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Rita Cortesi - One of the best experts on this subject based on the ideXlab platform.
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lipid nanostructures for antioxidant delivery a comparative preformulation study
Beilstein Journal of Nanotechnology, 2019Co-Authors: Elisabetta Esposito, Markus Drechsler, Paolo Mariani, Federica Carducci, Maddalena Sguizzato, Claudio Nastruzzi, Giuseppe Valacchi, Rita CortesiAbstract:This investigation is a study of new lipid nanoparticles for cutaneous antioxidant delivery. Several molecules, such as α-tocopherol and retinoic acid, have been shown to improve skin condition and even counteract the effects of exogenous stress factors such as smoking on skin aging. This work describes the design and development of lipid nanoparticles containing antioxidant agents (α-tocopherol or retinoic acid) to protect human skin against pollutants. Namely, solid lipid nanoparticles and nanostructured lipid carriers were prepared using different lipids (Tristearin, compritol, precirol or suppocire) in the presence or absence of caprylic/capric triglycerides. The formulations were characterized by particle size analysis, cryogenic transmission electron microscopy, small-angle X-ray diffraction, encapsulation efficiency, preliminary stability, in vitro cytotoxicity and protection against cigarette smoke. Nanostructured lipid carriers were found to reduce agglomerate formation and provided better dimensional stability, as compared to solid lipid nanoparticles, suggesting their suitability for antioxidant loading. Based on the preformulation study, Tristearin-based nanostructured lipid carriers loaded with α-tocopherol were selected for ex vivo studies since they displayed superior physico-chemical properties as compared to the other nanostructured lipid carriers compositions. Human skin explants were treated with α-tocopherol-loaded nanostructured lipid carriers and then exposed to cigarette smoke, and the protein levels of the stress-induced enzyme heme oxygenase were analyzed in skin homogenates. Interestingly, it was found that pretreatment with the nanoformulation resulted in significantly reduced heme oxygenase upregulation as compared to control samples, suggesting a protective effect provided by the nanoparticles.
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Production and Characterization of Nanoparticle Based Hyaluronate Gel Containing Retinyl Palmitate for Wound Healing
Current drug delivery, 2018Co-Authors: Elisabetta Esposito, Markus Drechsler, Paolo Mariani, Rita Cortesi, Federica Carducci, Alessandra Pecorelli, Maddalena Sguizzato, Franco Cervellati, Claudio Nastruzzi, Giuseppe ValacchiAbstract:BACKGROUND Wound healing is a biological process that can get in a state of pathologic inflammation, requiring the use of specific medications able to promote proper tissue repair. OBJECTIVE The study describes the production and characterization of nanoparticle based gel for wound healing treatment designed to deliver hyaluronic acid and retinyl palmitate onto the skin. METHODS Tristearin solid lipid nanoparticles and nanostructured lipid carriers based on a Tristearin and caprylic/capric triglyceride mixture were produced and characterized. Gel spreadability and viscosity were investigated. Drug diffusion and "in vitro" wound healing were assessed by Franz cell and scratch wound assay in keratinocytes. RESULTS Cryogenic transmission electron microscopy evidenced flat discoid nanoparticles. Photon correlation spectroscopy analysis indicated homogeneous dimensional distribution and mean diameter 132±46 nm. X-ray evidenced a lamellar inner structure of lipid nanoparticles. Nanostructured lipid carriers, being based on a heterogeneous solid/ liquid lipid mixture, could better solubilize retinyl palmitate and control its stability. The hyaluronic acid directly added into nanoparticles' dispersion enabled to obtain a shear-thinning gel suitable for cutaneous administration. Retynil palmitate diffusion was slower from the nanoparticulate gel with respect to the plain nanoparticle dispersion. The "wound healing" effect of nanoparticulate gel containing retinyl palmitate and hyaluronic acid, analyzed in HaCaT cells, showed significant differences in wounded areas between treated and control cells during the first 24 h postwounding suggesting a synergic effect of retinyl palmitate and hyaluronic acid in "in vitro" wound healing. CONCLUSIONS This study suggests that a nanoparticle based hyaluronate gel containing retinyl palmitate can be efficiently used for wound healing.
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Lipid nanoparticles for administration of poorly water soluble neuroactive drugs
Biomedical Microdevices, 2017Co-Authors: Elisabetta Esposito, Francesca Melancia, Patrizia Ratano, Patrizia Campolongo, Markus Drechsler, Paolo Mariani, Michela Servadio, Viviana Trezza, Federica Carducci, Rita CortesiAbstract:This study describes the potential of solid lipid nanoparticles and nanostructured lipid carriers as nano-formulations to administer to the central nervous system poorly water soluble drugs. Different neuroactive drugs, i.e. dimethylfumarate, retinyl palmitate, progesterone and the endocannabinoid hydrolysis inhibitor URB597 have been studied. Lipid nanoparticles constituted of Tristearin or Tristearin in association with gliceryl monoolein were produced. The nanoencapsulation strategy allowed to obtain biocompatible and non-toxic vehicles, able to increase the solubility of the considered neuroactive drugs. To improve URB597 targeting to the brain, stealth nanoparticles were produced modifying the SLN surface with polysorbate 80. A behavioural study was conducted in rats to test the ability of SLN containing URB597 given by intranasal administration to alter behaviours relevant to psychiatric disorders. URB597 maintained its activity after nanoencapsulation, suggesting the possibility to propose this kind of vehicle as alternative to unphysiological mixtures usually employed for animal and clinical studies.
Harry Reynaers - One of the best experts on this subject based on the ideXlab platform.
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study of the polymorphism of saturated monoacid triglycerides ii polymorphic behaviour of a 50 50 mixture of tripalmitin and Tristearin
Fett-lipid, 1992Co-Authors: M Kellens, Harry ReynaersAbstract:The polymorphic behaviour of a 50/50 blend of tripalmitin and Tristearin has been investigated in detail using differential scanning calorimetry and X-ray diffraction. The blend is characterized by a greater tendency to β'-crystallization as compared to the pure triglycerides. Tripalmitin and Tristearin, when mixed in a 1:1 ratio, are miscible in both the α-form and the β-form. In the β-form, however, demixing occurs, resulting in a 2-phase solid state. The characteristics of the α-form are considerably affected by the crystallization conditions, due to the formation of concentration gradients during crystallization. The β'-form can be obtained from the melt as well as via recrystallization of the α-form, and is characterized by a much higher stability as compared to the pure triglycerides. The X-ray diffraction data of the β'-form of the blend reveal a β1-crystal structure. The β'-form of the pure triglycerides, however, is characterized by a β'2-crystal structure. On the basis of the present data, however, no clear structural distinction can be made between β'2 and β'1. Untersuchung der Polymorphie von gesattigten einsaurigen Triglyceriden II: Polymorphes Verhalten einer Mischung von 50% Tripalmitin und 50% Tristearin Das polymorphe Verhalten einer Mischung von 50% Tripalmitin und 50% Tristearin wurde eingehend anhand der DSC-Methode und der Rontgenstrahlbeugung untersucht. Die Mischung ist gekennzeichnet durch eine grosere Neigung zur β'-Kristallisation im Vergleich zu den reinen Triglyceriden. Wenn Tripalmitin und Tristearin in einem Verhaltnis 1:1 gemischt werden, sind sie sowohl in der α-Form als auch in der β'-Form mischbar. In der β-Form tritt jedoch Entmischung auf, aus der ein fester Zustand in zwei Phasen resultiert. Die Kennzeichen der α-Form werden betrachtlich beeinflust durch die Kristallisationsbedingungen, die auf die Bildung von Konzentrationsgradienten wahrend der Kristallisation zuruckzufuhren sind. Die β'-Form kann sowohl aus der Schmelze als auch durch Umkristallisieren der α-Form erhalten werden und ist gekennzeichnet durch eine bedeutend hohere Stabilitat im Vergleich zu den reinen Triglyceriden. Die bei der Rontgenstrahlbeugung erhaltenen Daten der β'-Form der Mischung zeigen eine β'1-Kristallstruktur. Die β'-Form der reinen Triglyceride ist jedoch gekennzeichnet durch eine β'2-Kristallstruktur. Auf Basis der vorliegenden Daten kann jedoch kein deutlicher struktureller Unterschied zwischen β'2 und β'1 gemacht werden.
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study of the polymorphism of saturated monoacid triglycerides i melting and crystallization behaviour of Tristearin
Fett-lipid, 1992Co-Authors: M Kellens, Harry ReynaersAbstract:The crystallization and melting behaviour of Tristearin has been considered in detail. Both the thermal and structural characteristics of the β'- and β-crystal forms have been found to be largely dependent on the crystallization conditions. For the α-form, crystallization takes place very fast at low undercooling (T about 3°C). Upon melting, the α-form transforms directly to β, without any detectable appearance of a β'-form. The β'-form can only be obtained properly from the isotropic melt within a narrow temperature range (54 to 57°C). Above 57°C, β-crystallization becomes dominant. The main difference between the β'- and β-crystallization process is the induction time for crystallization. The decrease in β'-crystallization kinetics with increasing crystallization temperature is expressed in a longer induction time as well as in a slower rate of crystallization. In the case of the β-crystallization, the decrease in the overall crystallization rate mainly results from the sharp increase in induction time. The experimental data do not support the existence of distinct multiple subforms for the β'-form. The difference between β'2 and β'1 seems to be due to differences in the degree of ordering of the molecules in the β'-form. No significant differences have been observed between Tristearin and tripalmitin with respect to their polymorphic behaviour. Both triglycerides only differ from each other in the kinetics of the crystallization and transformation. Untersuchung der Polymorphie von gesattigten einsaurigen einsaurigen Triglyceriden I: Schmelz- und Kristallisationsverhalten von Tristearin Das Kristallisations- und Schmelzverhalten von Tristearin werden im Detail behandelt. Die Untersuchungen ergaben, das die thermischen und strukturellen Eigenschaften der β'- und β-Kristallformen sehr stark von den Kristallisationsbedingungen abhangig sind. Bei der α-Form findet die Kristallisation sehr schnell statt bei geringer Unterkuhlung (T etwa 3°C). Wahrend des Schmelzens wird die α-Form direkt in die β-Form umgewandelt, ohne das sich das Auftreten der β'-Form nachweisen last. Die β'-Form kann nur erhalten werden aus der isotropen Schmelze in einem sehr begrenzten Bereich (54 bis 57°C). Oberhalb 57°C dominiert die β-Form. Die Abnahme der Kinetik bei der β'-Kristallisation bei steigender Kristallisationstemperatur zeigt sich sowohl in einer langeren Induktionsperiode als auch in einer langsameren Kristallisationsgeschwindigkeit. Bei der β-Kristallisation resultiert der Abfall in der Gesamtkristallisationsgeschwindigkeit hauptsachlich aus dem starken Anstieg der Induktionsperiode. Die experimentellen Daten geben keinen Hinweis auf die Existenz von deutlich multiplen Subformen fur die β'-Form. Der Unterschied zwischen β'2- und β'1-Form ist anscheinend auf Unterschiede im Ordnungsgrad der Molekule in der β'-Form zuruckzufuhren. In bezug auf das polymorphe Verhalten liegen keine deutlichen Unterschiede zwischen Tristearin und Tripalmitin vor. Beide Triglyceride unterscheiden sich nur in der Kinetik der Kristallisation und Transformation.
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synchrotron radiation investigations of the polymorphic transitions in saturated monoacid triglycerides part 2 polymorphism study of a 50 50 mixture of tripalmitin and Tristearin during crystallization and melting
Chemistry and Physics of Lipids, 1991Co-Authors: M Kellens, W Meeussen, A Hammersley, Harry ReynaersAbstract:Abstract Time-resolved X-ray diffraction studies on the polymorphic behaviour and miscibility of tripalmitin and Tristearin in a 50:50 mixture have been performed using synchrotron radiation and DSC. Tripalmitin and Tristearin are miscible in both the α- and β′-form. They do not form a continuous solid solution in the β-form. The crystallization and melting process of the α-form is determined by the cooling rate: the lower the cooling rate, the more pronounced the formation of concentration gradients in the solid solution. Upon melting, the α-form firstly transforms to β′ and subsequently to β. The transition of α to β can take place with or without an intermediate β′-form. The β′-form can be obtained from the melt as well as by recrystallization from the α-form. The β′-form, crystallized from the α-phase, is characterized by a typical β ′ 2 -X-ray diffraction pattern: it is less stable and transform much easier to β as compared to the melt-crystallized β′-form, the latter being characterized by a β ′ 1 -diffraction pattern. The presence of crystal defects in the β′-crystal structure accelerates transformation to the β-polymorph.
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synchrotron radiation investigations of the polymorphic transitions of saturated monoacid triglycerides part 1 tripalmitin and Tristearin
Chemistry and Physics of Lipids, 1991Co-Authors: M Kellens, W Meeussen, R Gehrke, Harry ReynaersAbstract:Abstract Time-resolved X-ray diffraction studies of the polymorphic behaviour of tripalmitin and Tristearin during crystallization and melting, have been performed using synchrotron radiation in combination with DSC. Both triglycerides show a large tendency towards β-crystallization. Upon melting the α-phase, recrystallization to β occurs very quickly. The present data do not indicate the intervention of a detectable amount of β′-form during the transformation of α to β. The β′-form can be crystallized from the α-melt without the intervention of the β′-form. No indications are found to support the existence of a liquid-crystalline structure in the α-melt: the slower recrystallization to β, the more isotropic the melt. The α-β transition cannot be described as a simple rearrangement of the molecules, but seems to involve a nucleation and crystal growth process. The high crystallization rate of β from the α-melt as compared to a β-crystallization from the isotropic melt, mainly results from the much faster nucleation, the latter being accelerated by the persistence of crystallites in the α-melt. Melting of the β-form involves a simultaneous increase in disorder in the lateral direction (in the a—b-plane) and along the c-axis of the crystal cell (lamellar arrangement). The present data do not support the persistence of a bilayer structure in the melt above the β-melting temperature. The β′-form of tripalmitin and Tristearin can only be obtained from the isotropic melt and is characterized by a typical β′2-wide angle X-ray diffraction pattern. The two endotherms, appearing in the DSC-thermogram upon melting β′2, cannot be correlated with two independent β′-subforms (β′2 and β′1). Crystal perfection and crystallinity of the β′-form is considerably influenced by the crystallization conditions.
Elisabetta Esposito - One of the best experts on this subject based on the ideXlab platform.
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lipid nanostructures for antioxidant delivery a comparative preformulation study
Beilstein Journal of Nanotechnology, 2019Co-Authors: Elisabetta Esposito, Markus Drechsler, Paolo Mariani, Federica Carducci, Maddalena Sguizzato, Claudio Nastruzzi, Giuseppe Valacchi, Rita CortesiAbstract:This investigation is a study of new lipid nanoparticles for cutaneous antioxidant delivery. Several molecules, such as α-tocopherol and retinoic acid, have been shown to improve skin condition and even counteract the effects of exogenous stress factors such as smoking on skin aging. This work describes the design and development of lipid nanoparticles containing antioxidant agents (α-tocopherol or retinoic acid) to protect human skin against pollutants. Namely, solid lipid nanoparticles and nanostructured lipid carriers were prepared using different lipids (Tristearin, compritol, precirol or suppocire) in the presence or absence of caprylic/capric triglycerides. The formulations were characterized by particle size analysis, cryogenic transmission electron microscopy, small-angle X-ray diffraction, encapsulation efficiency, preliminary stability, in vitro cytotoxicity and protection against cigarette smoke. Nanostructured lipid carriers were found to reduce agglomerate formation and provided better dimensional stability, as compared to solid lipid nanoparticles, suggesting their suitability for antioxidant loading. Based on the preformulation study, Tristearin-based nanostructured lipid carriers loaded with α-tocopherol were selected for ex vivo studies since they displayed superior physico-chemical properties as compared to the other nanostructured lipid carriers compositions. Human skin explants were treated with α-tocopherol-loaded nanostructured lipid carriers and then exposed to cigarette smoke, and the protein levels of the stress-induced enzyme heme oxygenase were analyzed in skin homogenates. Interestingly, it was found that pretreatment with the nanoformulation resulted in significantly reduced heme oxygenase upregulation as compared to control samples, suggesting a protective effect provided by the nanoparticles.
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Production and Characterization of Nanoparticle Based Hyaluronate Gel Containing Retinyl Palmitate for Wound Healing
Current drug delivery, 2018Co-Authors: Elisabetta Esposito, Markus Drechsler, Paolo Mariani, Rita Cortesi, Federica Carducci, Alessandra Pecorelli, Maddalena Sguizzato, Franco Cervellati, Claudio Nastruzzi, Giuseppe ValacchiAbstract:BACKGROUND Wound healing is a biological process that can get in a state of pathologic inflammation, requiring the use of specific medications able to promote proper tissue repair. OBJECTIVE The study describes the production and characterization of nanoparticle based gel for wound healing treatment designed to deliver hyaluronic acid and retinyl palmitate onto the skin. METHODS Tristearin solid lipid nanoparticles and nanostructured lipid carriers based on a Tristearin and caprylic/capric triglyceride mixture were produced and characterized. Gel spreadability and viscosity were investigated. Drug diffusion and "in vitro" wound healing were assessed by Franz cell and scratch wound assay in keratinocytes. RESULTS Cryogenic transmission electron microscopy evidenced flat discoid nanoparticles. Photon correlation spectroscopy analysis indicated homogeneous dimensional distribution and mean diameter 132±46 nm. X-ray evidenced a lamellar inner structure of lipid nanoparticles. Nanostructured lipid carriers, being based on a heterogeneous solid/ liquid lipid mixture, could better solubilize retinyl palmitate and control its stability. The hyaluronic acid directly added into nanoparticles' dispersion enabled to obtain a shear-thinning gel suitable for cutaneous administration. Retynil palmitate diffusion was slower from the nanoparticulate gel with respect to the plain nanoparticle dispersion. The "wound healing" effect of nanoparticulate gel containing retinyl palmitate and hyaluronic acid, analyzed in HaCaT cells, showed significant differences in wounded areas between treated and control cells during the first 24 h postwounding suggesting a synergic effect of retinyl palmitate and hyaluronic acid in "in vitro" wound healing. CONCLUSIONS This study suggests that a nanoparticle based hyaluronate gel containing retinyl palmitate can be efficiently used for wound healing.
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Lipid nanoparticles for administration of poorly water soluble neuroactive drugs
Biomedical Microdevices, 2017Co-Authors: Elisabetta Esposito, Francesca Melancia, Patrizia Ratano, Patrizia Campolongo, Markus Drechsler, Paolo Mariani, Michela Servadio, Viviana Trezza, Federica Carducci, Rita CortesiAbstract:This study describes the potential of solid lipid nanoparticles and nanostructured lipid carriers as nano-formulations to administer to the central nervous system poorly water soluble drugs. Different neuroactive drugs, i.e. dimethylfumarate, retinyl palmitate, progesterone and the endocannabinoid hydrolysis inhibitor URB597 have been studied. Lipid nanoparticles constituted of Tristearin or Tristearin in association with gliceryl monoolein were produced. The nanoencapsulation strategy allowed to obtain biocompatible and non-toxic vehicles, able to increase the solubility of the considered neuroactive drugs. To improve URB597 targeting to the brain, stealth nanoparticles were produced modifying the SLN surface with polysorbate 80. A behavioural study was conducted in rats to test the ability of SLN containing URB597 given by intranasal administration to alter behaviours relevant to psychiatric disorders. URB597 maintained its activity after nanoencapsulation, suggesting the possibility to propose this kind of vehicle as alternative to unphysiological mixtures usually employed for animal and clinical studies.
M Kellens - One of the best experts on this subject based on the ideXlab platform.
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study of the polymorphism of saturated monoacid triglycerides ii polymorphic behaviour of a 50 50 mixture of tripalmitin and Tristearin
Fett-lipid, 1992Co-Authors: M Kellens, Harry ReynaersAbstract:The polymorphic behaviour of a 50/50 blend of tripalmitin and Tristearin has been investigated in detail using differential scanning calorimetry and X-ray diffraction. The blend is characterized by a greater tendency to β'-crystallization as compared to the pure triglycerides. Tripalmitin and Tristearin, when mixed in a 1:1 ratio, are miscible in both the α-form and the β-form. In the β-form, however, demixing occurs, resulting in a 2-phase solid state. The characteristics of the α-form are considerably affected by the crystallization conditions, due to the formation of concentration gradients during crystallization. The β'-form can be obtained from the melt as well as via recrystallization of the α-form, and is characterized by a much higher stability as compared to the pure triglycerides. The X-ray diffraction data of the β'-form of the blend reveal a β1-crystal structure. The β'-form of the pure triglycerides, however, is characterized by a β'2-crystal structure. On the basis of the present data, however, no clear structural distinction can be made between β'2 and β'1. Untersuchung der Polymorphie von gesattigten einsaurigen Triglyceriden II: Polymorphes Verhalten einer Mischung von 50% Tripalmitin und 50% Tristearin Das polymorphe Verhalten einer Mischung von 50% Tripalmitin und 50% Tristearin wurde eingehend anhand der DSC-Methode und der Rontgenstrahlbeugung untersucht. Die Mischung ist gekennzeichnet durch eine grosere Neigung zur β'-Kristallisation im Vergleich zu den reinen Triglyceriden. Wenn Tripalmitin und Tristearin in einem Verhaltnis 1:1 gemischt werden, sind sie sowohl in der α-Form als auch in der β'-Form mischbar. In der β-Form tritt jedoch Entmischung auf, aus der ein fester Zustand in zwei Phasen resultiert. Die Kennzeichen der α-Form werden betrachtlich beeinflust durch die Kristallisationsbedingungen, die auf die Bildung von Konzentrationsgradienten wahrend der Kristallisation zuruckzufuhren sind. Die β'-Form kann sowohl aus der Schmelze als auch durch Umkristallisieren der α-Form erhalten werden und ist gekennzeichnet durch eine bedeutend hohere Stabilitat im Vergleich zu den reinen Triglyceriden. Die bei der Rontgenstrahlbeugung erhaltenen Daten der β'-Form der Mischung zeigen eine β'1-Kristallstruktur. Die β'-Form der reinen Triglyceride ist jedoch gekennzeichnet durch eine β'2-Kristallstruktur. Auf Basis der vorliegenden Daten kann jedoch kein deutlicher struktureller Unterschied zwischen β'2 und β'1 gemacht werden.
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study of the polymorphism of saturated monoacid triglycerides i melting and crystallization behaviour of Tristearin
Fett-lipid, 1992Co-Authors: M Kellens, Harry ReynaersAbstract:The crystallization and melting behaviour of Tristearin has been considered in detail. Both the thermal and structural characteristics of the β'- and β-crystal forms have been found to be largely dependent on the crystallization conditions. For the α-form, crystallization takes place very fast at low undercooling (T about 3°C). Upon melting, the α-form transforms directly to β, without any detectable appearance of a β'-form. The β'-form can only be obtained properly from the isotropic melt within a narrow temperature range (54 to 57°C). Above 57°C, β-crystallization becomes dominant. The main difference between the β'- and β-crystallization process is the induction time for crystallization. The decrease in β'-crystallization kinetics with increasing crystallization temperature is expressed in a longer induction time as well as in a slower rate of crystallization. In the case of the β-crystallization, the decrease in the overall crystallization rate mainly results from the sharp increase in induction time. The experimental data do not support the existence of distinct multiple subforms for the β'-form. The difference between β'2 and β'1 seems to be due to differences in the degree of ordering of the molecules in the β'-form. No significant differences have been observed between Tristearin and tripalmitin with respect to their polymorphic behaviour. Both triglycerides only differ from each other in the kinetics of the crystallization and transformation. Untersuchung der Polymorphie von gesattigten einsaurigen einsaurigen Triglyceriden I: Schmelz- und Kristallisationsverhalten von Tristearin Das Kristallisations- und Schmelzverhalten von Tristearin werden im Detail behandelt. Die Untersuchungen ergaben, das die thermischen und strukturellen Eigenschaften der β'- und β-Kristallformen sehr stark von den Kristallisationsbedingungen abhangig sind. Bei der α-Form findet die Kristallisation sehr schnell statt bei geringer Unterkuhlung (T etwa 3°C). Wahrend des Schmelzens wird die α-Form direkt in die β-Form umgewandelt, ohne das sich das Auftreten der β'-Form nachweisen last. Die β'-Form kann nur erhalten werden aus der isotropen Schmelze in einem sehr begrenzten Bereich (54 bis 57°C). Oberhalb 57°C dominiert die β-Form. Die Abnahme der Kinetik bei der β'-Kristallisation bei steigender Kristallisationstemperatur zeigt sich sowohl in einer langeren Induktionsperiode als auch in einer langsameren Kristallisationsgeschwindigkeit. Bei der β-Kristallisation resultiert der Abfall in der Gesamtkristallisationsgeschwindigkeit hauptsachlich aus dem starken Anstieg der Induktionsperiode. Die experimentellen Daten geben keinen Hinweis auf die Existenz von deutlich multiplen Subformen fur die β'-Form. Der Unterschied zwischen β'2- und β'1-Form ist anscheinend auf Unterschiede im Ordnungsgrad der Molekule in der β'-Form zuruckzufuhren. In bezug auf das polymorphe Verhalten liegen keine deutlichen Unterschiede zwischen Tristearin und Tripalmitin vor. Beide Triglyceride unterscheiden sich nur in der Kinetik der Kristallisation und Transformation.
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synchrotron radiation investigations of the polymorphic transitions in saturated monoacid triglycerides part 2 polymorphism study of a 50 50 mixture of tripalmitin and Tristearin during crystallization and melting
Chemistry and Physics of Lipids, 1991Co-Authors: M Kellens, W Meeussen, A Hammersley, Harry ReynaersAbstract:Abstract Time-resolved X-ray diffraction studies on the polymorphic behaviour and miscibility of tripalmitin and Tristearin in a 50:50 mixture have been performed using synchrotron radiation and DSC. Tripalmitin and Tristearin are miscible in both the α- and β′-form. They do not form a continuous solid solution in the β-form. The crystallization and melting process of the α-form is determined by the cooling rate: the lower the cooling rate, the more pronounced the formation of concentration gradients in the solid solution. Upon melting, the α-form firstly transforms to β′ and subsequently to β. The transition of α to β can take place with or without an intermediate β′-form. The β′-form can be obtained from the melt as well as by recrystallization from the α-form. The β′-form, crystallized from the α-phase, is characterized by a typical β ′ 2 -X-ray diffraction pattern: it is less stable and transform much easier to β as compared to the melt-crystallized β′-form, the latter being characterized by a β ′ 1 -diffraction pattern. The presence of crystal defects in the β′-crystal structure accelerates transformation to the β-polymorph.
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synchrotron radiation investigations of the polymorphic transitions of saturated monoacid triglycerides part 1 tripalmitin and Tristearin
Chemistry and Physics of Lipids, 1991Co-Authors: M Kellens, W Meeussen, R Gehrke, Harry ReynaersAbstract:Abstract Time-resolved X-ray diffraction studies of the polymorphic behaviour of tripalmitin and Tristearin during crystallization and melting, have been performed using synchrotron radiation in combination with DSC. Both triglycerides show a large tendency towards β-crystallization. Upon melting the α-phase, recrystallization to β occurs very quickly. The present data do not indicate the intervention of a detectable amount of β′-form during the transformation of α to β. The β′-form can be crystallized from the α-melt without the intervention of the β′-form. No indications are found to support the existence of a liquid-crystalline structure in the α-melt: the slower recrystallization to β, the more isotropic the melt. The α-β transition cannot be described as a simple rearrangement of the molecules, but seems to involve a nucleation and crystal growth process. The high crystallization rate of β from the α-melt as compared to a β-crystallization from the isotropic melt, mainly results from the much faster nucleation, the latter being accelerated by the persistence of crystallites in the α-melt. Melting of the β-form involves a simultaneous increase in disorder in the lateral direction (in the a—b-plane) and along the c-axis of the crystal cell (lamellar arrangement). The present data do not support the persistence of a bilayer structure in the melt above the β-melting temperature. The β′-form of tripalmitin and Tristearin can only be obtained from the isotropic melt and is characterized by a typical β′2-wide angle X-ray diffraction pattern. The two endotherms, appearing in the DSC-thermogram upon melting β′2, cannot be correlated with two independent β′-subforms (β′2 and β′1). Crystal perfection and crystallinity of the β′-form is considerably influenced by the crystallization conditions.
Cortesi Rita - One of the best experts on this subject based on the ideXlab platform.
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Ellagic acid containing Nanostructured Lipid Carriers for topical application: a preliminary study
'MDPI AG', 2020Co-Authors: Hallan, Supandeep Singh, Esposito Elisabetta, Drechsler Markus, Mariani Paolo, Sguizzato Maddalena, Pavoni Gabriella, Baldisserotto Anna, Cortesi RitaAbstract:Ellagic acid (EA) is a potent antioxidant substance of natural origin characterized by poor biopharmaceutical properties and low solubility in water that limit their use. The aim of the present study was to develop lipid based nanoparticle formulations able to encapsulate EA for dermal delivery purpose. The EA-loaded nanoparticles were prepared using two different lipid compositions, namely Tristearin/tricaprylin (NLC-EA1) and Tristearin/labrasol (NLC-EA2). The influence of formulations on size, entrapment efficiency and stability of EA-loaded nanoparticles was investigated. Cryo-TEM and SAXS analysess showed that no morphological differences are evident among all the types of loaded and unloaded NLC. The macroscopic aspect of both NLC-EA1 and NLC-EA2 did not change by time. No difference in size is appreciable between empty and drug-containing NLC, thus the nanoparticle diameter is not affected by the presence EA and in general no variations of the diameters occur during time. The percentage of entrapment efficiency of both EA-loaded nanoparticles was almost quantitative. In addition NLC-EA1 maintain EA stability for almost 2 months, while NLC-EA2 up to 40 days. FRAP assay showed an antioxidant activity around 60% for both the loaded NLC, as compared to the solution. Although both types of NLC are characterized by some toxicity, NLC-EA1 are less cytotoxic than NLC-EA2. Taken together these results demonstrated that the inclusion of EA within NLC could improve the water solubility, allowing for a reduction of the dosage. Moreover, the maintaining of high antioxidant effect and low toxicity were evidenced for both types of NLC-EA
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Hyaluronate nanoparticulate gel containing retinyl palmitate
2019Co-Authors: Esposito Elisabetta, Pecorelli Alessandra, Drechsler Markus, Mariani Paolo, Cervellati Franco, Cortesi Rita, Sguizzato Maddalena, Valacchi GiuseppeAbstract:A nanoparticulate gel has been designed for wound healing treatment. Namely the vehicle has been specifically formulated to apply on the skin both hyaluronic acid and the antioxidant retinyl palmitate. The latter has been loaded in lipid nanoparticles suitable to solubilize this lipophilic molecule. Particularly retinyl palmitate has been encapsulated both in solid lipid nanoparticles and nanostructured lipid carriers, respectively constituted of pure Tristearin or a mixture of Tristearin and caprylic/capric triglyceride. Nanoparticles were characterized by discoidal and flat shape, lamellar inner structure, as evidenced by cryogenic transmission electron microscopy and x-ray, while their mean diameter was 132 nm, as measured by photon correlation spectroscopy. The presence of the liquid caprylic/capric triglyceride within nanostructured lipid carriers allowed to encapsulate retinyl palmitate more efficiently with respect to solid lipid nanoparticles. In order to obtain a gel to be applied on the wounds, hyaluronic acid has been directly added into the aqueous dispersion of nanostructured lipid carriers containing retinyl palmitate. The nanoparticulate gel “wound healing” effect has been evaluated in scratch wound assay in keratinocytes. The wounded areas of treated and control cells displayed significant differences during the first 24 h post-wounding, indicating a synergic effect of retinyl palmitate and hyaluronic acid
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Progesterone lipid nanoparticles: Scaling up and in vivo human study
'Elsevier BV', 2017Co-Authors: Esposito Elisabetta, Mariani Paolo, Sguizzato Maddalena, Drechsler M., Carducci F., Nastruzzi Claudio, Cortesi RitaAbstract:This investigation describes a scaling up study aimed at producing progesterone containing nanoparticles in a pilot scale. Particularly hot homogenization techniques based on ultrasound homogenization or high pressure homogenization have been employed to produce lipid nanoparticles constituted of Tristearin or Tristearin in association with caprylic-capric triglyceride. It was found that the high pressure homogenization method enabled to obtain nanoparticles without agglomerates and smaller mean diameters with respect to ultrasound homogenization method. X-ray characterization suggested a lamellar structural organization of both type of nanoparticles. Progesterone encapsulation efficiency was almost 100% in the case of high pressure homogenization method. Shelf life study indicated a double fold stability of progesterone when encapsulated in nanoparticles produced by the high pressure homogenization method. Dialysis and Franz cell methods were performed to mimic subcutaneous and skin administration. Nanoparticles constituted of Tristearin in mixture with caprylic/capric triglyceride display a slower release of progesterone with respect to nanoparticles constituted of pure Tristearin. Franz cell evidenced a higher progesterone skin uptake in the case of pure Tristearin nanoparticles. A human in vivo study, based on tape stripping, was conducted to investigate the performance of nanoparticles as progesterone skin delivery systems. Tape stripping results indicated a decrease of progesterone concentration in stratum corneum within six hours, suggesting an interaction between nanoparticle material and skin lipids
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Data on scaling up and in vivo human study of progesterone lipid nanoparticles
'Elsevier BV', 2017Co-Authors: Esposito Elisabetta, Drechsler Markus, Mariani Paolo, Sguizzato Maddalena, Nastruzzi Claudio, Carducci Federica, Cortesi RitaAbstract:Progesterone containing nanoparticles constituted of Tristearin or Tristearin in association with caprylic-capric triglyceride were produced in a lab scale by ultrasound homogenization and in a pilot scale by high pressure homogenization. A study was conducted to select the pressure to be used in order to obtain homogenously sized nanoparticles. The Dialysis method was performed to mimic subcutaneous administration of lipid nanoparticles. Mathematical analyses of the results were conducted to understand and compare the drug release mechanisms. A human in vivo study, based on tape stripping, was conducted to investigate the performance of nanoparticles as progesterone skin delivery systems. Tape stripped stratum corneum was analyzed by light microscopy
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Nanoformulations for dimethyl fumarate: Physicochemical characterization and in vitro/in vivo behavior
'Elsevier BV', 2017Co-Authors: Esposito Elisabetta, Drechsler Markus, Cortesi Rita, Fan Jie, Fu, Bingmei M, Calderan Laura, Mannucci Silvia, Boschi Federico, Nastruzzi ClaudioAbstract:Dimethyl fumarate has been demonstrated useful in relapsing remitting multiple sclerosis treatment (Tecfidera\uae). Nevertheless, since Tecfidera\uae capsules induce flushing, gastro-intestinal events and other more serious drawbacks, in this investigation a nanoparticle based system to be administered by an alternative way is proposed. In particular this study describes the preparation and characterization of dimethyl fumarate-containing solid lipid nanoparticles (SLN). Namely SLN based on Tristearin, Tristearin SLN treated with polysorbate 80 and cationic SLN constituted of Tristearin in mixture with dimethyldioctadecylammonium chloride were investigated. The effect of the presence of dimethyl fumarate, functionalization by polysorbate 80 and dimethyldioctadecylammonium chloride was studied on morphology and dimensional distribution of SLN, by photon correlation spectroscopy and cryogenic transmission electron microscopy. Dimethyl fumarate release from SLN, studied by Franz cell, evidenced a Fickian dissolutive type kinetic in the case of SLN treated by polysorbate 80. Moreover fluorescent SLN were produced and characterized in order to investigate their in vitro permeability and in vivo biodistribution in mice. An in vitro study of fluorescent SLN permeability performed through a model of mouse brain microvascular endothelial cells, indicated that cationic SLN displayed higher permeability values with respect to neutral SLN and SLN treated by polysorbate 80. Biodistribution of polysorbate 80 treated SLN was studied by fluorescent imaging after intraperitoneal or intranasal administration in mice. The in vivo images indicate that polysorbate 80 treated SLN were able to reach the brain, even if they prevalently accumulated in liver and spleen, especially by intraperitoneal route
