Some features of metastable zone width of various systems determined by polythermal method

Sangwal, K.

doi:10.1039/c0ce00065e

Cited by 38 publications

(33 citation statements)

References 13 publications

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“…In most of the cases u max o0.1, but u max E0.25 for NTOÀ water/NMP systems (where NMP is N-methyl-2pyrrolidone) has also been observed [13]. The observation that u max o0.1 means that both Eqs.…”

Section: Dependence Of Dimensionless Supercooling U Max On Cooling Ramentioning

confidence: 75%

Recent developments in understanding of the metastable zone width of different solute−solvent systems

Sangwal

2011

Journal of Crystal Growth

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Section: Dependence Of Dimensionless Supercooling U Max On Cooling Ramentioning

confidence: 75%

Recent developments in understanding of the metastable zone width of different solute−solvent systems

Sangwal

2011

Journal of Crystal Growth

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“…The lactose crystallisation mentioned earlier confirms the importance of the proliferation region in the commercial 10 crystallisation practice for the production of fine particles. In pharmaceutical and fine chemicals crystallisation, uniform, well-shaped crystals are commonly produced which shows what can be achieved empirically, or with computer control, for generally this must have been achieved without the knowledge 15 of the underlying reasons described here.…”

Section: Large Scale Considerationsmentioning

confidence: 61%

“…When the gap between the end of the fibre optic and the mirror 10 was decreased the sensitivity of the probe was likewise reduced and the metastable zone width changed significantly. It had been expected that halving the gap would halve the sensitivity, but the resulting charts suggested that the sensitivity may have decreased by a factor of a hundred-fold.…”

mentioning

confidence: 91%

“…In each case the curvetrajectory of the crystallisation, e,g. the turbidimetric value, will appear to slope upwards at an increasing incline, but 10 whether this is due in any particular case to several overlapping primary crystallisation events followed by varying intervals to the secondary nucleation, or to single or simultaneous nucleation events followed by crystal growth and continuously increasing proliferation, is impossible to determine merely by 15 the shape. So careful analysis of the crystallisation curves of the kind carried out by Dugua and Simon will be necessary to establish the true course of the crystallisation events 6768 .…”

Section: The Course Of the Crystallisationmentioning

confidence: 99%

“…White, Marziano and co-workers 16 have used the concept of a secondary nucleation threshold in the crystallisation of ibuprofen. It has also been 10 investigated in connection with lysozyme crystallisation 17 . Khaddour and Rocha 18 have investigated 'secondary nucleation within the metastable zone', which is presumably the same phenomenon, but have not considered it in relation to product formation.…”

Section: Introductionmentioning

confidence: 99%

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A perspective on the growth-only zone, the secondary nucleation threshold and crystal size distribution in solution crystallisation

Threlfall

Coles

2016

CrystEngComm

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The metastable zone between the solubility curve and the crystallisation curve can be divided into two regions, separated by the secondary nucleation threshold. At a supersaturation less than that of the secondary nucleation threshold seeds will grow but not proliferate. At greater supersaturations, they will proliferate. Although this concept has been known in connection with the commercial crystallisation of sucrose and of lactose for almost a century it is virtually unrecognised beyond the sugar and dairy 10 industries. The consequences are explored of the existence of such a boundary on the crystallisation process and the influence on crystal size distribution. It is recognised that the secondary nucleation threshold is the 'seeded metastable limit', but there are important consequences of avoiding the latter term. Mullin's 'Latent Period' is shown to be closely related to the 'growth only' zone within the metastable zone.15

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Continuous Crystallisation

Brown

McGlone

Florence

2017

Continuous Manufacturing of Pharmaceuticals

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Mixing 2) Nucleation 3) Growth 4) Filter/wash/dry Required to:  Produce consistent composition  Control crystallisation driving force  Influence flow rate, shear-kinetic effects  Consistent suspension of seed and product Controlled via:  Supersaturation  High shear  External fields, e.g. ultrasound, nonphotochemical laser induced nucleation  Seed. Seeds produced via dry milling, wet media milling, precipitation, recycle, dissolution, spray drying or secondary nucleation Controlled to avoid:  Fouling  Agglomeration  Dissolution  Crystalline form transformation(s) Controlled via:  Supersaturation (typically low) via cooling, anti-solvent, evaporation  Effective heat/mass transfer Ensures:  Efficient desupersaturation Controlled to avoid:  Fouling  Agglomeration  Attrition (particle breakage)  Dissolution  Crystalline form transformation(s) Required to:  Create filter cake  Remove mother liquor and impurities  Maintain particle attributes Controlled to avoid:  Agglomeration  Attrition (particle breakage)Continuous crystallisation has been implemented for many decades in other manufacturing sectors, typically for large volume commodity chemicals, and offers a range of potential advantages [16,17] including lower operating and capital costs, reduced down time and more efficient use of energy and materials. Cooling and anti-solvent crystallisation are commonly used in industrial applications and can be readily implemented in continuous. The aim is to follow a controlled trajectory through the solubility phase diagram (section 1.2).

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Some features of metastable zone width of various systems determined by polythermal method

Cited by 38 publications

References 13 publications

Recent developments in understanding of the metastable zone width of different solute−solvent systems

Recent developments in understanding of the metastable zone width of different solute−solvent systems

A perspective on the growth-only zone, the secondary nucleation threshold and crystal size distribution in solution crystallisation

Continuous Crystallisation

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