolute value of the Gibbs free energy also decreased, suggesting that a small value of n is beneficial to the stability of microemulsions.
研究领域:
胶体化学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2021
·
IF 5.816
Senliang Xi,Xiaojun Wang,Kudzaishe Caren Tome,Tonghuan Zhang,Zongying Han,Meng Gao,Shixue Zhou,Hao Yu
The hydrogen storage performances of MgH 2 improved by the addition of Ni and SAPO-34 were studied in detail. The mixture of MgH 2 with Ni and SAPO-34 was a physical reaction as shown by the X-ray diffraction (XRD) results. The SAPO-34 and Ni were uniformly distributed on the surface of MgH 2 . The thermodynamic and kinetic properties of 90MgH 2 /5Ni/5SAPO-34 were investigated by differential scanning calorimetry (DSC) and pressure-composition-isothermal (PCI) methods. The results showed that the dehydrogenation activation energy of 90MgH 2 /5Ni/5SAPO-34 decreased by 64.3 kJ/mol compared with that of MgH 2 . In addition, the relationship between the value of dehydrogenation heat and hydrogen content was also investigated by in-situ calorimetry. The enthalpy value of each sample in the dehydrogenation processes were calculated by in-situ calorimetry measurement. The dehydrogenation enthalpies of as-milled MgH 2 and 90MgH 2 /5Ni/5SAPO-34 were 63.2 kJ/mol H 2 and 53.6 kJ/mol H 2 , respectively. Thus, the co-doping of Ni and SAPO-34 contributed significantly to decrease the thermodynamic stability and improve the hydrogen sorption kinetic properties of MgH 2 .
研究领域:
材料科学
·
氢储能技术
·
物理化学
✓ 已验证
DOI
高影响因子
Journal of Energy Storage
·
2024
·
IF 8.9
Zheng Bo,Meiqi Zhou,Yibo Deng,Jianhua Yan,Kefa Cen,Yanguang Zhou,Huachao Yang
Water-in-salt and organic solvent-additive strategies have significantly improved the electrochemical stability window of aqueous electrolyte , while it still faces poor low-temperature thermodynamics stability and unsatisfied transport kinetics, as well as flammability risks caused by organic solvent . Herein we report a novel “cation-water-urea ternary interaction strategy” via environmental-friendly and non-flammable urea (CO(NH 2 ) 2 ) to solve the above dilemma. The cation-water-urea ternary interaction strategy preferentially develops CO(NH 2 ) 2 -cation solvation structures for weakened cation-anion associations, improved anti-salt-precipitation capability, and thus enhanced ionic conductivity , meanwhile it improves the low-temperature thermodynamics stability via the stronger CO(NH 2 ) 2 -water hydrogen-bond interactions to suppress the freezing and electrolysis of water. The optimum ternary aqueous electrolyte exhibits an ultralow freezing point (−70 °C), wide electrochemical stability window (2.9 V) and outstanding ionic conductivity (135 mS cm −1 @25 °C and 5.3 mS cm −1 @−50 °C), demonstrating superior performance compared to traditional organic solvent-additive and water-in-salt electrolytes. Finally, to demonstrate its potential for practical applications, ternary aqueous electrolyte-based supercapacitors are fabricated using commercial activated carbon electrodes, which exhibit outstanding capacitance retention (71.4 %) and much lower ion transport resistance even at ultralow temperature of −40 °C. This work proposes a novel ternary aqueous electrolyte with improved thermodynamics stability and kinetics for safe, low-temperature energy storage applications.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2024
·Vol. 107
·期 10
·6574-6582
·
IF 3.5
Weiping Gong,Duoduo Zhang,Lang Xiao,Jiahui Zhao,Ting Wang,Kai Li,Zhentin Zhao,Manuel Scharrer,Alexandra Navrotsky
The Aurivillius compounds in the Bi 2 O 3 –Fe 2 O 3 –TiO 2 system, combining ferroelectric, semiconducting, and ferromagnetic properties, have attracted particular interest. Formation kinetics and thermodynamic stability are the fundamental knowledge needed for modeling and predicting the temporal microstructure and property evolution during materials processing but have not yet been addressed by quantitative experimental measurement. This article focuses on the Bi n +1 Fe n –3 Ti 3 O 3 n +3 Aurivillius compounds on the Bi 4 Ti 3 O 12 –BiFeO 3 tie-line to elucidate the mechanisms and thermodynamic controls responsible for phase formation of compounds with various perovskite-like layers. Five high-purity Aurivillius compounds Bi 4 Ti 3 O 12 , Bi 5 FeTi 3 O 15 , Bi 6 Fe 2 Ti 3 O 18 , Bi 7 Fe 3 Ti 3 O 21 , and Bi 8 Fe 4 Ti 3 O 24 with integer n = 3–7 values were synthesized and their phase transformation properties and enthalpies of formation were studied by X-ray diffraction in situ, high temperature differential scanning calorimetry, and high temperature oxide melt solution calorimetry. Thermodynamic stability of the compounds decreases with increasing n , and formation kinetics gradually slow down, demonstrating the inherent difficulty to synthesize pure Aurivillius compounds with n larger than 8. This difficulty was confirmed by an impurity phase coexisting with Bi 9 Fe 5 Ti 3 O 27 .
研究领域:
材料科学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
Materials for Renewable and Sustainable Energy
·
2018
·Vol. 8
·期 1
·1-9
·
IF 0
Jiang L.,Zou Z. W.,Pei Q. M.,Zheng D. S.,Li F. S.,Tian Y. H.
Re 2 Mg(Ni 0.7 − x Co 0.2 Mn 0.1 Al x ) 9 ( x = 0‒0.04) alloys are prepared by induction melting, and the influence of the partial substitution of Ni by Al on the structure, hydrogen storage, and electrochemical properties of the alloys are investigated systematically. These alloys mainly consist of two main phases with LaNi 5 phase and (La,Mg) 2 Ni 7 phase, and minor LaNi 2 phase. The pressure-composition isotherms shows that, with Al content increasing in the alloys, the maximum hydrogen storage capacity decreased from 1.16 wt% ( x = 0) to 0.99 wt% ( x = 0.04). The changes of enthalpy and entropy reveal that the thermodynamic stability and the disordered degree of the hydride alloys increase with the Al addition. Results of electrochemical studies indicate that the substitution of Al for Ni can noticeably improve the cycle stability of the alloy electrode. The capacity retention after 80 cycles is enhanced from 63.6% ( x = 0) to 76.5% ( x = 0.04). However, the maximum discharge capacity of the alloys decreases. The Re 2 Mg(Ni 0.7 − x Co 0.2 Mn 0.1 Al x ) 9 ( x = 0‒0.04) alloys exhibit excellent dischargeability.
研究领域:
材料科学
·
氢能源研究
✓ 已验证
产品关联
DOI
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2024
·
IF 4.3
Yin Li,Li Xu,Jinbo Ouyang,Jiangtao Lei,Jun Hu,Xiaohong Xing,Peng Chen,Jiaqing Li,Changqing Zhong,Bo Yang,Heng Li
Polymorphism commonly exists in organic molecular crystals. The fingerprint features in low-frequency vibrational range are important information reflecting different intermolecular interactions of polymorphs. Interpreting these features is very helpful to understand vibrational property of polymorphs and reveal the thermodynamic stability. In this work, the low-frequency vibrations of form I and II of vanillin are investigated using terahertz time-domain spectroscopy. Static DFT calculation and ab initio molecular dynamics (AIMD) are employed to interpret their low-frequency vibrations of both forms in harmonic and anharmonic ways, respectively. Their low-frequency vibration characteristics in harmonic calculations are discussed, and anharmonic mode couplings between O H bond stretch and the stretching and bending motion of hydrogen bonds are uncovered. Moreover, the thermodynamic energies including electronic potential energy and vibrational/kinetic energy arising from nuclear motions are calculated. The result reveals that the stability order of the two forms is mainly dependent on their electric potential energy difference.
研究领域:
物理化学
·
晶体学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Liang Xu,Min Niu,Hongjie Wang,Lei Su,Hongfei Gao,Lei Zhuang
Material with superior damage tolerance, chemical durability, and structure stability is of increasing interest in high-level radioactive waste management and structural components for advanced nuclear systems. In this paper, high-entropy (La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 Gd 0.2 ) 2 Zr 2 O 7 with pyrochlore-type structure was synthesized through conventional solid-state method. The as-synthesized high-entropy oxide maintained crystalline after being irradiated by using Au 3+ with 9.0 MeV energy at the fluence of 4.5 × 10 15 ions·cm -2 , indicating its high tolerance to heavy-ion irradiation. The irradiation-induced order-disorder transition from pyrochlore structure to defective fluorite structure occurred in high-entropy (La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 Gd 0.2 ) 2 Zr 2 O 7 . After irradiation, no irradiation-induced segregation was observed at grain boundary. Moreover, the mechanical properties of high-entropy pyrochlore were improved. The heavy-ion irradiation resistance mechanisms of high-entropy pyrochlore were discussed in detail. Our work identified high-entropy (La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 Gd 0.2 ) 2 Zr 2 O 7 can be a promising candidate for immobilization of high-level radioactive waste as well as advanced nuclear reactor system from the perspective of irradiation resistance.
研究领域:
材料科学
·
核能工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）