scholarly journals Recent Advances in the Application of Characterization Techniques for Studying Physical Stability of Amorphous Pharmaceutical Solids

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1440
Author(s):  
Yanan Wang ◽  
Yong Wang ◽  
Jin Cheng ◽  
Haibiao Chen ◽  
Jia Xu ◽  
...  
Keyword(s):  
Physical Stability ◽  
Crystalline Form ◽  
Pharmaceutical Solids ◽  
Amorphous Form ◽  
Broadband Dielectric Spectroscopy ◽  
Characterization Techniques ◽  
Surface Grating ◽  
Recent Advances ◽  
Amorphous Drugs ◽  
Crystalline Forms

The amorphous form of a drug usually exhibits higher solubility, faster dissolution rate, and improved oral bioavailability in comparison to its crystalline forms. However, the amorphous forms are thermodynamically unstable and tend to transform into a more stable crystalline form, thus losing their advantages. In order to investigate and suppress the crystallization, it is vital to closely monitor the drug solids during the preparation, storage, and application processes. A list of advanced techniques—including optical microscopy, surface grating decay, solid-state nuclear magnetic resonance, broadband dielectric spectroscopy—have been applied to characterize the physicochemical properties of amorphous pharmaceutical solids, to provide in-depth understanding on the crystallization mechanism. This review briefly summarizes these characterization techniques and highlights their recent advances, so as to provide an up-to-date reference to the available tools in the development of amorphous drugs.

scholarly journals Amorphous Form of Carvedilol Phosphate—The Case of Divergent Properties

Molecules ◽  
2021 ◽  
Vol 26 (17) ◽  
pp. 5318
Author(s):  
Szymon Sip ◽  
Natalia Rosiak ◽  
Andrzej Miklaszewski ◽  
Patrycja Talarska ◽  
Ewa Dudziec ◽  
...  
Keyword(s):  
Solid Dispersions ◽  
Crystalline Form ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Amorphous Form ◽  
Lower Solubility ◽  
Ft Ir ◽  
Amorphous Dispersions ◽  
Diffraction Patterns ◽  
Crystalline Forms

The amorphous form of carvedilol phosphate (CVD) was obtained as a result of grinding. The identity of the obtained amorphous form was confirmed by powder X-ray diffraction (PXRD), different scanning calorimetry (DSC), and FT-IR spectroscopy. The process was optimized in order to obtain the appropriate efficiency and time. The crystalline form of CVD was used as the reference standard. Solid dispersions of crystalline and amorphous CVD forms with hydrophilic polymers (hydroxypropyl-β-cyclodextrin, Pluronic® F-127, and Soluplus®) were obtained. Their solubility at pH 1.2 and 6.8 was carried out, as well as their permeation through a model system of biological membranes suitable for the gastrointestinal tract (PAMPA-GIT) was established. The influence of selected polymers on CVD properties was defined for the amorphous form regarding the crystalline form of CVD. As a result of grinding (four milling cycles lasting 15 min with 5 min breaks), amorphous CVD was obtained. Its presence was confirmed by the “halo effect” on the diffraction patterns, the disappearance of the peak at 160.5 °C in the thermograms, and the changes in position/disappearance of many characteristic bands on the FT-IR spectra. As a result of changes in the CVD structure, its lower solubility at pH 1.2 and pH 6.8 was noted. While the amorphous dispersions of CVD, especially with Pluronic® F-127, achieved better solubility than combinations of crystalline forms with excipients. Using the PAMPA-GIT model, amorphous CVD was assessed as high permeable (Papp > 1 × 10−6 cm/s), similarly with its amorphous dispersions with excipients (hydroxypropyl-β-cyclodextrin, Pluronic® F-127, and Soluplus®), although in their cases, the values of apparent constants permeability were decreased.

scholarly journals Combinations of Freeze-Dried Amorphous Vardenafil Hydrochloride with Saccharides as A Way to Enhance Dissolution Rate and Permeability

2021 ◽  
Vol 14 (5) ◽  
pp. 453
Author(s):  
Gabriela Wiergowska ◽  
Dominika Ludowicz ◽  
Kamil Wdowiak ◽  
Andrzej Miklaszewski ◽  
Kornelia Lewandowska ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Density Functional ◽  
Hydroxypropyl Methylcellulose ◽  
Fold Increase ◽  
Crystalline Form ◽  
Amorphous Form ◽  
Freeze Dried ◽  
Apparent Solubility ◽  
Gastrointestinal Epithelium ◽  
The Impact

To improve physicochemical properties of vardenafil hydrochloride (VAR), its amorphous form and combinations with excipients—hydroxypropyl methylcellulose (HPMC) and β-cyclodextrin (β-CD)—were prepared. The impact of the modification on physicochemical properties was estimated by comparing amorphous mixtures of VAR to their crystalline form. The amorphous form of VAR was obtained as a result of the freeze-drying process. Confirmation of the identity of the amorphous dispersion of VAR was obtained through the use of comprehensive analysis techniques—X-ray powder diffraction (PXRD) and differential scanning calorimetry (DSC), supported by FT-IR (Fourier-transform infrared spectroscopy) coupled with density functional theory (DFT) calculations. The amorphous mixtures of VAR increased its apparent solubility compared to the crystalline form. Moreover, a nearly 1.3-fold increase of amorphous VAR permeability through membranes simulating gastrointestinal epithelium as a consequence of the changes of apparent solubility (Papp crystalline VAR = 6.83 × 10−6 cm/s vs. Papp amorphous VAR = 8.75 × 10−6 cm/s) was observed, especially for its combinations with β-CD in the ratio of 1:5—more than 1.5-fold increase (Papp amorphous VAR = 8.75 × 10−6 cm/s vs. Papp amorphous VAR:β-CD 1:5 = 13.43 × 10−6 cm/s). The stability of the amorphous VAR was confirmed for 7 months. The HPMC and β-CD are effective modifiers of its apparent solubility and permeation through membranes simulating gastrointestinal epithelium, suggesting a possibility of a stronger pharmacological effect.

Bubble-induced fast crystal growth of indomethacin polymorphs in a supercooled liquid

2021 ◽  
Vol 54 (5) ◽  
Author(s):  
Qin Shi ◽  
Fang Li ◽  
Jia Xu ◽  
Lingling Wu ◽  
Junbo Xin ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Physical Stability ◽  
Pharmaceutical Formulations ◽  
Supercooled Liquid ◽  
Pharmaceutical Solids ◽  
Liquid Bubble ◽  
Different Temperatures ◽  
Surface Crystal

Physical stability is one of the main challenges when developing robust amorphous pharmaceutical formulations. This article reports fast crystal growth behaviors of the γ and α forms of indomethacin (IMC) initiated by bubbles in the interior of a supercooled liquid. Bubble-induced crystal growth of γ-IMC exhibits approximately the same kinetics as its surface crystal growth, supporting the view that bubble-induced crystal growth is a surface-facilitated process. In contrast, the rates of bubble-induced crystal growth of α-IMC are much faster than those of its surface crystal growth. These results indicate that the bubble-induced crystal growth not only depends on the interface created by the bubble but also strongly correlates with the true cavitation of the bubble. Moreover, bubble-induced fast crystal growth of γ- and α-IMC can be terminated at different temperatures by cooling. These outcomes are meaningful for the in-depth understanding of physical stability and pre-formulation study of amorphous pharmaceutical solids showing surface-facilitated crystal growth.

scholarly journals Porous heterostructured clays - recent advances and challenges - revisão

Cerâmica ◽  
2013 ◽  
Vol 59 (352) ◽  
pp. 576-587 ◽  
Author(s):  
A. J. Schwanke ◽  
S. B. C. Pergher
Keyword(s):  
Catalyst Supports ◽  
Historical Aspects ◽  
Characterization Techniques ◽  
Recent Advances ◽  
Adsorptive Properties

Porous heterostructured clays - PCHs - are lamellar solids with acid and adsorptive properties serving as catalysts or catalyst supports formed on a template mechanism. This work provides information about porous heterostructured clays. Historical aspects of the development of lamellar solids to porous heterostructured clays will be discussed, and detailed information on synthesis and applicationaspects, as well as on the influence of eachreagent on these materials and the characterization techniques used to prove their formation will be given.

scholarly journals PREPARATION OF SPRAY DRIED COAMORPHOUS SOLIDS TO IMPROVE THE SOLUBILITY AND DISSOLUTION RATE OF ATORVASTATIN CALCIUM

2021 ◽  
Vol 83 (2) ◽  
pp. 77-83
Author(s):  
Yudi Wicaksono ◽  
Viddy Agustian Rosidi ◽  
Sri Yessika Saragih ◽  
Lyta Septi Fauziah ◽  
Dwi Setyawan
Keyword(s):  
Intermolecular Interactions ◽  
Single Phase ◽  
Crystalline Form ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Amorphous Form ◽  
Atorvastatin Calcium ◽  
Statin Drug ◽  
Low Solubility ◽  
Spray Dried

Atorvastatin calcium (AC) is a statin drug used to lower cholesterol. Its crystalline form is usually found in the market with low solubility properties. The amorphization of crystalline AC is a technique used to increase its solubility however; the amorphous form has less thermodynamic stability. Therefore, to increase the solubility properties of its crystalline form, an AC coamorphous solid was prepared. This coamorphous solid was prepared using spray drying techniques, and coformers such as isonicotinamide (INA) and maleic acid (MA). Furthermore, characterization was carried out using powder X-ray diffraction, differential scanning calorimetry, fourier transform infrared spectroscopy, and scanning electron microscopy, while the solubility properties test was conducted using the shake-flask and paddle method. The results showed that the spray-dried solids were coamorphous with single-phase homogeneous systems. Furthermore, the coamorphous solids, AC-INA and AC-MA were found to have a higher Tg than the melting points of other components, and formed intermolecular interactions between them. The higher Tg and presence of intermolecular interactions indicate that coamorphous solids are more stable than the amorphous form. Therefore, the results of the solubility and dissolution test showed that the coamorphous solid of AC-INA and AC-MA have better solubility properties compared to the AC crystalline form.

scholarly journals Description of the corundum stone, and its varieties, commonly known by the names of oriental Ruby, Sapphire, &c.; with observations on some other mineral substances

1832 ◽  
Vol 1 ◽  
pp. 82-87
Keyword(s):  
Analytical Description ◽  
Crystalline Form ◽  
Point Of View ◽  
Historical Account ◽  
East Indies ◽  
Mineral Substances ◽  
History Of ◽  
Crystalline Forms ◽  
Different Parts ◽  
Mineral System

In a former paper, printed in the Philosophical Transactions for the year 1798, Count de Bournon gave an analytical description of the crystalline forms of corundum from the East Indies and from China. From a note inserted at the beginning of the present com­munication, we learn, that the great number of specimens of that substance, since collected from different parts, chiefly of the East, have added so considerably to our knowledge relating to that sub­ject, as to render it necessary not only to correct, but even, in many respects, to alter our opinion concerning it : and that hence, rather than create intricacy by introducing this additional knowledge in the form of a supplement, he had thought it expedient to collect all the information that could be obtained into one point of view, in hopes of delivering, in the present paper, with the addition of a chemical analysis which we are taught to expect from Mr. Chenevix, a com­plete mineralogical history of this curious substance. The paper is prefaced by a short historical account of the opinions of former naturalists concerning the corundum stone, and its classi­fication in the mineral system. The first of these, who derived their knowledge chiefly from lapidaries, had no hesitation in placing it among the gems, the hardest of which they distinguished by the epithet Oriental, and subdivided them according to their colours. Romé de Lisle was the first who deduced distinctive characters from the crystalline forms of the different sorts, rejecting the colour as a fallacious character. The first chemists who undertook to analyse this stone, thought themselves authorized to consider it as consisting of new elementary earths; but afterwards it was thought, and it appears now with much reason, to belong to the class of those stones which are chiefly, if not entirely, composed of argill. Werner at length also undertook the analysis; but he retrograded somewhat from what has been since found to be the truth, by placing it between pitch-stone and felspar. Abbé Hauy at length, recurring again to the crystalline form, placed it immediately after felspar, and before the Ceylonite; from both which, however, it differs widely, both by its hardness and specific gravity.

scholarly journals Pharmaceutical Co-Crystallization: Regulatory Aspects, Design, Characterization, and Applications

2020 ◽  
Vol 10 (2) ◽  
pp. 203-212 ◽  
Author(s):  
Abdul Raheem Thayyil ◽  
Thimmasetty Juturu ◽  
Shashank Nayak ◽  
Shwetha Kamath
Keyword(s):  
Physical Stability ◽  
Multicomponent System ◽  
Active Pharmaceutical Ingredient ◽  
Free Drug ◽  
Crystalline Materials ◽  
Regulatory Aspects ◽  
Pharmaceutical Substances ◽  
Current Scenario ◽  
Crystalline Forms ◽  
Selection Of

Pharmaceutical co-crystals are novel class of pharmaceutical substances, which possess an apparent probability of advancement of polished physical properties offering stable and patentable solid forms. These multi-component crystalline forms influence pertinent physicochemical parameters like solubility, dissolution rate, chemical stability, physical stability, etc. which in turn result in the materials with superior properties to those of the free drug. Co-crystallization is a process by which the molecular interactions can be altered to optimize the drug properties. Co-crystals comprise a multicomponent system of active pharmaceutical ingredient (API) with a stoichiometric amount of a pharmaceutically acceptable coformer incorporated in the crystal lattice. By manufacturing pharmaceutical co-crystals, the physicochemical properties of a drug can be improved thus multicomponent crystalline materials have received renewed interest in the current scenario due to the easy administration in the pharmaceutical industry. There is an immense amount of literature available on co-crystals. However, there is a lack of an exhaustive review on a selection of coformers and regulations on co-crystals. The review has made an attempt to bridge this gap. The review also describes the methods used to prepare co-crystals with their characterization. Brief description on the pharmaceutical applications of co-crystals has also been incorporated here. Efforts are made to include reported works on co-crystals, which further help to understand the concept of co-crystals in depth.

Recent advances in functional mesoporous graphitic carbon nitride (mpg-C3N4) polymers

Nanoscale ◽  
2017 ◽  
Vol 9 (30) ◽  
pp. 10544-10578 ◽  
Author(s):  
Shaodong Sun ◽  
Shuhua Liang
Keyword(s):  
Carbon Nitride ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Fundamental Properties ◽  
Characterization Techniques ◽  
Recent Advances ◽  
Potential Applications ◽  
Emerging Issues

In this review, we selectively summarize the recent advances in mesoporous g-C3N4(mpg-C3N4), including synthesis strategies, characterization techniques, fundamental properties, functional modifications and potential applications. Several difficulties and emerging issues are also proposed.

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