神经酰胺Ⅱ脂质体的制备及在化妆品中的应用

通过乳化均质技术制备得到高含量(10%)神经酰胺Ⅱ脂质体,在偏光显微镜下观察到该脂质体粒径均一,具有大量的马耳他十字液晶结构;该神经酰胺Ⅱ脂质体稠度适宜,细腻光滑,稳定性好,水溶性好,通过简单搅拌即可应用到化妆品中,这在很大程度上解决了神经酰胺水溶性差,易结晶析出等问题。通过人体试验结果表明,使用添加1%神经酰胺Ⅱ脂质体(含10%神经酰胺Ⅱ)的乳霜,受试者的TEWL值(经表皮水分流失)在2h内可恢复85%,皮肤含水量在1h内增加39.58%,说明其具有良好的皮肤屏障修复性。     

神经酰胺脂质体——含角质层脂质膜的脂质体

角质层的渗透屏障大多是由饱和脂质如神经酰胺、胆固醇和游离脂肪酸组成。它是物质交换的有效阻隔并防止皮肤干燥。神经酰胺脂质体(Cerasomes)是一种脂质体,它的膜是由最重要的角质层脂质组成的。神经酰胺脂质体作为类皮肤膜的来源,它能加快受损屏障层的再生、降低皮肤刺激,并且它还提供了将角质层脂质应用于化妆品中简单而有效的途径。     

神经酰胺及其脂质体技术的国内外研究动态

介绍了Ceramides（神经酰胺）及其脂质体技术在化妆品、食品和药品等方面的应用，以及最新的研究进展。     

SOD—GC脂质体的制备及包封率的测定

半乳糖神经酰胺（Galactosyl ceramide,简称GC）是一种制备脂质体的新材料,性质稳定,具独特的护肤作用,以GC为主要膜材,用乙醇注入法制备包含有超氧化物歧化酶的脂质体（SOD-GC脂质体）;用SOD蛋白含量法和SOD活性法测定包封率,经正交法优化选择,最佳制备条件为膜脂量1.0mg/mL、SOD量0.1mg/mL,缓冲液pH5.8,此时包土率可达35.68%,两种包封率测定方法结果相近,可以相互参照,这种SOD-GC脂质体有望在护肝肤品和皮肤外用药物治疗等方面应用。     

维生素A神经酰胺脂质体的初步研究

采用神经酰胺为类脂质材料研制维生素A脂质体，通过提高维生素A的稳定性和透皮吸收以有助于其在化妆品中的应用。筛选优化了维生素A脂质体的制备工艺，通过高效液相色谱对包封率、载药量、粒径及形态结构进行了研究。结果显示，脂质体形态较为圆整，平均粒径为O．171μm，包封率达98．5％，载药量为2．0％。神经酰胺作为类脂质材料制得的维生素A脂质体包封率高，可较好地应用于化妆品中。     

神经酰胺的性质及其在化妆品中的应用

神经酰胺是皮肤保护的最重要组分。本就神经酰胺的性质、作用及其在化妆品中的应用作一简要介绍。     

高效液相色谱-蒸发光散射法测定脂质体中神经酰胺NP和AP含量

建立了高效液相色谱-蒸发光散射法检测神经酰胺脂质体中神经酰胺NP和神经酰胺AP两种成分含量的方法。神经酰胺脂质体原料样品经甲醇-异丙醇(体积比7∶3)破乳并超声处理,采用色谱柱Agilent ZORBAX StableBond C8(4.6×150 mm,3.5μm)分离,以纯乙腈为流动相A,含0.1%甲酸的甲醇-异丙醇(体积比7∶3)为流动相B进行梯度洗脱,流速为1.0 mL/min,柱温40℃,蒸发器温度90℃,雾化器温度70℃,氮气流速1.0 L/min。结果表明,神经酰胺脂质体中NP和AP的定量限分别为3和6μg/mL,检出限分别为1和2μg/mL,重复性和精密度RSD均小于2%,在NP为50～500μg/mL和AP为25～250μg/mL的质量浓度范围内线性关系良好(R²>0.999),不同质量浓度水平下的回收率为96.2%～105.1%。该方法简便可靠,重现性好,可用于不同脂质体中神经酰胺NP和AP的分离与含量测定。     

人体脸部皮肤角质层中神经酰胺提取及含量测定

建立人体脸部角质层中神经酰胺的提取及含量测定方法。本研究采用透明聚酯胶带对脸部皮肤角质层进行采样,采样面积为4.5cm~2;在角质层神经酰胺的提取上,选择甲醇作为溶解剂,角质细胞采用超声波细胞破碎仪进行破碎,使神经酰胺充分释放,确定提取时间为20min。本研究采用了高效液相色谱(HPLC)测定脸部皮肤角质层神经酰胺,色谱条件为ZORBAX系列SB-C18柱(4.6 mm×250 mm,5μm),流动相为甲醇/异丙醇(70/30),流速为1.0 mL/min,柱温为30℃,检测波长为205 nm,进样量10μL。结果标准品神经酰胺mix浓度在5～200 mg/L范围内与峰面积呈良好线性关系,相关系数R~2为0.99968(n=5),检出限为2.5 mg/L。该法对皮肤角质层神经酰胺测定的加标回收率为100.99%,相对标准偏差(RSD)分别为1.55%。此法可快速高效的对脸部皮肤角质层神经酰胺定量分析,得出测试者神经酰胺的含量为3.601μg/cm~2。结论本文将神经酰胺的高效液相色谱检测方法,应用到人体脸部皮肤角质层神经酰胺的检测中。从皮肤角质层的采样、角质层神经酰胺的提取及高效液相色谱检测的条件上等作出了优化,从而达到取更少的样本量亦能简便高效的检测。为皮肤无创检测特定物质提供了科学方法。     

神经酰胺ⅢB纳米脂质体的制备及功效评价

采用高压匀质技术制备了神经酰胺ⅢB纳米脂质体,平均粒径为71.7 nm,PDI(多分散性系数)为0.214,Zeta电位为-23.3 m V,载药量和包封率分别为2.3%和95.9%。采用Franz扩散池法考察了其体外透皮性能,结果显示,其24 h体外皮肤累积透过量为709.23μg/cm~2,皮肤滞留量为75.07μg/cm~2。相同神经酰胺ⅢB质量分数的纳米脂质体霜剂与普通霜剂相比,前者24 h皮肤滞留量提高了近6倍。比较了连续给药40 d前后小鼠皮肤的水合能力,结果显示,神经酰胺ⅢB纳米脂质体组小鼠皮肤水合能力较对照组有明显提高,小鼠皮肤中总神经酰胺质量浓度高于对照组。     

神经酰胺2/神经酰胺3/神经酰胺6Ⅱ复合纳米载体的保湿功效研究

通过纳米载体技术,将神经酰胺2、神经酰胺3和神经酰胺6Ⅱ进行包载,制备了神经酰胺复合纳米载体(舒胺修L).通过体外细胞实验,检测舒胺修L对人角质形成细胞(HaCaT)增殖、迁移及保湿因子分泌的影响.通过人体功效评价,检测舒胺修L安全性,以及对皮肤即时和长效保湿、经皮失水值的影响.结果 表明,舒胺修L粒径为14.46±0.11nm,多分散系数(PDI)为0.480±0.004,Zeta电位为-28.2±0.6mV,且安全无刺激.与游离成分相比,舒胺修L可促进HaCaT细胞的增殖和迁移,提高细胞保湿因子的分泌量,显著提高人体皮肤即时和长期含水量,减少皮肤经皮失水值.舒胺修L在保湿补水化妆品领域将有良好的应用前景.     

皮肤中神经酰胺的研究及应用现状

概述了神经酰胺的结构、理化性质及在体内的主要代谢途径。主要介绍了神经酰胺的制备、分离、检测方法,以及在医药、化妆品中的应用。展望了神经酰胺抗衰老、美白作用和在不同年龄阶段的应用,为神经酰胺更广泛安全的应用提供理论依据。     

Neue Pseudoceramide durch Verknüpfung von speziellen Fettstoffen mit Kohlenhydratderivaten

New Pseudoceramides Obtained by Combination of Oleochemical Speciality with Derivatives of Carbohydrates. In the last year lipid scientists paid more and more attention to the structural family of ceramides. After being discovered as an important role among the epidermal lipids in stabilizing the barrier function of the skin, ceramides found widespread application in skin care products. Their unique structure and variability as well as their strong influence on the lamellar liquid crystalline character of the horny layer lipids and thereby on the properties of the horny layer overall are pointed out. The structure of a ceramide on principle can be considered as a nonionic polar lipid consisting of an amidic hydrophilic central part which is combined with two fatty alkyl chains of different length. In the meantime some pseudoceramides have been prepared based on this principle, with properties similar to their natural prototypes, but much more inexpensive than those. The utilization of carbohydrate derivatives is relatively new. Syntheses and properties of some representative examples of this type of pseudoceramides are described.     

N-Palmitoyl Serinol Stimulates Ceramide Production through a CB1-Dependent Mechanism in In Vitro Model of Skin Inflammation

Ceramides, a class of sphingolipids containing a backbone of sphingoid base, are the most important and effective structural component for the formation of the epidermal permeability barrier. While ceramides comprise approximately 50% of the epidermal lipid content by mass, the content is substantially decreased in certain inflammatory skin diseases, such as atopic dermatitis (AD), causing improper barrier function. It is widely accepted that the endocannabinoid system (ECS) can modulate a number of biological responses in the central nerve system, prior studies revealed that activation of endocannabinoid receptor CB1, a key component of ECS, triggers the generation of ceramides that mediate neuronal cell fate. However, as the impact of ECS on the production of epidermal ceramide has not been studied, we here investigated whether the ECS stimulates the generation of epidermal ceramides in an IL-4-treated in vitro model of skin inflammation using N-palmitoyl serinol (PS), an analog of the endocannabinoid N-palmitoyl ethanolamine. Accordingly, an IL-4-mediated decrease in cellular ceramide levels was significantly stimulated in human epidermal keratinocytes (KC) following PS treatment through both de novo ceramide synthesis- and sphingomyelin hydrolysis-pathways. Importantly, PS selectively increases ceramides with long-chain fatty acids (FAs) (C22–C24), which mainly account for the formation of the epidermal barrier, through activation of ceramide synthase (CerS) 2 and Cer3 in IL-4-mediated inflamed KC. Furthermore, blockade of cannabinoid receptor CB1 activation by AM-251 failed to stimulate the production of total ceramide as well as long-chain ceramides in response to PS. These studies demonstrate that an analog of endocannabinoid, PS, stimulates the generation of specific ceramide species as well as the total amount of ceramides via the endocannabinoid receptor CB1-dependent mechanism, thereby resulting in the enhancement of epidermal permeability barrier function.     

神经酰胺及其分析与分离技术研究进展

神经酰胺是一种重要的生物活性物质 ,在医药、保健和化妆品行业具有广阔的应用前景。高效分析方法是深入研究神经酰胺性质的基础 ,分离技术的研究则是其广泛应用的前提。本文综述了神经酰胺的分析与分离技术的现有研究成果 ,并对进一步研究的方向进行了讨论     

Thermotropic phase properties of the hydroxyceramide/cholesterol system

The interaction of cholesterol with ceramides containing α-hydroxy fatty acyl chains (hydroxyceramides) has been studies as a foundation for characterizing the lipid bilayers of thestratum corneum. A relatively large quantity of cerebrosides was obtained from bovine brain and converted to ceramides through removal of the carbohydrate side chain. The ceramides were separated based on the absence or presence of hydroxy fatty acyl chains. The lyophilized hydroxyceramides showed a broad melting region at 92°C. Hydroxyceramides dispersed in water produced a relatively narrow, thermotropic transition at 75°C. The effect of cholesterol on this thermotropic phase transition of hydroxyceramides was determined by differential scanning calorimetry. With respect to the main transition, cholesterol caused a broadening of the phase transition at relatively low levels as well as a decrease in the peak transition temperature. The presence of cholesterol at levels in excess of 7 wt% gave rise to an additional low-temperature transition at 55°C. Upon immediate rescanning, this transition was exothermic, but with increasing incubation time the area under the excess heat capacity curve as a function of temperature became smaller. After two days or more, the transition observed was endothermic. At cholesterol levels between 40 and 50 wt%, multiple peaks were observed. From comparisons with related systems, the cooperative thermal transitions of hydroxyceramides with cholesterol are suggested to result from changes in hydrogen bonding or be due to phase separation. The composition of isolated brain ceramides is being compared with that reported for thestratum corneum.     

Fatty acid composition of free ceramides of kidney and cerebellum from a patient with Farber's disease

The fatty acid composition of ceramides has been determined in kidney and cerebellum of a patient with Farber's disease, which is characterized by ceramidase deficiency. Farber cerebellum and kidney contained a five- and ten-fold excess, respectively, of free ceramides. The nonhydroxy fatty acid patterns of the ceramides from Farber kidney and cerebellum showed considerable similarities to those from control tissues, whereas large amounts of ceramides containing hydroxy fatty acids are found in Farber's disease tissues.     

Plasma Ceramides and Triglycerides Are Elevated during Pregnancy in Association with Markers of Insulin Resistance in Hutterite Women

Changes in maternal insulin sensitivity and circulating lipids typically occur during the metabolic transitions of pregnancy and lactation. Although ceramides can cause insulin resistance in mammals, their potential roles during pregnancy and lactation are unknown. We hypothesized that changes in lipids like ceramide and triglycerides could occur across different reproductive states and relate to insulin resistance. Our objectives were to comprehensively characterize lipids in the plasma of pregnant, lactating, and nonpregnant and nonlactating (NPNL) women, and to evaluate the relationship between ceramides and the triglyceride index, a proxy of insulin resistance. Middle-aged Hutterite women from the South Dakota Rural Bone Health Study were classified by reproductive status as nonpregnant and nonlactating (NPNL; 19 observations), pregnant (14 observations), or lactating (31 observations). Several plasma lipids were elevated in pregnancy such as ceramides, triglycerides, and total- and high-density lipoprotein cholesterol. The triglyceride index was highest during pregnancy and was positively associated with long- and very long-chain ceramides. Lipidomics revealed lipid signatures specific to reproductive state, including triglycerides, phosphatidylcholines, sphingomyelins, and cholesteryl esters, which were also related to the triglyceride index. Our data support the possibility that ceramides contribute to the development of insulin resistance during pregnancy, and reveal distinct lipid signatures associated with pregnancy and lactation.     

Simultaneous quantitation of ceramides and 1,2-diacylglycerol in tissues by latroscan thin-layer chromatography-flame-ionization detection

Ceramides and 1,2-diacylglycerol have been demonstrated in intracellular signaling pathways. A method of simultaneous mass determination of ceramides and 1,2-diacylglycerol in tissues was developed using the latroscan which combines thin layer chromatography and flame ionization detection (TLC/FID) techniques. Because of relatively low amounts of these components in tissues, the fraction of nonpolar lipids, which included ceramides and glycerides, was eluted with chloroform/acetone mixture (3∶1, vol/vol) through a silicic acid column to eliminate the polar phospholipids. Development of Chromarods was carried out using three solvent systems in a four-step development technique. The relationship of the peak area ratio to weight ratio compared with cholesteryl acetate added as an internal standard was linear. The amount of ceramides increased with incubation of rat heart homogenate and human erythrocyte membranes in the presence of sphingomyelinase (E.C. 3.1.4.12). The latroscan TLC/FID system provided a quick and reliable assessment of ceramides and 1,2-diacylglycerol.     

Progress in the analysis of Stratum corneum ceramides

The stratum corneum with its unique structure of corneocytes and intercellular lipid lamellae enables a protection of human and other mammalian skin against transepidermal water loss and harmful substances from the environment. Among these lipids, ceramides play a key role. Several skin disorders such as psoriasis, atopic dermatitis and others show a disturbed barrier function, which can be linked in part to a changed ceramide pattern. Research in dermatology and cosmetic industry requires the use of analytical methods to characterize ceramides. However, the amazing variability of ceramide structures found in stratum corneum makes their analysis a challenge. This is to our knowledge the first review that deals with ceramide analysis. It is focused on stratum corneum ceramides which show much more complexity than intracellular ceramides known to be signal transducers. After a short summary of lipid extraction methods, we discuss the following set of methods: thin‐layer chromatography, gas chromatography, HPLC, LC/MS, mass spectrometry, NMR spectroscopy, vibrational spectroscopy, and X‐ray diffraction. It will be lined out which information about structure, concentration or physical state is available by means of each particular method. Although the focus is clearly on stratum corneum ceramides, some methods of general skin lipid analysis and structure analysis of sphingolipids are also discussed when appropriate.     

Antibody labeling of cholesterol/ceramide ordered domains in cell membranes

A monoclonal antibody raised against mixed monolayers of 60:40 mol % cholesterol/C16-ceramide of known structure was used to label cholesterol/ceramide-rich domains in cell membranes. The antibody, Cer-Chol 405F specifically recognizes the mixed crystalline and homogeneous phase in monolayers, but it does not interact with either of the components separately. It interacts differently with mixed monolayers that contain ceramides of different acyl chain length. When used on cells, the antibody labeling is sensitive to changes in cholesterol and ceramide levels, as well as to over-expression of specific ceramides; this is in agreement with the results that were obtained on lipid monolayers. This represents a proof of concept of the applicability of a new approach to the structural characterization of lipid microdomains in cell membranes. The approach consists of raising antibodies that recognize specific structural organizations of lipids in artificial mixtures, characterizing the antibody/ordered domain complexes in vitro, and subsequently using them to detect the presence of the same (or similar) domains in cell membranes.