Evidence map›Paper›PMID 41493349›Full record

ArticleJournal of biomaterials applications2026

Engineered zero-order drug release from degradable PEG hydrogels - A rapamycin case study.

Lage Ahrenstedt, Anel Oosthuysen, Peter Zilla, Jaco Theron, Deon Bezuidenhout

Abstract read
In one paragraph

Article in Journal of biomaterials applications, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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0citing papers in PubMed
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1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors.

Lage AhrenstedtCardiovascular Research Unit, University of Cape Town, Cape Town, South Africa.ORCID 0000-0001-8370-9637
Anel OosthuysenCardiovascular Research Unit, University of Cape Town, Cape Town, South Africa.ORCID 0009-0003-4200-1538
Peter ZillaCardiovascular Research Unit, University of Cape Town, Cape Town, South Africa.ORCID 0000-0001-9502-4109
Jaco TheronCardiovascular Research Unit, University of Cape Town, Cape Town, South Africa.ORCID 0009-0008-0380-4393
Deon BezuidenhoutCardiovascular Research Unit, University of Cape Town, Cape Town, South Africa.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

This study describes the derivatization of Rapamycin (Ra) with acryloyl chloride (AcCl) and iodoacetic acid (IAA), yielding hydrolysis-susceptible esters designed for controlled drug release at physiological pH. These esters were further conjugated to thiolated polyethylene glycols (PEGs), yielding compounds with enhanced water solubility, pendant thiol groups and with variation in the number of methylene groups between the ester and thioether moieties. Hydrogels were subsequently formed via conjugate addition reactions using multi-arm PEG macromers, specifically 8-arm PEG acrylates or vinyl sulphones, alongside thiolated PEG crosslinkers. The primary focus was to elucidate the impact of structural modifications surrounding the thioether ester linker on drug release kinetics. In vitro release studies demonstrated zero-order Ra elution over 7-19 days, modulated by gel architecture. Notably, Ra incorporated via α-thioether ester bonds exhibited significantly faster release than their β-thioether ester counterparts, with release rate increases of 11% and 31%, respectively, across the gel assemblies examined. This behavior was attributed to the electron-withdrawing effect of the adjacent thioether group, which enhanced ester hydrolysis. Additionally, creating a hydrogel more prone to swelling and degradation (by using the PEG acrylate multi-arm instead of the PEG vinyl sulphone equivalent) increased the overall drug release rate due to higher water uptake within the gel matrix. An alternative strategy involved Ra-based crosslinking, where Ra, di-functionalized with IAA, acted as a crosslinker for the PEG thiol multi-arm molecules. This assembly exhibited a biphasic release profile, initially mimicking the linear zero-order release of Ra mono-iodoacetic ester crosslinked with PEG acrylates, followed by an exponential burst phase. These findings provide critical insights into hydrogel design strategies for tailoring drug release kinetics, paving the way for advanced controlled drug delivery applications.

Indexed as

Drug CarriersHydrogelsPolyethylene GlycolsSirolimusDelayed-Action PreparationsDrug LiberationKineticsPolyether CompoundsSolubilityDelayed-Action PreparationsDrug CarriersHydrogelsPolyether CompoundsPolyethylene GlycolsSirolimusdrug deliveryhydrogelsPEGylationrapamycinrelease kineticszero-order elution

Identifiers

PMID41493349
PMCPMC13234310

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.