# Evidence: in situ salt formation

Parent: salt formation · class: solid-state property · names merged here: in situ salt formation

2 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.

## 2022 Duong — Combining enabling formulation strategies to generate supersaturated solutions of delamanid: In situ salt formation during amorphous solid dispersion fabrication for more robust release profiles · Dissolution / B. Supersaturation from ASD dissolution

[2022-duong-delamanid-in-situ-salt-asd-release](../../../cards/2022-duong-delamanid-in-situ-salt-asd-release/paper.html) · Dissolution / B. Supersaturation from ASD dissolution · measured · as: in situ salt formation

| id | kind | content | locator |
|---|---|---|---|
| P8 | method | rotary evaporation ASD | p.133; Figs. 3, 4, 7, 8, 9 |
| R16 | record, measured | 1H NMR of DLM free base vs DLM-edisylate — DMSO-d6 (P13) — piperidine ring proton peaks shifted downfield in the salt; almost no change for protons near the imidazole ring (Fig. S4) | p.137-138 |
| R17 | record, measured | IR of sulfonate salts vs free base — ATR-FTIR (P11) — salts: very broad, intense band 2770-2380 cm−1, maximum 2519 cm−1; free-base band at 2816 cm−1 (methylene groups next to the tertiary amine nitrogen) absent in the salt spectra (Fig. S5) | p.138 |
| R24 | record, measured | DLM concentration released from DLM-edisylate ASD tablets (µg/mL) — single stage (P15) and pH shift (P16); triplicate; "100%" curve = neat DLM-edisylate — sub-table below; text: neat DLM-edisylate no release in PBS pH 6.5; in acid slightly higher than the free base but lower than the amorphous solubility | Fig. 8, p.140; text p.138 |
| R26 | record, measured | DLM concentration released from 25% DL ASDs with HPMCP (µg/mL) — four salts and free base; single stage (P15) and pH shift (P16); triplicate — sub-table below; text: acid-stage concentration ranged from 20 to 35 µg/mL, highest for DLM-edisylate | Fig. 9, p.140; text p.139 |
| C62 | claim, conclusion, authors: abstract: asserted ("remarkable improvement"); discussion: asserted ("clear improvement"), "generally"; conclusions: "In general" | Certain sulfonic acid salts clearly raised the DL at which crystal-free ASDs could be obtained; completely amorphous salt ASDs with HPMCP improved release in single- and two-stage tests (25% DL); salt ASDs with HPMCP generally outperformed those with HPMCAS; conclusions: in situ salt formation prevented crystallization at higher DLs and improved release [rests on: R24, R26] | p.131, p.141 |

## 2023 Nguyen — Enteric coating of tablets containing an amorphous solid dispersion of an enteric polymer and a weakly basic drug: A strategy to enhance in vitro release · Dissolution / B. Supersaturation from ASD dissolution

[2023-nguyen-enteric-coating-delamanid-hpmcp-asd-release](../../../cards/2023-nguyen-enteric-coating-delamanid-hpmcp-asd-release/paper.html) · Dissolution / B. Supersaturation from ASD dissolution · measured · as: in situ salt formation

| id | kind | content | locator |
|---|---|---|---|
| P1 | method | spray-dried ASD | p.2 |
| R3 | record, measured | crystals on uncoated ASD films by PLM — spin-coated films of DLM free base, chloride and edisylate ASDs (P4), phosphate buffer pH 3.0, 1 h (P5) — birefringent needle- and star-shaped crystals spread over all three films; text: rapid crystallization, similar for free base and both salts | Fig. 2A (i-iii), p.5; text p.4 |
| R4 | record, measured | crystals on uncoated ASD films by SEM — films of DLM free base, edisylate and chloride ASDs, phosphate pH 3.0, 1 h (P5) — star- and needle-shaped crystals over the surface of all three films (1000×) | Fig. 3, p.5; text p.4 |
| C11 | claim, prior hypothesis, authors: asserted | Salt formation improved the physical stability of DLM ASDs but all formulations showed pH-dependent release variations; combining salt formation with an HPMCP-50 ASD stabilized amorphous DLM in the solid state and in intestinal-pH solutions [rests on: cited: refs 43, 64] | p.2, p.9 |
| C17 | claim, conclusion, authors: asserted ("Notably"; "could not completely eliminate") | Salt formation did not affect the crystallization tendency of DLM at pH 3.0 (similar for free base and both salts), in agreement with ref 43; neither changing the enteric polymer (ref 43) nor changing to a salt completely eliminated crystallization [rests on: R3, R4; cited: ref 43] | p.4, p.9 |