# Evidence: ionic interactions

Parent: — · class: molecular interaction · names merged here: electrostatic interaction; ionic interaction; ionic interactions

5 papers measured or used it, 3 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 Towler — An Investigation into the Influence of Counterion on the Properties of Some Amorphous Organic Salts · Solid state stability / Crystallization tendency

[2008-towler-counterion-amorphous-organic-salts](../../../cards/2008-towler-counterion-amorphous-organic-salts/paper.html) · Solid state stability / Crystallization tendency · used · as: ionic interaction

| id | kind | content | locator |
|---|---|---|---|
| C23 | claim, prior hypothesis, authors: asserted ("will be") | For salts, ionic interactions will be of greater importance in dictating Tg than hydrogen bonding and nonspecific cohesive forces, which matter in un-ionized systems [rests on: cited: refs 20, 41] | p.951 |
| C3 | claim, prior hypothesis, authors: asserted ("was attributed"; "was cited as a cause") | Amorphous sodium indomethacin has a much higher Tg than amorphous indomethacin; Tg of alkali-metal indomethacin salts decreases from lithium to cesium and all exceed the neutral form, attributed to stronger electrostatic interaction of smaller ions with the carboxylate; similar effects are known for inorganic salts and for loperamide-poly(acrylic acid) salt formation [rests on: cited: refs 19-23] | p.947-948 |

## 2012 Ilevbare — Effect of Binary Additive Combinations on Solution Crystal Growth of the Poorly Water-Soluble Drug, Ritonavir · Dissolution / D. Crystallization from solution

[2012-ilevbare-ritonavir-binary-additive-crystal-growth](../../../cards/2012-ilevbare-ritonavir-binary-additive-crystal-growth/paper.html) · Dissolution / D. Crystallization from solution · used · as: electrostatic interaction

| id | kind | content | locator |
|---|---|---|---|
| C41 | claim, mechanism, authors: "considered unlikely" | Electrostatic and hydrogen-bonding forces are unlikely to dominate complex formation between the polymers: water competes with hydrogen bonds, and the adipate (pKa ≈4.43) is nearly fully ionized at pH 6.8, removing it as a hydrogen-bonding group and causing charge repulsion [rests on: argument only; cited: refs 4, 49-51] | p.6057-6058 |

## 2013 Wegiel — Mid-infrared spectroscopy as a polymer selection tool for formulating amorphous solid dispersions · Solid state stability / Miscibility and drug-polymer interactions

[2013-wegiel-mid-ir-polymer-selection-polyphenol-asd-stability](../../../cards/2013-wegiel-mid-ir-polymer-selection-polyphenol-asd-stability/paper.html) · Solid state stability / Miscibility and drug-polymer interactions · measured · as: ionic interaction

| id | kind | content | locator |
|---|---|---|---|
| R6 | record, measured | IR 3600-2400 cm-1 region of quercetin-E100 films — P4; 0 (100% E100), 10, 30, 50% (w/w) quercetin — text: the E100 bands at 2820 and 2770 cm-1 diminish as quercetin increases and are absent at 50% (w/w) quercetin; naringenin-E100 spectra were described as similar (not shown). Figure: both bands sharp at 0 and 10%, smaller at 30%, absent at 50%; a broad band near ≈3400 cm-1 grows with quercetin content (read from Fig. 6) | Fig. 6, p.6; text p.5 |
| C16 | claim, assumption, authors: asserted | Ionic interactions between species are typically stronger than hydrogen bonds; only E100, with its basic dimethylamino group, can form them with the somewhat acidic polyphenols [rests on: argument only] | p.5 |
| C17 | claim, conclusion, authors: quercetin: "provides evidence"; naringenin: "indicated" | The loss of the 2820 and 2770 cm-1 bands, reported to arise from non-ionized dimethylamino groups of E100, marks the loss of un-ionized groups and provides evidence of an acid-base reaction between quercetin and E100; similar spectra indicated an acid-base interaction for naringenin-E100 [rests on: R6; cited: ref 32] | p.5 |
| C33 | claim, mechanism, authors: "can explained" (as printed) | E100 forms no strong hydrogen bonds because its dimethylamino group is ionized by the polyphenol and no longer available; this ionic interaction is much stronger than hydrogen bonding [rests on: R6, C17] | p.9 |
| C35 | claim, mechanism, authors: discussion: "appear to be the reason"; conclusions: "It is suggested"; "proposed" | Ionic drug-polymer interactions appear to be the reason for the extremely good stability of flavonoid-E100 dispersions, since little evidence of hydrogen bonding was found; conclusions: E100 was best for forming the ASD and among the best for stability, which is suggested to be due to the proposed ionic interaction [rests on: R6, R8, R9] | p.9, p.10 |

## 2020 Hate — Influence of Drug-Silica Electrostatic Interactions on Drug Release from Mesoporous Silica-Based Oral Delivery Systems · Mesoporous silica / Mesoporous silica

[2020-hate-drug-silica-electrostatic-interactions-mesoporous-release](../../../cards/2020-hate-drug-silica-electrostatic-interactions-mesoporous-release/paper.html) · Mesoporous silica / Mesoporous silica · measured · as: electrostatic interaction

| id | kind | content | locator |
|---|---|---|---|
| R14 | record, measured | amount of drug adsorbed on SBA-15 at pH 6.8 with competing adsorbates (mg/g, bars with error bars) — P3; KET and CLZ; 0.5 M urea or 50 mM TEA — sub-table below; text: KET and CLZ adsorption reduced drastically with TEA; with urea a small reduction for KET and no difference for CLZ | Fig. 6, p.17; text p.17 |
| R15 | record, measured | KET release in two-step test pH 1 to 6.8 with and without 50 mM TEA (total drug release %) — P7; KET-MPS; TEA added at 30 min — sub-table below; text: with TEA the KET concentration did not decrease after the shift and plateaued at 95% release | Fig. 7a, p.18; text p.17 |
| R16 | record, measured | CLZ release in two-step test pH 1 to 6.8 with and without 50 mM TEA (as R15) — P7; CLZ-MPS — sub-table below; text: CLZ concentration decreased to a lesser extent with TEA | Fig. 7b, p.18; text p.17-18 |
| C18 | claim, mechanism, authors: "This suggests"; "this hypothesis" | KET and CLZ adsorption is favoured at higher pH, where both drugs are partly ionized and silica is deprotonated above pH 2, so electrostatic drug-silica interactions are present at the higher pH values; this hypothesis was then tested with TEA and urea [rests on: R1, R2, R3, R4] | p.15-16 |
| C26 | claim, mechanism, authors: "can be attributed" | The KET-SBA-15 interaction seen in the isotherms at pH 4.5, 5.5 and 6.8 is attributed to electrostatic attraction between positively charged KET and negatively charged silica [rests on: R1, R2, R3] | p.20 |
| C28 | claim, conclusion, authors: "confirmed" | The reduced KET adsorption with TEA at pH 6.8 establishes that KET interacts with silica primarily by electrostatic interaction between cationic KET and SiO− groups [rests on: R14] | p.20 |
| C35 | claim, mechanism, authors: "seemed"; "indicated" | CLZ adsorption follows the KET trend and seems to be primarily electrostatic: it increases with pH in line with CLZ ionization and silica deprotonation, falls with TEA and is unchanged with urea [rests on: R1, R2, R4, R14] | p.21 |
| C48 | claim, generalisation, authors: asserted | Because all three compounds are weak bases, they primarily interacted with silica by electrostatic interaction; rising pH made the silica more negative and improved adsorption of positively charged drugs [rests on: R2, R3, R4, R14] | p.24 |

## 2020 Mccarthy — A Comparison of Drug Release and Adsorption Under Supersaturating Conditions for Ordered Mesoporous Silica with Indomethacin or Indomethacin Methyl Ester · Mesoporous silica / Mesoporous silica

[2020-mccarthy-indomethacin-indme-sba15-adsorption-release](../../../cards/2020-mccarthy-indomethacin-indme-sba15-adsorption-release/paper.html) · Mesoporous silica / Mesoporous silica · used · as: electrostatic interaction

| id | kind | content | locator |
|---|---|---|---|
| C7 | claim, assumption, authors: "anticipated"; "not expected" | At pH 2.2 the silanol groups are predominantly protonated and none of the species is ionized, so electrostatic interactions are not expected [rests on: cited: refs 26, 53] | p.34-35 |

## Mentioned only

- 2013 Ilevbare — [2013-ilevbare-polymers-crystal-growth-structurally-diverse-compounds](../../../cards/2013-ilevbare-polymers-crystal-growth-structurally-diverse-compounds/paper.html) · Dissolution / D. Crystallization from solution (ref C47 C51)
- 2017 Xie — [2017-xie-temperature-moisture-celecoxib-binary-ternary-asd-stability](../../../cards/2017-xie-temperature-moisture-celecoxib-binary-ternary-asd-stability/paper.html) · Solid state stability / Physical stability (ref 9)
- 2022 Hiew — [2022-hiew-combining-drug-salt-formation-asd-double-edged-sword](../../../cards/2022-hiew-combining-drug-salt-formation-asd-double-edged-sword/paper.html) · Dissolution / A. Release mechanism and LoC (ref C3)