Plamen Rosenov Simeonov

Mr. Plamen Rosenov Simeonov

orcid

Research Focus & Metrics

Academic Career Length

2Years (2025-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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13 June 2025 in Biomedicines
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Journal Article
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Radka Petkova BoyuklievaRadka Petkova Boyuklieva
Radka Petkova Boyuklieva
Nikolay ZaharievNikolay Zahariev
Nikolay Zahariev
PSPlamen Rosenov Simeonov
Plamen Rosenov Simeonov
Dimitar PenkovDimitar Penkov
Dimitar Penkov
Plamen KatsarovPlamen Katsarov
Plamen Katsarov
Nanotherapeutics have emerged as novel unparalleled drug delivery systems (DDSs) for the treatment of neurodegenerative disorders. By applying different technological approaches, nanoparticles can be engineered to possess different functionalities. In recent years, the developed, stimuli-responsive nanocarriers stand out as novel complex DDSs ensuring selective and specific drug delivery in response to different endogenous and exogenous stimuli. Due to the multifaceted pathophysiology of the nervous system, a major challenge in modern neuropharmacology is the development of effective therapies ensuring high efficacy and low toxicity. Functionalization of the nanocarriers to react to specific microenvironmental changes in the nervous system tissues or external stimulations significantly enhances the efficacy of drug delivery. This review discusses the microenvironmental characteristics of some common neurological diseases in-depth and provides a comprehensive overview on the progress of the development of exogenous and endogenous stimuli-sensitive nanocarriers for the treatment of Alzheimer’s and Parkinson’s disease.

11 September 2025 in Molecules
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Journal Article
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Stanislava IvanovaStanislava Ivanova
Stanislava Ivanova
ZDZoya Dzhakova
Zoya Dzhakova
Velislava TodorovaVelislava Todorova
Velislava Todorova
Radka Petkova BoyuklievaRadka Petkova Boyuklieva
Radka Petkova Boyuklieva
PSPlamen Rosenov Simeonov
Plamen Rosenov Simeonov
Plamen KatsarovPlamen Katsarov
Plamen Katsarov
Neurodegenerative diseases (NDDs) represent a class of incurable and progressive disorders characterized by the gradual degeneration of the structure and function of the nervous system, particularly the brain and spinal cord. A range of innovative therapeutic approaches is currently under investigation, such as stem cell-based therapies, gene-editing platforms such as CRISPR, and immunotherapies directed at pathogenic proteins. Moreover, phytochemicals such as β-caryophyllene and xanthohumol have demonstrated significant neuroprotective potential in preclinical models. These natural agents exert multifaceted effects by modulating neuroinflammatory pathways, oxidative stress responses, and aberrant protein aggregation—pathological mechanisms that are central to the development and progression of neurodegenerative disorders. Recent investigations have increasingly emphasized the optimization of the pharmacokinetic properties of β-caryophyllene and xanthohumol through the development of advanced drug-delivery systems, including polymer- and lipid-based nano- and microscale carriers. Such advancements not only enhance the bioavailability and therapeutic potential of these phytochemicals but also underscore their growing relevance as natural candidates in the development of future interventions for neurodegenerative disorders.

27 February 2026 in Pharmaceutics
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Plamen KatsarovPlamen Katsarov
Plamen Katsarov
PSPlamen Rosenov Simeonov
Plamen Rosenov Simeonov
Elisaveta ApostolovaElisaveta Apostolova
Elisaveta Apostolova
Yana GvozdevaYana Gvozdeva
Yana Gvozdeva
Radka Petkova BoyuklievaRadka Petkova Boyuklieva
Radka Petkova Boyuklieva
Vesela Yulieva KokovaVesela Yulieva Kokova
Vesela Yulieva Kokova
Background/Objectives: For successful wound management, dressings must be maintained in a moist environment to optimally enhance the microenvironment of the wound and efficiently deliver bioactive agents. Sodium humate has demonstrated potential wound-healing activity, although its topical delivery is still a challenge. This study aimed to develop and optimize polysaccharide-based dermal patches incorporating sodium-humate-loaded transferosomes and to assess their physicochemical and wound-healing properties. Methods: Transferosomes were obtained via thin-film hydration and prepared utilizing the Taguchi experimental design based on the impact of lipid content, lipid-to-surfactant ratio, and lipid-to-drug ratio on vesicle size, ζ-potential, and drug entrapment efficiency. The optimized transferosomes were loaded into alginate/HPMC composite dermal patches prepared through solvent evaporation. Results: The optimized transferosome formulation had an average size of 250.9 ± 2.3 nm, a ζ-potential of −3.57 ± 0.25, a high deformability of 93.01 ± 2.41%, and an effective drug-entrapment efficiency of 30.13 ± 1.04%. The use of transferosomes greatly affected patch thickness, moisture content, and surface morphology. A biphasic drug release profile of sodium humate was demonstrated via an in vitro release study, showing an initial burst followed by sustained drug release within 6 h. In vivo evaluation of transferosome-loaded patches showed that the formulations were able to effectively promote wound healing compared with the control. Conclusions: The developed transferosome-embedded alginate/HPMC dermal patches constitute a promising platform for the controlled topical administration of sodium humate and show promising enhancement of wound healing.

3 March 2026 in Polysaccharides
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PSPlamen Rosenov Simeonov
Plamen Rosenov Simeonov
Stanislava IvanovaStanislava Ivanova
Stanislava Ivanova
RARaina Ardasheva
Raina Ardasheva
Plamen KatsarovPlamen Katsarov
Plamen Katsarov
Liposomes remain one of the most utilized drug delivery systems due to their numerous advantages. However, they face significant challenges primarily due to their low colloidal stability as well as their rapid clearance by the reticuloendothelial and mononuclear phagocyte systems. Surface modifications have been identified as a highly effective approach to address these challenges. Various molecules can be utilized as surface modifiers. However, polysaccharides are widely employed in this regard, due to their unique characteristics, such as biocompatibility, biodegradability, and non-toxicity, as well as their ability to interact with the liposomal surface through different mechanisms. The aim of the present review is to provide a thorough analysis of polysaccharide-modified liposomes, highlighting recent advancements in their design, synthesis, and therapeutic applications. The utilization of polysaccharides as surface modifiers has been demonstrated to have several notable effects on liposomes. These effects include the enhancement of liposome properties, the provision of “stealth” properties, and the augmentation of colloidal stability. This review provides a comprehensive, polysaccharide-oriented analysis of liposomal surface modification strategies, along with a novel focus on the correlation between polysaccharide structure, modification method, and the resulting physicochemical and biological performance of the designed hybrid liposomes across a wide range of applications.

17 January 2026 in Polymers
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Nikolay ZaharievNikolay Zahariev
Nikolay Zahariev
Dimitar PenkovDimitar Penkov
Dimitar Penkov
Radka Petkova BoyuklievaRadka Petkova Boyuklieva
Radka Petkova Boyuklieva
PSPlamen Rosenov Simeonov
Plamen Rosenov Simeonov
Paolina LukovaPaolina Lukova
Paolina Lukova
Plamen KatsarovPlamen Katsarov
Plamen Katsarov
Introduction: Magnetic nanoparticles are widely investigated as multifunctional platforms for drug delivery and theranostic applications, yet their biomedical implementation is hindered by aggregation, limited colloidal stability, and insufficient biocompatibility. Hybrid biopolymer coatings can mitigate these issues while supporting drug incorporation. Aim: This study aimed to develop casein–pullulan-coated Fe3O4 nanocomposites loaded with xanthohumol, enhancing stability and enabling controlled release for potential theranostic use. Methods: Fe3O4 nanoparticles were synthesized through co-precipitation and incorporated into a casein–pullulan matrix formed via polymer complexation and glutaraldehyde crosslinking. A 32 full factorial design evaluated the influence of casein:pullulan ratio and crosslinker concentration on physicochemical performance. Nanocomposites were characterized for size, zeta potential, morphology, composition, and stability, while drug loading, encapsulation efficiency, and release profiles were determined spectrophotometrically. Molecular docking was performed to examine casein–pullulan interactions. Results: Uncoated Fe3O4 nanoparticles aggregated extensively, displaying mean sizes of ~292 nm, zeta potential of +80.95 mV and high polydispersity (PDI above 0.2). Incorporation into the biopolymer matrix improved colloidal stability, yielding particles of ~185 nm with zeta potentials near –35 mV. TEM and SEM confirmed spherical morphology and uniform magnetic core incorporation. The optimal formulation, consisting of a 1:1 casein:pullulan ratio with 1% glutaraldehyde, achieved 5.7% drug loading, 68% encapsulation efficiency, and sustained release of xanthohumol up to 84% over 120 h, fitting Fickian diffusion (Korsmeyer–Peppas R2 = 0.9877, n = 0.43). Conclusions: Casein–pullulan hybrid coatings significantly enhance Fe3O4 nanoparticle stability and enable controlled release of xanthohumol, presenting a promising platform for future targeted drug delivery and theranostic applications.

13 July 2026 in Polymers
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Journal Article
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PSPlamen Rosenov Simeonov
Plamen Rosenov Simeonov
Velislava TodorovaVelislava Todorova
Velislava Todorova
Tsvetelina Georgieva BatsalovaTsvetelina Georgieva Batsalova
Tsvetelina Georgieva Batsalova
Balik DzhambazovBalik Dzhambazov
Balik Dzhambazov
Stanislava IvanovaStanislava Ivanova
Stanislava Ivanova
Plamen KatsarovPlamen Katsarov
Plamen Katsarov
Xanthohumol (XN), a prenylated chalcone isolated from Humulus lupulus L., exhibits a wide range of biological activities, including antioxidant, anti-inflammatory, and chemopreventive effects. However, its therapeutic application is limited by poor aqueous solubility, low chemical stability, and rapid clearance from the systemic circulation. The present study aimed to develop and characterize a novel nano-sized drug-delivery system for XN that combines favourable colloidal stability, efficient encapsulation, sustained release, and reduced recognition by macrophages (“stealth-like” properties). To achieve this, XN-loaded cationic liposomes were coated with two marine polysaccharides, iota-carrageenan (CAR) and fucoidan (FUC), followed by Ca2+-mediated cross-linking. Liposomes were prepared by the ethanol injection method, and formulation parameters were optimized using a 23 + 1 full factorial design. Surface modification and cross-linking conditions were further optimized through polyelectrolyte titration and a Taguchi L9 orthogonal array. The resulting nanocarriers were evaluated for particle size, polydispersity, ζ-potential, encapsulation efficiency, release behavior, and cellular uptake. Both coatings significantly prolonged XN release compared with uncoated liposomes, with CAR-coated vesicles providing the most sustained release (≈55% over 48 h). In RAW264.7 macrophages, 50 µg/mL CAR-coated liposomes reduced cellular uptake by approximately 74% following 1-h incubation relative to uncoated controls and maintained this reduction over 2 h whereas FUC-coated vesicles afforded only transient early evasion. The cross-linked iota-carrageenan coating thus represents a promising strategy for conferring stable “stealth-like” characteristics to XN-loaded liposomes intended for prolonged drug delivery.