Erik Vasilev Dimitrov

Dr. Erik Vasilev Dimitrov

orcid

Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

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

Representative Publications

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3 October 2023 in Pharmaceutics
Verified
Journal Article
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Viliana GuglevaViliana Gugleva
Viliana Gugleva
KAKaterina Ahchiyska
Katerina Ahchiyska
DGDilyana Georgieva
Dilyana Georgieva
RMRositsa Asenova Mihaylova
Rositsa Asenova Mihaylova
SKSpiro Mihaylov Konstantinov
Spiro Mihaylov Konstantinov
DMDenitsa Momekova
Denitsa Momekova
Cannabidiol (CBD) is a promising drug candidate with pleiotropic pharmacological activity, whose low aqueous solubility and unfavorable pharmacokinetics have presented obstacles to its full clinical implementation. The rational design of nanocarriers, including niosomes for CBD encapsulation, can provide a plausible approach to overcoming these limitations. The present study is focused on exploring the feasibility of copolymer-modified niosomes as platforms for systemic delivery of CBD. To confer steric stabilization, the niosomal membranes were grafted with newly synthesized amphiphilic linear or star-shaped 3- and 4-arm star-shaped copolymers based on polyglycidol (PG) and poly(ε-caprolactone) (PCL) blocks. The niosomes were prepared by film hydration method and were characterized by DLS, cryo-TEM, encapsulation efficacy, and in vitro release. Free and formulated cannabidiol were further investigated for cytotoxicity and pro-apoptotic and anti-inflammatory activities in vitro in three human tumor cell lines. The optimal formulation, based on Tween 60:Span60:Chol (3.5:3.5:3 molar ration) modified with 2.5 mol% star-shaped 3-arm copolymer, is characterized by a size of 235 nm, high encapsulation of CBD (94%), and controlled release properties. Niosomal cannabidiol retained the antineoplastic activity of the free agent, but noteworthy superior apoptogenic and inflammatory biomarker-modulating effects were established at equieffective exposure vs. the free drug. Specific alterations in key signaling molecules, implicated in programmed cell death, cancer cell biology, and inflammation, were recorded with the niosomal formulations.

13 August 2023 in Pharmaceutics
Verified
Journal Article
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NTNatalia Toncheva-Moncheva
Natalia Toncheva-Moncheva
EDErik Vasilev Dimitrov
Erik Vasilev Dimitrov
GGGeorgy Grancharov
Georgy Grancharov
DMDenitsa Momekova
Denitsa Momekova
Petar Dimitrov PetrovPetar Dimitrov Petrov
Petar Dimitrov Petrov
S. RangelovS. Rangelov
S. Rangelov
The present study describes the development of novel block copolymer nanocarriers of the phytocannabinoid cannabidiol (CBD), designed to enhance the solubility of the drug in water while achieving high encapsulation efficiency and prolonged drug release. Firstly, a well-defined amphiphilic block copolymer consisting of two outer hydrophilic polyglycidol (PG) blocks and a middle hydrophobic block of poly(ε-caprolactone) bearing pendant cinnamyl moieties (P(CyCL-co-CL)) were synthesized by the click coupling reaction of PG-monoalkyne and P(CyCL-co-CL)-diazide functional macroreagents. A non-modified polyglycidol/poly(ε-caprolactone) amphiphilic block copolymer was obtained as a referent system. Micellar carriers based on the two block copolymers were formed via the solvent evaporation method and loaded with CBD following two different protocols—loading during micelle formation and loading into preformed micelles. The key parameters/characteristics of blank and CBD-loaded micelles such as size, size distribution, zeta potential, molar mass, critical micelle concentration, morphology, and encapsulation efficiency were determined by using dynamic and static multiangle and electrophoretic light scattering, transmission electron microscopy, and atomic force microscopy. Embedding CBD into the micellar carriers affected their hydrodynamic radii to some extent, while the spherical morphology of particles was not changed. The nanoformulation based on the copolymer bearing cinnamyl moieties possessed significantly higher encapsulation efficiency and a slower rate of drug release than the non-modified copolymer. The comparative assessment of the antiproliferative effect of micellar CBD vs. the free drug against the acute myeloid leukemia-derived HL-60 cell line and Sezary Syndrome HUT-78 demonstrated that the newly developed systems have pronounced antitumor activity.

18 October 2022 in Nanomaterials
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Journal Article
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EDErik Vasilev Dimitrov
Erik Vasilev Dimitrov
NTNatalia Toncheva-Moncheva
Natalia Toncheva-Moncheva
PBPavel Bakardzhiev
Pavel Bakardzhiev
Aleksander ForyśAleksander Foryś
Aleksander Foryś
JDJordan Doumanov
Jordan Doumanov
S. RangelovS. Rangelov
S. Rangelov
Spherical nucleic acids (SNAs)—nanostructures, consisting of a nanoparticle core densely functionalized with a shell of short oligonucleotide strands—are a rapidly emerging class of nanoparticle-based therapeutics with unique properties and specific applications as drug and nucleic acid delivery and gene regulation materials. In this contribution, we report on the preparation of hollow SNA nanoconstructs by co-assembly of an originally synthesized nucleolipid—a hybrid biomacromolecule, composed of a lipidic residue, covalently linked to a DNA oligonucleotide strand—with other lipids. The nucleolipid was synthesized via a click chemistry approach employing initiator-free, UV light-induced thiol-ene coupling of appropriately functionalized intermediates, performed in mild conditions using a custom-made UV light-emitting device. The SNA nanoconstructs were of a vesicular structure consisting of a self-closed bilayer membrane in which the nucleolipid was intercalated via its lipid–mimetic residue. They were in the lower nanometer size range, moderately negatively charged, and were found to carry thousands of oligonucleotide strands per particle, corresponding to a grafting density comparable to that of other SNA structures. The surface density of the strands on the bilayer implied that they adopted an unextended conformation. We demonstrated that preformed vesicular structures could be successfully loaded with either hydrophilic or hydrophobic dyes.

15 September 2025 in Pharmaceuticals
Verified
Journal Article
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Viliana GuglevaViliana Gugleva
Viliana Gugleva
KAKaterina Ahchiyska
Katerina Ahchiyska
ESElena Drakalska Sersemova
Elena Drakalska Sersemova
RMRositsa Asenova Mihaylova
Rositsa Asenova Mihaylova
NTNatalia Toncheva-Moncheva
Natalia Toncheva-Moncheva
DMDenitsa Momekova
Denitsa Momekova
Background/Objectives: The study describes the elaboration and evaluation of thermosensitive niosomes intended for the systemic application of daunorubicin hydrochloride. The attained stimulus sensitivity would determine the release of the chemotherapeutic predominantly at the target site, which ensures a higher drug concentration and leads to reduced systemic toxicity. The latter is highly beneficial, as the anthracycline antibiotic is known for its dose-dependent cardiotoxic effects. Methods: Conventional and copolymer-modified niosomes were prepared via thin-film hydration and the transmembrane ammonium gradient method, allowing us to assess the impacts of copolymer type-DHP-PiPOX (1,3-dihexadecyl-propane-2-ol-poly(2-isopropyl-2-oxazoline)) or DHP-PETEGA (1,3-dihexadecyl-propane-2-ol-poly(ethoxytriethylene glycol acrylate)) and their concentrations (0.5, 1, and 2.5 mol%), as well as the method of preparation, on the main physicochemical properties of the vesicles. Niosomes were characterized in terms of their size, polydispersity index (PDI), zeta potential, entrapment efficiency, morphology, and drug release properties. Thermosensitivity was evaluated by fluorescence studies, and the antiproliferative activity of optimized formulations was assessed against the acute myelocyte leukemia-derived HL-60 cell line. Results: Daunorubicin-loaded niosomes modified with DHP-PiPOX and DHP-PETEGA at 2.5 mol% exhibited suitable physicochemical properties for systemic application, with sizes below 200 nm (155 and 158 nm respectively), low PDI values of 0.25 and 0.29, spherical morphology, and high daunorubicin entrapment efficiency (68.6 and 66.5% respectively). The vesicles showed temperature-dependent drug release properties and superior antiproliferative activity compared to the free daunorubicin (IC50 values of 6.91 and 8.54 vs. 12.14). Conclusions: The obtained results indicate that the developed thermosensitive nanovesicles may serve as a suitable drug delivery system for the systemic application of daunorubicin hydrochloride.

19 February 2026 in Polymers
Verified
Journal Article
Open access
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NTNatalia Toncheva-Moncheva
Natalia Toncheva-Moncheva
EDErik Vasilev Dimitrov
Erik Vasilev Dimitrov
NDNiya Delcheva
Niya Delcheva
DMDenitsa Momekova
Denitsa Momekova
MKMagdalena Kondeva-Burdina
Magdalena Kondeva-Burdina
S. RangelovS. Rangelov
S. Rangelov
Amphiphilic copolymers based on polystyrene and polyglycidol combine the chemical inertness of polystyrene with the biocompatibility of polyglycidol, making them attractive materials for polymeric micelles. While comb-like architectures have been explored to control micellization behavior and biological response, a direct comparison between comb-like and coil-comb topologies in polystyrene–polyglycidol copolymers at identical polyglycidol content remains insufficiently investigated. In this work, amphiphilic comb-like and coil-comb polystyrene–polyglycidol copolymers were synthesized via copper-catalyzed azide–alkyne click chemistry by grafting a monoalkyne-terminated polyglycidol precursor onto azide-functionalized random and block styrene copolymers. The copolymers were characterized by size exclusion chromatography and nuclear magnetic resonance. Polymeric micelles were prepared by nanoprecipitation, and their self-assembly in aqueous solution was investigated by critical micelle concentration determination, dynamic and electrophoretic light scattering, and atomic force microscopy. Both copolymers formed stable aqueous dispersions and exhibited comparable critical micelle concentrations. At identical polyglycidol content, the random copolymer formed a uniform, monomodal micellar population, whereas the block-based coil-comb architecture led to bimodal size distributions, indicating the coexistence of two distinct micellar populations. The investigated systems showed low cytotoxicity and did not induce significant oxidative stress within the studied concentration range. On isolated rat brain sub-cellular fractions (synaptosomes, mitochondria and microsomes), administered alone, the comb-like and coil-comb polystyrene-polyglycidol copolymers did not reveal statistically significant neurotoxic effects. The results demonstrate that macromolecular architecture plays a key role in governing micellar organization and in vitro biological response in polystyrene–polyglycidol copolymers, highlighting their potential as architecture-controlled polymer-based nanocarriers.

3 September 2026 in European Polymer Journal
Verified
Journal Article
Closed access
YHYavor Hristov
Yavor Hristov
EDErik Vasilev Dimitrov
Erik Vasilev Dimitrov
Aleksander ForyśAleksander Foryś
Aleksander Foryś
MPMaria Petrova
Maria Petrova
CNChristo Novakov
Christo Novakov
S. RangelovS. Rangelov
S. Rangelov