The efficacy of potassium sorbate (K-sorb) as an antifungal, alone or combined with thiabendazole... more The efficacy of potassium sorbate (K-sorb) as an antifungal, alone or combined with thiabendazole (TBZ), and hot water at 53 C, was studied against blue mold on apples. Results demonstrated the fungistatic effect of K-sorb: 2000 mg L À1 significantly reduced Penicillium expansum growth, and a 24 h delay in fungi development was observed in the amended liquid culture. K-sorb at 1% significantly diminished decay incidence, especially when applied at 53 C. The performance of TBZ was not improved by the coapplication of K-sorb. Treatments efficacy was related to K-sorb distribution on fruit surface. ESEM and X-ray qualitative spectra analyses revealed an irregular distribution of K-sorb over the fruit surface and areas with salt accumulation. K-sorb residues remained quite unchanged until 3 d of storage then they declined progressively. Their degradation was influenced by water temperature: it was faster on fruit treated at 53 C. An inverse relation between P. expansum growth and K-sorb concentration was observed. After 72 h of incubation, P. expansum depleted 99% of K-sorb from liquid culture media. The low efficacy of K-sorb treatments against blue mold decay on apple fruit may be ascribed to the low persistence of K-sorb residues, to the irregular spatial distribution of the salt on the fruit surface, and the ability of P. expansum to degrade the salt.
... Topical 8-Methoxypsoralen Delivery Francesco Lai, Chiara Sinico, Donatella Valenti, Maria Let... more ... Topical 8-Methoxypsoralen Delivery Francesco Lai, Chiara Sinico, Donatella Valenti, Maria Letizia Manca, and Anna Maria Fadda∗ Dipartimento Farmaco Chimico Tecnologico, Università degli Studi di Cagliari, Via Ospedale 72, 09124 Cagliari, Italy ...
In this work, we compared the chemical stability of tretinoin (TRA) in methanol and in vesicular ... more In this work, we compared the chemical stability of tretinoin (TRA) in methanol and in vesicular suspensions exposed both to UV and artificial daylight conditions with the aim of evaluating the potential of niosomes as topical carriers capable of improving the stability ...
The stability of pyrethrins in formulations containing different combinations of antioxidant and ... more The stability of pyrethrins in formulations containing different combinations of antioxidant and sunscreen was studied with model system experiments. The mechanism of disappearance of pyrethrins was mainly due to photodegradation, but some loss by codistillation can occur. In formulations, the presence of mineral oil and emulsifiers determined a decrease on codistillation losses. The presence of the antioxidant in formulations even at high concentrations did not affect pyrethrin photodegradation rates, but rising amounts of sunscreen determined a progressive increase on half-life times of pyrethrins. A combination of sunscreen and antioxidant at low concentrations provided an effective protection against sunlight similar to that obtained by high amounts of sunscreen alone.
Journal of Environmental Science and Health, Part B, 2009
The degradation of the main azadirachtoids on tomatoes was studied after greenhouse treatment. Th... more The degradation of the main azadirachtoids on tomatoes was studied after greenhouse treatment. These experiments were carried out at 1 and 5× the concentration recommended by the manufacturer. In all experiments the deposition of azadirachtin A (AZA-A) was below the maximum residue level (MRL). Even if at the highest dose, AZA-A half-life time calculated as pseudo first order kinetic was 1.2 days in agreement with the recommended preharvest interval (PHI) of 3 days. Experiments with a model system showed that sunlight photodegradation is the main factor influencing the rate of disappearance of AZA-A after greenhouse treatment while tomato epicuticular waxes doubled the photodegradation rate of AZA-A in a commercial formulation.
Persistence of azadirachtins (A+B) and of the other limonoids (nimbin, salannin, deacetylnimbin, ... more Persistence of azadirachtins (A+B) and of the other limonoids (nimbin, salannin, deacetylnimbin, and deacetylsalannin) on peach leaves and fruits was studied using a commercial formulation (form. C) compared with an experimental formulation (form. E) prepared with coformulations allowed in organic culture. Field experiments were carried out using three concentrations: 1x, 5x, and 10x the dose recommended by the manufacturer. The EU maximum residue level (MRL) in fruits and vegetables for azadirachtin A is 1 mg/kg with a preharvest interval (PHI) of 3 days. At the recommended dose, azadirachtin A residue on fruits was not detectable (LOQ < 0.8 microg/kg). After field treatment at the 5x concentration, azadirachtoids were found with 22% in the epicuticular waxes and the remaining 78% on the fruit surface. No residues were found in the fruit pulp. The experimental formulation (E) produced lower residues on leaves and fruit compared with the commercial formulation (C), although formulation E showed greater stability. This is probably due to the amount of the active ingredients that diffuse into the epicuticular wax layer thus enhancing photostability of azadirachtoids.
Journal of Environmental Science and Health Part B-pesticides Food Contaminants and Agricultural Wastes, 2009
The degradation of the main azadirachtoids on tomatoes was studied after greenhouse treatment. Th... more The degradation of the main azadirachtoids on tomatoes was studied after greenhouse treatment. These experiments were carried out at 1 and 5× the concentration recommended by the manufacturer. In all experiments the deposition of azadirachtin A (AZA-A) was below the maximum residue level (MRL). Even if at the highest dose, AZA-A half-life time calculated as pseudo first order kinetic was 1.2 days in agreement with the recommended preharvest interval (PHI) of 3 days. Experiments with a model system showed that sunlight photodegradation is the main factor influencing the rate of disappearance of AZA-A after greenhouse treatment while tomato epicuticular waxes doubled the photodegradation rate of AZA-A in a commercial formulation.
The stability of pyrethrins in formulations containing different combinations of antioxidant and ... more The stability of pyrethrins in formulations containing different combinations of antioxidant and sunscreen was studied with model system experiments. The mechanism of disappearance of pyrethrins was mainly due to photodegradation, but some loss by codistillation can occur. In formulations, the presence of mineral oil and emulsifiers determined a decrease on codistillation losses. The presence of the antioxidant in formulations even at high concentrations did not affect pyrethrin photodegradation rates, but rising amounts of sunscreen determined a progressive increase on half-life times of pyrethrins. A combination of sunscreen and antioxidant at low concentrations provided an effective protection against sunlight similar to that obtained by high amounts of sunscreen alone.
Azadirachtoids were determined by liquid chromatography/mass spectrometry (LC/MS) in five methano... more Azadirachtoids were determined by liquid chromatography/mass spectrometry (LC/MS) in five methanolic seed extracts of the neem tree and in a commercial formulation. On average, seed extracts contain azadirachtin A (10.9%), azadirachtin B (3.5%), nimbin (10.4%), and large quantities of salannin (19.0%). The composition of the commercial formulations may present different azadirachtoids contents depending on the natural extracts used in the preparation. Because these compounds may also show insecticide activity, the efficacy on field of these formulations may be very different. Photodegradation of pure azadirachtoids was also studied. Azadirachtins and related compounds are very sensitive to sunlight, degrading rapidly, with half-lives of the order of 11.3 h for azadirachtin A and 5.5 h for azadirachtin B and few minutes for the other limonoids compounds studied. The residues of azadirachtins and the main constituents, e.g., salannin, nimbin, deacetylnimbin, and deacetylsalannin, of the neem seed extract were determined on strawberries after field treatment using two different formulations. This residue study on strawberry was carried out to assess not only the azadirachtin content but also the main azadirachtoids contents. Three days after field application at five times the dose recommended by the manufacturer, residues of azadirachtin A and B were 0.03 and 0.01 mg/kg, respectively, while residues of salannin (LOQ 0.01 mg/kg) and nimbin (LOQ 0.5 mg/kg) were not detectable.
The aim of this study was to formulate a new delivery system for ecological pesticides by the inc... more The aim of this study was to formulate a new delivery system for ecological pesticides by the incorporation of Artemisia arborescens L essential oil into solid lipid nanoparticles (SLN). Two different SLN formulations were prepared following the high-pressure homogenization technique using Compritol 888 ATO as lipid and Poloxamer 188 or Miranol Ultra C32 as surfactants. The SLN formulation particle size was determined using Photon correlation spectroscopy (PCS) and laser diffraction analysis (LD). The change of particle charge was studied by zeta potential (ZP) measurements, while the melting and recrystallization behavior was studied using differential scanning calorimetry (DSC). In vitro release studies of the essential oil were performed at 35°C. Data showed a high physical stability for both formulations at various storage temperatures during 2 months of investigation. In particular, average diameter of Artemisia arborescens L essential oil-loaded SLN did not vary during storage and increased slightly after spraying the SLN dispersions. In vitro release experiments showed that SLN were able to reduce the rapid evaporation of essential oil if compared with the reference emulsions. Therefore, obtained results showed that the studied SLN formulations are suitable carriers in agriculture.
The purpose of this work was to prepare sodium alginate beads as a device for the controlled rele... more The purpose of this work was to prepare sodium alginate beads as a device for the controlled release of essential oil for oral administration as an antiviral agent. Different formulations were prepared with sodium alginate as a natural polymer and calcium chloride or glutaraldehyde as a cross-linking agent. Loading capacities of between 86% and 100% were obtained in freshly prepared beads by changing exposure time to the cross-linking agent. Drying of the calcium alginate beads caused only a slight decrease in the loading efficiency. The surface morphology of the different bead formulations were studied using scanning electron microscopy (SEM). Stability studies over a 3-month period showed that glutaraldehyde reacted with some components ofArtemisia arborescens L essential oil, changing its composition. Calcium alginate beads showed an in vitro controlled release of the essential oil for the investigated 24 hours, while the use of glutaraldehyde as a cross-linking agent was found not appropriate because of the interactions with azulene derivatives and the low degree of matrix cross-linkage.
The aim of this paper was to ascertain the role of drug crystalline form and preparation procedur... more The aim of this paper was to ascertain the role of drug crystalline form and preparation procedure in nanosuspension formulations in order to optimise dissolution properties of lipophilic, poorly soluble drugs, thus improving their oral bioavailability. The non-steroidal anti-inflammatory drug diclofenac acid (DCF), which is known to exist in different crystal forms, was chosen as a model drug. To this purpose, the influence of homogenization technique was studied by preparing several nanosuspensions with two different crystalline forms of the drug (DCF1 and DCF2). Particle size and size distribution, morphology, microstructure, and thermal behaviour of the different formulations were studied by photon correlation spectroscopy (PCS), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and differential scanning calorimetry (DSC). Solubility studies of the bulk drug crystalline forms and dissolution experiments of nanosuspensions in comparison with different controls (bulk drug, physical mixtures, coarse suspensions) were carried out in different media: distilled water, simulated gastric fluid (SGF) and simulated intestinal fluid (SIF).
The influence of liposome composition, size, lamellarity and charge on the (trans)dermal delivery... more The influence of liposome composition, size, lamellarity and charge on the (trans)dermal delivery of tretinoin (TRA) was studied. For this purpose we studied both multilamellar (MLV) or unilamellar (UV) liposomes. Positively or negatively charged liposomes were obtained using either hydrogenated (PhospholiponR90H) or non-hydrogenated soy phosphatidylcholine (PhospholiponR90) and cholesterol, in combination with stearylamine or dicetylphosphate. Liposomal formulations were characterized by transmission electron microscopy (TEM) and optical and light polarized microscopy for vesicle formation and morphology, and by dynamic laser light scattering for size distribution. In order to obtain more information about the stability and the thermodynamic activity of the liposomal tretinoin, TRA diffusion through a lipophilic membrane was investigated. The effect of the vesicular incorporation of tretinoin on its accumulation into the newborn pig skin was also studied. The experiments were performed in vitro using Franz cells in occlusive conditions and were compared to three different controls. The tretinoin amount delivered through and accumulated in the several skin layers was detected by HPLC. Furthermore, TEM in combination with osmium tetroxide was used to visualize the skin structure after the liposomal administration. Overall obtained results showed that liposomes may be an interesting carrier for tretinoin in skin disease treatment, when appropriate formulations are used. In particular, negatively charged liposomes strongly improved newborn pig skin hydration and TRA retention, though no evidence of intact vesicle penetration was found. D
Questa riproduzione viene fornita a scopo di studio per un uso strettamente personale legge 833 d... more Questa riproduzione viene fornita a scopo di studio per un uso strettamente personale legge 833 del 22-04-1941 e successive modifiche ed integrazioni Distretto Biomedico Scientifico -Sezione, Biblioteca Farmaco Chimico Questa riproduzione viene fornita a scopo di studio per un uso strettamente personale legge 833 del 22-04-1941 e successive modifiche ed integrazioni Distretto Biomedico Scientifico -Sezione, Biblioteca Farmaco Chimico Questa riproduzione viene fornita a scopo di studio per un uso strettamente personale legge 833 del 22-04-1941 e successive modifiche ed integrazioni Distretto Biomedico Scientifico -Sezione, Biblioteca Farmaco Chimico
European Journal of Pharmaceutics and Biopharmaceutics, 2005
The effect of liposomal inclusion on the in vitro antiherpetic activity of Artemisia arborescens ... more The effect of liposomal inclusion on the in vitro antiherpetic activity of Artemisia arborescens L. essential oil was investigated. In order to study the influence of vesicle structure and composition on the antiviral activity of the vesicle-incorporated oil, multilamellar (MLV) and unilamellar (SUV) positively charged liposomes were prepared by the film method and sonication. Liposomes were obtained from hydrogenated (P90H) and non-hydrogenated (P90) soy phosphatidylcholine. Formulations were examined for their stability for over one year, monitoring the oil leakage from vesicles and the average size distribution. The antiviral activity was studied against Herpes simplex virus type 1 (HSV-1) by a quantitative tetrazolium-based colorimetric method. Results showed that Artemisia essential oil can be incorporated in good amounts in the prepared vesicular dispersions. Stability studies pointed out that vesicle dispersions were very stable for at least six months and neither oil leakage nor vesicle size alteration occurred during this period. After one year of storage oil retention was still good, but vesicle fusion was present. Antiviral assays demonstrated that the liposomal incorporation of A. arborescens essential oil enhanced its in vitro antiherpetic activity especially when vesicles were made with P90H. On the contrary, no significant difference in antiviral activity was observed between the free and SUV-incorporated oil. q (A.M. Fadda).
The efficacy of potassium sorbate (K-sorb) as an antifungal, alone or combined with thiabendazole... more The efficacy of potassium sorbate (K-sorb) as an antifungal, alone or combined with thiabendazole (TBZ), and hot water at 53 C, was studied against blue mold on apples. Results demonstrated the fungistatic effect of K-sorb: 2000 mg L À1 significantly reduced Penicillium expansum growth, and a 24 h delay in fungi development was observed in the amended liquid culture. K-sorb at 1% significantly diminished decay incidence, especially when applied at 53 C. The performance of TBZ was not improved by the coapplication of K-sorb. Treatments efficacy was related to K-sorb distribution on fruit surface. ESEM and X-ray qualitative spectra analyses revealed an irregular distribution of K-sorb over the fruit surface and areas with salt accumulation. K-sorb residues remained quite unchanged until 3 d of storage then they declined progressively. Their degradation was influenced by water temperature: it was faster on fruit treated at 53 C. An inverse relation between P. expansum growth and K-sorb concentration was observed. After 72 h of incubation, P. expansum depleted 99% of K-sorb from liquid culture media. The low efficacy of K-sorb treatments against blue mold decay on apple fruit may be ascribed to the low persistence of K-sorb residues, to the irregular spatial distribution of the salt on the fruit surface, and the ability of P. expansum to degrade the salt.
... Topical 8-Methoxypsoralen Delivery Francesco Lai, Chiara Sinico, Donatella Valenti, Maria Let... more ... Topical 8-Methoxypsoralen Delivery Francesco Lai, Chiara Sinico, Donatella Valenti, Maria Letizia Manca, and Anna Maria Fadda∗ Dipartimento Farmaco Chimico Tecnologico, Università degli Studi di Cagliari, Via Ospedale 72, 09124 Cagliari, Italy ...
In this work, we compared the chemical stability of tretinoin (TRA) in methanol and in vesicular ... more In this work, we compared the chemical stability of tretinoin (TRA) in methanol and in vesicular suspensions exposed both to UV and artificial daylight conditions with the aim of evaluating the potential of niosomes as topical carriers capable of improving the stability ...
The stability of pyrethrins in formulations containing different combinations of antioxidant and ... more The stability of pyrethrins in formulations containing different combinations of antioxidant and sunscreen was studied with model system experiments. The mechanism of disappearance of pyrethrins was mainly due to photodegradation, but some loss by codistillation can occur. In formulations, the presence of mineral oil and emulsifiers determined a decrease on codistillation losses. The presence of the antioxidant in formulations even at high concentrations did not affect pyrethrin photodegradation rates, but rising amounts of sunscreen determined a progressive increase on half-life times of pyrethrins. A combination of sunscreen and antioxidant at low concentrations provided an effective protection against sunlight similar to that obtained by high amounts of sunscreen alone.
Journal of Environmental Science and Health, Part B, 2009
The degradation of the main azadirachtoids on tomatoes was studied after greenhouse treatment. Th... more The degradation of the main azadirachtoids on tomatoes was studied after greenhouse treatment. These experiments were carried out at 1 and 5× the concentration recommended by the manufacturer. In all experiments the deposition of azadirachtin A (AZA-A) was below the maximum residue level (MRL). Even if at the highest dose, AZA-A half-life time calculated as pseudo first order kinetic was 1.2 days in agreement with the recommended preharvest interval (PHI) of 3 days. Experiments with a model system showed that sunlight photodegradation is the main factor influencing the rate of disappearance of AZA-A after greenhouse treatment while tomato epicuticular waxes doubled the photodegradation rate of AZA-A in a commercial formulation.
Persistence of azadirachtins (A+B) and of the other limonoids (nimbin, salannin, deacetylnimbin, ... more Persistence of azadirachtins (A+B) and of the other limonoids (nimbin, salannin, deacetylnimbin, and deacetylsalannin) on peach leaves and fruits was studied using a commercial formulation (form. C) compared with an experimental formulation (form. E) prepared with coformulations allowed in organic culture. Field experiments were carried out using three concentrations: 1x, 5x, and 10x the dose recommended by the manufacturer. The EU maximum residue level (MRL) in fruits and vegetables for azadirachtin A is 1 mg/kg with a preharvest interval (PHI) of 3 days. At the recommended dose, azadirachtin A residue on fruits was not detectable (LOQ < 0.8 microg/kg). After field treatment at the 5x concentration, azadirachtoids were found with 22% in the epicuticular waxes and the remaining 78% on the fruit surface. No residues were found in the fruit pulp. The experimental formulation (E) produced lower residues on leaves and fruit compared with the commercial formulation (C), although formulation E showed greater stability. This is probably due to the amount of the active ingredients that diffuse into the epicuticular wax layer thus enhancing photostability of azadirachtoids.
Journal of Environmental Science and Health Part B-pesticides Food Contaminants and Agricultural Wastes, 2009
The degradation of the main azadirachtoids on tomatoes was studied after greenhouse treatment. Th... more The degradation of the main azadirachtoids on tomatoes was studied after greenhouse treatment. These experiments were carried out at 1 and 5× the concentration recommended by the manufacturer. In all experiments the deposition of azadirachtin A (AZA-A) was below the maximum residue level (MRL). Even if at the highest dose, AZA-A half-life time calculated as pseudo first order kinetic was 1.2 days in agreement with the recommended preharvest interval (PHI) of 3 days. Experiments with a model system showed that sunlight photodegradation is the main factor influencing the rate of disappearance of AZA-A after greenhouse treatment while tomato epicuticular waxes doubled the photodegradation rate of AZA-A in a commercial formulation.
The stability of pyrethrins in formulations containing different combinations of antioxidant and ... more The stability of pyrethrins in formulations containing different combinations of antioxidant and sunscreen was studied with model system experiments. The mechanism of disappearance of pyrethrins was mainly due to photodegradation, but some loss by codistillation can occur. In formulations, the presence of mineral oil and emulsifiers determined a decrease on codistillation losses. The presence of the antioxidant in formulations even at high concentrations did not affect pyrethrin photodegradation rates, but rising amounts of sunscreen determined a progressive increase on half-life times of pyrethrins. A combination of sunscreen and antioxidant at low concentrations provided an effective protection against sunlight similar to that obtained by high amounts of sunscreen alone.
Azadirachtoids were determined by liquid chromatography/mass spectrometry (LC/MS) in five methano... more Azadirachtoids were determined by liquid chromatography/mass spectrometry (LC/MS) in five methanolic seed extracts of the neem tree and in a commercial formulation. On average, seed extracts contain azadirachtin A (10.9%), azadirachtin B (3.5%), nimbin (10.4%), and large quantities of salannin (19.0%). The composition of the commercial formulations may present different azadirachtoids contents depending on the natural extracts used in the preparation. Because these compounds may also show insecticide activity, the efficacy on field of these formulations may be very different. Photodegradation of pure azadirachtoids was also studied. Azadirachtins and related compounds are very sensitive to sunlight, degrading rapidly, with half-lives of the order of 11.3 h for azadirachtin A and 5.5 h for azadirachtin B and few minutes for the other limonoids compounds studied. The residues of azadirachtins and the main constituents, e.g., salannin, nimbin, deacetylnimbin, and deacetylsalannin, of the neem seed extract were determined on strawberries after field treatment using two different formulations. This residue study on strawberry was carried out to assess not only the azadirachtin content but also the main azadirachtoids contents. Three days after field application at five times the dose recommended by the manufacturer, residues of azadirachtin A and B were 0.03 and 0.01 mg/kg, respectively, while residues of salannin (LOQ 0.01 mg/kg) and nimbin (LOQ 0.5 mg/kg) were not detectable.
The aim of this study was to formulate a new delivery system for ecological pesticides by the inc... more The aim of this study was to formulate a new delivery system for ecological pesticides by the incorporation of Artemisia arborescens L essential oil into solid lipid nanoparticles (SLN). Two different SLN formulations were prepared following the high-pressure homogenization technique using Compritol 888 ATO as lipid and Poloxamer 188 or Miranol Ultra C32 as surfactants. The SLN formulation particle size was determined using Photon correlation spectroscopy (PCS) and laser diffraction analysis (LD). The change of particle charge was studied by zeta potential (ZP) measurements, while the melting and recrystallization behavior was studied using differential scanning calorimetry (DSC). In vitro release studies of the essential oil were performed at 35°C. Data showed a high physical stability for both formulations at various storage temperatures during 2 months of investigation. In particular, average diameter of Artemisia arborescens L essential oil-loaded SLN did not vary during storage and increased slightly after spraying the SLN dispersions. In vitro release experiments showed that SLN were able to reduce the rapid evaporation of essential oil if compared with the reference emulsions. Therefore, obtained results showed that the studied SLN formulations are suitable carriers in agriculture.
The purpose of this work was to prepare sodium alginate beads as a device for the controlled rele... more The purpose of this work was to prepare sodium alginate beads as a device for the controlled release of essential oil for oral administration as an antiviral agent. Different formulations were prepared with sodium alginate as a natural polymer and calcium chloride or glutaraldehyde as a cross-linking agent. Loading capacities of between 86% and 100% were obtained in freshly prepared beads by changing exposure time to the cross-linking agent. Drying of the calcium alginate beads caused only a slight decrease in the loading efficiency. The surface morphology of the different bead formulations were studied using scanning electron microscopy (SEM). Stability studies over a 3-month period showed that glutaraldehyde reacted with some components ofArtemisia arborescens L essential oil, changing its composition. Calcium alginate beads showed an in vitro controlled release of the essential oil for the investigated 24 hours, while the use of glutaraldehyde as a cross-linking agent was found not appropriate because of the interactions with azulene derivatives and the low degree of matrix cross-linkage.
The aim of this paper was to ascertain the role of drug crystalline form and preparation procedur... more The aim of this paper was to ascertain the role of drug crystalline form and preparation procedure in nanosuspension formulations in order to optimise dissolution properties of lipophilic, poorly soluble drugs, thus improving their oral bioavailability. The non-steroidal anti-inflammatory drug diclofenac acid (DCF), which is known to exist in different crystal forms, was chosen as a model drug. To this purpose, the influence of homogenization technique was studied by preparing several nanosuspensions with two different crystalline forms of the drug (DCF1 and DCF2). Particle size and size distribution, morphology, microstructure, and thermal behaviour of the different formulations were studied by photon correlation spectroscopy (PCS), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and differential scanning calorimetry (DSC). Solubility studies of the bulk drug crystalline forms and dissolution experiments of nanosuspensions in comparison with different controls (bulk drug, physical mixtures, coarse suspensions) were carried out in different media: distilled water, simulated gastric fluid (SGF) and simulated intestinal fluid (SIF).
The influence of liposome composition, size, lamellarity and charge on the (trans)dermal delivery... more The influence of liposome composition, size, lamellarity and charge on the (trans)dermal delivery of tretinoin (TRA) was studied. For this purpose we studied both multilamellar (MLV) or unilamellar (UV) liposomes. Positively or negatively charged liposomes were obtained using either hydrogenated (PhospholiponR90H) or non-hydrogenated soy phosphatidylcholine (PhospholiponR90) and cholesterol, in combination with stearylamine or dicetylphosphate. Liposomal formulations were characterized by transmission electron microscopy (TEM) and optical and light polarized microscopy for vesicle formation and morphology, and by dynamic laser light scattering for size distribution. In order to obtain more information about the stability and the thermodynamic activity of the liposomal tretinoin, TRA diffusion through a lipophilic membrane was investigated. The effect of the vesicular incorporation of tretinoin on its accumulation into the newborn pig skin was also studied. The experiments were performed in vitro using Franz cells in occlusive conditions and were compared to three different controls. The tretinoin amount delivered through and accumulated in the several skin layers was detected by HPLC. Furthermore, TEM in combination with osmium tetroxide was used to visualize the skin structure after the liposomal administration. Overall obtained results showed that liposomes may be an interesting carrier for tretinoin in skin disease treatment, when appropriate formulations are used. In particular, negatively charged liposomes strongly improved newborn pig skin hydration and TRA retention, though no evidence of intact vesicle penetration was found. D
Questa riproduzione viene fornita a scopo di studio per un uso strettamente personale legge 833 d... more Questa riproduzione viene fornita a scopo di studio per un uso strettamente personale legge 833 del 22-04-1941 e successive modifiche ed integrazioni Distretto Biomedico Scientifico -Sezione, Biblioteca Farmaco Chimico Questa riproduzione viene fornita a scopo di studio per un uso strettamente personale legge 833 del 22-04-1941 e successive modifiche ed integrazioni Distretto Biomedico Scientifico -Sezione, Biblioteca Farmaco Chimico Questa riproduzione viene fornita a scopo di studio per un uso strettamente personale legge 833 del 22-04-1941 e successive modifiche ed integrazioni Distretto Biomedico Scientifico -Sezione, Biblioteca Farmaco Chimico
European Journal of Pharmaceutics and Biopharmaceutics, 2005
The effect of liposomal inclusion on the in vitro antiherpetic activity of Artemisia arborescens ... more The effect of liposomal inclusion on the in vitro antiherpetic activity of Artemisia arborescens L. essential oil was investigated. In order to study the influence of vesicle structure and composition on the antiviral activity of the vesicle-incorporated oil, multilamellar (MLV) and unilamellar (SUV) positively charged liposomes were prepared by the film method and sonication. Liposomes were obtained from hydrogenated (P90H) and non-hydrogenated (P90) soy phosphatidylcholine. Formulations were examined for their stability for over one year, monitoring the oil leakage from vesicles and the average size distribution. The antiviral activity was studied against Herpes simplex virus type 1 (HSV-1) by a quantitative tetrazolium-based colorimetric method. Results showed that Artemisia essential oil can be incorporated in good amounts in the prepared vesicular dispersions. Stability studies pointed out that vesicle dispersions were very stable for at least six months and neither oil leakage nor vesicle size alteration occurred during this period. After one year of storage oil retention was still good, but vesicle fusion was present. Antiviral assays demonstrated that the liposomal incorporation of A. arborescens essential oil enhanced its in vitro antiherpetic activity especially when vesicles were made with P90H. On the contrary, no significant difference in antiviral activity was observed between the free and SUV-incorporated oil. q (A.M. Fadda).
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