The main objective of this work was the removal of eosin Y and green malachite from an aqueous me... more The main objective of this work was the removal of eosin Y and green malachite from an aqueous medium by using a cellulose-based biodegradable interpenetrated network (IPN). The IPN was obtained by the sequenced synthesis method. In the first step, cellulose was crosslinked with epichlorohydrin (ECH). In the second step, the obtained gels were swollen in a reactive mixture solution, which was based on the monomers 2-hydroxyethyl methacrylate (HEMA) and 1,6- hexanediol diacrylate (HDDA). After this, swelling equilibrium was reached through the gels’ exposition to UV radiation. An infrared spectroscopy (FTIR) was used to analyze the bond stretching, which confirmed the IPN’s formation. The swelling kinetics in aqueous mediums with different pH values showed a high swelling at a basic pH value and a low response in neutral and acidic media. The IPNs showed an improvement in water uptake, compared to the networks based on PHEMA or cellulose. The IPN was used to remove dyes from the wate...
Erythromycin is a macrolide antibiotic prescribed for the topical treatment of acne. Pharmacologi... more Erythromycin is a macrolide antibiotic prescribed for the topical treatment of acne. Pharmacologically, erythromycin has the disadvantage of being poorly soluble in water. This leads to formulation challenges in semisolid dosage forms. In recent years, many published studies have shown the ability of cyclodextrins to form complexes with drugs. These new complexes are characterized by much improved solubility and permeation compared to the „parent“ molecule. The aim of this study was to synthesize an inclusion complex of erythromycin and lactide-β-cyclodextrin for the formulation of semisolid bases and the development of innovative topical preparations with erythromycin. The erythromycin-lactide-βcyclodextrin complex was characterized by scanning electron microscopy and Fourier-transform infrared spectroscopy. Semisolid formulations were pharmacologically evaluated by in vitro dissolution test and kinetic analysis of drug release by fitting to representative mathematical models. The ...
The present paper aims to formulate and characterize four phytotherapeutic ointments based on Hip... more The present paper aims to formulate and characterize four phytotherapeutic ointments based on Hippophae fructus, Calendulae flos, Bardanae folium, and Millefolii herba, which are included in a novel ointment base. In order to investigate the healing properties of the ointments, in vivo experimental wound models of linear incision, circular excision, and thermal burn were performed on Wistar rats. Topical treatment was performed daily for 21 days. Determination of the wound contraction rate (WCR), the period of reepithelization, and histopathological examination were achieved. Additionally, for the tested ointments, oscillatory and rotational rheological tests were carried out, and for the extracts, HPLC analysis was performed. The results demonstrate that the tested novel ointments are safe for use and the most effective ointment proved to be the one based on Arctium lappa, followed by that of Calendulae flos.
Developing biomaterials with optimal loading properties and controlled release of drugs is a prio... more Developing biomaterials with optimal loading properties and controlled release of drugs is a priority of medical research. Clinoptilolite is a natural zeolite used in various industrial processes. Its texture and structure recommend its use as a biocompatible matrix for the development of modified release drug delivery systems. The present study aims to develop and characterize modified-release systems based on bexarotene loaded clinoptilolite. Bexarotene is a retinoid that is used as an anticancer agent in the topical treatment of cutaneous T-cell lymphoma. By adding bexarotene to these systems, skin delivered antineoplastic therapy with bexarotene can be improved. Clinoptilolite was obtained by purifying the volcanic tuffs from Mirsid quarry, Salaj Romania. After thermal and chemical purification, two monoionic forms of clinoptilolite were obtained. They were labeled as Na-CLI and H-CLI, respectively. Their texture and structure were characterized by specific methods. Subsequently...
The high interest in polymers from natural resources prompted us to investigate the use of enzyma... more The high interest in polymers from natural resources prompted us to investigate the use of enzymatically synthesized polyglobalide (PGL) in the preparation of polymer networks with potential applications as biomaterials for drug delivery devices. Polymer networks were obtained under mild conditions by photoinitiated thiol-ene coupling between PGL and a poly(ethylene glycol- co-thiomalate) (PEG-SH) copolymer obtained by polycondensation. The obtained polymer networks were thoroughly characterized by Raman spectroscopy, scanning electron microscopy, titration of thiol groups and elemental analysis. Our study took into consideration the synthesis parameters for the polymer networks, such as the total polymer concentration and the SH/C=C functionality molar ratio. Swelling in both THF and water was assessed, and the potential of the materials for drug delivery was determined. The scanning electron microscopy images showed that the prepared polymer networks may have different morphologie...
Natural proteins have been extensively studied as matrices for tissue engineering, due to their e... more Natural proteins have been extensively studied as matrices for tissue engineering, due to their excellent biocompatibility and biological properties associated with increasing cell proliferation. By generating complex materials, cell and tissue functions can be tailored to obtain a specific direction, according to the medical needs. The aim of this paper was to obtain scaffolds based on collagen, hyaluronan and sericin, with morphology and physical-chemical properties adequate for controlled drug delivery systems. In this aim various tests were performed: in vitro swelling and degradation studies, Fourier Transform Infrared spectroscopy (FT-IR), Scanning Electronic Microscopy (SEM) and thermogravimetric analysis. Loading and releasing of ibuprofen is also discussed. The results indicate that scaffolds based on collagen, hyaluronan and sericin have a porous structure, strength and stability adequate for skin tissue engineering. The obtained scaffolds swell, degrade and have controlle...
Some of the most dangerous diseases of the eye are related to the posterior segment. Diseases suc... more Some of the most dangerous diseases of the eye are related to the posterior segment. Diseases such as age-related macular degeneration, cytomegalovirus retinitis, diabetic retinopathy, posterior uveitis and retinitis pigmentosa are difficult to treat using classical methods because of the many internal barriers of the eye which affect the drug efficiency. In this review, we will summarize the main research directions in the field of medicamentous treatment of posterior eye disorders belonging to the controlled drug delivery concept. The review is starting with the most important knowledge regarding anatomy and pathology of the posterior segment of the eye and is continuing with the current treatment methods of the eye posterior segment illnesses and drawbacks of these methods, the drugs administration pathways to the posterior segment of the eye. The last three sections present the state of the art regarding the latest discoveries including the commercial products in the modern drug delivery systems; the main classes of materials treated in the present review are implants, hydrogels and nano- microparticulate systems.
Composite membranes prepared from mixtures of 3-glycidoxypropyl trimethoxysilane (GPTMS) and diff... more Composite membranes prepared from mixtures of 3-glycidoxypropyl trimethoxysilane (GPTMS) and different diamines containing polyether segments were synthesized by the sol-gel process. The membranes were obtained by coating asymmetric porous polyacrylonitrile (PAN) supports with the silane solutions. The composite membranes were characterized by single and mixed gas permeation and by atomic force microscopy. The selectivity increased by increasing the molecular weight
The critical stage in producing blends of biomacromolecules consists in the mixing of component s... more The critical stage in producing blends of biomacromolecules consists in the mixing of component solutions to generate homogenous diluted colloidal systems. Simple experimental investigations allow the establishment of the design rules of recipes and the procedures for preparing homogenous and compositionally reproducible mixtures. Starting from purified solutions of atelocollagen, hyaluronan and native gellan, having as low as possible inorganic salts content, initial binary and ternary mixtures can be prepared up to a total dry matter content of 0.150 g/dL, in no co-precipitating conditions. Two pH manipulation ways are feasible for homogenous mixing: (i) unbuffered prior correction at pH 5.5, and (ii) "rigid" buffering at pH 9.0, using organic species. Atelocollagen including co-precipitates can be obtained in the presence of one or both polysaccharides, preferably in pH domains far from the isoelectric point of scleroprotein. A critical behavior has been observed in mixtures containing gellan, due to its macromolecular dissimilarities compared with atelocollagen. In optimal binary mixtures, the coordinates of threshold points on the phase diagrams are 0.028% w/w atelocollagen/0.025% w/w hyaluronan, and 0.022% w/w atelocollagen/0.020% w/w gellan. Uni- or bi-phasic ternary systems having equilibrated ratios of co-precipitated components can be prepared starting from initial mixtures containing up to 0.032 g/dL atelocollagen, associated with, for example, 0.040 g/dL hyaluronan and 0.008 g/dL gellan, following the first pH manipulation way.
Journal of Materials Science: Materials in Medicine, 2008
Bromine-containing methacrylate, 2-(2-bromopropionyloxy) ethyl methacrylate (BPEM), had been used... more Bromine-containing methacrylate, 2-(2-bromopropionyloxy) ethyl methacrylate (BPEM), had been used in the formulation of acrylic radiopaque cements. The effect of this monomer incorporated into the liquid phase of acrylic bone cement, on the curing parameters, thermal properties, water absorption, density, compression tests and radiopacity was studied. A decrease of maximum temperature and an increase of the setting time were observed with the addition of the bromine-containing monomer in the radiolucent cement composition. Adding BPEM in radiolucent acrylic bone cements composition results in the decrease of glass transition temperature and increase of its thermal stability. Acrylic bone cements modified with bromine-containing comonomer are characterized by polymerization shrinkage lower than the radiolucent cement. Addition of bromine-containing comonomer in radiolucent acrylic bone cement composition determines the increase of compressive strength. Acrylic bone cements modified with bromine-containing comonomer proved to be radiopaque.
Journal of Bioactive and Compatible Polymers, 2013
A new approach to prepare polymeric capsules was developed to obtain an efficient controlled rele... more A new approach to prepare polymeric capsules was developed to obtain an efficient controlled release system for pain treatment. Capsules with a mean diameter between 400 and 1000 nm were prepared using an interfacial condensation method between a natural polymer, chitosan, and a synthetic one, poly(maleic anhydride- alt-vinyl acetate). The influence of different reaction parameters on capsule diameter and properties was investigated. Zeta-potential determinations indicated a good stability of the capsules in aqueous solution containing KCl. Scanning electron microscopy confirmed the submicron dimensions and the spherical shape of the capsules. The thermal properties of the capsules were determined by differential scanning calorimetry and thermogravimetric analysis. In addition, these particles presented a good swelling capacity, which was influenced by the reaction parameters used in this study (molar ratio between the two polymers, the volume ratio between aqueous and organic phase...
The present work deals with the study of obtaining the spherical particles containing brewer yeas... more The present work deals with the study of obtaining the spherical particles containing brewer yeast cells immobilized in a hydrogel matrix based on gellan and gellan/carboxymethyl cellulose (sodium salt). The influence of some factors of the process for obtaining the particles, by the ionic gelation with magnesium acetate used as crosslinking agent, by an extrusion process through capillary, on the particles properties such as structural stability, on morphological characteristics and on behavior in aqueous and alcoholic medium of the particles with or without yeast cells immobilized was studied. The particles were obtained from the mixtures of the two polysaccharides and theirs properties were compared to those based only on gellan. One can observe a certain influence of the CMCNa amount on the above mentioned properties essentially determined by their higher crosslinking density of the polymers mixture compared to those prepared only with gellan. Biocatalytic properties of the part...
The main objective of this work was the removal of eosin Y and green malachite from an aqueous me... more The main objective of this work was the removal of eosin Y and green malachite from an aqueous medium by using a cellulose-based biodegradable interpenetrated network (IPN). The IPN was obtained by the sequenced synthesis method. In the first step, cellulose was crosslinked with epichlorohydrin (ECH). In the second step, the obtained gels were swollen in a reactive mixture solution, which was based on the monomers 2-hydroxyethyl methacrylate (HEMA) and 1,6- hexanediol diacrylate (HDDA). After this, swelling equilibrium was reached through the gels’ exposition to UV radiation. An infrared spectroscopy (FTIR) was used to analyze the bond stretching, which confirmed the IPN’s formation. The swelling kinetics in aqueous mediums with different pH values showed a high swelling at a basic pH value and a low response in neutral and acidic media. The IPNs showed an improvement in water uptake, compared to the networks based on PHEMA or cellulose. The IPN was used to remove dyes from the wate...
Erythromycin is a macrolide antibiotic prescribed for the topical treatment of acne. Pharmacologi... more Erythromycin is a macrolide antibiotic prescribed for the topical treatment of acne. Pharmacologically, erythromycin has the disadvantage of being poorly soluble in water. This leads to formulation challenges in semisolid dosage forms. In recent years, many published studies have shown the ability of cyclodextrins to form complexes with drugs. These new complexes are characterized by much improved solubility and permeation compared to the „parent“ molecule. The aim of this study was to synthesize an inclusion complex of erythromycin and lactide-β-cyclodextrin for the formulation of semisolid bases and the development of innovative topical preparations with erythromycin. The erythromycin-lactide-βcyclodextrin complex was characterized by scanning electron microscopy and Fourier-transform infrared spectroscopy. Semisolid formulations were pharmacologically evaluated by in vitro dissolution test and kinetic analysis of drug release by fitting to representative mathematical models. The ...
The present paper aims to formulate and characterize four phytotherapeutic ointments based on Hip... more The present paper aims to formulate and characterize four phytotherapeutic ointments based on Hippophae fructus, Calendulae flos, Bardanae folium, and Millefolii herba, which are included in a novel ointment base. In order to investigate the healing properties of the ointments, in vivo experimental wound models of linear incision, circular excision, and thermal burn were performed on Wistar rats. Topical treatment was performed daily for 21 days. Determination of the wound contraction rate (WCR), the period of reepithelization, and histopathological examination were achieved. Additionally, for the tested ointments, oscillatory and rotational rheological tests were carried out, and for the extracts, HPLC analysis was performed. The results demonstrate that the tested novel ointments are safe for use and the most effective ointment proved to be the one based on Arctium lappa, followed by that of Calendulae flos.
Developing biomaterials with optimal loading properties and controlled release of drugs is a prio... more Developing biomaterials with optimal loading properties and controlled release of drugs is a priority of medical research. Clinoptilolite is a natural zeolite used in various industrial processes. Its texture and structure recommend its use as a biocompatible matrix for the development of modified release drug delivery systems. The present study aims to develop and characterize modified-release systems based on bexarotene loaded clinoptilolite. Bexarotene is a retinoid that is used as an anticancer agent in the topical treatment of cutaneous T-cell lymphoma. By adding bexarotene to these systems, skin delivered antineoplastic therapy with bexarotene can be improved. Clinoptilolite was obtained by purifying the volcanic tuffs from Mirsid quarry, Salaj Romania. After thermal and chemical purification, two monoionic forms of clinoptilolite were obtained. They were labeled as Na-CLI and H-CLI, respectively. Their texture and structure were characterized by specific methods. Subsequently...
The high interest in polymers from natural resources prompted us to investigate the use of enzyma... more The high interest in polymers from natural resources prompted us to investigate the use of enzymatically synthesized polyglobalide (PGL) in the preparation of polymer networks with potential applications as biomaterials for drug delivery devices. Polymer networks were obtained under mild conditions by photoinitiated thiol-ene coupling between PGL and a poly(ethylene glycol- co-thiomalate) (PEG-SH) copolymer obtained by polycondensation. The obtained polymer networks were thoroughly characterized by Raman spectroscopy, scanning electron microscopy, titration of thiol groups and elemental analysis. Our study took into consideration the synthesis parameters for the polymer networks, such as the total polymer concentration and the SH/C=C functionality molar ratio. Swelling in both THF and water was assessed, and the potential of the materials for drug delivery was determined. The scanning electron microscopy images showed that the prepared polymer networks may have different morphologie...
Natural proteins have been extensively studied as matrices for tissue engineering, due to their e... more Natural proteins have been extensively studied as matrices for tissue engineering, due to their excellent biocompatibility and biological properties associated with increasing cell proliferation. By generating complex materials, cell and tissue functions can be tailored to obtain a specific direction, according to the medical needs. The aim of this paper was to obtain scaffolds based on collagen, hyaluronan and sericin, with morphology and physical-chemical properties adequate for controlled drug delivery systems. In this aim various tests were performed: in vitro swelling and degradation studies, Fourier Transform Infrared spectroscopy (FT-IR), Scanning Electronic Microscopy (SEM) and thermogravimetric analysis. Loading and releasing of ibuprofen is also discussed. The results indicate that scaffolds based on collagen, hyaluronan and sericin have a porous structure, strength and stability adequate for skin tissue engineering. The obtained scaffolds swell, degrade and have controlle...
Some of the most dangerous diseases of the eye are related to the posterior segment. Diseases suc... more Some of the most dangerous diseases of the eye are related to the posterior segment. Diseases such as age-related macular degeneration, cytomegalovirus retinitis, diabetic retinopathy, posterior uveitis and retinitis pigmentosa are difficult to treat using classical methods because of the many internal barriers of the eye which affect the drug efficiency. In this review, we will summarize the main research directions in the field of medicamentous treatment of posterior eye disorders belonging to the controlled drug delivery concept. The review is starting with the most important knowledge regarding anatomy and pathology of the posterior segment of the eye and is continuing with the current treatment methods of the eye posterior segment illnesses and drawbacks of these methods, the drugs administration pathways to the posterior segment of the eye. The last three sections present the state of the art regarding the latest discoveries including the commercial products in the modern drug delivery systems; the main classes of materials treated in the present review are implants, hydrogels and nano- microparticulate systems.
Composite membranes prepared from mixtures of 3-glycidoxypropyl trimethoxysilane (GPTMS) and diff... more Composite membranes prepared from mixtures of 3-glycidoxypropyl trimethoxysilane (GPTMS) and different diamines containing polyether segments were synthesized by the sol-gel process. The membranes were obtained by coating asymmetric porous polyacrylonitrile (PAN) supports with the silane solutions. The composite membranes were characterized by single and mixed gas permeation and by atomic force microscopy. The selectivity increased by increasing the molecular weight
The critical stage in producing blends of biomacromolecules consists in the mixing of component s... more The critical stage in producing blends of biomacromolecules consists in the mixing of component solutions to generate homogenous diluted colloidal systems. Simple experimental investigations allow the establishment of the design rules of recipes and the procedures for preparing homogenous and compositionally reproducible mixtures. Starting from purified solutions of atelocollagen, hyaluronan and native gellan, having as low as possible inorganic salts content, initial binary and ternary mixtures can be prepared up to a total dry matter content of 0.150 g/dL, in no co-precipitating conditions. Two pH manipulation ways are feasible for homogenous mixing: (i) unbuffered prior correction at pH 5.5, and (ii) "rigid" buffering at pH 9.0, using organic species. Atelocollagen including co-precipitates can be obtained in the presence of one or both polysaccharides, preferably in pH domains far from the isoelectric point of scleroprotein. A critical behavior has been observed in mixtures containing gellan, due to its macromolecular dissimilarities compared with atelocollagen. In optimal binary mixtures, the coordinates of threshold points on the phase diagrams are 0.028% w/w atelocollagen/0.025% w/w hyaluronan, and 0.022% w/w atelocollagen/0.020% w/w gellan. Uni- or bi-phasic ternary systems having equilibrated ratios of co-precipitated components can be prepared starting from initial mixtures containing up to 0.032 g/dL atelocollagen, associated with, for example, 0.040 g/dL hyaluronan and 0.008 g/dL gellan, following the first pH manipulation way.
Journal of Materials Science: Materials in Medicine, 2008
Bromine-containing methacrylate, 2-(2-bromopropionyloxy) ethyl methacrylate (BPEM), had been used... more Bromine-containing methacrylate, 2-(2-bromopropionyloxy) ethyl methacrylate (BPEM), had been used in the formulation of acrylic radiopaque cements. The effect of this monomer incorporated into the liquid phase of acrylic bone cement, on the curing parameters, thermal properties, water absorption, density, compression tests and radiopacity was studied. A decrease of maximum temperature and an increase of the setting time were observed with the addition of the bromine-containing monomer in the radiolucent cement composition. Adding BPEM in radiolucent acrylic bone cements composition results in the decrease of glass transition temperature and increase of its thermal stability. Acrylic bone cements modified with bromine-containing comonomer are characterized by polymerization shrinkage lower than the radiolucent cement. Addition of bromine-containing comonomer in radiolucent acrylic bone cement composition determines the increase of compressive strength. Acrylic bone cements modified with bromine-containing comonomer proved to be radiopaque.
Journal of Bioactive and Compatible Polymers, 2013
A new approach to prepare polymeric capsules was developed to obtain an efficient controlled rele... more A new approach to prepare polymeric capsules was developed to obtain an efficient controlled release system for pain treatment. Capsules with a mean diameter between 400 and 1000 nm were prepared using an interfacial condensation method between a natural polymer, chitosan, and a synthetic one, poly(maleic anhydride- alt-vinyl acetate). The influence of different reaction parameters on capsule diameter and properties was investigated. Zeta-potential determinations indicated a good stability of the capsules in aqueous solution containing KCl. Scanning electron microscopy confirmed the submicron dimensions and the spherical shape of the capsules. The thermal properties of the capsules were determined by differential scanning calorimetry and thermogravimetric analysis. In addition, these particles presented a good swelling capacity, which was influenced by the reaction parameters used in this study (molar ratio between the two polymers, the volume ratio between aqueous and organic phase...
The present work deals with the study of obtaining the spherical particles containing brewer yeas... more The present work deals with the study of obtaining the spherical particles containing brewer yeast cells immobilized in a hydrogel matrix based on gellan and gellan/carboxymethyl cellulose (sodium salt). The influence of some factors of the process for obtaining the particles, by the ionic gelation with magnesium acetate used as crosslinking agent, by an extrusion process through capillary, on the particles properties such as structural stability, on morphological characteristics and on behavior in aqueous and alcoholic medium of the particles with or without yeast cells immobilized was studied. The particles were obtained from the mixtures of the two polysaccharides and theirs properties were compared to those based only on gellan. One can observe a certain influence of the CMCNa amount on the above mentioned properties essentially determined by their higher crosslinking density of the polymers mixture compared to those prepared only with gellan. Biocatalytic properties of the part...
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Papers by Marcel Popa