The original article, published on 17 December 2019 in Polymer Bulletin volume 77, pages 6063 to 6083, reported the development and optimization of hydrogel networks built from pectin, a naturally occurring polysaccharide most familiar to consumers as the gelling agent in jams and jellies. In pharmaceutical science, pectin has attracted intense interest because it is biocompatible, biodegradable, inexpensive, and derived from renewable plant sources such as citrus peel and apple pomace. The research team, led by authors affiliated with Government College University Faisalabad, the University of Sargodha, The University of Lahore, and The Islamia University of Bahawalpur in Pakistan, set out to tune the swelling behavior, gel fraction, and drug release kinetics of these hydrogels so that nifedipine could be released steadily over an extended period rather than in a sudden burst.

Nifedipine is a calcium channel blocker widely prescribed for hypertension and angina, and its delivery profile matters enormously for patient safety. The drug is notoriously photolabile and poorly water soluble, and conventional immediate-release formulations have been associated with sharp drops in blood pressure and reflex tachycardia. Controlled-release matrices, including hydrogel systems, are designed to smooth out these peaks and troughs by allowing water to penetrate the polymer network, dissolve the drug, and then diffuse outward through the swollen mesh at a rate governed by crosslinking density, polymer composition, and mesh size. A pectin-based system with adjustable properties would, in principle, let formulators dial in the desired release rate simply by changing formulation variables, a proposition with genuine commercial and clinical appeal.

That is precisely why the concerns flagged by the Editor-in-Chief strike at the heart of the paper’s credibility. According to the expression of concern, Figure 5 of the pectin hydrogel article appears to be identical to Figure 2c in a separate 2018 publication on chondroitin sulfate-based hydrogels of loxoprofen, which appeared in Carbohydrate Polymers. The overlap involves two different polymers, two different drugs, and two different experimental contexts, making the apparent duplication particularly troubling. In materials characterization, figures typically present spectroscopic traces, swelling curves, or release profiles that are unique to a specific formulation under specific conditions. When the same figure surfaces in studies of unrelated polymer-drug combinations, it raises the possibility that the underlying experiments were not performed as described, or that images were reused to fill gaps in the data record.

The second concern is subtler but no less consequential. The Editor-in-Chief notes that the acrylic acid trace in Figure 2 of the pectin study appears highly similar to the trace in Figure 2 of yet another 2018 paper, this one describing a cross-linked sodium alginate-g-poly(acrylic acid) hydrogel network for the delivery of loxoprofen sodium, published in Advanced Polymer Technology. In that case, the similarity persists even though the x-axis appears to have been shifted slightly. Fourier transform infrared spectroscopy and related analytical traces are fingerprints of chemical structure, and while spectra of related acrylate-based networks can resemble one another, a near-duplicate trace with a minor axis shift suggests digital manipulation rather than independent measurement. Shifting an x-axis is a classic red flag in image-integrity investigations because it can make copied data look superficially distinct while preserving the underlying pattern.

Compounding these figure-level concerns is the authors’ response, or lack thereof. The expression of concern states that the authors have not provided the original scanning electron microscopy images, both before and after expansion, upon request. SEM micrographs are central evidence in hydrogel characterization, revealing pore morphology and network structure that correlate directly with swelling and diffusion behavior. When authors cannot or will not produce the raw image files underlying published micrographs, editors and readers lose the ability to verify that the images depict the samples in question. The notice also records that the authors have not responded to any correspondence from the editor or publisher regarding the expression of concern, leaving the issues unresolved and the scientific record in limbo.

Editorial Expressions of Concern occupy an important and often misunderstood niche in scholarly publishing. Unlike a retraction, which withdraws a paper’s findings from the literature, an expression of concern signals that doubts exist but that an investigation is incomplete, inconclusive, or ongoing. Journals typically issue them when institutional inquiries are pending, when authors are unresponsive, or when the evidence of problems is strong but not yet definitive. Readers are advised in this case to interpret the results with caution, which in practical terms means that researchers citing the paper should acknowledge its contested status and that clinicians or formulators should not rely on its reported optimization data without independent confirmation. The notice is linked to the original article through Crossmark, Springer Nature’s version-of-record update service, ensuring that anyone accessing the 2019 paper will see the alert.

The episode also shines a light on the broader challenge of image integrity in polymer and pharmaceutical sciences, fields that generate enormous volumes of spectroscopic traces, micrographs, and kinetic curves. Duplicate and manipulated figures have been documented across disciplines, and automated screening tools now routinely flag similarities that might once have escaped notice. The two earlier papers referenced in the expression of concern, both involving overlapping authorship with the pectin study, illustrate how concerns can cluster around related bodies of work. When a single figure or trace appears in multiple publications describing different chemical systems, the credibility of all affected papers comes into question, because at least some of the published data cannot reflect real experiments as described.

For the field of natural polymer drug delivery, the stakes extend beyond one paper. Pectin, alginate, chondroitin sulfate, and related polysaccharides remain genuinely promising scaffolds for controlled release, and well-executed studies continue to advance the area. But the credibility of that literature depends on the verifiability of individual results, and expressions of concern like this one serve as a reminder that optimization claims, release profiles, and structural characterizations must rest on data that can withstand scrutiny. Whether the 2019 pectin-nifedipine study is ultimately retracted, corrected, or exonerated, the case underscores a simple principle on which the entire enterprise of pharmaceutical materials science depends: the figures in a paper must be the honest record of the experiments the paper claims to describe.

Subject of Research: An Editorial Expression of Concern raised over a pectin-based hydrogel study for controlled nifedipine delivery in Polymer Bulletin

Article Title: Editorial Expression of Concern (EEoC): Pectin-based hydrogels with adjustable properties for controlled delivery of nifedipine: development and optimization

Article References: Editorial Expression of Concern (EEoC): Pectin-based hydrogels with adjustable properties for controlled delivery of nifedipine: development and optimization. (n.d.). https://doi.org/10.1007/s00289-026-06680-3

Image Credits: AI Generated

DOI: 10.1007/s00289-026-06680-3

Keywords: pectin hydrogels, nifedipine, controlled drug delivery, Editorial Expression of Concern, Polymer Bulletin, research integrity, image duplication, scanning electron microscopy, polysaccharide polymers, drug release kinetics, Springer Nature, pharmaceutics

The original review aimed to bridge the gap between abstract mathematical descriptions of spacetime and the grand narrative of the universe’s birth, specifically focusing on the inflationary epoch – the period of exponential expansion hypothesized to have occurred mere fractions of a second after the Big Bang. Inflation is a cornerstone of modern cosmology, explaining phenomena like the universe’s remarkable flatness and homogeneity. Momeni’s work purportedly navigates through sophisticated concepts such as Riemannian curvature, which describes how spacetime is bent by mass and energy, and the less-explored concept of torsion, which relates to the “twisting” of spacetime. Moreover, the paper extends its pedagogical reach into the realm of “extended gravity theories,” a diverse collection of theoretical frameworks that go beyond Einstein’s General Relativity, proposing modifications or additions to our understanding of gravity itself. The ambition was clearly to provide a unified and accessible viewpoint on these complex subjects and their potential roles in cosmic inflation.

However, the Editorial Expression of Concern, while not explicitly detailing alleged flaws, suggests that Momeni’s review paper has raised questions that warrant significant attention from the scientific community. Such an expression is not a retraction, but rather a formal alert to readers and peers that there are reservations regarding certain aspects of the published work. This could range from concerns about the interpretation of existing literature, the validity of the presented theoretical connections, or even the pedagogical clarity and accuracy with which these complex ideas have been conveyed. The very fact that such a notification has been issued implies that the paper, despite its intended educational purpose, may have inadvertently opened a Pandora’s Box of theoretical challenges or interpretations that require rigorous scrutiny and potential rectification before its findings can be fully assimilated into cosmological discourse.

The genesis of this concern likely lies in the intricate and often subtle interplay between geometric properties of spacetime and the dynamics of the universe. General Relativity, our current benchmark for gravity, describes spacetime as a four-dimensional manifold whose curvature governs gravitation. Inflationary cosmology, in its standard formulation, relies on a hypothetical scalar field (the inflaton field) that drives this rapid expansion. Momeni’s review, by examining curvature and torsion, and by venturing into extended gravity theories, probes whether alternative geometric descriptions of spacetime itself, independent of or in conjunction with such scalar fields, could account for inflation. These alternative theories often posit that gravity behaves differently at very high energies or very small scales, precisely the conditions prevailing in the early universe, thus offering fertile ground for new inflationary models.

The exploration of “torsion” in the context of cosmology is particularly provocative. In standard General Relativity, spacetime is a “torsionless manifold.” However, theories inspired by gauge theories and differential geometry predict the existence of torsion, which could represent a different aspect of spacetime structure than curvature. Introducing torsion into cosmological models could, in principle, lead to novel gravitational dynamics. Some theories suggest that torsion might play a role in generating the initial density fluctuations observed in the Cosmic Microwave Background, or even in driving the inflationary expansion itself, potentially without invoking additional scalar fields, a significant departure from the standard inflationary paradigm. Momeni’s review, by attempting to unpack these complex relationships pedagogically, seems to have brought these speculative ideas to the forefront for broader consideration.

Furthermore, the inclusion of “extended gravity theories” within the scope of the review is crucial. These theories, such as $f(R)$ gravity, scalar-tensor theories, and theories with higher-order curvature invariants, all aim to supersede or supplement Einstein’s theory. They often achieve this by introducing new fields or by modifying the Einstein-Hilbert action, the fundamental mathematical expression that defines gravity in General Relativity. In the context of inflation, these extended theories offer a rich landscape for devising new inflationary potentials and mechanisms. Some theories predict different inflationary histories, potentially resolving challenges faced by the standard model, or leading to specific observational signatures that could be tested with future astronomical observations. Momeni’s review apparently sought to illuminate these diverse theoretical avenues.

The issuance of an Expression of Concern by the journal editors suggests that Momeni’s pedagogical exposition of these advanced topics may have glossed over critical distinctions, perhaps mischaracterized key theoretical results, or presented speculative ideas as more established than they are. It is possible that in simplifying complex mathematical frameworks for a broader audience, certain nuances essential for accurate understanding have been lost, leading to potentially misleading conclusions or interpretations. The rigorous standards of physics peer review demand an uncompromising commitment to accuracy, and any perceived deviation from these standards, even if unintentional, necessitates a formal acknowledgment to safeguard the integrity of scientific progress.

This situation underscores the inherent difficulty in formulating a universally accepted theory of cosmic inflation. Despite its remarkable explanatory power, the standard inflationary model still faces theoretical challenges and a lack of direct observational evidence for the inflaton field itself. The search for alternative mechanisms, including those rooted in more exotic gravitational descriptions, remains an active and vital area of research. Momeni’s review, by bringing together a wide array of geometric and gravitational concepts, was intended to stimulate this search, but may have done so in a way that has provoked more questions than it has answered about the validity and clarity of the presented information.

The implications of this Editorial Expression of Concern extend far beyond the specific paper itself. It serves as a potent reminder of the critical role of careful scholarship and accurate representation in scientific communication. For aspiring cosmologists and students, understanding the foundational principles of gravity and spacetime is paramount. Any educational resource that misrepresents these principles, however inadvertently, can hinder rather than help. The scientific community will undoubtedly be dissecting Momeni’s review with renewed vigor, seeking to understand precisely what aspects have drawn the editors’ concern and how these might impact ongoing research into the earliest moments of our universe.

The paper’s focus on “From geometry to cosmology” highlights a fundamental philosophical and scientific trend: that our understanding of the universe at its grandest scales is intimately tied to our understanding of spacetime geometry at its most fundamental level. Momeni’s attempt to link abstract mathematical concepts like curvature and torsion to the tangible, albeit ancient, phenomenon of cosmic inflation represents a noble scientific endeavor. However, the subsequent Expression of Concern suggests that the bridge built between these disciplines in the review may have structural weaknesses that require immediate attention and potential repair before it can be safely traversed by the broader scientific community.

The publication of the paper in Eur. Phys. J. C (European Physical Journal C), a reputable journal known for its focus on particles, fields, gravitation, and cosmology, adds weight to the significance of the Expression of Concern. Journals of this stature uphold rigorous peer-review processes, and the decision to issue such a notification indicates a significant problem identified by the editorial board and possibly by external reviewers as well. This event therefore becomes a case study in academic scrutiny, emphasizing the dynamic and self-correcting nature of scientific inquiry, where even well-intentioned comprehensive reviews can become catalysts for deeper investigation and clarification.

The discussion around Momeni’s review also implicitly questions the boundaries between pedagogical exposition and original research. While the paper is described as a “pedagogical review,” the concepts it engages with are at the cutting edge of theoretical physics. Bridging these domains requires an exceptional level of clarity and precision. The concern raised is a testament to the fact that simplifying complex scientific ideas for educational purposes must be done with scrupulous adherence to factual accuracy and theoretical rigor. Failure to do so can lead to the propagation of misunderstandings, potentially setting back the learning curve for many researchers.

In essence, this Editorial Expression of Concern serves as an urgent summons to the scientific community to re-examine the foundations of inflationary cosmology and the theoretical frameworks that aim to describe its very origins. It compels us to critically evaluate how abstract geometric concepts are translated into cosmological narratives and the reliability of alternative gravity theories in explaining our universe’s infancy. The potential for viral dissemination of this news underscores the fact that fundamental questions about our cosmos, especially those involving the frontiers of theoretical physics, capture the imagination and spark intense intellectual debate across the globe, making the process of scientific discovery and refinement a public spectacle of sorts.

The gravity of this situation cannot be overstated. If the concerns raised are substantial, they could necessitate a revision of how certain aspects of inflationary theory are presented and understood by a new generation of physicists. It highlights that even established cosmological paradigms like inflation are subject to ongoing refinement and challenge, and that the tools we use to probe them – our understanding of gravity, geometry, and theoretical frameworks – are themselves constantly evolving and require meticulous scrutiny. This is not merely an academic squabble; it is a potential recalibration of our cosmic origin story, driven by the relentless pursuit of scientific truth and accountability.

The widespread distribution of this news within scientific circles will undoubtedly foster a rigorous and transparent examination of Momeni’s work. This process, however uncomfortable it may be for the author and the publisher, is ultimately beneficial for the advancement of science. It ensures that scientific claims are robustly tested, that theoretical models are precisely articulated, and that educational content accurately reflects the current state of knowledge. The outcome of this heightened scrutiny will likely inform future research directions, potentially leading to clearer, more robust, and more verifiable theories about the universe’s most explosive beginnings.

This incident also serves as a potent reminder of the human element in scientific endeavor. While science strives for objectivity, the interpretation and presentation of complex theories can be subject to human judgment and error. The Editorial Expression of Concern, in this context, acts as a crucial safety mechanism, allowing the scientific community to collectively identify and address potential flaws, ensuring that the edifice of scientific knowledge is built on the strongest possible foundation, brick by careful brick. The ensuing discussion promises to be one of the most significant discussions of the year in theoretical physics.

Subject of Research: Cosmic Inflation, Gravitational Theories, Spacetime Geometry, Curvature, Torsion

Article Title: Editorial Expression of Concern: From geometry to cosmology: a pedagogical review of inflation in curvature, torsion, and extended gravity theories.

Article References:

Momeni, D. Editorial Expression of Concern: From geometry to cosmology: a pedagogical review of inflation in curvature, torsion, and extended gravity theories.
Eur. Phys. J. C 85, 1196 (2025). https://doi.org/10.1140/epjc/s10052-025-14953-w

DOI: 10.1140/epjc/s10052-025-14953-w