Different effect of impact and shear mechanical treatment on mechanochemical cocrystallization of piroxicam and succinic acid

Tumanov, Ivan A.; Achkasov, A. F.; Myz, S. A.; Boldyreva, Elena V.; Болдырев, В. В.

doi:10.1134/s0012500814080059

Cited by 23 publications

(38 citation statements)

References 7 publications

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“…Ex situ analysis has demonstrated that the type of mechanical treatment [14,24,25], the addition of liquid [14,26,27], a polymer [28,29] and starting polymorph [14] can all play a role in determining the outcome of a polymorphic transformation. This phenomenon is of particular importance to industry, where the solid form of a material is vital to the integrity of its function and the legalities that surround its applications.…”

Section: Introductionmentioning

confidence: 99%

The effect of ball mass on the mechanochemical transformation of a single-component organic system: anhydrous caffeine

2018

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ABSTARCTMechanochemical methodologies, particularly ball milling, have become commonplace in many laboratories. In the present work, we examine the effects of milling ball mass on the polymorphic conversion of anhydrous caffeine. By investigating a single-phase system, the rate-limiting step of particle-particle contact formation is eliminated. It is found that larger milling balls lead to considerably faster conversion rates. Modelling of the transformation rate suggests that a single, time-independent rate constant is insufficient to describe the transformation. Instead, a convolution of at least two rate-determining processes is required to correctly describe the transformation. This suggests that the early stages of the transformation are governed only by the number of particle-ball collisions. As the reaction proceeds, these collisions less frequently involve reactant, and the rate becomes limited by mass transport, or mixing, even in originally single-phase systems, which become multi-phase as the product is formed. Larger milling balls are less hindered by poorly mixed material. This likely results from a combination of higher impact energies and higher surface areas associated with the larger milling balls. Such insight is important for the selective and targeted design of mechanochemical processes.

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Section: Introductionmentioning

confidence: 99%

The effect of ball mass on the mechanochemical transformation of a single-component organic system: anhydrous caffeine

2018

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“…This clearly demonstrates the notable differences in the effects of impact and shear mechanical treatment on the transformation of solids. 48 …”

Section: Liquid-assisted Grinding (Lag) Of ε-Chlorpropamidementioning

confidence: 99%

“…48 Samples (ca. 30 mg) were subjected to continuous mechanical shearing between two circular, roughened glass plates, while under the pressure of several metal weights.…”

Section: Shearmentioning

confidence: 99%

“…47 It has been documented for some other organic molecular crystals that different types of treatment (such as shear or impact) may have different or even opposing effects on a transformation. 48,49 It is therefore important to compare the outcome of the transformations on different types of mechanical treatment. In the present work we used custom-built model devices [48][49][50][51][52] to compare the effects of shear and restricted impact, and compared them with the outcome of grinding with a mortar and pestle.…”

Section: Introductionmentioning

confidence: 99%

“…48,49 It is therefore important to compare the outcome of the transformations on different types of mechanical treatment. In the present work we used custom-built model devices [48][49][50][51][52] to compare the effects of shear and restricted impact, and compared them with the outcome of grinding with a mortar and pestle. The discovery of a new method to obtain pure β-CPA, reported here, enabled us to explore the stability of both β-and ε-CPA to mechanical manipulation for solid form processing, depending on the choice of added liquid and the type of mechanical treatment.…”

Section: Introductionmentioning

confidence: 99%

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Polymorphism of chlorpropamide on liquid-assisted mechanical treatment: choice of liquid and type of mechanical treatment matter

et al. 2018

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Different types of mechanical treatment (tableting, grinding, milling, etc.) are important technological operations in the pharmaceutical industry. Solid materials are not merely comminuted during such treatment, but can undergo polymorphic transitions and amorphisation. A liquid is often added to the solid sample on purpose, e.g. in order to facilitate comminution. In many cases, liquid is present inadvertently, either as a result of trace solvent following up-stream operations, or sorbed from the atmosphere. This work explores the liquid-assisted mechanical treatment of two metastable forms of a model pharmaceutical compound chlorpropamide (CPA), namely the β-and ε-forms. We investigate the stability of these polymorphs to mechanical treatment in the presence of a series of fluids that have affinity for different fragments of the CPA molecule. In addition to variation in fluids, the effect of different mechanical treatment is explored, employing model shear and restricted impact devices, alongside grinding in a mortar. CPA offers a clear example of the drastically different results of shear and impact on mechanochemical polymorphism, on the importance of the careful selection of solvent for liquid-assisted treatment, and on the possible role of even trace quantities of solvent. Further, this work demonstrates the importance of the starting polymorph in determining the outcome of a mechanochemical process. All of these factors can have notable consequence on the outcome of technological operations that include mechanical treatment.

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Challenges of Mechanochemistry: Is In Situ Real‐Time Quantitative Phase Analysis Always Reliable? A Case Study of Organic Salt Formation

et al. 2017

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Mechanochemical methods offer unprecedented academic and industrial opportunities for solvent‐free synthesis of novel materials. The need to study mechanochemical mechanisms is growing, and has led to the development of real‐time in situ X‐ray powder diffraction techniques (RI‐XRPD). However, despite the power of RI‐XRPD methods, there remain immense challenges. In the present contribution, many of these challenges are highlighted, and their effect on the interpretation of RI‐XRPD data considered. A novel data processing technique is introduced for RI‐XRPD, through which the solvent‐free mechanochemical synthesis of an organic salt is followed as a case study. These are compared to ex situ studies, where notable differences are observed. The process is monitored over a range of milling frequencies, and a nonlinear correlation between milling parameters and reaction rate is observed. Kinetic analysis of RI‐XRPD allows, for the first time, observation of a mechanistic shift over the course of mechanical treatment, resulting from time evolving conditions within the mechanoreactor.

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Different effect of impact and shear mechanical treatment on mechanochemical cocrystallization of piroxicam and succinic acid

Cited by 23 publications

References 7 publications

The effect of ball mass on the mechanochemical transformation of a single-component organic system: anhydrous caffeine

The effect of ball mass on the mechanochemical transformation of a single-component organic system: anhydrous caffeine

Polymorphism of chlorpropamide on liquid-assisted mechanical treatment: choice of liquid and type of mechanical treatment matter

Challenges of Mechanochemistry: Is In Situ Real‐Time Quantitative Phase Analysis Always Reliable? A Case Study of Organic Salt Formation

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