首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
A study was carried out to establish whether the draft EEC method for determining overall (global) migration of the constituents of plastics-packaging materials into a fatty-food simulant could be applied to samples of commercially available homogeneous plastics materials and whether it would be possible to use extraction with a volatile solvent under appropriate conditions of time and temperature in cases where, for some reason, the fat test cannot be used. The results obtained show that the draft EEC method can be applied without insuperable problems to most commercially available homogeneous plastics-packaging materials. Moreover, taking into account the poor reproducibility and accuracy associated in some cases with global-migration tests in olive oil, the determination of global migration into isooctane (contact time 2 hr at 40 degrees C) seems to be a suitable substitute for determinations using exposure to olive oil for 10 days at 40 degrees C.  相似文献   

2.
A new controlled-release technology that is based on electrorheological fluids (ERF) is described, and a model system is investigated. Humidified starch (duration of humidification is 30-35 minutes) was used as a filler material (approximately 20% w/w) in olive oil to make the ER system, and benzocaine (BZN) was used as the model drug. The average particle size of starch in the olive oil was approximately 200 nm. 1N HCl was used as the receiver medium and BZN was assayed by UV spectroscopy at 226 nm. A series of studies was done at five temperatures (25 degrees, 30 degrees, 35 degrees, 40 degrees, and 45 degrees C) and two external electric fields (E-fields) that were generated by applying potential drops across the diffusion apparatus of 0 V and 290 V. Control studies of BZN release from olive oil without filler showed little or no increase in release rates resulting from application of E-fields. In addition, while reversing the polarity for BZN in olive oil caused differences in release rates, these differences were too small to explain the results obtained for the ER systems. It was found that release of BZN increased significantly with the application of the electric field (approximately 53% increase at 25 degrees C). A plot of the log of the release rate vs 1/T was linear for the 0 V data but deviated from linearity for the 290 V data. The increase in release rates due to the E-field became smaller as the temperature was increased. The results are consistent with (but are not sufficient to prove) the hypothesis that the increased release rate is due to a small amount of ordering of the cornstarch filler particles in response to the applied E-field, which results in a reduction in the tortuosity of the system.  相似文献   

3.
Indirect food additive migration from polymeric food packaging materials   总被引:1,自引:0,他引:1  
Many foods contact polymeric packaging materials which contain residues of the polymerization process or additives employed to facilitate processing. The extent of migration of such materials from the packaging to foods is the focus of the present article. A major experimental program using eight polymer-migrant systems is described. Migration was measured to food-simulating liquids (FSL) and to foods. Accelerated tests were conducted with FSL under FDA guidelines conditions so as to develop correlations between such data and those found using foods under normal storage temperatures and shelf lives. In the majority of tests, the migration was found to be approximately proportional to the square root of time, to increase significantly with a rise in temperature, and to be proportional to the initial concentration of migrant in the polymer. Stirring in the FSL or food phase was generally not important except for the system involving dioctyl adipate migrating from polyvinyl chloride film. In some instances, after a period of time, migration rates became very low, and this effect was attributed to saturating the FSL or food phase with migrant. The foods comprised a variety of types, including liquid, semisolid, solid, and dry; both oily and aqueous foods were included. The physical steps involved in migration include the diffusion of the migrant from the interior of the film to the surface, where it can dissolve in the external FSL or food phase. The nature of the FSL or food is shown to be very important in that components can penetrate the polymer and dramatically increase migration rates. Consistent with the FDA guidelines in effect at the time of this study, testing was performed with five FSL (water, 3% acetic acid, 8% and 50% ethanol, and n-heptane) at 49 degrees C. Detailed comparisons were made between the migrations to foods and to FSL; following are the more relevant conclusions. (1) Three percent acetic acid showed no advantage over water as a food simulant even in those cases where the food could be considered acidic in nature. (2) Water, when used as an FSL at 49 degrees C for 5 days, overestimated migration in aqueous foods in about 75% of the cases. In some instances, however, the water phase became saturated with migrant. In other situations, this test protocol underpredicted migration--especially in those cases where there were components in the food that were able to penetrate into the polymer and enhance migration (such as orange juice).(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   

4.
The transfer of stearyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate from high- and low-density polyethylenes and polypropylene as well as that of n-butyl stearate from high-impact polystyrene into several foodstuffs and into different food simulants under normal storage conditions was determined radioanalytically. Additionally, the transfer of these additives into the food simulants under the standard conditions usually requested by the authorities was determined. From these figures ‘correction factors’ were calculated, relating the amounts of additives transferred from the plastics materials into the foodstuffs under normal conditions of storage to the transfer of these additives from the test specimens into food simulants (e.g. olive oil and HB 307) under the standard test condition of exposure at 40°C for 10 days.  相似文献   

5.
In this study, effects of high-temperature heating on antioxidant defense potential (AOP) and malondialdehyde (MDA) levels were investigated in several types of oils ingested by humans. Natural olive oil, refined olive oil, sunflower oil, and soy oil were examined. High-temperature heating to 180 degrees C significantly decreased AOP. This was accompanied by a significant increase in MDA levels. The observed changes were quantitatively greater in soy and sunflower oil compared to olive oil. The loss in antioxidant defense potential and elevation in peroxidation products may be associated with enhanced disease processes.  相似文献   

6.
Chitosan films were loaded with NE nettle (Urtica dioica L.) extract (NE) at concentrations of 0, 0.5, 1 and 1.5%w/w in the free or nanoliposomal form to obtain active and nanoactive films, respectively. The antioxidant potential of the films containing NE-loaded nanoliposomes was decreased in comparison of free NE incorporated films. Diffusion of NE to soybean oil was enough to delay the induction of the oxidation of soybean oil stored for 60 days in contact with chitosan based films. Release studies indicated that the release rate of NE in 95% ethanol simulant significantly decreased by the nanoencapsulation of NE. The diffusion coefficient (D) for chitosan films containing 1.5%w/w of free and encapsulated NE at 25?°C was 18.80 and 3.68?×?10?7 cm2 s?1, respectively. Moreover, the formation of nanoliposomes diminished the increasing effect of temperature on the release rate as when storage temperature increased from 4?°C to 40?°C.  相似文献   

7.
Oleogels are semisolid systems obtained with an organogelator and a hydrophobic liquid that have been investigated over the past few years and that could play an important role as dermatological bases. Recently, we have developed an oleogel of sorbitan monostearate (19wt.%) and sweet almond oil (SM-SAO) and another one of cholesterol (3.5wt.%) and liquid paraffin (Ch-LP). The aim of this work is to access their physical stability using three different methodologies. The gels were stored at different temperatures (20 and 40 degrees C) over a 3-month period. Appearance and textural properties were assessed on each month. An accelerated test was also performed where the temperature changed between 4 and 40 degrees C every 24h, during 7 days. Rheological tests were also carried out as they could provide useful elements to predict stability. The gels were quite stable at 20 degrees C, being the SM-SAO gel the most stable. The textural properties of both gels were influenced by temperature. The decrease of the textural parameters, observed after storage at 40 degrees C and in the cycling test, was more significant for the SM-SAO gel. A good correlation was found between rheological analysis and conventional stability tests. The heating/cooling cycle test provided useful information in a short period of time.  相似文献   

8.
Intravenous lipid emulsions are used for total parenteral nutrition and as carriers for lipophilic drugs. Exposure to the high temperature (121 degrees C) required for steam sterilization may cause coalescence and an increase in droplet size. The purpose of this study was to investigate whether an increase in the electrostatic repulsive force between oil droplets produced by formulation modification improves the thermal stability of lipid emulsions during autoclaving. The addition of a small amount, 0.66 or 1.32 mmol/kg (mm), of purified anionic phospholipid fractions (phosphatidic acid, phosphatidylglycerol, or phosphatidylinositol) to the standard formula increased the zeta potential from its normal value of -11 mV to -39 mV. Emulsions with the larger negative zeta potential did not exhibit any change in oil droplet size or distribution during steam sterilization at 121 degrees C for 15 min. The autoclaved emulsions having the larger negative zeta potential did not exhibit any evidence of coalescence when samples were stored for 1 month at 4 degrees C, room temperature, or 40 degrees C. Reduction of the negative surface charge of the oil droplets by the addition of stearylamine confirmed that the surface charge was an important factor, as emulsions having a reduced negative surface charge separated into two phases during autoclaving.  相似文献   

9.
《Pharmaceutical biology》2013,51(3):332-337
Context: Olive [Olea europaea L. (Oleaceae)] is a long-lived evergreen tree that is widespread in different parts of the world.

Objective: Olive oil has been reported to relieve pain; however, there is still insufficient data in the literature on the subject. Thus, it is considered worthwhile investigating the antinociceptive and anti-inflammatory effects of olive oil in adult male Balb/C mice.

Materials and methods: The antinociceptive effects were studied using formalin, hot plate and writhing tests. The acute anti-inflammatory effects of olive oil in mice were studied using xylene ear edema test. Olive oil (1, 5 and 10?ml/kg body wt.) was injected intraperitoneally. Intact animals served as controls.

Results: Our results showed that the olive oil only decreased the second phase of formalin-induced pain. In the hot plate test, olive oil did not raise the pain threshold over the 60?min duration of the test. Olive oil exhibited antinociceptive activity against writhing-induced pain by acetic acid. In the xylene ear edema test, olive oil showed significant anti-inflammatory activity in the mice.

Discussion and conclusion: The present data indicated that olive oil has antinociceptive and anti-inflammatory effects in mice but further investigation of these effects is required to elucidate the mechanism(s) involved in analgesic and anti-inflammatory effects of Olea europaea oil.  相似文献   

10.
Objectives of this work were studying physico-chemical change and heat stability of olive oils flavoured by selected Tunisian aromatic plants. Flavoured olive oils were prepared by maceration of fresh plant materials (rosemary, lavender, sage, menthe, basil, lemon and thyme) with olive oil at a 5% w/w level for 15 days. A sensorial evaluation was applied to select more appreciate flavoured olive oils by consumers. An oxidative procedure was applied to test the stability of selected flavoured olive oils: oils samples were kept in glass bottles and heated at 60 and 130 °C during 55 days and 6 h, respectively. The resistance to oxidation of these selected flavoured oils was compared to a control samples by measuring PV, K232 and K270 values and change in chlorophyll, carotenes and polyphénols contents. Obtained results show that addition of aromatic plants causes a slight increase in free acidity and viscosity of aromatised olive oils. L*, b* and a* values show that addition of thyme cause a great change in olive oil colours. Heat stability results shows that from selected aromatic plants, rosemary was effectiveness against oxidation followed by thyme and lemon. However, olive oil flavoured with basil exhibit a similar behaviour versus thermal oxidation then the natural olive oil.  相似文献   

11.
Oral administration of sodium fluoride (40 mg/kg body weight) from day 6 of gestation to day 21 of lactation caused, compared with vehicle control, significantly lowered level of calcium and phosphorus in the serum of both P and F1 generation rats. Administration of vitamin C (50 mg/kg body weight), D (2 ng/0.2 ml olive oil/animal), E (2 mg/0.2 ml olive oil/animal) and a combination (vitamin C + D + E) along with NaF caused significant amelioration in serum calcium in P generation and serum phosphorus in both P and F1 generation rats as compared with only NaF-treated group. Serum calcium concentration was only partially recovered (P and F1 generation) on NaF withdrawal during lactation, as well as, on cotreatment (F1 generation) with vitamins. However, serum phosphorus level was significantly recovered on NaF withdrawal.  相似文献   

12.
目的对精制橄榄油进行凝胶法干扰试验,建立精制橄榄油细菌内毒素的检查方法。方法按2010年版《中国药典》(二部)"细菌内毒素检查法",用不同厂家的鲎试剂对不同批号的精制橄榄油分别进行干扰试验。结果精制橄榄油稀释至浓度83.4mg/mL或以下稀释浓度的溶液对细菌内毒素检查法无干扰作用。结论精制橄榄油注射液进行细菌内毒素检查是可行的。  相似文献   

13.
Silicone oil is often applied to the inner surface of glass syringes and cartridges to reduce friction between the glass surface and elastomeric plunger stopper. This oil can appear as intrinsic and non-proteinaceous particles in the ejected fluid or drug product. Limited data is available to understand the impact of age (time between syringe manufacture and filling) on silicone oil migration into the drug product. This study compares subvisible particle count and extrusion force of siliconized syringes from two different manufacturers stored at ambient condition for 2-3 (fresh syringes) and 13-14 (aged syringes) months then filled and placed at 40°C for an additional three months. The fresh syringes exhibit a 2.5-fold increase in subvisible particle count compared to those aged ones. Moreover, the fresh syringes exhibit up to a 2-fold increase in extrusion force. These findings suggest the degree and amount of silicone oil migration is influenced by the time in storage of the glass syringe prior to filling. This rapid communication highlights syringe storage time prior to filling as a factor to be considered during development.  相似文献   

14.
To examine the human exposure to a novel silver and copper nanoparticle (AgNP and CuNP)/polystyrene-polyethylene oxide block copolymer (PS-b-PEO) food packaging coating, the migration of Ag and Cu into 3% acetic acid (3% HAc) food simulant was assessed at 60 °C for 10 days. Significantly lower migration was observed for Ag (0.46 mg/kg food) compared to Cu (0.82 mg/kg food) measured by inductively coupled plasma – atomic emission spectrometry (ICP-AES). In addition, no distinct population of AgNPs or CuNPs were observed in 3% HAc by nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM). The predicted human exposure to Ag and Cu was used to calculate a margin of exposure (MOE) for ionic species of Ag and Cu, which indicated the safe use of the food packaging in a hypothetical scenario (e.g. as fruit juice packaging). While migration exceeded regulatory limits, the calculated MOE suggests current migration limits may be conservative for specific nano-packaging applications.  相似文献   

15.
General-purpose and high-impact polystyrenes (GPPS and HIPS, respectively) are used in many food-contact applications for the packaging of aqueous-based, fatty and dry foods. The correlation of residual styrene concentrations in polystyrene with styrene migration into food-stimulating solvents is of interest in order to predict the potential exposure of consumers to styrene from food-packaging applications. Studies of the migration of styrene into 8% ethanol and cooking oil from a GPPS and a HIPS polymer, each containing three different residual styrene levels, have been completed at temperatures ranging from 70 to 180 degrees F (21 to 82 degrees C). The results showed that the amount of styrene migrating from both polymers into cooking oil was proportional to the square root of the time of exposure, and the total amount of styrene migrating was proportional to the residual levels of styrene in the polymers. The calculated diffusion coefficients were found to be independent of the residual levels of styrene in a given polymer at a given temperature. While the partition equilibrium was not approached when the polymers were exposed to cooking oil, it was observed in the 8%-ethanol exposure studies. The calculated partition coefficients between the polymers and 8% ethanol appeared to be independent of the residual levels of styrene in the polymers at a given temperature. Linear relationships were observed between the logs of the diffusion and partition coefficients and the inverse of the absolute temperature of exposure.  相似文献   

16.
Cadmium (Cd) is one of the most common heavy metal pollutants. It is accumulated particularly in liver and kidney. The present study examined the possible protective effect of olive oil and colocynth oil consumption against Cd-induced damage on plasma lipids and stress biochemical parameters of rats. Male albino Wistar rats were randomly divided into 6 groups of 5 animals each and treated orally with Cd (50 mg/l), olive oil and colocynth oil (4%) alone or in combination with cadmium for 8 weeks. It was shown that Cd exposure induced significant increases in the activities of serum alanine aminotransferase, aspartate aminotransferase, lipid peroxidation levels (MDA) and protein carbonyl contents in exposed groups of rats compared to control group while the antioxidant enzymes, reduced glutathione and vitamins (C, A and E) were significantly decreased. Co-treatment with olive oil or colocynth oil significantly improved the oxidative damage induced by Cd. The antioxidant potential in plasma and liver were markedly restored with a significant decline in MDA levels and activity of transaminases.In conclusion, these results suggest that olive oil or colocynth oil consumption could protect the rat liver against Cd-induced injury by increasing the activities of antioxidant enzymes and reducing oxidative stress.  相似文献   

17.
We previously reported that both hyperthermia and hypothermia induced micronuclei in mouse bone marrow cells (Asanami and Shimono, 1997a, 1997b, 1999). To investigate the effects of temperature on chromosome aberration in vitro, we conducted chromosome aberration and micronucleus tests under hyper- and hypothermic conditions using Chinese hamster lung (CHL) cells. In the chromosome aberration test, we observed positive responses at 40 degrees C and 41 degrees C for 24 hr, and at 42 degrees C for 6 hr and over. In the micronucleus test, we observed positive responses at 31 degrees C, 33 degrees C, and 40 degrees C for 24 hr, and at 42 degrees C for 2 hr. The results suggest that in CHL cells, hypothermic conditions can induce micronuclei while hyperthermic conditions can induce both chromosome aberrations and micronuclei.  相似文献   

18.
Preparation and characterization of two-phase melt systems of lidocaine   总被引:1,自引:0,他引:1  
The melting point of lidocaine was significantly lowered when mixed with thymol and/or aqueous ethanol. Mixtures of lidocaine and thymol at ratios within the range of 30:70-70:30 (w:w) became homogeneous oils at 25 degrees C. In a pH 9.2 carbonate buffer containing 25% ethanol, lidocaine (5%, w:w) also liquefied at 25 degrees C. The studies led to the development of novel two-phase melt systems of lidocaine (TMS) which consisted of a highly concentrated oil phase of lidocaine and an alcoholic aqueous phase. A compositional phase diagram showed that in aqueous dispersions of lidocaine, concurrent use of thymol and ethanol depressed the melting point of lidocaine more effectively than when they were used individually. Both thymol and aqueous ethanol were necessary as melting point depressing agents to achieve the highest possible lidocaine concentration of 87% (w:w) in the oil phase of a TMS at 25 degrees C. Containing an internal oil phase and an external aqueous phase at ambient temperature, such a TMS can be readily formulated into topical O/W cream after addition of proper surfactants and thickening agents. In an anesthetic activity test using mouse tail-flick model, a 5% lidocaine cream prepared was highly effective as shown by the prolonged latency time of the mice to a heat stimulus as compared with a placebo (P<0.05).  相似文献   

19.
反胶束体系中猪胰脂肪酶水解橄榄油的动力学研究   总被引:1,自引:0,他引:1  
目的:系统研究猪胰脂肪酶在二(2-乙基已基)丁二酸酯磺酸钠(AOT)/异辛烷反胶束体系中水解橄榄油的动力学行为。方法:考察温度,wo([H2O]/[AOT]),pH和表面活性剂的浓度对酶反应的影响以及酶的稳定性。结果:酶反应符合常规的一级反应动力不模型,活化有Ea=43.68kJ/mol;最佳pH值为7.7。结论:高浓度表面活性剂对酶表现非竞争性抑制作用;wo是决定酶稳定性的关键。  相似文献   

20.
As a novel alternative to the incorporation into hard gelatin capsules or tablets, extended-release (Aquacoat- or Eudragit RS-coated) or enteric (Eudragit L-coated) pellets were embedded into congealed tablet-shaped PEG-plugs of different molecular weights, which rapidly released the pellets upon contact with aqueous fluids. The lower-molecular-weight PEGs (600 and 1000) were not suitable carrier materials: they dissolved the coatings or significantly increased their permeability. The release characteristics of the original pellets were maintained after embedding the pellets into the higher-molecular-weight PEGs 4000 or 10000. The shelf-life stability was a function of storage temperature and coating material. Stored at 40 degrees C, Aquacoat-coated pellets embedded in PEG 4000 exhibited a decreased drug release because of curing effects, while storage at 20 degrees C or below resulted in stable release profiles over a 3 month period. Eudragit RS-coated pellets, stored at room temperature or above, showed an increased release, and the carrier material possibly migrated into the film, thus increasing its permeability. At 4 degrees C, the release was stable over a 6 month period.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号