# Evidence: insoluble drug-polymer complex

Parent: drug-polymer complexation · class: molecular interaction · names merged here: insoluble drug-polymer complex; insoluble drug-polymer complex formation

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.

## 2020 Trasi — Physical stability and release properties of lumefantrine amorphous solid dispersion granules prepared by a simple solvent evaporation approach · Solid state stability / Physical stability

[2020-trasi-lumefantrine-asd-granules-solvent-evaporation](../../../cards/2020-trasi-lumefantrine-asd-granules-solvent-evaporation/paper.html) · Solid state stability / Physical stability · used · as: insoluble drug-polymer complex

| id | kind | content | locator |
|---|---|---|---|
| C43 | claim, mechanism, authors: "could conceivably"; "indicates"; "not the likely explanation" | An insoluble drug-polymer complex could conceivably explain the low drug and polymer release (as for PVP with polyacrylic acid), but the much better dissolution at 20% loading means complex formation is not the likely explanation [rests on: R18; cited: ref 24] | p.11 |

## 2025 Bapat — Impact of HPMCAS Grade on the Release of Weakly Basic Drugs from Amorphous Solid Dispersions · Dissolution / A. Release mechanism and LoC

[2025-bapat-hpmcas-grade-weak-base-asd-release-complexation](../../../cards/2025-bapat-hpmcas-grade-weak-base-asd-release-complexation/paper.html) · Dissolution / A. Release mechanism and LoC · measured · as: insoluble drug-polymer complex formation

| id | kind | content | locator |
|---|---|---|---|
| R9 | record, measured; DL column derived (relation not printed) | % polymer complexed with drug (mean ± SD, n = 3) and corresponding ASD drug loading — drug and polymer from THF into pH 6.0 phosphate buffer (P9), polymer 0.5 mg/mL — sub-table below; rows a-l are also plotted in Fig. 6 | Table 4, p.402 |
| R10 | record, measured; MF column cited (ref 3) | % HPMCAS complexation with CNZ versus CNZ/COOH molar ratio, points not in Table 4 (error bars SD, n = 3) — pH 6.0 phosphate buffer (P9) — sub-table below; LF and HF points at 0.25-2.0 plot R9.a-l | Fig. 6, p.402 |
| R11 | record, measured; MF column cited (ref 3) | % HPMCAS complexation with LOR versus pH (error bars SD, n = 3) — 1:1 LOR/COOH molar ratio, phosphate buffers (P9) — sub-table below; the same points are replotted in Fig. S1 | Fig. 7, p.403; Fig. S1, SI p.2 |
| R12 | record, measured | % HPMCAS complexation with CNZ at pH 5.8 (error bars SD, n = 3); the pH 6.0 series in the same figure plot R9.a-d (LF) and R10 (MF, cited) — phosphate buffer pH 5.8 (P1 row c, P9) — sub-table below | Fig. 8, p.403 |
| R17 | record, measured | appearance and pellet of the complexation controls — P9, pH 6.0 — drug stock alone: drug precipitated, turbid, pellet assayed as drug; polymer stock alone: polymer fully dissolved, no pellet after centrifugation; drug + polymer stock: turbid, pellet containing polymer | p.399-400 |
| E2 | equation | percent polymer complexed (supernatant mass balance): % polymer complexed = (1 − polymer in the supernatant/total polymer in the solution) × 100 | p.400 |

## 2025 Kaur — Impact of drug-polymer complexation and media properties on the release performance of amorphous solid dispersions containing a weakly basic drug and hydroxypropyl methylcellulose acetate succinate · Dissolution / A. Release mechanism and LoC

[2025-kaur-bdq-hpmcas-complexation-media-asd-release](../../../cards/2025-kaur-bdq-hpmcas-complexation-media-asd-release/paper.html) · Dissolution / A. Release mechanism and LoC · measured · as: insoluble drug-polymer complex

| id | kind | content | locator |
|---|---|---|---|
| R5 | record, measured | percent polymer complexation versus BDQ:COOH molar ratio — HPMCAS LF, buffers at initial pH 5.8-10.5 (P7) — sub-table below | Fig. 1A, p.5 |
| R6 | record, measured | percent polymer complexation versus BDQ:COOH molar ratio in SIF — HPMCAS LF; FeSSIF-V2 and FaSSIF-V1 (P7, P9); the pH 5.8 and pH 6.5 buffer series in Fig. 1B are the R5.a and R5.c data — sub-table below | Fig. 1B, p.5 |
| R7 | record, measured | percent polymer complexation versus BDQ:COOH molar ratio — HPMCAS MF, buffers pH 5.8-10.5 (P7) — sub-table below | Fig. 2A, p.5 |
| R8 | record, measured | percent polymer complexation versus BDQ:COOH molar ratio in SIF — HPMCAS MF; FeSSIF-V2 and FaSSIF-V1 (P7, P9); the pH 5.8 and pH 6.5 buffer series in Fig. 2B are the R7.a and R7.c data — sub-table below | Fig. 2B, p.5 |
| R11 | record, measured | ATR-FTIR of insoluble complexes — LF complexes at stock ratio R6 from pH 5.8, 6.0, 6.5, 7.0, 8.5, 10.5 (Fig. 3A); MF complexes from pH 5.8, 6.0, 6.5, 7.0, 8.5 (Fig. 3B; insufficient sample at pH 10.5) (P10) — pH 6.0, 6.5, 7.0 residues: band at 1720 cm⁻¹ (C=O; neat polymer band at ≈1735-1740 cm⁻¹, read from Fig. 3) plus BDQ bands at 1210-1285, 1380-1490 and 1530-1650 cm⁻¹ that are much broader than in crystalline BDQ; pH 8.5 and 10.5 residues: sharper bands matching crystalline BDQ; pH 10.5 (LF): HPMCAS bands essentially absent; pH 5.8 residues: two extra bands (≈1400 and ≈1580 cm⁻¹, read from Fig. 3) marked with asterisks | Fig. 3, p.5; text p.6 |
| C12 | claim, conclusion, authors: asserted | For LF, complexation extent versus initial pH ranks 6.0 > 5.8 > 6.5 > 7.0 > 8.5 > 10.5, and MF shows a similar trend; complexation rises with BDQ:COOH ratio to plateaus above 85-90% at pH 5.8 and 6.0 where virtually no polymer stays in solution; it falls from more than 90% at pH 6.0 to less than 5% at pH 10.5 (abstract: about 90% at pH 6.0, decreasing with increasing pH) [rests on: R5, R7] | p.1, p.4 |
| C56 | claim, mechanism, authors: "was attributed"; "attributed to" | The poor release in pH 6.5 buffer is attributed to an insoluble ionic complex between drug and polymer, facilitated by high mutual ionization at this pH (abstract: complex in the ASD particle); the precipitate is attributed to hydrophobic ion pairs between cationic drug and anionic carboxylate groups [rests on: R5, R7, R13, R20, R11] | p.1, p.11 |