Petre Makreski

Ss. Cyril and Methodius University in Skopje Faculty of Natural Sciences and Mathematics-Skopje · Institute of Chemistry

Alongside oil and natural gas, coal is the most abundant non-renewable fossil fuel resource currently utilised worldwide. Although continuous efforts have been made in recent decades to replace the use of coal with various alternative energy sources (hydro, nuclear, wind, solar), coal is expected to remain the most important source of heat and elec...

Crystal engineering of multicomponent crystals offers opportunities for both generic active pharmaceutical ingredients (APIs) and innovative APIs (under patent protection) to be noncovalently bound with a wide range of organic compounds, forming new solid phases such as salts or cocrystals. These multicomponent crystals can enhance the physicochemi...

When screening the content of trace elements in minerals or other inorganic compounds, the detection limit is raised and determination by spectroscopic techniques is often questionable or even impossible due to their interference with the matrix elements of the minerals. Thus, some valuable trace elements may remain undetected, which lowers the est...

Sport nutrition supplements (SNS) are vulnerable to adulteration with melamine, artificially augmenting their protein content as determined by conventional assay methodologies. Vibrational spectroscopy techniques are suitable for the detection of adulteration because it allows rapid analysis, requires minimal sample preparation, and can perform num...

This study aimed to investigate the influence of formulation and process variables on the physicochemical properties and drug release behavior of oxaliplatin (OXP)-loaded ORMOSIL (Organically Modified Silicate) nanoparticles. ORMOSIL nanoparticles were synthesized using sol-gel methods, employing co-condensation (addition of TEOS and APTES at the b...

In this study, Temozolomide (TMZ), a drug used in the treatment of anaplastic astrocytoma and glioblastoma multiforme, was incorporated in multiwalled carbon nanotubes (MWCNTs) and hybrid carbon nanotubes with graphene (MWCNTs-G) functionalized by polyethylene glycol (PEG). The aim was to evaluate the potential of these nanocarriers for targeted de...

Many analytical methods have been successfully employed for the study of minerals, in particular, vibrational infrared (FTIR) and Raman spectroscopies and X-ray powder diffraction (XRPD). The advantages of the vibrational spectroscopic techniques for identifying and characterizing minerals include: rapid and versatile use; qualitative and quantitat...

Cultivation of Cannabis for medicinal purposes primarily relies on seed propagation with expected variations in yield, cannabinoid content, growth rate and seed material non-uniformity. This study aims to employ digital methods for morphological analysis and infrared spectroscopy, combining them with multivariate analysis to characterize and differ...

BaTiO 3 nanofibers (BT NFs), prepared by electrospinning, were used as a filler for electrospun poly(vinylidene fluoride‐ co ‐trifluoroethylene) (PVDF‐TrFE) nanocomposite mats. The phase structure and the effect of poling conditions on the piezoelectric properties of PVDF‐TrFE/BT nanocomposites were investigated. The results showed an improved degr...

Coal exploration is a very demanding task, highly dependent on geological and economic factors and the utilization of coal. This lecture text includes information on a variety of geological techniques used in the exploration of coal and coal-bearing sequences, as well as on the calculation, assessment, classification, and reporting of coal resource...

The vibrational dynamics of rutile (TiO2) as a function of temperature has been studied by combining molecular dynamics (MD) simulations in conjunction with the generalized two-dimensional correlation spectroscopy analysis (2D COS) technique. Molecular dynamics simulations within the microcanonical ensemble were performed with the self-consistent c...

The crystal structures of two pseudopolymorphic forms of S(+)clopidogrel–picrate are reported. Form 1 crystallizes in the monoclinic space group P21 with an ionic couple S(+)ClopH+·Pic− and a molecule of solvent ethanol in the asymmetric unit, while Form 2 crystallizes in the monoclinic space group C2 with two ionic couples in the asymmetric unit....

When screening the content of trace elements in minerals or other inorganic compounds, the detection limit is raised and determination by spectroscopic techniques is often questionable or even impossible due to their interference with the matrix elements of the minerals. Thus, some valuable trace elements may remain undetected, which lowers the est...

Piezoelectric (PE) materials play an important role in the emerging field of micro and wearable electronics. Achieving high PE response is a key feature for their use in energy harvesting and sensing systems. In this study, highly porous lightweight composite foams composed of PVDF‐TrFE (70/30 and 80/20 mol%) and different BaTiO 3 content (5, 10, a...

Polyvinylidene fluoride (PVDF) is a good candidate for use in wearable electronics due to its flexibility, ease of processing, and ability to generate electrical charge in response to applied mechanical stress. In this work, lowdensity polyvinylidene fluoride (PVDF) nanocomposites containing nano-sized BaTiO3 with cubic symmetry were fabricated by...

Lipid nano-systems were prepared and characterized in a series of well-established in vitro tests that could assess their interactions with the hCMEC/D3 and SH-SY5Y cell lines as a model for the blood–brain barrier and neuronal function, accordingly. The prepared formulations of nanoliposomes and nanostructured lipid carriers were characterized by...

Samples from the opus sectile panel excavated from the Episcopal Residence building at the archaeological site of Stobi were examined using X‐ray powder diffraction, SEM‐EDS and Raman spectroscopy. The analyzed samples, exhibiting plentiful color and surface variations, comprise the reconstructed sectile panel as well as represent the in situ groun...

The need for rapid, fast and nondestructive determination of the epoxy equivalent weight (EEW) of the resins was the underlying motivation to develop and propose an accurate and efficient method by means of micro-Raman spectroscopy. Three bands of interest that were assigned to the epoxide vibrations (around 640, 918 and 1250 cm−1), were marked. Th...

As probably the most complex natural (geological) material, as well as a parent of the industrial revolution and the most important source of heat and electricity in the world, coal has attracted and continues to attract special attention of scientists and the entire world population. In this context, this lecture text is intended to provide both c...

A low-dose tablet formulation, containing a potent Benzodiazepine derivative Alprazolam was developed, considering the achievement of appropriate content uniformity of the active substance in powder blends and tablets as a major challenge. Two different types of lactose monohydrate (Tablettose 80 and Granulac 200) and two different types of dry mix...

Rapid development of nanomedicines necessitates advancement in internalization techniques which can accurately distinguish between the complex environments of cells and nanocarriers. Internalization (or endocytosis) studies of oil red O labeled and label-free PEGylated-lecithin/cholesterol nanoliposomes was performed using micro-Raman spectroscopy....

The raw diatomaceous earth from the vicinity of Bitola (North Macedonia) showed low bulk density (0.61-0.69 g/cm3), high-water absorption (75-81%) and porosity (66- 72%). The chemical composition was determined with ICP-MS, revealing the following results for the diatomaceous earth: SiO2 (63.69 wt%), Al2O3 (11.79 wt%), Fe2O3 (5.95 wt%), MnO (0.15 w...

A detailed thermal analysis investigation of title BCS class II active pharmaceutical ingredients with low solubility and high permeability and known polymorphism were reported. Differential scanning calorimetry (DSC) and thermogravimetry analysis (TG) were used as primary screening techniques to assess into the polymorphic stability of the studied...

Poly(vinylidene fluoride) (PVDF) displays ferroelectric, piezoelectric and pyroelectric behavior and it is widely used in high-tech applications including sensors, transducers, energy harvesting devices and actuators. The crystallization of this polymer into highly polar β phase is desirable but is hard to achieve without applying specific thermo-m...

A successful optimization of the electrospinning parameters for obtainment of biodegradable polyester urethane (DP) webs of fibers, neat and graphene oxide (GO) modified , was performed. The effect of the processing parameters (distance between the needle tip and the collector, applied voltage, and flowing rate), solution type and polymer concentra...

Diclofenac sodium 0.1% is a commonly used NSAID with well-documented clinical efficacy in reducing postoperative inflammation; however, its corneal tolerability and ophthalmic tissue bioavailability require further improvement. Advanced micellar delivery systems composed of block-copolymers and chitosan showing fine balance between the mucoadhesion...

Considering the potential of Salvia officinalis in prevention and treatment of Alzheimer’s disease (AD), as well as the ability of nanostructured lipid carriers (NLC) to successfully deliver drug molecules across blood–brain barrier (BBB), the objective of this study was design, development, optimization and characterization of freeze‐dried salvia...

The subject of this research work was to analyze the structural and morphological changes of TiO2 as a result of incorporation of CNTs and interpret the underlying principles for the observed interactions. Hybrid TiO2/CNTs nanostructures were prepared by simplified solgel method followed by monitoring the thermally-induced alterations occurring up...

This lecture text condenses the characteristics of quartz and its rich palette of varieties. The mineralogy and crystallography of quartz and its forms, the origin of its colors, and their important physical and chemical characteristics are discussed. The geological occurrence of quartz and its varieties in the world is also presented, with special...

Strontium ferromolybdate, Sr2FeMoO6, is an important member of the family of double perovskites with the possible technological applications in the field of spintronics and solid oxide fuel cells. Its preparation via a multi-step ceramic route or various wet chemistry-based routes is notoriously difficult. The present work demonstrates that Sr2FeMo...

The present work outlines the biosynthesis of silver nanoparticles (AgNPs) using black pepper fruit extract (piperine) as bioreductive and capping agent, followed by their conjugation with piperine and characterization thereof. Several approaches for elucidation of the properites of both non-conjugated and piperine-conjugated AgNPs were implemented...

The decarboxylation of Δ9-tetrahydrocannabinolic acid (THCA) plays pivotal role in the potency of medical cannabis and its extracts. Our present work aims to draw attention to mid-infrared (MIR) spectroscopy to in-situ monitor and decipher the THCA decarboxylation reaction in the solid state. The initial TG/DTG curves of THCA, for a first time, out...

Reduced graphene oxide (rGO) is one of the graphene derivatives that can be employed to engineer bioactive and/or electroactive scaffolds. However, the influence of its low and especially high concentrations on scaffolds’ overall properties and cytotoxicity has yet to be explored. In this study, polyethylene oxide (PEO)-based scaffolds containing f...

Particle size distribution (PSD) is often considered as critical material attribute for active pharmaceutical ingredients (APIs), and the need for regular evaluation stands as an important quality control parameter in the pharmaceutical industry. Near-infrared (NIR) spectroscopy, used routinely for API identification, was introduced as analytical t...

This lecture text presents features of the fascinating mineral corundum and its gem varieties, ruby and sapphire. The geologic occurrences of its varieties and the best-known world localities are presented in detail. The mineralogy and crystallography of corundum, as well as its occurrence forms, are discussed. The origin of their colour varieties...

The diatomaceous earth (DE), collected from the Mariovo region in North Macedonia, was characterized and thermally modified. The material represents a sedimentary rock of biogenic origin, soft solid that can be easily disintegrated, with white to grayish color, with bulk density of 0.51–0.55 g/cm3, total porosity of 61–63%, and specific gravity of...

p>The decarboxylation of Δ9-tetrahydrocannabinolic acid (THCA) plays pivotal role in the potency of medical cannabis and its extracts. However, the literature data point out substantial variations in the process reaction rate and conversion efficacy due to variability of the temperature, heat transfer efficacy, raw material attributes, consequently...

The decarboxylation of Δ9-tetrahydrocannabinolic acid (THCA) plays pivotal role in the potency of medical cannabis and its extracts. However, the literature data point out substantial variations in the process reaction rate and conversion efficacy due to variability of the temperature, heat transfer efficacy, raw material attributes, consequently r...

Tetrahydrocannabinol (THC) and cannabidiol (CBD) are the most notable Cannabis components with pharmacological activity and their content in the plant flowers and extracts are considered as critical quality parameters. The new Medical Cannabis industry needs to adopt the quality standards of the pharmaceutical industry, however, the variability of...

The Allchar ore deposit is a long-standing enigma for scientists in the fields of geology, geochemistry, mineralogy, physics, chemistry, biology, astrology and other interdisciplinary scientific areas, but also for all enthusiasts interested in discovery of the Sun’s secrets. Although the ore deposit has been known for a long time (since the 12th o...

The subject of research was to monitor and evaluatethe changes in the structure and properties of nanoscaled TiO2 exposed to the X-ray and e-beam irradiation. The studied nanoscaled TiO2 was synthesized using sol-gel method and subsequently exposed to thermal treatment to obtain anatase crystalline structure. Powder diffraction (XRPD) and Raman spe...

Solid-state compatibility of API with excipients is essential step in the preformulation stage of early development of new finished dosage form. Thermal analysis and vibrational spectroscopy are complementary techniques that play pivotal role to assess the solid-state compatibility of API with excipients. Their coupling and combination with multiva...

Ionizing irradiation passing through materials interacts with their building units inducing changes in the structure. This causes modification of their properties and alteration of their performance. Generally, the ionizing irradiation used for material modification can be part of the electromagnetic spectrum (X-ray or γ-ray irradiation) or can hav...

The subject of this research was to monitor and evaluate the effect of X-rays and e-beam irradiation on the structure of nanoscaled TiO 2 and its properties. The samples of nanoscaled TiO 2 were synthesized using the sol-gel method and subsequently exposed to thermal treatment to obtain the anatase crystalline structure. X-ray powder diffraction (X...

Content uniformity is a critical attribute for potent and low-dosage formulations of active pharmaceutical ingredient (API) that, in addition to the formulation parameters, plays pivotal role during pharmaceutical development and production. However, when API content is low, implementing a vibrational spectroscopic analytical tool to monitor the co...

To improve the ability of the rice husk to purify colored wastewater, effluent from the alkaline scouring of cotton yarn was used immediately after the scouring (without cooling and additionally added chemicals) in order to remove the non-cellulosic silicon-lignin shield from the rice husk’s surface. This rice husk, with 93.8 mg/g adsorption capaci...

Clayey diatomite is the local name for a mixture of diatomaceous earth and clay minerals. It represents a greyish, soft, very light, weakly cemented, fine biogenetic sedimentary rock. The studied material is taken from the vicinity of Bitola city (Republic of Macedonia). Here, clayey diatomite was treated up to three temperature intervals (800, 100...

This lecture text is aimed at teaching some insight into phase transitions of minerals. It summarizes the results of a detailed study of the reaction mechanism of photoinduced solid-state transformation of the mineral realgar (α-As4S4) to its distinct polymorph pararealgar by a combination of in situ single-crystal X-ray photodiffraction, Fourier t...

Trepel is the local name for a mixture of diatomaceous earth and clay minerals. It represents a greyish, soft, very light, weakly cemented, fine biogenetic sedimentary rock. The studied material is taken from the vicinity of Bitola city (Republic of Macedonia). Here, trepel was treated up to three temperature intervals (800, 1000 and 1200 C) for a...

Royal jelly (RJ) is secretion from the hypopharyngeal glands of worker bees, which serves as food for the queen bee and enabling larvae growth. Having biological properties already proven, RJ has considerable commercial appeal and is used in many sectors (pharmacy, food industries, and cosmetic products) nowadays. However, due to its chemical compl...

The physico-mechanical, chemical and mineralogical characteristics of volcanic glass (perlite) from the Mariovo region (Macedonia) as well as the mineralogical changes that occur during its thermal treatment were investigated to demonstrate its utilization for industrial use. The native perlite was characterized by chemical analysis, X-ray powder d...

The aims of this study were: (a) to determine if the presence of probiotic bacteria in an aging medium, that is, artificial saliva in this study, has relevant effects on the surface roughness and the chemical composition of two main alloys used in dentistry (NiTi and stainless steel [SS]) and (b) in the case of NiTi, if these effects are influenced...

Trastuzumab is a humanized monoclonal antibody approved for treatment of HER2 (human epidermal growth factor 2) positive breast cancer. Conjugation of trastuzumab offers a promising strategy of selective anticancer therapy. Trastuzumab-emtansin is a new generation of cytotoxic drug conjugated antibody with higher tumour selectivity and less toxicit...

This lecture text demonstrates how the mineral lorandite is used as a detector of solar neutrinos. Because the age of the lorandite deposit in Allchar, North Macedonia, is known, this opened the possibility to determine the solar neutrino flux over the last 4.3 million years

Out of many functionalities of zinc oxide, its magnetic properties are only sparsely explored. Herein we report on the evolution of ferromagnetism of undoped ZnO nanoparticles, depending on the zinc source used for the synthesis. We started from mechanochemical synthesis of phase pure nanocrystalline hydrozincite, Zn 5 (CO 3 ) 2 (OH) 6 (ZnHC) by mi...

Infrared and Raman spectroscopy are effective techniques that allow collecting information about secondary structure of proteins, including antibodies. Trastuzumab, antibody used in our study was in a freeze-dried form, conjugated with different bifunctional chelators and linked with the stable isotopes of lutetium and yttrium. The characterization...

The work represents a pioneering attempt to couple TG analysis and hot-stage t-ATR-FTIR spectroscopy to describe the dehydration and dehydroxylation behaviors of very rare and complex hydrous Ca–hydrogen arsenate minerals [pharmacolite, CaHAsO4·2H2O, and picropharmacolite, Ca4Mg(AsO3OH)2(AsO4)2·11H2O]. The results are compared with the hydrous arse...

An UV-spectrophotometric method for simultaneous determination of amlodipine and captopril has been developed and validated. Simultaneous equation method is applied for the quantification of both drugs, which is based upon the measurement of absorbance at two wavelengths, λmax = 236 and 213 nm for amlodipine and captopril, respectively, in 0.1 N HC...

The content of major, minor and various trace elements in three manganese minerals from the Republic of Macedonia was determined. The studied minerals belong to the carbonate group [kutnohorite, Ca(Mn2+, Mg,Fe2+)(CO3)2, from Sasa mine] and to the inosilicate subgroup [carpholite, Mn2+Al2Si2O6(OH)4, from Vrbsko locality; rhodonite (Mn2+,Fe2+,Mg,Ca)S...

Equal-channel angular pressing (ECAP) was used as a technique for severe plastic deformation (SPD) on Al alloy AA3004. This technique produced fully dense materials of refined grain structure to sub-micrometer dimensions and advanced mechanical properties. The ECAP processing of samples was conducted as 1 to 4 passes through the die at room tempera...

Objectives: The aim of the present explorative study was to prepare and optimize finasteride loaded topical gel formulations by using three factor [propylene glycol (PG), Tween® 80, and sodium lauryl sulphate (SLS)], five level central composite design. Results: Optimized finasteride topical gel formulation (F4), containing PG, Tween® 80, and SL...

This work represents the first complete experimental and theoretical study of the infrared (IR) spectra of pharmacolite, Ca(AsO3OH)·2H2O; vladimirite, Ca4(AsO3OH)(AsO4)2·4H2O; and picropharmacolite, Ca4Mg(AsO3OH)2(AsO4)2·11H2O. IR spectra, collected at both room and liquid nitrogen temperature, have shown similar spectral view among minerals in the...

Context: Development, experimental design and in vitro in vivo correlation (IVIVC) of controlled-release matrix formulation. Objective: Development of novel oral controlled delivery system for indapamide hemihydrate, optimization of the formulation by experimental design and evaluation regarding IVIVC on a pilot scale batch as a confirmation of...

The aim of this study was to test the diatomaceous earth from a deposit near Rožden Village (Macedonia) as a raw material for low temperature hydrothermal production of porous ceramics. Hydrothermal synthesis of porous ceramics has been carried out under saturated steam pressure at 130 °C for a period of 1, 2 and 3 hours. The objective of this work...