The Confusion of Indexing Aspirin Crystals

Aubrey‐Medendorp, Clare; Parkin, Sean; Li, Tonglei

doi:10.1002/jps.21055

Cited by 28 publications

(49 citation statements)

References 18 publications

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“…The dominant surface of the grown crystal was (100), and the crystal morphology was the same to previous reports [11,12]. A 6-pass tandem Fabry-Perot interferometer was used to measure the Brillouin spectra of aspirin in a wide temperature range from 100 K in the solid phase to 433 K in the liquid phase.…”

Section: Methodsmentioning

confidence: 99%

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Acoustic properties of aspirin in its various phases and transformation stages studied by Brillouin scattering

Kim

Lee

et al. 2011

Journal of Non-Crystalline Solids

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Section: Methodsmentioning

confidence: 99%

“…Aspirin crystals exhibit a monoclinic phase (P2 1 /c) with 4 formula units in one unit cell [11]. The aspirin crystal consists of centrosymmetric dimers linked by a pair of hydrogen bonds between carboxyl groups.…”

Section: Introductionmentioning

confidence: 99%

Acoustic properties of aspirin in its various phases and transformation stages studied by Brillouin scattering

Kim

Lee

et al. 2011

Journal of Non-Crystalline Solids

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“…In order to determine the surface chemistry of a specific crystal facet, information on crystal structure and the miller indices of that particular crystal face is required [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Can vacuum morphologies predict solubility and intrinsic dissolution rate? A case study with felodipine polymorph form IV

Kumar

Thipparaboina

Shastri

2015

Journal of Computational Science

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“…19,25 The quantitative crystal evaluation of this study showed that the crystal habits of aspirin were also highly dependent on the crystallization temperature. Two factors, substrate diffusion and dissolution rate from specific crystal surfaces in solution, were considered to be involved in the definition of crystal habits.…”

Section: ■ Results and Discussionmentioning

confidence: 98%

“…Here, it is likely that the growth rate of crystals along the short axis (i.e., perpendicular to the long axis) where {110} and {011} crystal faces dominate was highest at this temperature. 19,25 At lower temperatures, growth of crystals was diffusion limited, while at temperatures above 20°C…”

Section: ■ Results and Discussionmentioning

confidence: 98%

Crystal Growth of Aspirin Using a Temperature-Controlled Microfluidic Device

Tokuhisa

Kawasaki

Kisailus

et al. 2015

Crystal Growth & Design

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Identifying the most appropriate polymorph of active pharmaceutical ingredients is one of the important steps in drug development, since their bioactivities are largely dependent on their solid forms. However, the sample preparation for the characterization of crystal forms is time-consuming and requires large quantities of sample. Here, we introduce a microfluidic device-based method to prepare a sub-millimeter-sized single aspirin crystal from a small quantity of material. For the crystal preparation, a device equipped with a solution flow system and temperature controller was placed under the microscope. To use the device, concentration−temperature phase diagrams were generated, and regions where dominant nucleation or crystal growth with specific directions were clearly determined. By observing time-dependent changes of crystal number and size with solution temperature, a pathway to grow a single crystal of aspirin was determined and applied to prepare a submillimeter-sized crystal from 250 μg of aspirin. The obtained crystal was sufficiently large for single-crystal X-ray diffraction analysis, which usually requires 10 mg to 1 g of material per crystallization experiment. Thus, this method can be adapted as an efficient approach to uncovering the crystallization process to obtain required crystal forms with minimal sample consumption. ■ INTRODUCTIONSolid form selection of active pharmaceutical ingredients (APIs) is an important issue in drug development since the bioactivities of APIs are largely dependent on the crystal polymorph or form, size, and morphology. 1,2 The selection of solid form often determines the fate of commercial viability of pharmaceutical products. 2 The primary mode of crystal screening is conducted via a high-throughput workflow system, which enables automation of the entire crystallization procedure. 3 In order to select the best crystal form with desired physicochemical properties for drug development, a number of crystallization conditions on the basis of solvent, salt and substrate concentrations, pH, and temperature have been investigated. 4 Crystal forms found using a high-throughput workflow system are then re-examined through multistep scaleup experiments in order to evaluate reproducibility and characterize specific physicochemical parameters, such as packing arrangement (e.g., molar volume, hygroscopicity), thermodynamic properties (e.g., melting point, entropy, enthalpy, solubility, vapor pressure, free energy), kinetic attributes (e.g., dissolution rate, reaction rates, stability), surface features (e.g., surface free energy, crystal habit, wettability), and mechanical properties (e.g., hardness, tableting, flow ability). 5,6 Here, it is critical to assess the aforementioned parameters in a timely manner due to the highly competitive intellectual property arena as well as providing quick insight into new opportunities for "life-cycle management of the product". 4 During the analysis of selected crystal forms in scale-up experiments, powder X-ray diffraction (XRD) is general...

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The Confusion of Indexing Aspirin Crystals

Cited by 28 publications

References 18 publications

Acoustic properties of aspirin in its various phases and transformation stages studied by Brillouin scattering

Acoustic properties of aspirin in its various phases and transformation stages studied by Brillouin scattering

Can vacuum morphologies predict solubility and intrinsic dissolution rate? A case study with felodipine polymorph form IV

Crystal Growth of Aspirin Using a Temperature-Controlled Microfluidic Device

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