固体药物的多晶型现象及研究进展

固体药物中的多晶型现象普遍存在,且多晶型影响着固体药物的质量和疗效,故对固体药物多晶型现象进行研究具有十分重要的意义。从药物晶型及多晶型现象、优势药物晶型、固体药物的转晶现象、晶型影响药品质量的评价方法、药物多晶型的研究现状及进展等五个方面介绍了固体药物的多晶型现象及研究进展,为固体药物多晶型现象研究提供参考。     

药物共晶多晶型的研究进展

药物多晶型现象是影响药物稳定性和疗效的重要因素。近年来,越来越多的共晶体系被发现存在多晶型现象,而且不同晶型的共晶也表现出了性能上的差异。共晶多晶型的研究也因此受到了越来越多的关注。综述了近几年有关药物共晶多晶型的报道,解释了共晶多晶型的概念,并对其进行了分类（合成子多晶型、堆积多晶型、构象多晶型以及互变异构多晶型）,重点介绍了目前共晶多晶型的筛选方法。此外,强调了共晶药物由于晶型不同而引起的性能差异。     

添加剂对氨基酸多晶型溶液结晶过程影响的研究进展

氨基酸的不同晶型往往表现出不同的理化性质和药用效果。因此通过调控氨基酸多晶型溶液结晶过程得到目标晶型非常重要,其中添加剂对不同晶型的影响直接且有效,是控制晶型生产常采用的手段。本文综述了不同种类添加剂对氨基酸多晶型溶液结晶过程的影响。首先,以水溶液中不能直接得到的甘氨酸γ晶型为例,阐明了酸、碱和无机盐对其成核的促进作用,从电荷补偿角度分析了该类添加剂对不同晶型生长过程的影响机理。其次,阐述了tailor-made添加剂对氨基酸晶体形态和晶型的调控作用,重点分析了不同结构的tailor-made添加剂对晶型转变的影响规律。介绍了醇-水等混合溶剂对不同氨基酸多晶型结晶过程的选择性影响。最后,在以上分析的基础上,对通过添加剂分子设计制备不同目标晶型进行了展望。     

硫酸氢氯吡格雷球形结晶工艺及其生长机理

本文测定了硫酸氢氯吡格雷Ⅰ、Ⅱ晶型在仲丁醇中的溶解度,通过过程分析和优化,制备了纯Ⅰ晶型的硫酸氢氯吡格雷球形晶体。与非球形晶体比较,球形晶体在堆密度、流动性、粒度分布以及稳定性等方面均占优势。本文考察了不同温度、残留溶剂对硫酸氢氯吡格雷晶习与晶型的影响,研究了硫酸氢氯吡格雷球形结晶过程晶体的生长机理。     

β晶型含量与其晶体形态对等规聚丙烯韧性的共同作用

利用超声波振动制备了不同尺寸的β成核剂二环己基对苯二甲酰胺(DCHT), 并加入到等规聚丙烯(iPP)中。通过改变不同尺寸成核剂的含量研究成核剂尺寸对iPP力学性能、β晶型的含量和iPP的超分子结构的影响。结果表明,β成核剂的尺寸可以影响DCHT在iPP中的溶解度,因而β晶体的晶体形态随之改变。随着DCHT含量的增加,"花状"晶和穿晶两种晶体形态相应产生。因此可以推断,在同一种晶体形态下,β晶型的含量会决定iPP的韧性。但当晶体形态不同时,形态是主要决定因素。     

人工神经网络在半水盐酸帕罗西汀溶解度预测中的应用

溶解度的测定与预测对于多晶型体的晶体生长和结晶过程中的多晶型控制至关重要.利用激光监视装置,首次测得了半水盐酸帕罗西汀在不同溶剂体系中的溶解度,共计308组数据;采用多参数人工神经网络模型,随机选取308组数据中的184组数据进行人工神经网络的训练,考察了不同隐含层节点数对神经网络训练效果的影响,得到了优化后的人工神经网络模型,利用剩余的124组数据对优化后的模型进行检测,平均预测误差小于0.7％.预测结果表明,优化后的人工神经网络模型可以胜任半水盐酸帕罗西汀溶解度预测的任务.     

KIO_3晶体成核和结晶习性的研究

本文研究了KIO_3晶体的溶解度、单相析晶区、成核规律及结晶习性。实验表明,溶液中的HIO_3含量、过饱和度及离子的聚集态是影响晶核质量的关键因素。在通常条件下只能得到KIO_3多晶或孪晶。我们在7％相似文献   

表面诱导药物多晶型成核的研究进展

表面诱导成核是指在异相成核过程中,利用异质表面与溶质分子的相互作用来调控成核过程。表面诱导成核不仅可以降低成核能垒促进成核,而且可以在不改变溶剂、温度等条件下对晶型进行调控。近年来,表面诱导成核在药物新晶型的筛选和亚稳晶型的调控两方面得到了广泛研究。本文综述了异质表面影响多晶型成核的机理,介绍了用于诱导多晶型成核的四种异质表面——聚合物、有机小分子晶体、自组装单层膜（SAMs）和凝胶,总结了四种表面选择与设计的策略。最后,对目前存在的问题进行了总结,对未来的发展进行了展望。     

普瑞巴林晶型Ⅰ在纯溶剂及丙酮-水混合溶剂中的溶解度测定与关联

通过平衡法测定了283.15~328.15 K温度下普瑞巴林晶型I在水、甲醇、乙醇、丙酮、四氢呋喃、N,N-二甲基甲酰胺、乙酸乙酯及丙酮-水混合溶剂中的溶解度,实验结果表明:普瑞巴林晶型I在所测定的所有纯溶剂及丙酮-水混合溶剂中的溶解度均随温度的升高而增大;在丙酮-水混合溶剂中,溶解度随着丙酮的摩尔分数的增加而降低,在丙酮的摩尔分数达到0.83附近时溶解度最小,接近0。采用修订的Apelblat经验方程和(CNIBS)/Redlich-Kister方程对溶解度数据进行关联,结果令人满意。所得实验数据和拟合模型为普瑞巴林在工业结晶及药物多晶型等方面的研究提供了重要的依据。     

农药多晶型研究进展

农药的不同晶型会使产品的物理化学性质有所差异，进而影响作用效果，因此农药多晶型一直是研究的重点。介绍了农药多晶型，以及多晶型的制备和表征方法。此外，重点介绍了发现的不同类别的农药多晶型。通过综述农药多晶型的研究现状，对促进农药多晶型的研究具有重要的意义。     

Beitrag zu den Grundlagen der Lösungs-Kristallisation von Stearinsäure

Contribution to the Fundaments of Solvent Cristallization of Stearic Acid After a short review of the informations available concerning the habit and polymorphism of the three polymorphs of stearic acid, more recent results are discussed. From exact determinations of the solubility of stearic acid in decane, methanol and butanone, it was possible to calculate the stability regions of the three polymorphs. The enthalpies of dissolution as calculated from the solubility were checked by direct solution calorimetry. The determination of the occurrence domains of the polymorphs showed the A and C polymorph to precipitate preferentially at room temperature. It could be shown for the (110) face of stearic acid growing from butanone solutions, that surface diffusion is the rate controlling step. The differences in the growth behaviour between the B and C polymorph are not yet fully understood.     

The Solubility of ϵ-CL-20 in Selected Materials

The solubility of the epsilon polymorph of CL-20 was determined in thirteen liquids over the temperature range of ambient to 74°C using high performance liquid chromatography. The experiments included ϵ-CL-20 produced by two different synthesis routes; one lot contained a higher level of polymorphic impurity, the other lot contained a higher level of non-CL-20 impurity.In general, the ϵ-CL-20 was found to be highly soluble in the solvents with carbonyl groups, and relatively insoluble in hydrocarbons and materials containing ether linkages. The amount of phase conversion to γ-CL-20 which occured during the solubility testing was measured using FTIR, and ranged from essentially zero to ∼ 10% conversion. It appears that the presence of β-CL-20 in the virgin ϵ-CL-20 lots will affect the amount of gamma-phase present in the final residue.     

Highly disordered ionic distribution in α-dicalcium silicate for structure relaxation

Dicalcium silicate, which is found in steelmaking slag for dephosphorization, exists as the hexagonal α phase at high temperatures. The α-dicalcium silicate forms a solid solution with tricalcium phosphate in the entire composition range, although the reason for high solubility of phosphorus remains unclear in view of the crystal structure. It has previously been reported that the crystal structure of α-dicalcium silicate consists of a symmetric arrangement of Ca²⁺ ions and SiO₄⁴⁻ tetrahedra, although other polymorphs exhibit asymmetric arrangements. However, because the occupation probability of each atomic site in the α polymorph is not limited to unity, it has not been qualified how these ions are exactly arranged. In this study, the ionic distribution in the α polymorph of dicalcium silicate was evaluated by first-principles calculation based on density functional theory (DFT), as well as by molecular dynamics (MD) simulation with a polarizable ion model optimized by DFT calculation. The results indicated that the completely symmetric ionic arrangement, as reported for the α phase, is the most unstable. Electronic-state calculation and MD simulation indicated that a highly disordered ionic arrangement spontaneously forms in the α-phase crystal for structure relaxation when held at high temperatures, or when phosphorus is incorporated.     

Influence of Solvents on Solution‐Mediated Polymorphic Transformation of the Polymorphs of L‐Histidine

Solution‐mediated polymorphic transformation (SMPT) of the metastable polymorph B of L‐histidine (L‐his) into the stable polymorph A in water‐antisolvent solutions was performed. Methanol, acetone, and acetonitrile served as antisolvents. The SMPT was studied via nucleated batch antisolvent crystallization process by determining the change of the fraction of the stable polymorph A of L‐his in the crystal phase with time during the crystallization process. The fraction of the stable polymorph A of L‐his was assessed offline by Raman spectroscopy. The transformation time depended on the fractions of form A obtained at the initial stage of crystallization. The transformation rate of the metastable polymorph B into the stable polymorph A at lower antisolvent volume fraction was faster than at higher antisolvent volume fraction. The transformation time of polymorph B into polymorph A in water‐acetonitrile solution was the shortest compared to the other solutions.     

Polymorphism of 3,3′-dihydroxy-β,β-carotene-4,4′-dione (Astaxanthin)

Astaxanthin (AXT) 3,3′-dihydroxy-β,β-carotene-4,4′-dione, from the group of carotenoid, specifically as xanthophyll, is investigated in this work on its polymorphism. The method to obtain a second polymorph of AXT is described. Polymorph I can be purchased as a commercial product or obtained via phase transformation from polymorph II. Polymorph II can be prepared from polymorph I by a thermal treatment carried out in a differential scanning calorimetry (DSC). The resulting crystals are characterized by different analytical techniques. X-ray powder diffractometer (XRPD) and resonance Raman spectroscopy prove the existence of two different crystalline polymorphs. Simultaneous thermal analysis (STA) gives additional information on their thermal behaviors. Polymorph I melts at 230 °C and polymorph II melts at 216 °C. Phase transition experiment carried out by slurry conversion experiment reveals two polymorphs are monotropically related. Polymorph II is the metastable form.     

空心钛酸钡的制备及其形成机理

以二氧化钛（TiO₂）和八水合氢氧化钡[Ba（OH）₂·8H₂O]为原料,采用水热合成法,成功制备出具有四方相晶型和空心形貌结构的钛酸钡粉体。利用透射式电子显微镜（TEM）和X射线衍射（XRD）对样品的形貌结构和晶型做了表征,通过研究反应过程中钛酸钡粉体的结构和晶型随时间的变化过程,对空心钛酸钡的形成机理做了详细的探讨,并考察了不同反应温度和钡浓度对钛酸钡粉体结晶和生长的影响。研究结果表明：反应温度和钡浓度会影响钛酸钡粉体的晶型和形貌,并以此提出了一种空心钛酸钡的形成机理;当反应温度为180 ℃、钡浓度为3.0 mmol/L时,能获得粒径分布均匀的四方相晶型的空心钛酸钡粉体。     

药物多晶型的研究进展

多晶型研究是制药领域的一个研究热点,而多晶型体系的分子组装规律及其控制手段是最为关键的研究内容。介绍了多晶型的分子组装规律,即成核理论（包括经典成核理论以及新兴的二步成核理论）,以及多晶型的调控方法,并重点介绍目前新型的调控手段（如离子液体、模板剂以及微通道技术等）。此外,结合药物晶型转化的实际案例,说明晶型转化技术在药物产品质量调控中的重要作用。     

Operation design for controlling polymorphism in the anti-solvent crystallization by using ternary phase diagram

In the pharmaceutical production, to control polymorph formation is important from the viewpoint of the productivity and the bioavailability. Anti-solvent or drowning-out crystallization is widely used in the pharmaceutical industry for high yield production. However, anti-solvent addition method to control polymorph formation in anti-solvent crystallization has not been discussed enough. In this study, indomethacin (IMC) which has three polymorphs was used. The purpose of this study is to establish a production method of the target polymorph in the anti-solvent crystallization (IMC–acetone–heptane system). The simulation model for determination of anti-solvent feed rate based on the ternary phase diagram was proposed. The stability of the polymorph of IMC crystal in the solution was changed not only with temperature but also with composition of the mixed solvent. From the experimental and simulation results, the design strategy of anti-solvent crystallization was proposed.     

Phase stability in scandia‐zirconia nanocrystals

Scandia‐zirconia system has great technological interest as it has the highest ionic conductivity among doped zirconia ceramics. However, polymorphism is the most important limiting factor for application of this material. Considering that there is a strong grain size dependence on phase transitions in this class of materials, mapping out the stable polymorph as a function of grain size and composition may lead to more efficient compositional design. In this article, the phase stability of zirconia‐scandia nanocrystals was investigated based on experimental thermodynamic data. Exploiting recent advances in microcalorimetry, reliable surface energy data for five polymorphs of scandia‐zirconia system: monoclinic, tetragonal, cubic, rhombohedral β and γ are reported for the first time. Combining surface energy values with bulk enthalpy data obtained from oxide melt drop solution calorimetry allowed us to create a predictive phase stability diagram that shows the stable zirconia polymorph as a function of composition and grain size of the specimen within the range of 0‐20 mol% scandia.