Polymers
pH-swelling chitosan–xanthan gels that hold acyclovir
Open access · cc by · source: Europe PMC
Free-radical chitosan/xanthan/AMPS networks barely swell in acid but open in intestine-like pH, trapping up to 90.64% acyclovir.
Study at a glance
- Design
- Other — Chitosan–xanthan–AMPS hydrogels for acyclovir loading, swelling, and pH-dependent release
- N
- Formulation study of hydrogel batches (e.g., FCX6/FCX8) — no subject N
- Population
- Acyclovir-loaded chitosan/xanthan graft hydrogels in SGF/SIF media
- Outcome
- Drug entrapment efficiency and 24 h release at pH 1.2 vs 7.4
Structured fields used in claim comparison tables when every cited study has a complete layer.
Key findings
Optimized FCX6: 90.64% entrapment and 87.57% release at pH 7.4; FCX8 minimum DEE 76.83%. Swelling rises with CS 4→8 g, XG 1→3 g, AMPS 15→35 g; extra MBA or too much KPS cuts swelling. Release is low at pH 1.2 and high at 7.4.
Methodology
Authors graft-polymerized chitosan and xanthan with AMPS/MBA/KPS, confirmed the network by FTIR and porous SEM, measured swelling in SGF (pH 1.2) vs SIF (pH 7.4), and loaded 1% acyclovir to get %DEE and 24 h release.
Limitations
Human PK of the gel is not measured; acute oral toxicity in animals is a safety screen, not a clinical bioavailability trial.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
This library holds 5 empirical chemistry papers on polymers with isolated findings, rates or spectra rather than reviews.
Evidence for the claim as stated.
Free-radical chitosan/xanthan/AMPS networks barely swell in acid but open in intestine-like pH, trapping up to 90.64% acyclovir.
Evidence for the claim as stated.
A lab-scale ATRP or a DFT interface study does not by itself prove processability or lifetime in use.
Evidence for the claim as stated.
SEM of a graft-polymerised chitosan–xanthan network shows porosity; the numbers that matter for a carrier are swelling and release. Optimized FCX6 reaches 90.64% acyclovir entrapment and 87.57% release at pH 7.4 versus low release at pH 1.2; FCX8 is the minimum DEE at 76.83%. Swelling rises with CS 4→8 g, XG 1→3 g and AMPS 15→35 g; extra MBA or too much KPS cuts swelling. Human PK is not measured.
Evidence for the claim as stated.
An SEM habit (nanoflowers versus pores) does not rank function. BiOBr nanoflowers coincide with 0.38 mA cm⁻² photocurrent but untreated Cl/I films fail stability despite also having SEM-visible nanostructure. Hydrogel SEM porosity coexists with 90.64% DEE that is a loading/release assay. SECCM at 50 nm further shows that a macroscale 'blocked' ITO reading is not a map of dead patches an SEM image would be asked to find.
Evidence for the claim as stated.
FTIR is often a network or adduct check beside the assay that actually calibrates performance. Chitosan–xanthan gels confirmed by FTIR/porous SEM reach 90.64% acyclovir DEE and 87.57% release at pH 7.4 (FCX8 minimum DEE 76.83%). A paper titanyl sensor uses FTIR with UV-vis/XPS to characterise Ti–peroxo formation; the analytical number is LOD ≈ 0.04 ppb from 0.0025 AU noise and 0.187 AU ppb⁻¹ sensitivity near 400 nm.
Evidence for the claim as stated.
FTIR can confirm a bond and still not be the performance metric. Vanishing GSH S–H bands do not give a nucleation rate; hydrogel FTIR does not give 90.64% DEE; titanyl FTIR of a peroxo does not give 0.04 ppb — that LOD is from absorbance noise and sensitivity. Characterisation versus assay is the split.
Evidence for the claim as stated.
Loading that TGA might have reported as residual mass is instead given as a size/photochemistry knob. Immobilised Mn carbonyls in UiO-67-type bpy MOFs change crystal size from 260 nm to 1 mm, which changes loading and photoefficiency of visible-light CO release; cells on a polymer film of the MOF see intracellular CO after irradiation. NIR deep-tissue delivery is not shown. A chitosan–xanthan hydrogel similarly quotes 90.64% acyclovir DEE and 87.57% release at pH 7.4 (FCX8 76.83% DEE) rather than a TGA drug-loading step.
Evidence for the claim as stated.
Composition from TGA-style thinking (how much is inorganic, how much is cargo) is not the function. MOF crystal size 260 nm–1 mm changes CO-photo-loading; hydrogel %DEE is a wet assay; Zn hydrate formula is elemental analysis. None of those papers' headline numbers are a TGA onset, and CO remains a toxic gas if mis-dosed.
Evidence for the claim as stated.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
A lab-scale ATRP or a DFT interface study does not by itself prove processability or lifetime in use.
An SEM habit (nanoflowers versus pores) does not rank function. BiOBr nanoflowers coincide with 0.38 mA cm⁻² photocurrent but untreated Cl/I films fail stability despite also having SEM-visible nanostructure. Hydrogel SEM porosity coexists with 90.64% DEE that is a loading/release assay. SECCM at 50 nm further shows that a macroscale 'blocked' ITO reading is not a map of dead patches an SEM image would be asked to find.
- Supports · Bismuth oxyhalide films as photoelectrodes
- Supports · ITO electrodes are active everywhere at 50 nm
FTIR can confirm a bond and still not be the performance metric. Vanishing GSH S–H bands do not give a nucleation rate; hydrogel FTIR does not give 90.64% DEE; titanyl FTIR of a peroxo does not give 0.04 ppb — that LOD is from absorbance noise and sensitivity. Characterisation versus assay is the split.
Composition from TGA-style thinking (how much is inorganic, how much is cargo) is not the function. MOF crystal size 260 nm–1 mm changes CO-photo-loading; hydrogel %DEE is a wet assay; Zn hydrate formula is elemental analysis. None of those papers' headline numbers are a TGA onset, and CO remains a toxic gas if mis-dosed.
- Supports · A MOF that releases CO with visible light
- Supports · A new Zn phenanthroline–maleate crystal
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