# Evidence: diffusion-controlled crystal growth

Parent: crystal growth · class: kinetics · names merged here: diffusion-controlled crystal growth; diffusion-controlled growth; diffusion-limited crystal growth; mass-transport-limited crystal growth

4 papers measured or used it, 0 only mentioned it (of 207 kept papers). Papers in year order; each section heading ends with the paper's category / subcategory. Generated by tools/build_evidence.py from registry/concepts.csv and the cards; do not edit.

## 2010 Kestur — Effects of the Molecular Weight and Concentration of Polymer Additives, and Temperature on the Melt Crystallization Kinetics of a Small Drug Molecule · Solid state stability / Physical stability

[2010-kestur-pvp-mw-concentration-temperature-felodipine-melt-crystallization](../../../cards/2010-kestur-pvp-mw-concentration-temperature-felodipine-melt-crystallization/paper.html) · Solid state stability / Physical stability · used · as: diffusion-limited crystal growth

| id | kind | content | locator |
|---|---|---|---|
| C23 | claim, conclusion, authors: "indicating"; "consistent with" | Lowering T has competing effects (lower mobility, higher driving force); since growth in the felodipine/PVP mixtures decreases with supercooling over 70-110 °C (ΔT in R17), the transport term dominates and growth is diffusion-limited, as reported for crystalline polymers and small organic molecules at high supercooling [rests on: R13, R17; cited: refs 28, 29] | p.3592 |

## 2012 Alonzo — Characterizing the Impact of Hydroxypropylmethyl Cellulose on the Growth and Nucleation Kinetics of Felodipine from Supersaturated Solutions · Dissolution / D. Crystallization from solution

[2012-alonzo-hpmc-felodipine-growth-nucleation-supersaturation](../../../cards/2012-alonzo-hpmc-felodipine-growth-nucleation-supersaturation/paper.html) · Dissolution / D. Crystallization from solution · used · as: diffusion-controlled growth

| id | kind | content | locator |
|---|---|---|---|
| C3 | claim, assumption, authors: asserted | An overall growth order g of 1 means diffusion-controlled growth (transport to the incorporation site is rate limiting) and g of 2 integration-controlled growth (incorporation into the lattice is rate limiting); g is commonly between 1 and 2 [rests on: cited: refs 22, 24] | p.1539 |
| C33 | claim, mechanism, authors: abstract: asserted ("shifted"); discussion: "This suggests" | HPMC shifts felodipine growth toward integration control, from a combination of integration and diffusion control without HPMC [rests on: R13; C3] | p.1538, p.1544 |

## 2013 Kestur — Evaluation of the crystal growth rate of felodipine polymorphs in the presence and absence of additives as a function of temperature · Solid state stability / Physical stability

[2013-kestur-felodipine-polymorph-crystal-growth-pvp-additives](../../../cards/2013-kestur-felodipine-polymorph-crystal-growth-pvp-additives/paper.html) · Solid state stability / Physical stability · used · as: diffusion-controlled crystal growth

| id | kind | content | locator |
|---|---|---|---|
| R16 | record, cited | molecular layers added to the crystal in one structural relaxation time — diffusion-controlled growth (ref 13); GC growth of ROY polymorphs (ref 14) — 0.1-1 layers (diffusion-controlled); 1700-2400 layers (GC, different ROY polymorphs) | p.12 |
| C22 | claim, prior hypothesis, authors: asserted (cited) | Yu and co-workers explain GC growth as diffusionless: GC rates far exceed diffusion-based predictions; diffusion-controlled growth adds 0.1-1 layers per structural relaxation time against 1700-2400 for GC growth, too many for substantial diffusion or relaxation, and new-layer addition has been related to oscillatory motions in the glass and liquid [rests on: cited: refs 5, 13, 14, 19; R16] | p.11-12 |
| C23 | claim, mechanism, authors: "supporting the supposition" | About 500 layers added per structural relaxation time at 45 °C supports the supposition that form I also exhibits the diffusionless growth mode, whereas form II, with less than one layer, does not show this fast mode [rests on: R18, R16] | p.12 |

## 2016 Sato — Acceleration of the crystal growth rate of low molecular weight organic compounds in supercooled liquids in the presence of polyhydroxybutylate · Solid state stability / Physical stability

[2016-sato-phb-crystal-growth-supercooled-organic-compounds](../../../cards/2016-sato-phb-crystal-growth-supercooled-organic-compounds/paper.html) · Solid state stability / Physical stability · used · as: mass-transport-limited crystal growth

| id | kind | content | locator |
|---|---|---|---|
| C14 | claim, prior hypothesis, authors: asserted; "typically" | Crystal growth rate depends on thermodynamic driving force (free energy difference) and kinetic factors (viscosity) as in Eq. 1, which polymer additives may both affect; these give the bell-shaped growth-rate curve, with thermodynamic control near Tm and mass-transport control at large undercooling, and a maximum typically near 0.94 Tm [rests on: cited: refs 23-25; E1, E2] | p.6 |
| C15 | claim, assumption, authors: "is expected to be" | Because the growth experiments were run at large undercoolings, below the temperature of maximum growth, the growth rate is expected to depend on the mass transport rate of the drug to the crystal surface [rests on: E2; argument only] | p.6 |
| C25 | claim, mechanism, authors: "most likely"; conclusions: asserted | The retardation most likely stems from polymer molecules physically impeding transport of crystallizing molecules to the crystal surface (conclusions: PHB acts as a crystal growth inhibitor by reducing the transport rate) [rests on: R3, R11] | p.7-8 |
| E2 | equation | temperature of maximum crystal growth rate: T_max ≈ 0.94 Tm ("A maximum in crystal growth rate typically occurs at a temperature equivalent to 0.94*Tm") | p.6 |