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PubMed1994

Ouabain and digitoxin as modulators of chick embryo cardiomyocyte energy metabolism.

The effects of 0.1 nmol/l ouabain (CAS 630-60-4) and digitoxin (CAS 71-63-6) on oxygen consumption rate (OCR) and the contractility of cultured chick embryo cardiomyocytes were investigated using a perfusion system which allowed microscopic observation during the experiment. contractility was assessed by a novel image analysis procedure. During substrate free perfusion the OCR was increased on application of 0.1 nmol/l ouabain or digitoxin for 60 min, whilst contractility was not affected. Digitoxin (0.1 nmol/l) elicited no change in the OCR in the presence of glucose, pyruvic acid, lactic acid and caprylic acid. Ouabain (0.1 nmol/l) did not affect the OCR or contractility in the presence of glucose, pyruvic acid and lactic acid, however together with caprylic acid the OCR was increased significantly. These results demonstrate a hitherto unknown stimulation of fatty acid utilization by low concentrations of ouabain.

Animals↗
PubMed2001

Comparative quantitative fatty acid analysis of triacylglycerols using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and gas chromatography.

Quantitative analyses of fatty acids from five triacylglycerol products, coconut oil, palm kernel oil, palm oil, lard and cocoa butter, were carried out using two analytical methods: matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) and gas chromatography (GC), in an effort to validate the application of MALDI-TOFMS in quantitative fatty acid analysis. For the GC analysis, transmethylated products were used, whereas, for the MALDI-TOF analysis, saponified products were used. Under MALDI-TOF conditions, the acids were detected as sodiated sodium carboxylates [RCOONa + Na](+) consistent with the mode of ionization that was previously reported. Thus, the MALDI-TOF mass spectrum of saponified coconut oil showed the presence of sodiated sodium salts of caprylic acid (7.5 +/- 0.67, m/z 189), capric acid (6.9 +/- 0.83, m/z 217), lauric acid (47.8 +/- 0.67, m/z 245), myristic acid (20.4 +/- 0.51, m/z 273), palmitic acid (9.8 +/- 0.47, m/z 301), linoleic acid (0.9 +/- 0.07, m/z 325), oleic acid (4.8 +/- 0.42, m/z 327) and stearic acid (2.0 +/- 0.13, m/z 329). Saponified palm kernel oil had a fatty acid profile that included caprylic acid (3.5 +/- 0.59), capric acid (4.7 +/- 0.82), lauric acid (58.6 +/- 2.3), myristic acid (20.9 +/- 1.5), palmitic acid (7.2 +/- 1.1), oleic acid (3.8 +/- 0.62) and stearic acid (1.2 +/- 0.15). Saponified palm oil gave myristic acid (0.83 +/- 0.18), palmitic acid (55.8 +/- 1.7), linoleic acid (4.2 +/- 0.51), oleic acid (34.5 +/- 1.5), stearic acid (3.8 +/- 0.26) and arachidic acid (0.80 +/- 0.22). Saponified lard showed the presence of myristic acid (1.5 +/- 0.24), palmitic acid (28.9 +/- 1.3), linoleic acid (13.7 +/- 0.67), oleic acid (38.7 +/- 1.4), stearic acid (12.8 +/- 0.64) and arachidic acid (2.4 +/- 0.35). Finally, for saponified cocoa butter, the fatty acid distribution was: palmitic acid (32.3 +/- 1.0), linoleic acid (2.6 +/- 0.35), oleic acid (34.9 +/- 1.7) and stearic acid (30.3 +/- 1.6). Quantitative gas chromatographic analysis of the corresponding methyl esters from these triacylglycerol products yielded data that were mostly in agreement with the MALDI-TOFMS data. The MALDI-TOF experiment, however, proved to be superior to the GC experiment, particularly with regard to baseline resolution of unsaturated acids. Furthermore, the ability of MALDI-TOFMS to detect low concentrations of fatty acids rendered it more sensitive than the GC methodology.

Animals↗
PubMedDate not supplied

Kinetics of drug binding to human serum albumin: allosteric and competitive inhibition at the benzodiazepine binding site by free fatty acids of various chain lengths.

The inhibition of dansylsarcosine (DS) binding at the benzodiazepine binding site of human serum albumin has been studied in the presence of saturated and unsaturated free fatty acids (FFA) of various chain lengths (C6-C20, C18:1, C18:2). In order to determine the mechanism of displacement, velocity constants for association (k2) and dissociation (k-2) and binding constants (KA and KA') have been measured using the stopped-flow method. The inhibitory effect of FFA on DS binding kinetics at site II is dependent of their structure. With increasing amounts of FFA the association velocity constant of DS binding decreases from 520 s-1 (fatty acid free albumin) by a factor of 3-10 and affinity decreases according to FFA chain length. Inhibition is strongest in the presence of caprylic, capric and lauric acid (C8-C12) i.e. with more than one mole FFA per mole albumin, DS association could no longer be measured. Short chain caproic and the long chain FFA C14-C20 showed only a less inhibitory effect since in the presence of a twofold excess k2 ranged between 100 and 200 s-1. Dissociation velocity of DS from the benzodiazepine binding site could be measured in relationship to FFA chain length using ibuprofene, another drug binding at site II. Dissociation velocity constants k-2 remained constant up to 2 moles FFA per mole albumin (k-2 = 16-18 s-1). A rise in k-2 to 70 s(-1) was seen, however, when 2-4 moles capric, lauric, myristic and palmitic (C10-C16) acid were bound, whereas no change was observed when increasing concentrations of caproic, caprylic, stearic and arachic acid.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding, Competitive↗
PubMed1975

Studies on tocopherol derivatives: V. Intestinal absorption of several d,1-3,4-3H2-alpha-tocopheryl esters in the rat.

Twelve d,1-3,4-3H2-alpha-tocopheryl esters were synthesized from d,1-3,4-3H2-alpha-tocopherol. They were acetate, propionate, butyrate, isobutyrate, caprylate, palmitate, acid succinate, benzoate, nicotinate, o-hydroxybenzoate, o-acetoxybenzoate, and pivalate. The hydrolysis of these esters with bile-pancreatic juice and with 9,000 x g supernatant of small intestine and liver homogenates of rats was examined. When these esters were incubated in small intestine or liver supernatants, hydrolysis occurred at a similar rate. In the incubation experiments, alpha-tocopheryl acetate, propionate, butyrate, isobutyrate, caprylate, palmitate, and acid succinate were classified as an easily hydrolyzable group. Alpha-tocopheryl benzoate and nicotinate were in a moderately hydrolyzable group. O-hydroxybenzoate and pivalate, which resisted hydrolysis, were in a scarcely hydrolyzable group. O-acetoxybenzoate was easily hydrolyzed to the o-hydroxybenzoate. Hydrolysis on straight chain fatty acid esters of alpha-tocopherol easily occurred in bile-pancreatic juice. In in vivo experiments, the lymphatic absorption rate of 6 esters, acetate, palmitate, acid succinate, nicotinate, o-hydroxybenzoate, and pivalate, was measured on thoracic duct fistula rats. Easily hydrolyzable esters were recovered mostly in lymph as alpha-tocopherol, whereas, an ester which strongly resisted hydrolysis, such as pivalate, appeared mainly unchanged. This fact suggested that hydrolysis of alpha-tocopheryl esters was not necessarily a prerequisite for intestinal absorption. The percentage of absorption of slowly hydrolyzed esters in lymph was relatively lower than that of moderately or easily hydrolyzable esters.

Animals↗
PubMed1997

Crystallization of monoacylated proteins: influence of acyl chain length.

The crystallization of monoacylated proteins has been investigated using a model system. Acylated derivatives of bovine pancreatic ribonuclease A, differing in their acyl chain lengths (10 to 16 carbon atoms), have been prepared using reverse micelles as microreactors. With one fatty acid moiety per polypeptide chain, covalently attached to the NH2 terminus of the protein, all the modified proteins have similar enzymatic activity and hydrodynamic radius as the native protein. Only the caprylated derivative can give crystals which diffract to high resolution. The resolved structure indicates that: (i) the protein folding is not modified by the chemical modification, (ii) the capryl moiety is not buried within the molecule but available for external interactions. Dynamic light scattering experiments on concentrated solutions show that the protein-protein interactions are dependent on acyl chain length. Proteins with the longest attached chains (14 and 16 carbon atoms) tend to self-associate through acyl group interactions.

Acylation↗
PubMed2002

Distribution of medium-chain FA in different lipid classes after administration of specific structured TAG in rats.

Structured TAG (STAG) containing medium-chain FA (MCFA) in the sn-1,3 positions and essential FA in the sn-2 position were synthesized by lipase-catalyzed acidolysis. In our previous studies we found that part of the MCFA from STAG could be absorbed in the small intestine; however, it was unclear how they were absorbed. In order to get a better understanding of the metabolism of STAG to improve future design and application of STAG, in the present study lymph lipids collected after feeding STAG were fractionated into different classes and the FA composition of each lipid class was studied by GC after methylation to FAME. Caprylic acid was detected in the fraction of TAG only after administration of 1,3-dioctanoyl-2-linoleyl-sn-glycerol (8:0/18:2/8:0), whereas lauric acid was detected in TAG, DAG, and FFA as well as phospholipids after administration of 1,3-didodecanoyl-2-linoleyl-sn-glycerol (12:0/18:2/12:0). We conclude that the enterocyte has the ability to reacylate the MCFA into TAG and that the intestinal absorption of MCFA from STAG mainly occurs by resynthesis of TAG. Caprylic acid from STAG is not incorporated into phospholipids, whereas lauric acid from STAG can be incorporated into phospholipids.

Animals↗
PubMed1984

Determination of molecular weights by differential cryoscopy on small volumes of dilute solutions of oligopeptides.

A differential cryoscope of the equilibrium type is described. It requires only 1 ml of sample for a molecular-weight determination of a solute in a solvent that freezes below room temperature. The instrument is sensitive to +/- 0.0002 degrees C, which corresponds to +/- 0.0001 mol of solute per 1000 g of water. The apparatus was evaluated by measuring the freezing point depressions of 0.015 M urea and 0.01 M alanine in water, the measured molecular weights being accurate to within +/- 5%. The molecular weights of the following oligopeptides were then measured to determine their states of aggregation in the cited solvents: Ac-Asn-Pro-Tyr-NHMe in H2O and dimethyl sulfoxide and cyclo(L-alanyl-L-alanyl-epsilon-aminocaproyl), cyclo(L-alanyl-D-alanyl-epsilon-aminocaproyl), cyclo(L-alanyl-L-analyl-omega-capryl), cyclo(L-alanyl-D-alanyl-omega-capryl), and Ac-Tyr-Pro-Asn-NHMe in dimethyl sulfoxide.

Dimethyl Sulfoxide↗
PubMed1993

Dye-ligand affinity purification of human complement factor B and beta 2 glycoprotein I.

The rapid purification of human factor B using dye-ligand chromatography is described. The 50% ammonium sulphate supernatant of fresh human serum is equilibrated in pH 7.4, 25 mM Tris buffer containing 0.5 mM CaCl2 and 0.5 mM MgCl2, with 25 mM sodium caprylate and chromatographed on Cibacron Blue F3GA-agarose. Caprylic acid binds to the fatty acid binding site of albumin, preventing it from binding to the resin which thus retains a high capacity for binding factor B. Factor B together with the homologous protein beta 2I are eluted from the column by a linear gradient of KCl. Subsequent NaCl gradient FPLC on Hiload S-Sepharose, equilibrated in 10 mM potassium phosphate, 5 mM EDTA, pH 7.0, provides both factor B and beta 2I in homogeneous form.

Chromatography, Affinity↗
PubMedDate not supplied

The immunochemistry of sandwich ELISAs--V. The capture antibody performance of polyclonal antibody-enriched fractions prepared by various methods.

Studies compare the performance of antibody-enriched serum fractions prepared by various methods, when adsorbed on polystyrene microtiter wells as capture antibodies (CAbs) and tested against multivalent antigens. The criteria of performance in the RIA used included antigen capture capacity (AgCC) and the nmol of functional capture sites per microtiter well (CAbt). Affinity purified polyclonal (pAb) and monoclonal antibodies (mAb) were employed as reference CAbs. AgCC was highest for enriched fractions prepared using caprylic acid and a high-pressure SpG affinity column. The performance of capture antibodies is expressed by an equation which was empirically derived and experimentally tested; CAbt x AgCC/ng adsorbed IgG. In terms of this parameter, CAb-enriched fractions prepared with caprylic acid performed best. The data reported also provide insight into solid-phase ligand immunochemistry. Adsorbed polyclonal CAb performed with remarkable homogeneity in percent bound and in Scatchard plots. Values obtained for CAbt from Steward-Petty plots were directly correlated with the length of the LBR of log-log percent bound plots but indicated that less than 10% of the potential capture sites of polyclonal CAbs remained functional after adsorption; mAb showed a more serious loss of activity. The loss of CAbt was a general phenomenon for all preparations tested although relative to their antibody content, certain antibody-enriched fractions retained a higher proportion of CAbt than their affinity-purified counterparts. Comparative studies in which the activity of adsorbed mAb and pAb was compared to the same antibodies immobilized by a non-adsorptive procedure, indicated that adsorbed CAbs also express lower affinity. The studies we report offer a single parameter criterium for comparatively evaluating CAb performance while simultaneously revealing the need to develop immobilization procedures that can preserve CAbt and antibody affinity so that immunoassays with wide dynamic ranges and high AgCC can be developed without waste of antibody.

Adsorption↗
PubMed2004

Assessment of the viral safety of antivenoms fractionated from equine plasma.

Antivenoms are preparations of intact or fragmented (F(ab')2 or Fab) immunoglobulin G (IgG) used in human medicine to treat the severe envenomings resulting from the bites and stings of various animals, such as snakes, spiders, scorpions, or marine animals, or from the contact with poisonous plants. They are obtained by fractionating plasma collected from immunized horses or, less frequently, sheep. Manufacturing processes usually include pepsin digestion at acid pH, papain digestion, ammonium sulphate precipitation, caprylic acid precipitation, heat coagulation and/or chromatography. Most production processes do not have deliberately introduced viral inactivation or removal treatments, but antivenoms have never been found to transmit viruses to humans. Nevertheless, the recent examples of zoonotic diseases highlight the need to perform a careful assessment of the viral safety of antivenoms. This paper reviews the characteristics of equine viruses of antivenoms and discusses the potential of some manufacturing steps to avoid risks of viral contamination. Analysis of production parameters indicate that acid pH treatments and caprylic acid precipitations, which have been validated for the manufacture of some human IgG products, appear to provide the best potential for viral inactivation of antivenoms. As many manufacturers of antivenoms located in developing countries lack the resources to conduct formal viral validation studies, it is hoped that this review will help in the scientific understanding of the viral safety factors of antivenoms, in the controlled implementation of the manufacturing steps with expected impact on viral safety, and in the overall reinforcement of good manufacturing practices of these essential therapeutic products.

Animals↗
PubMed2005

Production and purification of ovine anti-tetanus antibody.

We used the ovine as bioreactor for the production and optimization of anti-tetanus toxin antibody. Four female sheep were immunized with human tetanus vaccine (TT-alum) every two weeks for 16 weeks, after which serum was collected and its titer was estimated by ELISA. The highest titer obtained was 39,000 IU ml-1. To optimize a purification protocol for ovine anti-tetanus toxin, we used four procedures; weak anion (DEAE-Sephadex), weak cation (CM-Sephadex), ammonium sulfate precipitation alone or in combination with caprylic acid. Fifty percent saturation with ammonium sulfate combined with caprylic acid gave us the highest yield of protein with specific activity and the purest Fab product.

Animals↗
PubMed2005

Overexpression and characterization of a lipase from Bacillus subtilis.

A novel plasmid, pBSR2, was constructed by incorporating a strong lipase promoter and a terminator into the original pBD64. A mature lipase gene from Bacillus subtilis strain IFFI10210, an existing strain for lipase expression, was cloned into the plasmid pBSR2 and transformed into B. subtilis A.S.1.1655. Thus, an overexpression strain, BSL2, was obtained. The yield of lipase is about 8.6 mg protein/g of wet weight of cell mass and 100-fold higher than that in B. subtilis strain IFFI10210. The recombinant lipase was purified in a three-step procedure involving ammonium sulfate fractionation, ion exchange, and gel filtration chromatography. Characterizations of the purified enzyme revealed a molecular mass of 24 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, maximum activity at 43 degrees C and pH 8.5 for hydrolysis of p-nitrophenyl caprylate. The values of Km and Vm were found to be 0.37 mM and 303 micromol mg-1 min-1, respectively. The substrate specificity study showed that p-nitrophenyl caprylate is a preference of the enzyme. The metal ions Ca2+, K+, and Mg2+ can activate the lipase, whereas Fe2+, Cu2+, and Co2+ inhibited it. The activity of the lipase can be increased about 48% by sodium taurocholate at the concentration of 7 mM and inhibited at concentrations over 10 mM.

Bacillus subtilis↗
PubMed1996

Topology of gel-phase domains and lipid mixing properties in phase-separated two-component phosphatidylcholine bilayers.

The influence of the lipid mixing properties on the lateral organization in a two-component, two-phase phosphatidylcholine bilayer was investigated using both an experimental (fluorescence recovery after photobleaching (FRAP)) and a simulated (Monte Carlo) approach. With the FRAP technique, we have examined binary mixtures of 1-stearoyl-2-capryl-phosphatidylcholine/1,2-distearoyl-phosphat idylcholine (C18C10PC/DSPC), and 1-stearoyl-2-capryl-phosphatidylcholine/1,2-dipalmitoyl-phospha tid ylcholine (C18C10PC/DPPC). Comparison with the 1,2-dimyristoyl-phosphatidylcholine/1,2-distearoyl-phosphatidylcholine (DMPC/DSPC) previously investigated by FRAP by Vaz and co-workers (Biophys. J., 1989, 56:869-876) shows that the gel phase domains become more effective in restricting the diffusion coefficient when the ideality of the mixture increases (i.e., in the order C18C10PC/DSPC-->C18C10PC/DPPC-->DMPC/DSPC). However, an increased lipid miscibility is accompanied by an increasing compositional dependence: the higher the proportion of the high-temperature melting component, the less efficient the gel phase is in compartmentalizing the diffusion plane, a trend that is best accounted for by a variation of the gel phase domain shape rather than size. Computer-simulated fluorescence recoveries obtained in a matrix obstructed with obstacle aggregates of various fractal dimension demonstrate that: 1) for a given obstacle size and area fraction, the relative diffusion coefficient increases linearly with the obstacle fractal dimension and 2) aggregates with a lower fractal dimension are more efficient in compartmentalizing the diffusion plane. Comparison of the simulated with the experimental mobile fractions strongly suggests that the fractal dimension of the gel phase domains increases with the proportion of high-temperature melting component in DMPC/DSPC and (slightly) in C18C10PC/DPPC.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed2003

Fatty acids as an energy source for the operation of axoplasmic transport.

Fatty acids are utilized as a cellular energy source. In the present study, we investigated whether fatty acids could affect axoplasmic transport. Cultured mouse superior cervical ganglion neurons were placed in the glucose-containing medium (145 mM NaCl, 5 mM KCl, 1 mM CaCl(2), 1 mM MgCl(2), 5 mM D-glucose, 10 mM Hepes, pH 7.3, 37 degrees C), and axoplasmic transport of particles in neurites was observed under video-enhanced contrast microscopy. A variety of fatty acids (acetate (C2), caproate (C6), caprylate (C8), caprate (C10), 2-decenoate (C10:1), arachidonate (C20:4); 0.1-1 mM) caused a transient increase in the amount of particles transported in both anterograde and retrograde directions. The increasing effects of fatty acids were dose-dependent. A half-maximum effective dose (ED(50)) for acetate was 0.8 mM, which is similar to the reported K(m) value of acetyl-CoA synthetase for acetate. The ED(50) for caprylate was 28 microM, which is near the K(m) value of acyl-CoA synthetase for medium- and long-chain fatty acids. Application of 5 mM malonate, an inhibitor of the citrate cycle, induced a steady-state decrease in axoplasmic transport, indicating that energy derived from the citrate cycle is required for the maintenance of axoplasmic transport. The increasing effect of acetate (1 mM) on axoplasmic transport was completely abolished by pretreatment with malonate (5 mM), suggesting that acetate produces ATP for axoplasmic transport via the citrate cycle. Alternatively, the effect of caprate (1 mM) was retained after treatment with malonate. Thus, fatty acids except acetate produce ATP probably through both the beta-oxidation pathway and the citrate cycle, increasing axoplasmic transport. Since the effect of fatty acids was transient, certain negative feedback mechanisms might be involved. The removal of glucose from the medium resulted in a low steady-state level of axoplasmic transport. Under such condition, the acetate (1 mM)-induced transient increase in axoplasmic transport remained. Since intracellular ATP must be low under glucose-free condition, intracellular ATP concentrations are unlikely to be involved in the feedback system. Instead, acetyl-CoA or its downstream products in the citrate cycle might lead to feedback inhibition. Application of citrate (5 mM) caused a strong decrease following a transient increase in axoplasmic transport, whereas no other acetyl-CoA product decreased axoplasmic transport. Thus, excessive citrate may be one of factors leading to feedback inhibition of metabolic pathways to arrest and reverse the increase in axoplasmic transport induced by fatty acids.

Animals↗
PubMed1997

A direct stereoselective synthesis of 7 beta-hydroxytestosterone.

Although 7 beta-hydroxytestosterone is a known product of hepatic androgen metabolism, there are no published methods for its chemical synthesis except from the equally difficult to obtain 7 beta-hydroxy-4-androstene-3,17-dione. We found that several seemingly straightforward routes for its synthesis failed. Consequently, we tried to produce 7 beta-hydroxytestosterone by enzymatic oxidation of 5-androstene-3 beta, 7 beta, 17 beta-triol with cholesterol oxidase (Brevibacterium sp.), a procedure previously used to synthesize 7 beta-hydroxy-4-cholesten-3-one from 3 beta, 7 beta-dihydroxycholesterol (Alexander and Fisher 1995). However, 5-androstene-3 beta, 7 beta, 17 beta-triol was, at best, a very poor substrate for the enzyme leading to the production of 7 beta-hydroxytestosterone in only trace amounts. Thus, we explored a strategy for the enzymatic synthesis in which a C8-ester at C-17 (5-androstene-3 beta, 7 beta, 17 beta-triol 17-caprylate) would serve to mimic the bulky and hydrophobic side chain of cholesterol and thus allow the C19-steroid to act as an effective substrate. When this ester was incubated with cholesterol oxidase, it was converted efficiently to 7 beta-hydroxytestosterone-17-caprylate. Attempts to remove the ester group by several mild hydrolytic procedures caused elimination of the 7 beta-hydroxyl group; we, therefore, obtained 7 beta-hydroxytestosterone by incubation of the intermediate ester with porcine lipase.

Hydroxytestosterones↗
PubMed2001

Part III. Direct enzymatic esterification of lactic acid with fatty acids.

Lipase catalyzed esterification reactions between lactic acid and several fatty acids have been studied. Difficulties arise in esterifying lactic acid because of the potential for this substance to act both as an acyl donor and as a nucleophile. These difficulties were minimized via strategies which greatly increased the yield of the desired ester. Use of the companion fatty acid in excess with respect to lactic acid in an apolar solvent (n-hexane) in which the lactic is not completely dissolved has been employed to minimize the potential for lactic acid to act as an acyl donor in a self-polymerization reaction.Beneficial and sinergistic effects of both silica gel and molecular sieves on conversion to the desired product are described. However, careful control of the amount of molecular sieves used is required. This fact is a consequence of two opposing effects of this material: i.e. adsorption of both lactic acid and water from the reaction mixture. For reaction between caprylic and lactic acids, use of an excessive amount of enzyme reduces the extent of conversion to 2-O-caproyl-lactic acid.A very pure ester of the L-enantiomer (optical rotation of [alpha]D(25) = -23.5) can be prepared in n-hexane using a four fold excess of caprylic acid and Candida antarctica lipase. Optimum reaction conditions lead to 35% yield of 2-O-caproyl-lactic acid, a result which is close to the maximum yield that can be enantioselectively obtained from commercial grade lactic acid (68 mole per cent monomer).

Journal Article↗
PubMed2000

Review of the toxicologic properties of medium-chain triglycerides.

Medium chain triglycerides (MCTs) are a family of triglycerides, containing predominantly, caprylic (C(8)) and capric (C(10)) fatty acids with lesser amounts of caproic (C(6)) and lauric (C(12)) fatty acids. MCTs are widely used for parenteral nutrition in individuals requiring supplemental nutrition and are being more widely used in foods, drugs and cosmetics. MCTs are essentially non-toxic in acute toxicity tests conducted in several species of animals. In ocular and dermal irritation testing MCTs exhibit virtually no potential as ocular or dermal irritants, even with prolonged eye or skin exposure. MCTs exhibit no capacity for induction of hypersensitivity. Ninety-day toxicity tests did not result in notable toxicity, whether the product was administered in the diet up to 9375mg/kg body weight/day or by intramuscular (im) injection (up to 0. 5ml/kg/day, rabbits). There was no evidence that intravenous (iv) or dietary administration of MCTs adversely affected the reproductive performance of rats or resulted in maternal toxicity, foetal toxicity or teratogenic effects at doses up to 4.28g/kg body weight/day (iv) or 12,500mg/kg body weight/day (dietary). There was no evidence that dietary administration of MCTs adversely affected the reproductive performance of pigs or resulted in maternal toxicity, foetal toxicity or teratogenic effects at doses up to 4000mg/kg body weight/day in the diet. In rabbits, following iv administration, the maternal and foetal no-observed-adverse-effect levels (NOAELs) were between 1.0 and 4.28g/kg body weight/ day. A 2-year study in rats, conducted with a closely related compound (tricaprylin, a triglyceride with C(8) fatty acids), provided no evidence of a carcinogenic effect when the material was administered by oral gavage at levels up to 10ml/kg (9.54g/kg) per day. Although tricaprylin was found to be positive in one of five strains of Salmonella typhimurium in the presence of metabolic activation in an Ames mutagenicity assay, the results of the carcinogenicity test with tricaprylin and mutagenicity tests with caprylic acid indicate that MCTs do not have the potential to be carcinogenic or mutagenic. The safety of human dietary consumption of MCTs, up to levels of 1g/kg, has been confirmed in several clinical trials.

Animals↗
PubMed2000

Nonionic oil-in-water microemulsions: the effect of oil type on phase behaviour.

The formation of oil-in-water (o/w) microemulsions stabilized by the nonionic surfactants, polyoxyethylene-10-dodecyl ether, polyoxyethylene-10-oleyl ether, N,N-dimethyldodecylamine-N-oxide and N,N-dimethyloleylamine-N-oxide and containing a variety of pharmaceutically acceptable oils, namely ethyl butyrate, ethyl caprylate, ethyl oleate and the triglycerides, soybean oil, Miglyol 812 and tributyrin, has been examined at 298 K. The effect on microemulsion formation of replacing water with phosphate buffered saline (PBS) and complete PBS has been established. In addition, the effect of changing temperature (from 298 to 310 K) on the phase behaviour of microemulsions formulated using PBS as continuous phase has been determined. Although some small differences in phase behaviour were noted when altering the continuous phase, the greatest difference in phase behaviour was observed when changing the experimental temperature, particularly for microemulsions stabilized by polyoxyethylene-10-oleyl ether. Regardless of the temperature and aqueous phase used, however the larger molecular volume oils (soybean oil, Miglyol 812 and ethyl oleate) were solubilized to a lower extent than the smaller molecular volume oils (namely, ethyl butyrate and ethyl caprylate). The only exception to this rule was when polyoxyethylene-10-oleyl ether was used as surfactant, particularly at 298 K, where it was the larger molecular volume oils that were solubilized to the greatest extent. Cloud point/phase inversion temperature experiments suggested that the higher molecular volume oils were incorporated into the microemulsions prepared using the polyoxyethylene-based surfactants in a different way than the smaller molecular volume oils and suggest that the smaller molecular volume oils are acting in much the same way as a cosurfactant in that they interchelate with their hydrophilic group interspersed in the surfactant head group region. As N,N-dimethyldodecylamine-N-oxide does not exhibit a cloud point it was not possible to determine the mode of oil incorporation in microemulsions prepared with this surfactant.

Amines↗