An improved GLC method for a rapid, simultaneous analysis of both medium chain fatty acids and medium chain triglycerides in plasma

Final Report on the Safety Assessment of Trilaurin, Triarachidin, Tribehenin, Tricaprin, Tricaprylin, Trierucin, Triheptanoin, Triheptylundecanoin, Triisononanoin, Triisopalmitin, Triisostearin, Trilinolein, Trimyristin, Trioctanoin, Triolein, Tripalmitin, Tripalmitolein, Triricinolein, Tristearin, Triundecanoin, Glyceryl Triacetyl Hydroxystearate, Glyceryl Triacetyl Ricinoleate, and Glyceryl Stearate Diacetate

Triesters of glycerin and aliphatic acids, known generically as glyceryl triesters and specifically as Trilaurin, etc., are used in cosmetic products as occlusive skin-conditioning agents and/or non-aqueous viscosity-increasing agents. Hundreds of glyceryl triesters are used in a wide variety of cosmetic products at concentrations ranging from a few tenths of a percent to 46%. Glyceryl triesters are also known as triglycerides; ingested triglycerides are metabolized to monoglycerides, free fatty acids, and glycerol, all of which are absorbed in the intestinal mucosa and undergo further metabolism. Dermal absorption of Triolein in mice was nil; the oil remained at the application site. Only slight absorption was seen in guinea pig skin. Tricaprylin and other glyceryl triesters have been shown to increase the skin penetration of drugs. Little or no acute, subchronic, or chronic oral toxicity was seen in animal studies unless levels approached a significant percentage of caloric intake. Subcutaneous injections of Tricaprylin in rats over a period of 5 weeks caused a granulomatous reaction characterized by oil deposits surrounded by macrophages. Dermal application was not associated with significant irritation in rabbit skin. Ocular exposures were, at most, mildly irritating to rabbit eyes. No evidence of sensitization or photosensitization was seen in a guinea pig maximization test. Most of the genotoxicity test systems were negative. Tricaprylin, Trioctanoin, and Triolein have historically been used as vehicles in carcinogenicity testing of other chemicals. In one study, subcutaneous injection of Tricaprylin in newborn mice produced more tumors in lymphoid tissue than were seen in untreated animals, whereas neither subcutaneous or intraperitoneal injection in 4-to 6-week-old female mice produced any tumors in another study. Trioctanoin injected subcutaneously in hamsters produced no tumors. Trioctanoin injected intraperitoneally in pregnant rats was associated with an increase in mammary tumors in the offspring compared to that seen in offspring of untreated animals, but similar studies in pregnant hamsters and rabbits showed no tumors in the offspring. One study of Triolein injected subcutaneously in rats showed no tumors at the injection site. As part of an effort to evaluate vehicles used in carcinogenicity studies, the National Toxicology Program conducted a 2-year carcinogenicity study in rats given Tricaprylin by gavage. This treatment was associated with a statistically significant dose-related increase in pancreatic acinar cell hyperplasia and adenoma, but there were no acinar carcinomas, the incidence of mononuclear leukemia was less, and nephropathy findings were reduced, all compared to corn oil controls. Overall, the study concluded that Tricaprylin did not offer significant advantages over corn oil as vehicles in carcinogenicity studies. Trilaurin was found to inhibit the formation of neoplasms initiated by dimethylbenzanthracene (DMBA) and promoted by croton oil. Tricaprylin was not teratogenic in mice or rats, but some reproductive effects were seen in rabbits. A low level of fetal eye abnormalities and a small percentage of abnormal sperm were reported in mice injected with Trioctanoin as a vehicle control. Clinical tests of Trilaurin at 36.3% in a commercial product applied to the skin produced no irritation reactions. Trilaurin, Tristearin, and Tribehenin at 40%, 1.68%, and 0.38%, respectively, in commercial products were also negative in repeated-insult patch tests. Tristearin at 0.32% in a commercial product induced transient, mild to moderate, ocular irritation after instillation into the eyes of human subjects. Based on the enhancement of penetration of other chemicals by skin treatment with glyceryl triesters, it is recommended that care be exercised in using them in cosmetic products. On the basis of the available data, the following 23 glyceryl triesters are considered safe as used in cosmetics: Trilaurin, Triarachidin, Tribehenin, Tricaprin, Tricaprylin, Trierucin, Triheptanoin, Triheptylundecanoin, Triisononanoin, Triisopalmitin, Triisostearin, Trilinolein, Trimyristin, Trioctanoin, Triolein, Tripalmitin, Tripalmitolein, Triricinolein, Tristearin, Triundecanoin, Glyceryl Triacetyl Hydroxystearate, Glyceryl Triacetyl Ricinoleate, and Glyceryl Stearate Diacetate. Some of these are not currently in use, but would be considered safe if used at concentrations similar to those glyceryl triesters that are in use as cosmetic ingredients.

Rational Design of a Chromo- and Fluorogenic Hybrid Chemosensor Material for the Detection of Long-Chain Carboxylates

A strategy for the rational design of a new optical sensor material for the selective recognition of long-chain carboxylates in water is presented. The approach relies on the combination of structure-property relationships to single out the optimal molecular sensor unit and the tuning of the sensing characteristics of an inorganic support material. A spacer-substituted 7-urea-phenoxazin-3-one was employed as the signaling moiety and a mesoporous trimethylsilylated UVM-7 (MCM-41 type) material served as the solid support. The sensor material shows the advantageous features of both modules that is absorption and emission in the visible spectral range, a fluorescence red-shift and enhancement upon analyte coordination, and the amplification of noncovalent (binding) and hydrogen-bonding (recognition) interactions in the detection event. Besides these basic results that are related to the design and performance of the sensor material, the paper discusses general aspects of amido-substituted phenoxazinone photophysics and addresses some general features of molecular anion recognition chemistry in aqueous vs nonaqueous media, utilizing steady-state and time-resolved optical as well as NMR spectroscopies. Detailed studies on potentially competing biochemical species and a first access to the schematic model of the response of the sensor material as obtained by a combination of fluorescence lifetime distribution analysis and Langmuir-type fitting of the gross binding constants complement the key issues of the paper.

Accumulation of 3-hydroxy-fatty acids in the culture medium of long-chain L-3-hydroxyacyl CoA dehydrogenase (LCHAD) and mitochondrial trifunctional protein-deficient skin fibroblasts: implications for medium chain triglyceride dietary treatment of LCHAD deficiency

Dietary management of long-chain l-3-hydroxyacyl CoA dehydrogenase (LCHAD) deficiency involves a regimen that contains adequate carbohydrate, protein, and essential lipids, and supplementation with medium-chain fatty acids in the form of medium-chain triglycerides, providing energy from fats that bypasses the long-chain metabolic block. This study analyzes the effects of dietary treatment of LCHAD deficiency in an in vitro model. Cultured skin fibroblasts from LCHAD-deficient and normal individuals were grown in media supplemented with physiologic combinations of medium-chain fatty acids octanoate and decanoate, and the long-chain palmitate. Medium was removed from the cells after various incubation times, and assayed for 3-hydroxy-intermediates of fatty acid oxidation. The 3-hydroxy-fatty acids were measured by stable-isotope dilution gas chromatography/mass spectrometry. We found that the addition of medium-chain fatty acids caused a decrease in the accumulation of long-chain fatty acid oxidation intermediates in LCHAD-deficient cells when the cells were incubated in untreated medium, and also when they were incubated in this medium with palmitate added. Medium with decanoate alone was better at achieving this effect than medium with only octanoate added. A 1:3 ratio of octanoate to decanoate worked best over an extended time period in LCHAD-deficient cells in untreated medium, whereas a 1:1 ratio of octanoate to decanoate worked best in the same cells incubated in medium containing palmitate. In all dietary medium-chain triglyceride preparations, the ratio of octanoate was greater than that of decanoate. Our results suggest that a medium-chain triglyceride preparation that is higher in decanoate may be more effective in reducing the accumulation of potentially toxic long-chain 3-hydroxy-fatty acids in LCHAD deficiency.

A new HPLC method for the direct analysis of triglycerides of dicarboxylic acids in biological samples

Dicarboxylic acids (DA) are alternate lipid substrates recently proposed in parenteral nutrition. Two new derivatives of DA, a triglyceride of sebacic (TGC10) and one of dodecanedioic (TGC12) acid have been synthesised in order to reduce the amount of sodium given with the unesterified forms. The present paper describes a rapid and direct high-performance liquid chromatographic method (HPLC) for the analysis of these substances in both plasma and urine. Thirty-six male Wistar rats were rapidly injected with 64 mg of TGC10 or 53 mg of TGC12. The triglycerides and their products of hydrolysis were measured in plasma samples taken at different times. For the dose of 500 ng the intra-assay variations ranged from 6. 80+/-0.35% for TGC10 to 18.6+/-3.20% for TGC12 and the inter-assay variations were from 4.44+/-2.21% for TGC10 to 15.0+/-6.72% for TGC12. The detection limit for both triglycerides was 5 ng. This rapid and direct HPLC method could have practical implications in monitoring the concentration of both triglycerides and free forms of DA in biological samples of patients who might benefit from the administration of these substances during parenteral nutrition regimens.