# Evidence: cosolvency

Parent: — · class: solution behaviour · names merged here: cosolvency; cosolvent effect; cosolvent solubilization

3 papers measured or used it, 1 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.

## 2008 Marsac — Recrystallization of Nifedipine and Felodipine from Amorphous Molecular Level Solid Dispersions Containing Poly(vinylpyrrolidone) and Sorbed Water · Solid state stability / Physical stability

[2008-marsac-nifedipine-felodipine-pvp-sorbed-water-recrystallization](../../../cards/2008-marsac-nifedipine-felodipine-pvp-sorbed-water-recrystallization/paper.html) · Solid state stability / Physical stability · measured · as: cosolvency

| id | kind | content | locator |
|---|---|---|---|
| R12 | record, measured (points); derived (fits, E5) | mole fraction solubility in NMP-water co-solvent (error bars one SD, n = 3) — crystalline nifedipine and felodipine, P8, 25 °C — sub-table below; printed fits: log S = −0.04×(wt% water) − 0.89, R² = 0.96 (nifedipine); log S = −0.06×(wt% water) − 0.56, R² = 0.98 (felodipine); text: same solubility for both drugs estimated at about 25 wt% water | Fig. 9, p.654; text p.654 |
| E5 | equation | log-linear cosolvency relation: log S = −0.04 × (wt% water) − 0.89 (nifedipine, R² = 0.96); log S = −0.06 × (wt% water) − 0.56 (felodipine, R² = 0.98) | p.654 |
| C39 | claim, conclusion, authors: "approximately"; "Based on these data" | Solubility in NMP-water falls approximately log-linearly with water content for both drugs, typical of many co-solvent systems; water is a stronger anti-solvent for felodipine, whose slope is more negative [rests on: R12, E5; cited: ref 43] | p.654 |

## 2008 Marsac — Spontaneous Crystallinity Loss of Drugs in the Disordered Regions of Poly(Ethylene Oxide) in the Presence of Water · Solid state stability / PEG dispersions

[2008-marsac-peo-water-spontaneous-drug-crystallinity-loss](../../../cards/2008-marsac-peo-water-spontaneous-drug-crystallinity-loss/paper.html) · Solid state stability / PEG dispersions · used · as: cosolvency

| id | kind | content | locator |
|---|---|---|---|
| C24 | claim, mechanism, authors: "most likely"; "must be reduced" | Water most likely sorbs into the amorphous PEO regions that solubilize the drug; as every drug is far less soluble in water than in PEG 400, water must reduce the thermodynamic driving force for drug dissolution into these regions relative to pure amorphous PEO [rests on: R14] | p.3190 |
| C33 | claim, mechanism, authors: asserted ("will") | Sorbed water lowers drug solubility in the water-amorphous PEO cosolvent but increases the volume of solvent available; the larger disordered PEO fraction then dissolves additional drug (Fig. 7) [rests on: argument only; R9] | p.3192 |
| C38 | claim, mechanism, authors: conclusions: asserted ("was related"); introduction: "could be rationalized" | The degree of transformation was related to the ability of the drug to dissolve in the water-amorphous PEO cosolvent regions; the extent of loss can be rationalized by moisture-induced changes in polymer structure and the drug properties [rests on: R14, R16] | p.3192; p.3183 |

## 2009 Rumondor — Phase Behavior of Poly(vinylpyrrolidone) Containing Amorphous Solid Dispersions in the Presence of Moisture · Solid state stability / Physical stability

[2009-rumondor-pvp-asd-moisture-induced-immiscibility](../../../cards/2009-rumondor-pvp-asd-moisture-induced-immiscibility/paper.html) · Solid state stability / Physical stability · used · as: cosolvent effect

| id | kind | content | locator |
|---|---|---|---|
| C37 | claim, mechanism, authors: p.1502: asserted; p.1504: "will potentially create a thermodynamically unfavorable environment" | In a purely thermodynamic route the dry one-phase drug-PVP mixture is the free energy minimum; sorbed water interacts favourably with the polymer and raises matrix polarity, the hydrophobic drug interacts unfavourably with the polymer-water "cosolvent", whose miscibility with the drug falls as its water content rises, and separation into drug-rich and polymer-rich regions lowers the free energy [rests on: argument only] | p.1502, p.1504 |
| C44 | claim, prior hypothesis, authors: asserted | The cosolvent effect has been documented for ternary solvent systems and reported for felodipine-PVP-water [rests on: cited: refs 17, 27, 37; R27] | p.1504 |

## Mentioned only

- 2015 Chen — [2015-chen-bile-salts-crystallization-inhibitors-supersaturated-solutions](../../../cards/2015-chen-bile-salts-crystallization-inhibitors-supersaturated-solutions/paper.html) · Dissolution / D. Crystallization from solution (ref 3)