气相色谱法同时测定食品中34种脂肪酸

本文建立了气相色谱法同时测定食品中34种脂肪酸的方法。食品中的脂肪酸经酸水解后,用石油醚-乙醚(1+1)提取脂肪,KOH/CH3OH皂化和甲酯化,生成脂肪酸甲酯,GC-FID检测。该方法回收率在91.28%～109.59%之间,相对标准偏差小于8.48%,34种脂肪酸的检出限在1.32mg/kg～3.36mg/kg之间,能满足实际检测工作的需要。本方法准确、灵敏,检测的脂肪酸种类多,具有实际推广价值。     

Penetration enhancing effects of selected natural oils utilized in topical dosage forms

Abstract

Context: Various natural products, including oils, have been utilized as penetration enhancers due to their “safety profiles”. These oils contain fatty acids promoting skin permeability through lipid fluidization within the stratum corneum; and might therefore be able to effectively enhance transdermal drug delivery.

Objective: We investigated possible penetration enhancing properties of selected oils, utilizing flurbiprofen as marker compound in emulgel formulations. The formulations were compared to a liquid paraffin emulgel and a hydrogel to establish any significant penetration enhancing effects.

Methods: Gas chromatographic analysis of the natural oils was performed at ambient temperature to determine the fatty acid composition in each selected natural oils. Franz cell diffusion studies and tape stripping methods were employed to study delivery of the marker into, and through the skin.

Results: The following rank order for the emulgel flux-values was obtained: Hydrogel >>>> olive oil >> liquid paraffin >> coconut oil > grape seed oil >> Avocado oil ≥ Crocodile oil >> Emu oil.

Discussion: Results suggested that oils containing predominantly mono-unsaturated oleic acid, on average increased the flux of the marker to a larger extent than oils containing an almost even mixture of both mono- and poly-unsaturated fatty acids. Oils comprising saturated fatty acids (SFAs) with alkyl chains between C₁₂ and C₁₄, increased the marker flux to a higher extent than oils containing C₁₆–C₁₈ SFAs. Effects observed for branched fatty acids, however, did not vary significantly from effects for unbranched fatty acids with the same carbon chain length.

Conclusion: Natural oils possess penetration enhancing effects.     

Poloxamer 407 as a Thermogelling and Adhesive Polymer for Rectal Administration of Short-Chain Fatty Acids

Objectives: The purpose of the study was to gel a rectal solution of short-chain fatty acids to decrease the loss of active materials in the colonic lumen and thereby optimize their absorption. Methods: Five thermogels were prepared with poloxamer 407 at concentrations ranging from 17% to 20%. Their viscosities were measured at room temperature and 37°C, and their gelling temperatures were determined. The adhesive properties of each gel were assessed in vitro at 37°C. Short-chain fatty acid release was studied using Guyot cells. Results: From the threshold concentration of 17.5%, the solutions, Newtonian at room temperature (50-80 mPa · s), gelled at 37°C. The higher the concentration, the higher the viscosity (1750 to 49,000 mPa · s), the lower the gelling temperature (27.6°C to 23.4°C), and the stronger the work of adhesion (2.2 to 4.5 mJ). Short-chain fatty acid release from the 18% polymer gel was decreased by 60% compared to the rectal solution. Conclusion: The 18% poloxamer 407 concentration provided a solution that was liquid at room temperature, that gelled at 37°C, possessed adhesive properties, and controlled short-chain fatty acid release.     

Poloxamer 407 as a Thermogelling and Adhesive Polymer for Rectal Administration of Short-Chain Fatty Acids

Objectives: The purpose of the study was to gel a rectal solution of short-chain fatty acids to decrease the loss of active materials in the colonic lumen and thereby optimize their absorption. Methods: Five thermogels were prepared with poloxamer 407 at concentrations ranging from 17% to 20%. Their viscosities were measured at room temperature and 37°C, and their gelling temperatures were determined. The adhesive properties of each gel were assessed in vitro at 37°C. Short-chain fatty acid release was studied using Guyot cells. Results: From the threshold concentration of 17.5%, the solutions, Newtonian at room temperature (50–80 mPa · s), gelled at 37°C. The higher the concentration, the higher the viscosity (1750 to 49,000 mPa · s), the lower the gelling temperature (27.6°C to 23.4°C), and the stronger the work of adhesion (2.2 to 4.5 mJ). Short-chain fatty acid release from the 18% polymer gel was decreased by 60% compared to the rectal solution. Conclusion: The 18% poloxamer 407 concentration provided a solution that was liquid at room temperature, that gelled at 37°C, possessed adhesive properties, and controlled short-chain fatty acid release.     

GC/MS分析纸浆及沉积树脂中脂肪酸组成

本文用色谱-质谱联用分析了纸浆及其沉积物的树脂中的脂肪酸成分。结果表明:纸浆中脂肪酸成分主要是油酸、9,11-十八碳二烯酸和软脂酸。沉积树脂的脂肪配成分基本上与之相同。纸浆中甘油三酸酯的脂肪酸的主要成分是油酸和软脂酸。纸浆中的甘油三酸酯是导致制浆造纸过程中产生树脂障碍的主要有害成分之一。     

脂肪酸二元低共熔混合物相变温度和潜热的理论预测

对低共熔混合物相变温度和潜热的理论预测公式进行了选择和验证,对脂肪酸类二元低共熔混合物的配比、熔点和熔化潜热进行了理论计算。从实际的计算过程来看,计算值与实验值吻合得很好,可以用来计算脂肪酸类低共熔混合物的热特性参数。在15种脂肪酸类低共熔混合物中,熔点最低为10.2℃,最高为51.5℃;熔化潜热最低为138.6J/g,最高为187.5J/g。从工程实际应用来看,脂肪酸类低共熔混合物适用于低温采暖、生活热水、相变墙体、温控混凝土、相变服装等领域。     

Interactions of Skin with Gold Nanoparticles of Different Surface Charge,Shape, and Functionality

The interactions between skin and colloidal gold nanoparticles of different physicochemical characteristics are investigated. By systematically varying the charge, shape, and functionality of gold nanoparticles, the nanoparticle penetration through the different skin layers is assessed. The penetration is evaluated both qualitatively and quantitatively using a variety of complementary techniques. Inductively coupled plasma optical emission spectrometry (ICP‐OES) is used to quantify the total number of particles which penetrate the skin structure. Transmission electron microscopy (TEM) and two photon photoluminescence microscopy (TPPL) on skin cross sections provide a direct visualization of nanoparticle migration within the different skin substructures. These studies reveal that gold nanoparticles functionalized with cell penetrating peptides (CPPs) TAT and R₇ are found in the skin in larger quantities than polyethylene glycol‐functionalized nanoparticles, and are able to enter deep into the skin structure. The systematic studies presented in this work may be of strong interest for developments in transdermal administration of drugs and therapy.     

A Eutectic Mixture of Natural Fatty Acids Can Serve as the Gating Material for Near‐Infrared‐Triggered Drug Release

A smart release system responsive to near‐infrared (NIR) light is developed for intracellular drug delivery. The concept is demonstrated by coencapsulating doxorubicin (DOX) (an anticancer drug) and IR780 iodide (IR780) (an NIR‐absorbing dye) into nanoparticles made of a eutectic mixture of naturally occurring fatty acids. The eutectic mixture has a well‐defined melting point at 39 °C, and can be used as a biocompatible phase‐change material for NIR‐triggered drug release. The resultant nanoparticles exhibit prominent photothermal effect and quick drug release in response to NIR irradiation. Fluorescence microscopy analysis indicates that the DOX trapped in the nanoparticles can be efficiently released into the cytosol under NIR irradiation, resulting in enhanced anticancer activity. A new platform is thus offered for designing effective intracellular drug‐release systems, holding great promise for future cancer therapy.     

The Solubility of C60 Fullerene in Long Chain Fatty Acids Esters

A series of fatty acid esters of glycerol as linseed, sunflower, soybean and olive oils have been tested as C₆₀ fullerene solvents together with a mixture of methyl ester fatty acids derived from brassica oilseeds and used as a biofuel known as “biodiesel.” All the oils evaluated are effective solvents of C₆₀. The solubility of C₆₀ in the selected vegetable oils has been determined spectrophotometrically. The C₆₀ solubility in vegetable oils may pave the way for easier application of C₆₀ fullerene in medicinal chemistry and in additive chemistry for varnishes and fuels. It has been found that C₆₀ is not only soluble in the fatty acid esters but is also reactive with them under mild conditions, giving addition products easily recognized by a characteristic absorption band at 435 nm. The addition reaction mechanism has been discussed.