# Evidence: multilayer adsorption

Parent: — · class: thermodynamics · names merged here: multilayer adsorption

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.

## 2019 Dening — Application of an adsorption isotherm to explain incomplete drug release from ordered mesoporous silica materials under supersaturating conditions · Mesoporous silica / Mesoporous silica

[2019-dening-adsorption-isotherm-incomplete-release-sba15](../../../cards/2019-dening-adsorption-isotherm-incomplete-release-sba15/paper.html) · Mesoporous silica / Mesoporous silica · measured · as: multilayer adsorption

| id | kind | content | locator |
|---|---|---|---|
| R2 | record, measured; Qa derived (E1) | adsorption isotherm of ritonavir on SBA-15, Qa vs Ce — P3; Ci 0.625–30 μg/mL; mean ± SD, n = 3 — text: 39 ± 5 mg/g at Ci 0.625 μg/mL; 424 ± 29 mg/g at Ci 30 μg/mL; Ce at Ci 30 μg/mL approximately 25 μg/mL (p. 190); most Ci and Ce supersaturated; no crystallization observed over the experimental period; 14 points in sub-table R2 a–n (read from Fig. 1) | Fig. 1 and Section 4.2, p. 189; Section 4.3, p. 190 |
| R7 | record, measured | pyrene I1/I3 emission ratio — P5; mean ± SD, n = 3 — sub-table R7 a–d; row b vs row a p > 0.05; row d vs row a p = 0.054 | Table 2 and Section 4.3, p. 190 |
| C11 | claim, conclusion, authors: asserted ("well past") | Ritonavir adsorption exceeded the theoretical monolayer surface coverage (253 mg/g), supported by the fluorescence data. [rests on: R2, R3, R7] | Section 4.2, p. 189; Section 5.1, p. 194 |
| C20 | claim, conclusion, authors: indicating; not quite statistically significant; lends some support | The lower I1/I3 with ritonavir plus SBA-15 indicates that the probe reached drug-rich layers adsorbed in the mesopores; though not quite significant, this lends some support to adsorption beyond monolayer coverage. [rests on: R7] | Section 4.3, p. 190 |
| C31 | claim, mechanism, authors: we hypothesize | The adsorption mechanism is hypothesized to change after Qm: at or below Qm ritonavir binds specific SBA-15 sites; above Qm, with the best sites saturated and the solution supersaturated, a constant proportion adsorbs as multilayers in the mesopores. [rests on: R15, R6] | Section 4.8, p. 193 |

## 2020 Hate — Interplay of Adsorption, Supersaturation and the Presence of an Absorptive Sink on Drug Release from Mesoporous Silica-Based Formulations · Mesoporous silica / Mesoporous silica

[2020-hate-atazanavir-mesoporous-silica-adsorption-absorptive-sink-release](../../../cards/2020-hate-atazanavir-mesoporous-silica-adsorption-absorptive-sink-release/paper.html) · Mesoporous silica / Mesoporous silica · used · as: multilayer adsorption

| id | kind | content | locator |
|---|---|---|---|
| C25 | claim, conclusion, authors: "This also suggested"; "possibly" | The BET monolayer coverage of 4.5 mg/g is much lower than the geometric estimate, and beyond it there was possibly multilayer adsorption [rests on: R3, R1] | p.7 |
| C39 | claim, mechanism, authors: "can be attributed"; "may also imply"; "most likely" | The thermal transitions at 30 and 50% DL come from overfilled pores, with excess drug on the exterior particle surface, since drug in the pores would not crystallize; they may also imply multilayer adsorption; this agrees with the bulk-like IR spectra [rests on: R9, R12; cited: refs 19, 75] | p.13-14 |

## 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 · measured · as: multilayer adsorption

| id | kind | content | locator |
|---|---|---|---|
| R7 | record, measured | IND adsorption isotherm, Qa (mg/g) versus Ce (µg/mL), mean (n = 3) — P7, IND Ci 1-60 µg/mL — sub-table below (all values ≈, read from Fig. 4a; individual Ci not given) | Fig. 4a, p.21 |
| R8 | record, measured | INDME adsorption isotherm, Qa (mg/g) versus Ce (µg/mL), mean (n = 3) — P7, INDME Ci 1-14 µg/mL — sub-table below (all values ≈, read from Fig. 4b; individual Ci not given) | Fig. 4b, p.21 |
| R6 | record, measured | pyrene I1/I3 ratio — McIllvaine buffer pH 2.2 with HPMC 100 µg/mL, 37 °C, pyrene 0.25 µg/mL (P5); * = above the LLPS concentration; n not stated — sub-table below | Table 2, p.20 |
| C17 | claim, mechanism, authors: "it is anticipated"; "suggesting" | The lower I1/I3 of drug with SBA-15, smaller than with drug-rich droplets, suggests multilayer adsorption of the drugs, since pyrene is expected to interact with adsorbed multilayers [rests on: R6.d, R6.f] | p.20 |
| C43 | claim, mechanism, authors: discussion: "suggest"; conclusion: "Multilayer adsorption was observed" | The isotherm models indicate multilayer adsorption, consistent with the fluorescence data; the BET monolayer is about 30 mg/g, while the maximum adsorbed near the amorphous solubility, about 300 mg/g, far exceeds it [rests on: R10, R7, R8, R6] | p.36, p.40 |
| X10 | extractor note | claim-data gap — The multilayer claim (C43) compares the maximum adsorbed (≈300 mg/g) with the BET Qm of 29-31 mg/g, while the geometric monolayer from Eq. 3, drawn in Fig. 4, is 287 and 269 mg/g; against that line the highest points (≈289 IND, ≈342 mg/g INDME) are at or only modestly above one monolayer. The two monolayer estimates differ tenfold and are not reconciled — C43, C18, R10, R16, R7, R8 — treat multilayer adsorption as model-dependent |  |