Cristina Ott - Academia.edu (original) (raw)

Papers by Cristina Ott

Nanomaterials

Conventional and herbal active principles can be combined in a beneficial harmony using their bes... more Conventional and herbal active principles can be combined in a beneficial harmony using their best features and compensating for the certain weaknesses of each. The study will answer the question, “how can willow bark extract (Wbe) or ivy leaf extract (Ile) influence the photoprotective, skin permeation and hydration properties of Bioactive Lipid Nanocarriers (BLN) loaded with UV-filters and selected herbals?”. BLN-Wbe/Ile-UV-filters were characterized for particle size, zeta potential, thermal behavior, entrapment efficiency and drug loading. The formulated BLN-hydrogels (HG) were subjected to in vitro release and permeation experiments. The in vitro determination of sun protection factors, as well as comparative in vitro photostability tests, rheology behavior and in vivo hydration status have been also considered for hydrogels containing BLN-Ile/Wbe-UV-filters. Photoprotection of BLN-HG against UVA rays was more pronounced as compared with the UVB (UVA-PF reached values of 30, wh...

In this work it have been investigated the difference of the encapsulation efficiency and the rel... more In this work it have been investigated the difference of the encapsulation efficiency and the release behavior of silica nanotubes and MCM-41 by using Ibuprofen as drug model. The highest encapsulation efficiency was in MCM-41, while the highest loaded Ibuprofen amount was in silica nanotubes. According to their larger size folded, silica nanotubes release percentage was around 80% which is higher than MCM-41 which was around 26%. It is worth mentioning that TEOS was used as silica precursor, and CTAB as a surfactant for the synthesis of both the nanostructured materials alike. In această lucrare au fost investigate diferenţele între eficienţa de încapsulare şi comportarea la eliberarea controlată a unor nanotuburi de silice şi respectiv MCM-41 utilizând Ibuprofen ca model. Cea mai mare eficienţă de încapsulare a fost obţinută pentru MCM-41 în timp ce nanotuburile de silice au încapsulat cea mai mare cantitate de Ibuprofen datorită spaţiului interior. Experimentele de eliberare favo...

Raportăm sinteza unor silice dopate cu Cr cu diferite morfologii obţinute prin polimerizarea sol-... more Raportăm sinteza unor silice dopate cu Cr cu diferite morfologii obţinute prin polimerizarea sol-gel a tetraetoxisilicatului în prezenţa unor organogelifianţi derivaţi de D-sorbitol (1,3 :2,4-bis-O-benzilidene-D-sorbitol, DBS şi derivaţii săi substituiţi cu grupe nitro şi metoxi) şi a bromurii de hexadeciltrimetilamoniu, catalizată de S-(+)-1-feniletilamină-tricarbonil-crom care este şi sursa de Cr pentru o încărcare de 10% Cr/SiO 2. Au fost observate două tipuri de morfologii : tuburi de silice cu diametre de 300-500nm şi lungimi între 10-15µm pentru organogelifiantul cu grupe nitro şi respectiv granule aglomerate tip « colier » pentru ceilalţi Analizele EDX şi XPS au arătat o distribuţie uniformă a ionilor de Cr pe suprafaţa matricei de silice constând în 80%Cr 3+ şi respectiv 20%Cr 6+. We report the synthesis of Cr-doped silica with different morphologies by sol-gel polymerization of tetraethoxysilicate in the presence of D-sorbitol derived organogelators (1,3:2,4-bis-O-benzylide...

Functionalized organogelators derived from 1,3;2,4-bis-O-benzylidene-D-sorbitol with methoxy and ... more Functionalized organogelators derived from 1,3;2,4-bis-O-benzylidene-D-sorbitol with methoxy and carbonylaminoethyl methacrylate moieties were prepared, characterized and their gelation ability was evaluated in order to be utilized as additives for dental materials obtained by photopolymerization of several dimethacrylate (DMA) monomers.

Vegetable oils and plant extracts have captured a special attention due to their high antioxidant... more Vegetable oils and plant extracts have captured a special attention due to their high antioxidant potential and also due to the preference of consumers for natural ingredients in many cosmetic products. The main objective of the present study was represented by the obtaining and characterization of active vegetable oils and extracts by using appropriate biotechnological procedure that allows to maintain a high content and biocosmetic potential of ω-3, -6, -9 and of carotenoids. In this context, several vegetable oils, e.g. hemp, milk thistle, safflower and black cumin oils have been obtained by cold pressing of row materials from native Romanian flora and analyzed by FT-IR spectroscopy, gas chromatography coupled with mass spectrometry (GC-MS) and 1H-RMN in order to establish the profile of unsaturated and polyunsaturated fatty acids. In a further study, two of the previous oils (e.g. safflower and milk thistle oils) have been selected for obtaining and stabilization of carrot extra...

This study aimed to investigate the release behavior of doxorubicin(DOX) from nanostructured sili... more This study aimed to investigate the release behavior of doxorubicin(DOX) from nanostructured silica tubes as carrier. The nanostructured silica nanotubes were synthesized according to the sol-gel method using tetraethoxysilane (TEOS) as silica precursor in the presence of cetyl trimethylammonium bromide (CTAB) and D-sorbitol derived organogelator as structure directing agents. The silica nanotubes were successfully prepared and their morphology has been examined with scanning electron microscopy (SEM). The release of doxorubicin was carried out by using two different release media, of pH values 7.4 and 5.5 respectively. The release was carried out by using HPLC system and the results have been reported indicating the difference in the release behavior between these two different pH media.

Lipid based particles such as solid lipid nanoparticles and nanostructured lipid carriers are amo... more Lipid based particles such as solid lipid nanoparticles and nanostructured lipid carriers are among the most promising carrier systems used in many domains, e.g. medicine, cosmetics and food industry. The aim of this study was to evaluate the influence of various kinds of solid lipid matrices on synthesis of effective nanostructured lipid carriers with appropriate average diameters and physical stability. For this purpose two solid lipid mixtures (glycerol monostearate with carnauba wax and glycerol monostearate with beeswax) in combination with three kinds of vegetable oils enriched in w-3, -5, -6 and -9 fatty acids (e.g. raspberry oil, rice oil, pomegranate oil) have been used for preparation of lipid nanocarriers. The free lipid nanocarriers and ivy leaves extract loaded nanocarriers were synthesized by high shear homogenization coupled with high pressure homogenization. The effect of surfactants mixture and loading with vegetable mixture has been followed by dynamic light scatte...

www.amfiteatrueconomic.ro, 2020

The aim of the study is to determine and confirm the main vectors that define the concept of sust... more The aim of the study is to determine and confirm the main vectors that define the concept of sustainable university based on the example of a higher education institution that is representative for the Romanian economic higher education system. As objectives the authors defined the following: clarifying the concept of sustainable university based on the literature review; determining the main groups of stakeholders of the university and classifying them tridimensional; researching the perception regarding the vectors needed for the sustainable development of the university. The research stems from the three main stakeholders' categories, in the authors' opinion. A quantitative marketing research was undertaken on two main stakeholders' categories: students, and representatives of the business environment that are part of the Alumni Association of the university. Using the factor analysis, the four vectors that define, in the authors opinion, the sustainable university were validated, which was confirmed. A qualitative research based on a focus group among academia and management counterbalanced the results of the study, confirming through results the stated hypotheses. The limitations of the current study stem from the involvement of only a part of the university's stakeholders. Future research could investigate the perception of other stakeholders.

Revista de Chimie, 2008

Several catanionic organogelators derived from 1,3 :2,4-bis-O-(p-aminobenzylidene)-D-sorbitol (p-... more Several catanionic organogelators derived from 1,3 :2,4-bis-O-(p-aminobenzylidene)-D-sorbitol (p-NH2-DBS) and hydroxy derivatives of natural fatty acids were synthesized, characterized and their gelation ability was evaluated. SEM observations of the xerogels formed by association of 1,3 :2,4-bis-O-(p-aminobenzylidene)-D-sorbitol and 12-hydroxystearic acid showed important modifications in the morphology and depend upon the nature of solvent as compared with the xerogels formed by each individual organogelator.

Chemical Engineering Science, 2019

h i g h l i g h t s Bioactive lipid nanocarriers-BLN with willow barck extract-Wbe and indomethac... more h i g h l i g h t s Bioactive lipid nanocarriers-BLN with willow barck extract-Wbe and indomethacin-Ind. Scavenging capacity of free oxygen radicals exceeds 90% for Wbe and Ind loaded-BLN. Remarkable protective effect on L929 cells, with apoptosis values of 11.6 to 15.9% BLN-Wbe manifested high ability to reduce TNF-a and IL-6 inflammatory marker levels. BLN-Wbe-Ind-hydrogels assured gradual release of both natural and synthetic actives.

Raportăm sinteza unor silice dopate cu Cr cu diferite morfologii obţinute prin polimerizarea sol-... more Raportăm sinteza unor silice dopate cu Cr cu diferite morfologii obţinute prin polimerizarea sol-gel a tetraetoxisilicatului în prezenţa unor organogelifianţi derivaţi de D-sorbitol (1,3 :2,4-bis-O-benzilidene-D-sorbitol, DBS şi derivaţii săi substituiţi cu grupe nitro şi metoxi) şi a bromurii de hexadeciltrimetilamoniu, catalizată de S-(+)-1-feniletilamină-tricarbonil-crom care este şi sursa de Cr pentru o încărcare de 10% Cr/SiO 2 . Au fost observate două tipuri de morfologii : tuburi de silice cu diametre de 300-500nm şi lungimi între 10-15µm pentru organogelifiantul cu grupe nitro şi respectiv granule aglomerate tip « colier » pentru ceilalţi Analizele EDX şi XPS au arătat o distribuţie uniformă a ionilor de Cr pe suprafaţa matricei de silice constând în 80%Cr 3+ şi respectiv 20%Cr 6+ . We report the synthesis of Cr-doped silica with different morphologies by sol-gel polymerization of tetraethoxysilicate in the presence of D-sorbitol derived organogelators (1,3:2,4-bis-O-benzyli...

Journal of Photochemistry and Photobiology B: Biology, 2015

Basal cell carcinoma (BCC) is one of the commonest malignancies occurred on sun-exposed skin, mai... more Basal cell carcinoma (BCC) is one of the commonest malignancies occurred on sun-exposed skin, mainly by UV-B radiation, of lighter-skinned individuals. The aim of the present study was to develop advanced drug delivery formulations used in BCC therapy that overcomes chemotherapy-induced side-effects of skin photosensitivity by an integrative approach of nanoencapsulation in conjunction with combination therapy that uses chemotherapeutic, chemoprotective and sunscreen agents. The combination of anticancer drug together with sunscreen agent is very useful in therapy, especially for individuals who are more exposed to the sun without using a sunscreen. Nanostructured lipid carriers (NLCs) employed as drug delivery systems were co-loaded with 5-fluorouracil (5-FU), a hydrophilic chemotherapeutic drug, and ethylhexyl salicylate (EHS), a lipophilic UV-B sunscreen agent. The NLCs were developed using bioactive squalene (50.8% w/w) from amaranth seed oil as chemoprotective agent. By varying the concentrations of 5-FU and EHS, the co-loaded NLCs presented particle sizes of about 100nm, acceptable physical stability with values smaller than -25mV and appropriate entrapment efficiency that reaches values over 65% for both types of drugs. The UV-B blocking ability of EHS loaded into NLCs were influenced by the concentration of 5-FU. The amaranth oil offered a capacity of 70% in scavenging the free radicals. In vitro drug release showed that NLCs presented sustained release of 5-FU that followed the Fick's law of diffusion.

Journal of Nanoscience and Nanotechnology, 2015

In this study the conventional oils used for lipid nanocarriers (NLCs) synthesis were replaced by... more In this study the conventional oils used for lipid nanocarriers (NLCs) synthesis were replaced by high concentration of fish oils (e.g., fish oil concentrated in omega-3 fatty acids, fish oil enriched in omega-3 and omega-6 fatty acids and salmon oil), in order to produce appropriate lipid based nanosystems able to entrap willow bark extract (WBE). Formulation factors such as the nature of the fish oil, glycerol content and WBE loading were evaluated to produce optimum lipid based nanosystems with suitable physical stability and enhanced antioxidant activity. The synthesized WBE-NLC showed spherical and homogeneous particles and average diameters in the range of 200-250 nm, as determined by TEM measurements. The electrokinetic potentials were negative for all free- and WBE-loaded NLCs, with values between -29.1 ÷ - 35.8 mV, which reveal an excellent physical stability. By scanning calorimetry measurements it has been shown that the lipid crystallization and melting behavior of NLCs before and after loading with WBE were no significantly influenced by the type of fish oil used and only in a few NLCs formulations an obvious perturbation of lipid network have been detected. The chemiluminescence technique has been used to assess the effect of fish oil type on the in vitro antioxidant activity of WBE-NLCs. Ability of WBE entrapped within NLCs to scavange the free radicals was greater than for native WBE and fish oils. The difference between the antioxidant activity of WBE-NLC (98%) and those of pure WBE (AA% = 77.2) and fish oil (AA% = 83.7), may be explained by the occurrence of a synergistic effect between the components of lipid nanocarriers.

Industrial Crops and Products, 2015

Vegetable oils are well-known for their beneficial health effects, mainly due to their antioxidan... more Vegetable oils are well-known for their beneficial health effects, mainly due to their antioxidant activity, which is maintained or enhanced when they are encapsulated at nanoscale. This study aims to design new nanostructured lipid carriers (NLCs) containing various vegetable oils and their combinations in order to obtain efficient formulations with UV protection performance and antioxidant activity. Pomegranate seed oil, wheat germ oil, blackcurrant seed oil, sesame seed oil, carrot root oil, raspberry seed oil and rice bran oil were used for obtaining NLCs, as carriers for a photoprotective agent that absorbs the UVA radiation: diethylamino hydroxybenzoyl hexyl benzoate. The NLCs were characterized by mean particle size, physical stability over time, and entrapment efficiency of the UVA filter. The UV protection performance was assessed using both in vitro sun protection factor (SPF) and the UVA protection factor (UVAPF). The antioxidant activity was determined by chemiluminescence analysis. All vegetable oils used led to the development of appropriate NLCs, having mean particle sizes ranging between 100 nm and 145 nm and good physical stability with zeta potential values less negative than −35 mV. The UV protection factors were evaluated on the individual vegetable oils and on cream formulations based on NLCs. Out of the seven cream formulations, the best UV protection was assured by the pomegranate seed oil based cream resulting in a SPF of 4.1 and an UVAPF of 7.8. Knowing that a synergistic interaction can occur among the active compounds of different oils, new NLCs were developed by using a mixture of pomegranate seed oil and one of the other oils. The NLCs based on pomegranate seed oil combined with wheat germ oil have shown the best entrapment efficiency (70%) and photoprotection (SPF of 5.1 and a UVAPF of 9.5). All vegetable oils showed a good antioxidant activity, which was improved by their incorporation into NLCs. The results have shown that vegetable oils and especially their combinations can be used as renewable raw materials in designing effective and eco-friendly photoprotective nanostructured formulations.

scientificbulletin.upb.ro

D-Sorbitol derived organogelators have been used as templates for syntheses of nanostructured sil... more D-Sorbitol derived organogelators have been used as templates for syntheses of nanostructured silica by the sol-gel polymerization of tetraethoxysilicate. The polymerization reactions were conducted in the presence of benzyl amine as catalyst. The resulting gels ...

Australian Journal of Chemistry, 1982

The condensation of 3-amino-4-methylaminopyridazine with pyruvaldehyde dimethyl acetal in methano... more The condensation of 3-amino-4-methylaminopyridazine with pyruvaldehyde dimethyl acetal in methanolic hydrogen chloride has been shown (by X-ray analysis) to give 3-methoxy-2-methyl-8-methylaminoimidazo[1,2-b]pyridazine. The crystals are triclinic, space group P1, with a 8.090(1),b 11.357(2), c l1.618 (2) �, α 88.81(2), β 70.27(2), γ 89.47(2)�, Z 4. The structure was refined to an R factor (on F) of 0.050 by full-matrix least-squares techniques. Similar reactions were observed with other 3-aminopyridazines, 2-aminopyrazine and 2-aminopyrimidine.

revistadechimie.ro

A new enantioselective synthesis of α-aminoacids based on stereoselective alkylation of the Schif... more A new enantioselective synthesis of α-aminoacids based on stereoselective alkylation of the Schiff bases generated from glycine ethyl ester and planar-chiral tricarbonyl-chromium complexes of aryl-aldehydes or ketones is reported. In order to improve stereoselectivity of above ...

Polymers for Advanced Technologies

Nanomaterials

Conventional and herbal active principles can be combined in a beneficial harmony using their bes... more Conventional and herbal active principles can be combined in a beneficial harmony using their best features and compensating for the certain weaknesses of each. The study will answer the question, “how can willow bark extract (Wbe) or ivy leaf extract (Ile) influence the photoprotective, skin permeation and hydration properties of Bioactive Lipid Nanocarriers (BLN) loaded with UV-filters and selected herbals?”. BLN-Wbe/Ile-UV-filters were characterized for particle size, zeta potential, thermal behavior, entrapment efficiency and drug loading. The formulated BLN-hydrogels (HG) were subjected to in vitro release and permeation experiments. The in vitro determination of sun protection factors, as well as comparative in vitro photostability tests, rheology behavior and in vivo hydration status have been also considered for hydrogels containing BLN-Ile/Wbe-UV-filters. Photoprotection of BLN-HG against UVA rays was more pronounced as compared with the UVB (UVA-PF reached values of 30, wh...

In this work it have been investigated the difference of the encapsulation efficiency and the rel... more In this work it have been investigated the difference of the encapsulation efficiency and the release behavior of silica nanotubes and MCM-41 by using Ibuprofen as drug model. The highest encapsulation efficiency was in MCM-41, while the highest loaded Ibuprofen amount was in silica nanotubes. According to their larger size folded, silica nanotubes release percentage was around 80% which is higher than MCM-41 which was around 26%. It is worth mentioning that TEOS was used as silica precursor, and CTAB as a surfactant for the synthesis of both the nanostructured materials alike. In această lucrare au fost investigate diferenţele între eficienţa de încapsulare şi comportarea la eliberarea controlată a unor nanotuburi de silice şi respectiv MCM-41 utilizând Ibuprofen ca model. Cea mai mare eficienţă de încapsulare a fost obţinută pentru MCM-41 în timp ce nanotuburile de silice au încapsulat cea mai mare cantitate de Ibuprofen datorită spaţiului interior. Experimentele de eliberare favo...

Raportăm sinteza unor silice dopate cu Cr cu diferite morfologii obţinute prin polimerizarea sol-... more Raportăm sinteza unor silice dopate cu Cr cu diferite morfologii obţinute prin polimerizarea sol-gel a tetraetoxisilicatului în prezenţa unor organogelifianţi derivaţi de D-sorbitol (1,3 :2,4-bis-O-benzilidene-D-sorbitol, DBS şi derivaţii săi substituiţi cu grupe nitro şi metoxi) şi a bromurii de hexadeciltrimetilamoniu, catalizată de S-(+)-1-feniletilamină-tricarbonil-crom care este şi sursa de Cr pentru o încărcare de 10% Cr/SiO 2. Au fost observate două tipuri de morfologii : tuburi de silice cu diametre de 300-500nm şi lungimi între 10-15µm pentru organogelifiantul cu grupe nitro şi respectiv granule aglomerate tip « colier » pentru ceilalţi Analizele EDX şi XPS au arătat o distribuţie uniformă a ionilor de Cr pe suprafaţa matricei de silice constând în 80%Cr 3+ şi respectiv 20%Cr 6+. We report the synthesis of Cr-doped silica with different morphologies by sol-gel polymerization of tetraethoxysilicate in the presence of D-sorbitol derived organogelators (1,3:2,4-bis-O-benzylide...

Functionalized organogelators derived from 1,3;2,4-bis-O-benzylidene-D-sorbitol with methoxy and ... more Functionalized organogelators derived from 1,3;2,4-bis-O-benzylidene-D-sorbitol with methoxy and carbonylaminoethyl methacrylate moieties were prepared, characterized and their gelation ability was evaluated in order to be utilized as additives for dental materials obtained by photopolymerization of several dimethacrylate (DMA) monomers.

Vegetable oils and plant extracts have captured a special attention due to their high antioxidant... more Vegetable oils and plant extracts have captured a special attention due to their high antioxidant potential and also due to the preference of consumers for natural ingredients in many cosmetic products. The main objective of the present study was represented by the obtaining and characterization of active vegetable oils and extracts by using appropriate biotechnological procedure that allows to maintain a high content and biocosmetic potential of ω-3, -6, -9 and of carotenoids. In this context, several vegetable oils, e.g. hemp, milk thistle, safflower and black cumin oils have been obtained by cold pressing of row materials from native Romanian flora and analyzed by FT-IR spectroscopy, gas chromatography coupled with mass spectrometry (GC-MS) and 1H-RMN in order to establish the profile of unsaturated and polyunsaturated fatty acids. In a further study, two of the previous oils (e.g. safflower and milk thistle oils) have been selected for obtaining and stabilization of carrot extra...

This study aimed to investigate the release behavior of doxorubicin(DOX) from nanostructured sili... more This study aimed to investigate the release behavior of doxorubicin(DOX) from nanostructured silica tubes as carrier. The nanostructured silica nanotubes were synthesized according to the sol-gel method using tetraethoxysilane (TEOS) as silica precursor in the presence of cetyl trimethylammonium bromide (CTAB) and D-sorbitol derived organogelator as structure directing agents. The silica nanotubes were successfully prepared and their morphology has been examined with scanning electron microscopy (SEM). The release of doxorubicin was carried out by using two different release media, of pH values 7.4 and 5.5 respectively. The release was carried out by using HPLC system and the results have been reported indicating the difference in the release behavior between these two different pH media.

Lipid based particles such as solid lipid nanoparticles and nanostructured lipid carriers are amo... more Lipid based particles such as solid lipid nanoparticles and nanostructured lipid carriers are among the most promising carrier systems used in many domains, e.g. medicine, cosmetics and food industry. The aim of this study was to evaluate the influence of various kinds of solid lipid matrices on synthesis of effective nanostructured lipid carriers with appropriate average diameters and physical stability. For this purpose two solid lipid mixtures (glycerol monostearate with carnauba wax and glycerol monostearate with beeswax) in combination with three kinds of vegetable oils enriched in w-3, -5, -6 and -9 fatty acids (e.g. raspberry oil, rice oil, pomegranate oil) have been used for preparation of lipid nanocarriers. The free lipid nanocarriers and ivy leaves extract loaded nanocarriers were synthesized by high shear homogenization coupled with high pressure homogenization. The effect of surfactants mixture and loading with vegetable mixture has been followed by dynamic light scatte...

www.amfiteatrueconomic.ro, 2020

The aim of the study is to determine and confirm the main vectors that define the concept of sust... more The aim of the study is to determine and confirm the main vectors that define the concept of sustainable university based on the example of a higher education institution that is representative for the Romanian economic higher education system. As objectives the authors defined the following: clarifying the concept of sustainable university based on the literature review; determining the main groups of stakeholders of the university and classifying them tridimensional; researching the perception regarding the vectors needed for the sustainable development of the university. The research stems from the three main stakeholders' categories, in the authors' opinion. A quantitative marketing research was undertaken on two main stakeholders' categories: students, and representatives of the business environment that are part of the Alumni Association of the university. Using the factor analysis, the four vectors that define, in the authors opinion, the sustainable university were validated, which was confirmed. A qualitative research based on a focus group among academia and management counterbalanced the results of the study, confirming through results the stated hypotheses. The limitations of the current study stem from the involvement of only a part of the university's stakeholders. Future research could investigate the perception of other stakeholders.

Revista de Chimie, 2008

Several catanionic organogelators derived from 1,3 :2,4-bis-O-(p-aminobenzylidene)-D-sorbitol (p-... more Several catanionic organogelators derived from 1,3 :2,4-bis-O-(p-aminobenzylidene)-D-sorbitol (p-NH2-DBS) and hydroxy derivatives of natural fatty acids were synthesized, characterized and their gelation ability was evaluated. SEM observations of the xerogels formed by association of 1,3 :2,4-bis-O-(p-aminobenzylidene)-D-sorbitol and 12-hydroxystearic acid showed important modifications in the morphology and depend upon the nature of solvent as compared with the xerogels formed by each individual organogelator.

Chemical Engineering Science, 2019

h i g h l i g h t s Bioactive lipid nanocarriers-BLN with willow barck extract-Wbe and indomethac... more h i g h l i g h t s Bioactive lipid nanocarriers-BLN with willow barck extract-Wbe and indomethacin-Ind. Scavenging capacity of free oxygen radicals exceeds 90% for Wbe and Ind loaded-BLN. Remarkable protective effect on L929 cells, with apoptosis values of 11.6 to 15.9% BLN-Wbe manifested high ability to reduce TNF-a and IL-6 inflammatory marker levels. BLN-Wbe-Ind-hydrogels assured gradual release of both natural and synthetic actives.

Raportăm sinteza unor silice dopate cu Cr cu diferite morfologii obţinute prin polimerizarea sol-... more Raportăm sinteza unor silice dopate cu Cr cu diferite morfologii obţinute prin polimerizarea sol-gel a tetraetoxisilicatului în prezenţa unor organogelifianţi derivaţi de D-sorbitol (1,3 :2,4-bis-O-benzilidene-D-sorbitol, DBS şi derivaţii săi substituiţi cu grupe nitro şi metoxi) şi a bromurii de hexadeciltrimetilamoniu, catalizată de S-(+)-1-feniletilamină-tricarbonil-crom care este şi sursa de Cr pentru o încărcare de 10% Cr/SiO 2 . Au fost observate două tipuri de morfologii : tuburi de silice cu diametre de 300-500nm şi lungimi între 10-15µm pentru organogelifiantul cu grupe nitro şi respectiv granule aglomerate tip « colier » pentru ceilalţi Analizele EDX şi XPS au arătat o distribuţie uniformă a ionilor de Cr pe suprafaţa matricei de silice constând în 80%Cr 3+ şi respectiv 20%Cr 6+ . We report the synthesis of Cr-doped silica with different morphologies by sol-gel polymerization of tetraethoxysilicate in the presence of D-sorbitol derived organogelators (1,3:2,4-bis-O-benzyli...

Journal of Photochemistry and Photobiology B: Biology, 2015

Basal cell carcinoma (BCC) is one of the commonest malignancies occurred on sun-exposed skin, mai... more Basal cell carcinoma (BCC) is one of the commonest malignancies occurred on sun-exposed skin, mainly by UV-B radiation, of lighter-skinned individuals. The aim of the present study was to develop advanced drug delivery formulations used in BCC therapy that overcomes chemotherapy-induced side-effects of skin photosensitivity by an integrative approach of nanoencapsulation in conjunction with combination therapy that uses chemotherapeutic, chemoprotective and sunscreen agents. The combination of anticancer drug together with sunscreen agent is very useful in therapy, especially for individuals who are more exposed to the sun without using a sunscreen. Nanostructured lipid carriers (NLCs) employed as drug delivery systems were co-loaded with 5-fluorouracil (5-FU), a hydrophilic chemotherapeutic drug, and ethylhexyl salicylate (EHS), a lipophilic UV-B sunscreen agent. The NLCs were developed using bioactive squalene (50.8% w/w) from amaranth seed oil as chemoprotective agent. By varying the concentrations of 5-FU and EHS, the co-loaded NLCs presented particle sizes of about 100nm, acceptable physical stability with values smaller than -25mV and appropriate entrapment efficiency that reaches values over 65% for both types of drugs. The UV-B blocking ability of EHS loaded into NLCs were influenced by the concentration of 5-FU. The amaranth oil offered a capacity of 70% in scavenging the free radicals. In vitro drug release showed that NLCs presented sustained release of 5-FU that followed the Fick's law of diffusion.

Journal of Nanoscience and Nanotechnology, 2015

In this study the conventional oils used for lipid nanocarriers (NLCs) synthesis were replaced by... more In this study the conventional oils used for lipid nanocarriers (NLCs) synthesis were replaced by high concentration of fish oils (e.g., fish oil concentrated in omega-3 fatty acids, fish oil enriched in omega-3 and omega-6 fatty acids and salmon oil), in order to produce appropriate lipid based nanosystems able to entrap willow bark extract (WBE). Formulation factors such as the nature of the fish oil, glycerol content and WBE loading were evaluated to produce optimum lipid based nanosystems with suitable physical stability and enhanced antioxidant activity. The synthesized WBE-NLC showed spherical and homogeneous particles and average diameters in the range of 200-250 nm, as determined by TEM measurements. The electrokinetic potentials were negative for all free- and WBE-loaded NLCs, with values between -29.1 ÷ - 35.8 mV, which reveal an excellent physical stability. By scanning calorimetry measurements it has been shown that the lipid crystallization and melting behavior of NLCs before and after loading with WBE were no significantly influenced by the type of fish oil used and only in a few NLCs formulations an obvious perturbation of lipid network have been detected. The chemiluminescence technique has been used to assess the effect of fish oil type on the in vitro antioxidant activity of WBE-NLCs. Ability of WBE entrapped within NLCs to scavange the free radicals was greater than for native WBE and fish oils. The difference between the antioxidant activity of WBE-NLC (98%) and those of pure WBE (AA% = 77.2) and fish oil (AA% = 83.7), may be explained by the occurrence of a synergistic effect between the components of lipid nanocarriers.

Industrial Crops and Products, 2015

Vegetable oils are well-known for their beneficial health effects, mainly due to their antioxidan... more Vegetable oils are well-known for their beneficial health effects, mainly due to their antioxidant activity, which is maintained or enhanced when they are encapsulated at nanoscale. This study aims to design new nanostructured lipid carriers (NLCs) containing various vegetable oils and their combinations in order to obtain efficient formulations with UV protection performance and antioxidant activity. Pomegranate seed oil, wheat germ oil, blackcurrant seed oil, sesame seed oil, carrot root oil, raspberry seed oil and rice bran oil were used for obtaining NLCs, as carriers for a photoprotective agent that absorbs the UVA radiation: diethylamino hydroxybenzoyl hexyl benzoate. The NLCs were characterized by mean particle size, physical stability over time, and entrapment efficiency of the UVA filter. The UV protection performance was assessed using both in vitro sun protection factor (SPF) and the UVA protection factor (UVAPF). The antioxidant activity was determined by chemiluminescence analysis. All vegetable oils used led to the development of appropriate NLCs, having mean particle sizes ranging between 100 nm and 145 nm and good physical stability with zeta potential values less negative than −35 mV. The UV protection factors were evaluated on the individual vegetable oils and on cream formulations based on NLCs. Out of the seven cream formulations, the best UV protection was assured by the pomegranate seed oil based cream resulting in a SPF of 4.1 and an UVAPF of 7.8. Knowing that a synergistic interaction can occur among the active compounds of different oils, new NLCs were developed by using a mixture of pomegranate seed oil and one of the other oils. The NLCs based on pomegranate seed oil combined with wheat germ oil have shown the best entrapment efficiency (70%) and photoprotection (SPF of 5.1 and a UVAPF of 9.5). All vegetable oils showed a good antioxidant activity, which was improved by their incorporation into NLCs. The results have shown that vegetable oils and especially their combinations can be used as renewable raw materials in designing effective and eco-friendly photoprotective nanostructured formulations.

scientificbulletin.upb.ro

D-Sorbitol derived organogelators have been used as templates for syntheses of nanostructured sil... more D-Sorbitol derived organogelators have been used as templates for syntheses of nanostructured silica by the sol-gel polymerization of tetraethoxysilicate. The polymerization reactions were conducted in the presence of benzyl amine as catalyst. The resulting gels ...

Australian Journal of Chemistry, 1982

The condensation of 3-amino-4-methylaminopyridazine with pyruvaldehyde dimethyl acetal in methano... more The condensation of 3-amino-4-methylaminopyridazine with pyruvaldehyde dimethyl acetal in methanolic hydrogen chloride has been shown (by X-ray analysis) to give 3-methoxy-2-methyl-8-methylaminoimidazo[1,2-b]pyridazine. The crystals are triclinic, space group P1, with a 8.090(1),b 11.357(2), c l1.618 (2) �, α 88.81(2), β 70.27(2), γ 89.47(2)�, Z 4. The structure was refined to an R factor (on F) of 0.050 by full-matrix least-squares techniques. Similar reactions were observed with other 3-aminopyridazines, 2-aminopyrazine and 2-aminopyrimidine.

revistadechimie.ro

A new enantioselective synthesis of α-aminoacids based on stereoselective alkylation of the Schif... more A new enantioselective synthesis of α-aminoacids based on stereoselective alkylation of the Schiff bases generated from glycine ethyl ester and planar-chiral tricarbonyl-chromium complexes of aryl-aldehydes or ketones is reported. In order to improve stereoselectivity of above ...

Polymers for Advanced Technologies