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1.
Exogenously supplied alpha-lipoic acid (LA) has proven to be effective as an antioxidant. In an effort to develop a water-soluble
formulation for topical administration, LA was formulated in the form of solid lipid nanoparticles (SLN), nanostructure lipid
carriers (NLC), and nanoemulsion (NE) and characterized in terms of physical and biological properties. Mean particle size
of 113, 110, and 121 nm were obtained for NE, NLC, and SLN, respectively, with narrow size distribution. Zeta potential was
approximately in the range of −25 to −40 mV. Disc and spherical structures of nanoparticles were observed by cryo-scanning
electron microscopy. Entrapment efficiency of LA in three formulations was found to be more than 70%. After 120 days of storage
at 25°C, physical stability of all formulations remained unchanged whereas the entrapment efficiency of SLN and NLC could
be maintained, suggesting relative long-term stability. Prolonged release of LA formulation following the Higuchi model was
found where a faster release was observed from NE compared with that of SLN and NLC. More than 80% of cell survivals were
found up to 1 μM of LA concentrations. Antioxidant activity analysis demonstrated that all LA-loaded formulations expressed
antioxidant activity at a similar magnitude as pure LA. These results suggest that chosen compositions of lipid nanoparticles
play an important role on drug loading, stability, and biological activity of nanoparticles. Both SLN and NLC demonstrated
their potential as alternative carriers for aqueous topical administration of LA. 相似文献
2.
Lovastatin, a hypocholesterolemic agent, is a secondary metabolite produced by filamentous microorganism Aspergillus terreus in submerged batch cultivation. Lovastatin production by pellets and immobilized siran cells was investigated in an airlift
reactor. The process was carried out by submerged cultivation in continuous mode with the objective of increasing productivity
using pellet and siran supported growth of A terreus. The continuous mode of fermentation improves the rate of lovastatin production. The effect of dilution rate and aeration
rate were studied in continuous culture. The optimum dilution rate for pellet was 0.02 h −1 and for siran carrier was 0.025 h −1. Lovastatin productivity using immobilized siran carrier (0.0255 g/L/h) was found to be greater than pellets (0.022 g/L/h).
The productivity by both modes of fermentation was found higher than that of batch process which suggests that continuous
cultivation is a promising strategy for lovastatin production. 相似文献
3.
In order to apply emulsion-based delivery systems to food, they have to be stable in a protein rich environment. This study investigated the stability of solid lipid nanoparticles (SLN) during heat treatment in the presence or absence of β-lactoglobulin (BLG). SLN were stabilized either by Tween 20 (TS) or by the protein itself (BS) and were enriched to a total BLG content of 56 mg/mL. The sizes of both types of SLN were initially in the range of 170 nm. The amount of free protein was determined before and after enrichment with BLG. As revealed by particle size and zeta potential measurements, a protein layer of BLG (hard corona) adsorbed on BS but not on TS. By contrast, a soft corona was formed around both BS and TS. SLN were heat treated in the presence and absence of protein and were characterized regarding size and zeta potential. According to transmission electron microscopy imaging, heating did not affect the shape of TS and BS: TS were platelets, whereas BS exhibited a spherical or platelet like shape. Upon heat treatment, the particle size of TS increased to about 3.5 fold of the initial size (to appr. 600 nm) in the presence and in the absence of excess protein. The cloudy protein layer (soft corona) around TS could thus not prevent coalescence of TS. By contrast, BS did not experience a change in particle size. Hence, by the choice of emulsifier, an encapsulation system that is stable against heat treatment can be obtained. 相似文献
4.
Solid lipid nanoparticles (SLNs) of duloxetine hydrochloride (DLX) were prepared to circumvent the problems of DLX, which
include acid labile nature, high first-pass metabolism, and high-dosing frequency. The DLX-SLNs were prepared by using two
different techniques, viz. solvent diffusion method and ultrasound dispersion method, and evaluated for particle size, zeta potential, entrapment efficiency,
physical characteristics, and chemical stability. Best results were obtained when SLNs were prepared by ultrasound dispersion
method using glyceryl mono stearate as solid lipid and DLX in ratio of 1:20 and mixture of polysorbate 80 and poloxamer 188
as surfactant in concentration of 3%. The mean particle size of formulation and entrapment efficiency was 91.7 nm and 87%,
respectively, and had excellent stability in acidic medium. Differential scanning calorimetry and X-ray diffraction data showed
complete amorphization of DLX in lipid. In vitro drug release from SLNs was observed for 48 h and was in accordance with Higuchi kinetics. In vivo antidepressant activity was evaluated in mice by forced swim test. DLX-SLNs showed significant enhancement in antidepressant
activity at 24 h when administered orally in comparison to drug solution. These results confirm the potential of SLNs in enhancing
chemical stability and improving the efficacy of DLX via oral route. The SLN dispersion was converted into solid granules
by adsorbing on colloidal silicon dioxide and characterized for particle size after redispersion, morphology, and flow properties.
Results indicated that nanoparticles were successfully adsorbed on the carrier and released SLNs when dispersed in water. 相似文献
5.
This study was designed to investigate whether a non-protein nanostructured lipid carrier (NLC) resembling high-density lipoprotein
(HDL) could deliver a hydrophobic anti-atherogenic drug, lovastatin, to foam cells. Lovastatin-loaded NLC (LT-NLC) was prepared
by a nanoprecipitation/solvent diffusion method. The LT-NLC-apoprotein (LT-NLC-apo) was prepared by incubating LT-NLC with
native HDL. The physicochemical parameters of LT-NLC were characterized in terms of particle size, zeta potential, morphology,
entrapment efficiency, and crystallization behavior. Targeting behavior and mechanism were demonstrated by the incubation
of LT-NLC-apo with a RAW 264.7 macrophage-derived foam cell model in the presence or absence of very-low-density lipoprotein
(VLDL) and lipase. The results showed that LT-NLC was solid spherical or oval in shape with an average diameter of 13.8 ± 2.2 nm,
zeta potential of −29.3 ± 0.2 mV and entrapment efficiency of 96.2 ± 1.3%. Phagocytosis studies showed that uptake of LT-NLC-apo
by macrophages was significantly lower than LT-NLC ( p < 0.01), suggesting that LT-NLC-apo could possibly escape recognition from macrophages in vivo. The uptake was increased twofold when LT-NLC-apo was incubated with transfected foam cells containing VLDL and lipase. These
results indicated that non-protein NLC resembling HDL could be a useful tool to deliver lipophilic anti-atherogenic drugs
to foam cells, and that uptake could be enhanced by the VLDL receptor pathway. 相似文献
6.
The aim of this work was to produce and characterize cetyl palmitate-based solid lipid nanoparticles (SLN) containing insulin, and to evaluate the potential of these colloidal carriers for oral administration. SLN were prepared by a modified solvent emulsification-evaporation method based on a w/o/w double emulsion. The particle size, zeta potential and association efficiency of unloaded and insulin-loaded SLN were determined and were found to be around 350 nm, negatively charged and the insulin association efficiency was over 43%. After oral administration of insulin-loaded SLN to diabetic rats, a considerable hypoglycemic effect was observed during 24 hours. These results demonstrated that SLN promote the oral absorption of insulin. 相似文献
7.
The influence of the morphology and differentiation of Aspergillus terreus hyphae on the formation of mevinolinic acid (lovastatin) and (+)-geodin was tested. Lovastatin titre was the highest (above
60 mg l −1) in the system with smaller pellets (diameter below 1.5 mm) and high biomass concentration (above 10 g l −1 in the idiophase). These biomass features were induced by the higher initial number of spores in the preculture (above 2 × 10 10 l −1). At the initial number of spores below 2 × 10 9 l −1 (+)-geodin biosynthesis was the most efficient but it was rather connected with the elevated C/N ratio than with the pellet
size. In order to quantify the hyphal differentiation in fungal pellets a special approach was used. The sectioning of the
stained pellets together with the image analysis and calculation procedures were applied. The analysis of hyphal differentiation
indicated that lovastatin formation was correlated with the fraction of the active, growing hyphae. 相似文献
8.
Tetrandrine (TET) is a poorly water-soluble bisbenzylisoquinoline alkaloid. In this study, TET solid lipid nanoparticles (SLNs) were prepared by a melt–emulsification and ultrasonication technique. Precirol ® ATO 5, glyceryl monostearate, and stearic acid were used as the lipid matrix for the SLNs, while Lipoid E80, Pluronic F68, and sodium deoxycholate were used as emulsifying and stabilizing agents. The physicochemical characteristics of the TET–SLNs were investigated when it was found that the mean particle size and zeta potential of the TET–SLNs were 134 ± 1.3 nm and −53.8 ± 1.7 mV, respectively, and the entrapment efficiency (EE) was 89.57% ± 0.39%. Differential scanning calorimetry indicated that TET was in an amorphous state in SLNs. TET–SLNs exhibited a higher release rate at a lower pH and a lower release rate at a higher pH. The release pattern of the TET–SLNs followed the Weibull model. The pharmacokinetics of TET–SLNs after intravenous administration to male rats was studied. TET–SLN resulted in a higher plasma concentration and lower clearance. The biodistribution study indicated that TET–SLN showed a high uptake in reticuloendothelial system organs. In conclusion, TET–SLNs with a small particle size, and high EE, can be produced by the method described in this study. The SLN system is a promising approach for the intravenous delivery of tetrandrine.Key words: characterization, pharmacokinetics, preparation, solid lipid nanoparticles, tetrandrine 相似文献
9.
Stable solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) formulations to enhance the dissolution rates of poorly soluble drug spironolactone (SP) were being developed. Probe ultra-sonication method was used to prepare SLNs and NLCs. All NLCs contained stearic acid (solid lipid carrier) and oleic acid (liquid lipid content), whereas, SLNs were prepared and optimised by using the solid lipid only. The particles were characterised in terms of particle size analysis, thermal behaviour, morphology, stability and in vitro release. The zeta sizer data revealed that the increase in the concentration of oleic acid in the formulations reduced the mean particle size and the zeta potential. The increase in concentration of oleic acid from 0 to 30% ( w/ w) resulted in a higher entrapment efficiency. All nanoparticles were almost spherically shaped with an average particle size of about ~170 nm. The DSC traces revealed that the presence of oleic acid in the NLC formulations resulted in a shift in the melting endotherms to a higher temperature. This could be attributed to a good long-term stability of the nanoparticles. The stability results showed that the particle size remained smaller in NLC compared to that of SLN formulations after 6 months at various temperatures. The dissolution study showed about a 5.1- to 7.2-fold increase in the release of the drug in 2 h compared to the raw drug. Comparing all nanoparticle formulations indicated that the NLC composition with a ratio of 70:30 (solid:liquid lipid) is the most suitable formulation with desired drug dissolution rates, entrapment efficiency and physical stability. 相似文献
10.
The purpose of this research was to study the effect of the lipid matrix on the entrapment of olanzapine (OL). OL-loaded solid lipid nanoparticles (SLNs) were prepared using lipids like glyceryl monostearate (GMS), Precirol ATO 5 (PRE), glyceryl tristearate (GTS), and Witepsol E85 (WE 85)--and poloxamer 407 and hydrogenated soya phosphatidylcholine as stabilizers--using a hot melt emulsification high-pressure homogenization technique, and then characterized by particle size analysis, zeta potential, differential scanning calorimetry (DSC), and powder X-ray diffraction (pXRD). Homogenization at 10,000 psi for 3 cycles resulted in the formation of SLNs with a mean particle size of approximately 190 nm for the 4 lipids investigated. The highest partition coefficient for OL between the melted lipid and pH 7.4 phosphate buffer (pH 7.4 PB) was obtained with GTS. The entrapment efficiency was in the following order: GTS SLNs > PRE SLNs > WE 85 SLNs > GMS SLNs. DSC and pXRD showed that much of the incorporated fraction of OL existed in the amorphous state after incorporation into SLNs. A sharp increase in the flocculation of the SLN dispersions was observed upon addition of 0.6 M aqueous sodium sulfate solution. Nanoparticle surface hydrophobicity was in the following order: GTS SLNs > PRE SLNs > WE 85 SLNs > GMS SLNs. A significant increase in size and zeta potential was observed for GTS SLN and WE 85 SLN dispersions stored at 40 degrees C. Release of OL from the SLNs was sustained up to 48 hours in pH 7.4 PB and obeyed Higuchi's release kinetics. 相似文献
11.
The inclusion of bioactive compounds, such as carotenoids, omega-3 fatty acids, or phytosterols, is an essential requisite
for the production of functional foods designed to improve the long-term health and well-being of consumers worldwide. To
incorporate these functional components successfully in a food system, structurally sophisticated encapsulation matrices have
to be engineered, which provide maximal physical stability, protect ingredients against chemical degradation, and allow for
precise control over the release of encapsulated components during mastication and digestion to maximize adsorption. A novel
encapsulation system initially developed in the pharmaceutical industries to deliver lipophilic bioactive compounds is solid
lipid nanoparticles (SLN). SLN consist of crystallized nanoemulsions with the dispersed phase being composed of a solid carrier
lipid–bioactive ingredient mixture. Contrary to larger colloidal solid lipid particles, specific crystal structures can be
“dialed-in” in SLN by using specific surfactant mixtures and ensuring that mean particle sizes are below 100–200 nm. Moreover,
in SLN, microphase separations of the bioactive compound from the solidifying lipid matrix can be prevented resulting in an
even dispersion of the encapsulated compound in the solid matrix thereby improving chemical and physical stability of the
bioactive. In this review article, we will briefly introduce the structure, properties, stability, and manufacturing of solid
lipid particles and discuss their emerging use in food science. 相似文献
12.
Ultrasonication was employed to prepare solid lipid nanoparticles (SLN). The model traditional Chinese medicine, tetrandrine (TET), was incorporated into SLN. The TET–loaded SLN (TET–SLN) were spherical in the photograph of transmission electron microscope (TEM). The particle size measured by laser diffraction (LD) was found to be 157.3 ± 8.2 nm. Zeta potential analyzer suggested the zeta potential of TET–SLN was −29.36 ± 3.68 mV in distilled water. The entrapment efficiency (EE%) was determined with the sephadex gel chromatogram and high-performance liquid chromatogram (HPLC), and up to 90.59% of TET was incorporated. Stability evaluation showed relatively long-term stability with only slight particle growth ( P > 0.05) after storage at room temperature for 4 weeks. Therefore, ultrasonication is demonstrated to be a simple, available and effective method to prepare high quality SLN loaded traditional Chinese medicine. 相似文献
13.
The aim of this work was to produce and characterize solid lipid nanoparticles (SLN) containing levothyroxine sodium for oral administration, and to evaluate the kinetic release of these colloidal carriers. SLNs were prepared by microemulsion method. The particle size and zeta potential of levothyroxine sodium-loaded SLNs were determined to be around 153 nm,?43 mV (negatively charged), respectively by photon correlation spectroscopy. The levothyroxine entrapment efficiency was over 98 %. Shape and surface morphology were determined by TEM and SEM. They revealed fairly spherical shape of nanoparticles.SLN formulation was stable over a period of 6 months. There were no significant changes in particle size, zeta potential and polydispersity index and entrapment efficiency, indicating that the developed SLNs were fairly stable. 相似文献
14.
The purpose of this study was to prepare miconazole nitrate (MN) loaded solid lipid nanoparticles (MN-SLN) effective for topical
delivery of miconazole nitrate. Compritol 888 ATO as lipid, propylene glycol (PG) to increase drug solubility in lipid, tween
80, and glyceryl monostearate were used as the surfactants to stabilize SLN dispersion in the SLN preparation using hot homogenization
method. SLN dispersions exhibited average size between 244 and 766 nm. All the dispersions had high entrapment efficiency
ranging from 80% to 100%. The MN-SLN dispersion which showed good stability for a period of 1 month was selected. This MN-SLN
was characterized for particle size, entrapment efficiency, and X-ray diffraction. The penetration of miconazole nitrate from
the gel formulated using selected MN-SLN dispersion as into cadaver skins was evaluated ex-vivo using franz diffusion cell. The results of differential scanning calorimetry (DSC) showed that MN was dispersed in SLN in
an amorphous state. The MN-SLN formulations could significantly increase the accumulative uptake of MN in skin over the marketed
gel and showed a significantly enhanced skin targeting effect. These results indicate that the studied MN-SLN formulation
with skin targeting may be a promising carrier for topical delivery of miconazole nitrate. 相似文献
15.
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.
Published: January 3, 2006 相似文献
16.
In this study, solid lipid nanoparticles (SLNs) were successfully prepared by an ultrasonic and high-pressure homogenization
method to improve the oral bioavailability of the poorly water-soluble drug cryptotanshinone (CTS). The particle size and
distribution, drug loading capacity, drug entrapment efficiency, zeta potential, and long-term physical stability of the SLNs
were characterized in detail. A pharmacokinetic study was conducted in rats after oral administration of CTS in different
SLNs, and it was found that the relative bioavailability of CTS in the SLNs was significantly increased compared with that
of a CTS-suspension. The incorporation of CTS in SLNs also markedly changes the metabolism behavior of CTS to tanshinone IIA.
These results indicate that CTS absorption is enhanced significantly by employing SLN formulations, and SLNs represent a powerful
approach for improving the oral absorption of poorly soluble drugs. 相似文献
17.
Colorectal cancer is a global concern, and its treatment is fraught with non-selective effects including adverse side effects requiring hospital visits and palliative care. A relatively safe drug formulated in a bioavailability enhancing and targeting delivery platform will be of significance. Metformin-loaded solid lipid nanoparticles (SLN) were designed, optimized, and characterized for particle size, zeta potential, drug entrapment, structure, crystallinity, thermal behavior, morphology, and drug release. Optimized SLN were 195.01?±?6.03 nm in size, ?17.08?±?0.95 mV with regard to surface charge, fibrous in shape, largely amorphous, and release of metformin was controlled. The optimized size, charge, and shape suggest the solid lipid nanoparticles will migrate and accumulate in the colon tumor preventing its proliferation and subsequently leading to tumor shrinkage and cell death. 相似文献
18.
The aim of this research was to advance solid lipid nanoparticle (SLN) preparation methodology by preparing glyceryl monostearate (GMS) nanoparticles using a temperature-modulated solidification process. The technique was reproducible and prepared nanoparticles without the need of organic solvents. An anticancer agent, 5-fluorouracil (5-FU), was incorporated in the SLNs. The SLNs were characterized by particle size analysis, zeta potential analysis, differential scanning calorimetry (DSC), infrared spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM), drug encapsulation efficiency, in vitro drug release, and in vitro cell viability studies. Particle size of the SLN dispersion was below 100 nm, and that of redispersed lyophilizates was ~500 nm. DSC and infrared spectroscopy suggested that the degree of crystallinity did not decrease appreciably when compared to GMS. TEM and AFM images showed well-defined spherical to oval particles. The drug encapsulation efficiency was found to be approximately 46%. In vitro drug release studies showed that 80% of the encapsulated drug was released within 1 h. In vitro cell cultures were biocompatible with blank SLNs but demonstrated concentration-dependent changes in cell viability to 5-FU-loaded SLNs. The 5-FU-loaded SLNs can potentially be utilized in an anticancer drug delivery system.KEY WORDS: atomic force microscopy, calorimetry (DSC), FTIR, particle size, solid lipid nanoparticles 相似文献
19.
The aim of this study is to investigate the potential of nanostructured lipid carriers (NLCs) in improving the oral bioavailability of a lipid lowering agent, fenofibrate (FEN). FEN-loaded NLCs (FEN-NLCs) were prepared by hot homogenization followed by an ultrasonication method using Compritol 888 ATO as a solid lipid, Labrafil M 1944CS as a liquid lipid, and soya lecithin and Tween 80 as emulsifiers. NLCs were characterized in terms of particle size and zeta pote\ntial, surface morphology, encapsulation efficiency, and physical state properties. Bioavailability studies were carried out in rats by oral administration of FEN-NLC. NLCs exhibited a spherical shape with a small particle size (84.9 ± 4.9 nm). The drug entrapment efficiency was 99% with a loading capacity of 9.93 ± 0.01% ( w/ w). Biphasic drug release manner with a burst release initially, followed by prolonged release was depicted for in vitro drug release studies. After oral administration of the FEN-NLC, drug concentration in plasma and AUC t-∞ was fourfold higher, respectively, compared to the free FEN suspension. According to these results, FEN-NLC could be a potential delivery system for improvement of loading capacity and control of drug release, thus prolonging drug action time in the body and enhancing the bioavailability.KEY WORDS: bioavailability, fenofibrate, nanoparticles, nanostructured lipid carriers 相似文献
20.
Three compounds capsaicin, curcumin and ferulic acid showing hypolipidemic activity have been tested in adult Wistar rats
fed high fat diets. Capsaicin (0.20 mg%) fed to female rats along with a 30% saturated fat diet lowered the rate of weight
gain, liver and serum triglycerides. In male rats it lowered only the liver and serum total and very low density and low density
lipoprotein triglycerides whether fed continuously for 13 or 8 weeks after interchanging the control and test diets from the
5th week onwards. Capsaicin fed to female rats in 30% mixed fat diet increased the rate of weight gain, lowered liver and
serum triglycerides, lowered adipose tissue lipoprotein lipase, elevated the hormone sensitive lipase and serum free fatty
acids. Capsaicin in 30% saturated fat diet lowered both the enzyme activities to a much lesser extent. Curcumin and ferulic
acid (both at 25 mg%) in 30% saturated fat diet tended to lower the rate of weight gain, liver total lipids and serum triglycerides.
It is of significance that a common dietary compound ‘capsaicin’ in the range of human intake triggers lipid lowering action
in rats fed high fat diets.
This paper was presented at the 55th Annual Meeting of the Society of Biological Chemists (India) held at Trivandrum during
December 15–17th, 1986. 相似文献
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