# Evidence: critical point

Parent: — · class: phase behaviour · names merged here: critical point; plait point

3 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.

## 2023 Deac — Dissolution Mechanisms of Amorphous Solid Dispersions: A Close Look at the Dissolution Interface · Dissolution / A. Release mechanism and LoC

[2023-deac-asd-dissolution-interface](../../../cards/2023-deac-asd-dissolution-interface/paper.html) · Dissolution / A. Release mechanism and LoC · used · as: plait point

| id | kind | content | locator |
|---|---|---|---|
| C68 | claim, generalisation, authors: "Intuitively, it is expected"; "serves as an arbiter for approximating" | Because the volume of the hydrophobic phase decides whether it forms a network, a hydration path entering the two-phase region right of the plait point (through the hydrophobic binodal) makes the hydrophobic phase the majority and should give a continuous network, and one entering left of it a discrete phase; the plait point position therefore approximates the maximum LoC of a binary ASD [rests on: argument only] | p.2232 |
| C69 | claim, generalisation, authors: "can result in"; "are also favorable" | Associative systems have the plait point to the left and can have a low maximum LoC; segregative systems have it to the right and a higher maximum LoC; a smaller miscibility gap also favours a higher maximum LoC (Fig. 18) [rests on: argument only; C65] | p.2232 |

## 2023 Deac — Dissolution Mechanisms of Amorphous Solid Dispersions: Role of Drug Load and Molecular Interactions · Dissolution / A. Release mechanism and LoC

[2023-deac-asd-drug-load-molecular-interactions-loc](../../../cards/2023-deac-asd-drug-load-molecular-interactions-loc/paper.html) · Dissolution / A. Release mechanism and LoC · used · as: plait point

| id | kind | content | locator |
|---|---|---|---|
| C63 | claim, mechanism, authors: discussion: "are hypothesized"; conclusions: "It is suggested"; "It is speculated herein"; "may be closely related" | Strong drug-polymer interactions lower the LoC by shifting the plait point to a lower drug/polymer ratio, which raises the polymer content of the hydrophobic binode and so the hydrophobic-phase volume at a given drug load, favouring an interconnected barrier; associative ASDs therefore need less drug than segregative ones to reach the minimum hydrophobic volume for a barrier, and barrier formation may be closely related to the plait-point position, partly governed by drug-polymer interactions [rests on: R3, R8; argument only] | p.734 |
| C49 | claim, mechanism, authors: asserted ("hence") | Because the associative plait point lies at lower drug content, the step from a small to a large hydrophobic phase, and hence the LoC, occurs at a lower drug load than in a segregative system [rests on: argument only (Fig. 10)] | p.733 |
| C36 | claim, generalisation, authors: "approximately"; "is expected" | The hydrophobic-phase volume at initial separation versus drug load is approximately a step function with the step at the plait point, so significant or full continuity of the hydrophobic phase is expected near the plait point [rests on: argument only (Fig. 8d)] | p.731 |
| X14 | extractor note | claim-data gap — The central mechanism (strong interactions shift the plait point, enlarge the hydrophobic phase and make it continuous at a lower drug load) is drawn on schematic diagrams (Figs. 8-10, one with horizontal tie lines); no ternary diagram, tie line, plait point, gel-layer morphology or hydrophobic-phase volume was measured, and the link to the LoC rests on the rank agreement of four analogues with cited LoCs — C63, C49, C62, C66, C36, R8 — treat the plait-point mechanism as the authors' hypothesis ("hypothesized", "speculated") |  |

## 2024 Deac — Dissolution Mechanisms of Amorphous Solid Dispersions: Application of Ternary Phase Diagrams To Explain Release Behavior · Dissolution / A. Release mechanism and LoC

[2024-deac-asd-ternary-phase-diagrams-release](../../../cards/2024-deac-asd-ternary-phase-diagrams-release/paper.html) · Dissolution / A. Release mechanism and LoC · measured · as: critical point

| id | kind | content | locator |
|---|---|---|---|
| R22 | record, measured and simulated | MePHPH-PVPVA-water phase diagram — 37 °C; experimental binodes and tie lines from R15.a-e; film points from R2; PC-SAFT binodal, spinodal, tie lines, critical point (P19) — experimental and computed tie lines negatively sloped; the tie line of the lowest-water mixture (R15.d) does not pass through its total composition (text); inhomogeneous films at 10, 20 and 30% DL, 80% RH lie outside the computed binodal (text p.1911); computed critical point ≈29 wt% MePHPH, ≈59 wt% PVPVA, ≈12 wt% water (read from Fig. 9) | Fig. 9, p.1910; text p.1910-1911 |
| R23 | record, measured and simulated | PHPH-PVPVA-water phase diagram — 37 °C; experimental binodes and tie lines from R15.f-i; homogeneous mixtures R15.j-l; PC-SAFT (P19) — experimental and computed tie lines positively sloped and close in slope; the homogeneous mixtures R15.j-l lie inside the computed binodal; computed critical point ≈2.6 wt% PHPH, ≈59.5 wt% PVPVA, ≈38 wt% water (read from Fig. 10) | Fig. 10, p.1910; text p.1911 |
| R25 | record, simulated and measured | TIPP and MeTIPP computed diagrams with dilute experimental tie-line slope — P6, P19; 37 °C — plait point ≈10 wt% TIPP, ≈62 wt% PVPVA, ≈29 wt% water; plait point ≈23 wt% MeTIPP, ≈46 wt% PVPVA, ≈31 wt% water; dilute tie-line slope (PVPVA:drug of hydrophobic phase) ≈0.6 for TIPP and ≈0.2 for MeTIPP (all read from Fig. S17); numerical dilute compositions not printed | Fig. S17, SI p.23; SI p.8-9 |
| R35 | record, derived (E12, P20) | Wα at onset of water-induced phase separation versus DL — PC-SAFT diagrams, hydration path to spinodal, local equilibrium; (a) MePHPH-PVPVA, (b) PHPH-PVPVA — (a) Wα ≈0.02 at ≈5% DL rising to ≈0.15 at ≈27% DL; dry critical point (Wα 0.5) at ≈33% DL; ≈0.82 at ≈39.5% DL rising to ≈0.85 at ≈67% DL; no computed point between ≈27 and ≈39.5% DL other than the critical point. (b) ≈0.02 at ≈0.9% DL to ≈0.16 at ≈3.0% DL; critical point ≈3.7% DL; ≈0.82 at ≈4.5% DL, ≈0.80-0.86 up to ≈29% DL (all read from Fig. 16); overlaid micrographs: the persistent-morphology images of R18 (10-60% DL) and R19 (5-20% DL) | Fig. 16, p.1915 |
| R37 | record, cited and derived | LoC from release studies versus DL of predicted phase inversion (critical point composition) — PVPVA ASDs; LoC from ref 18; prediction from PC-SAFT diagrams (P19) — sub-table below; text: LoCs 5, 10, 30 and ~40 wt% for PHPH, TIPP, MeTIPP, MePHPH | Fig. 18, p.1916; text p.1902 |
| C64 | claim, generalisation, authors: abstract: "approximately corresponded"; conclusions: "it was demonstrated"; "This suggested" | The hydrophobic-phase fraction can be calculated versus initial DL from experimental and computed diagrams and approximates the phase inversion point; since the hydrophobic phase grows rapidly once the drug:polymer ratio exceeds the critical point, this suggests the critical point can serve as a surrogate for the phase inversion point (abstract: critical point composition approximately corresponds to the DL where the hydrophobic phase becomes interconnected) [rests on: R35, R37] | p.1900, p.1916-1917 |
| X7 | extractor note | claim-data gap — C61 (PC-SAFT accurately calculates critical point compositions) rests on agreement of predicted inversion DL with cited LoC values (R37); no critical point was measured, and for PHPH the authors state that experimental binodes place the real gap inside the computed one (C34) — C61, C34, R23, R37 — treat as agreement with cited LoC, not as validation of computed critical points |  |