SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
While studies on the extraction of drugs by various organic solvents are numerous, very few direct comparisons of all the commonly used extraction solvents have been made. Review of the literature and some specific studies undertaken by the author show that the solvents more frequently used in toxicology are not all alike but vary with respect to type of drug being extracted. Hexane, 1-chlorobutane, dichloromethane, chloroform, isopropyl ether, ethyl ether, ethyl acetate, and 1-butanol all extract nonpolar drugs quite efficiently; drugs which have polar functional groups such as alcohols, phenols, carboxylic acids, imides, amides, esters, and sulfonamides require more polar solvents for their removal from aqueous solution in high yield. Ethyl ether and other ethers, ethyl acetate, and ketones are hydrogen bond acceptor molecules and therefore extract electron donor solutes more readily than chloroform, the most commonly used electron donor solvent. Alcohols such as 1-butanol are excellent general drug extractors but pose other problems such as odor and emulsion formation. Hexane, on the other end of the polarity scale, extracts polar solutes very poorly. Thus, chloroform and ethyl ether are the most versatile solvents, although dichloromethane and 1-chlorobutane are finding more use. Solvent costs and health hazards vary within the group of solvents discussed. 1-Chlorobutane and chloroform are relatively expensive, while ethyl ether, hexanes, and dichloromethane are less expensive. No solvent is 100% safe with respect to fire, explosion, and health hazard. While chloroform has the lowest TLV, a safety limit, some of the other solvents have higher vapor pressures. The most useful solvent for small volume extractions is chloroform or chloroform with a small percentage of an alcohol. Although poor recoveries are obtained for many drugs by the small volume extraction technique, more and more use of this approach is expected in the future.
Mixidine, a very soluble base which is completely ionized in all physiological fluids, was found to form ion-pairs as demonstrated by its ability to partition into 1-butanol from acidic solutions. A similar relationship was observed for the effect of acids on the absorption of intraduodenally and orally administered solutions of mixidine in rats (as determined by lethality). Studies also demonstrated that the pH-lethality effects were not specific for a particular counterion. Mixidine was more lethal when administered intraduodenally than when administered orally, and the counterions per se were not lethal in the doses used.
A rapid, sensitive, and specific method of analysis for atenolol is described. Metoprolol is used as the internal standard. Atenolol and metoprolol are extracted into 1-butanol--benzene. Interfering components present in palsma and urine, but not discolored saliva, are removed during an acid wash and reextraction into ether. Drug and internal standard are converted to the pentafluoropropionate derivatives, which are quantitated by GLC with electron-capture detection and characterized by chemical-ionization mass spectrometry. The method should be applicable to measurement of other beta-adrenergic blocking agents with similar structures.
Tetracycline complexation with calcium and organic ligands was studied using fluorescence, circular dichroism, and solvent extraction methods. The results were used to interpret the mechanism of the commonly used fluorometric methods for the analysis of tetracycline in biological fluids. Tetracycline formed ternary calcium complexes with barbital sodium and L-tryptophan in alkaline solutions. The circular dichroism studies indicate that the calcium ion in these complexes is bound to the C-4 dimethylamino and the C-12a hydroxyl groups of tetracycline. These ternary complexes are strongly fluorescent and can be extracted easily into 1-butanol or ethyl acetate. Based on the characteristics of the ternary complexes and of the tetracycline degradation products, it is concluded that only the active form of tetracycline can be complexed and extracted for fluorescence analysis.
By using previously developed pertrimethylsilylation and methoxime formation procedures, the GLC--mass spectra of pertrimethylsilyl and pertrimethylsilyl methoxime derivatives of 12 doxorubicin and daunorubicin glycone analogs, mostly synthesized in this laboratory, were studied. The fragmentation pathways were readily interpretable, and the patterns were highly specific for corresponding structural changes, thus supporting the previous contention that this method has potential for the identification of doxorubicin and daunorubicin metabolites. Four aglycone metabolites were identified, on the basis of their GLC--mass spectra, in the hydrolysate of the 1-butanol extract of bile obtained from a doxorubicin-treated rabbit.
The solubility of granulopoiesis inhibiting factor (GIF) in various aqueous and organic solvents was investigated. GIF is soluble in water, 10% acetic acid, and 10% pyridine. It is not extractable by 1-butanol at low and high pH. A high solubility was found in polar organic solvents (ethanol-acetone 9:1, and chloroform-methanol 1:1), whereas GIF seems to be insoluble in pure chloroform.
Three strains of Streptomyces rimosus were grown on four different media. The one suitable for the production of oxytetracycline by Streptomyces rimosus 12907 was modified by black strap molasses, fodder yeast (40% total protein) and rice bran. The volume of the fermentation medium was sealed up in a 1200-litre fermentor aerated with sterile air obtained from a system used in the purification of air. 850 g crude oxytetracycline was obtained when the fermented medium (700 litres) was extracted with 1-butanol.
A simple and convenient method for the purification of human plasma lecithin-cholesterol acyltransferase was developed. The method involves the adsorption of the enzyme from diluted human plasma on DEAE-Sephadex, treatment with 1-butanol in the presence of (NH4)2SO4, DEAE-Sephadex chromatography, treatment with dextran sulfate in the presence of Ca2+, and hydroxyapatite chromatography. The enzyme purified showed a single main band by polyacrylamide gel electrophoresis in the presence and absence of sodium dodecyl sulfate. In addition, the enzyme obtained was stable for more than four weeks, when it was kept at 4 degrees C under N2 in a buffer of low ionic strength. The purified enzyme was used to study its specificity toward the acyl acceptor. This specificity was found to be broad in that not only sterols but also long chain primary alcohols exhibited considerable acceptor activity. Furthermore, in agreement with our previous observations with crude enzyme (Piran, U. and Nishida, T. (1976) J. Biochem. (Tokyo) 80, 887-889), the purified enzyme was found to be capable of hydrolyzing the ester linkage at the carbon-2 position of phosphatidylcholine. The transesterification, as well as the hydrolytic reaction, required the presence of the cofactor polypeptide, apolipoprotein A-I.
Thiourea and diethylthiourea, two compounds which react with hydroxyl radicals, inhibited NADPH-dependent microsomal oxidation of ethanol and 1-butanol. Inhibition by both compounds was more effective in the presence of the catalase inhibitor, azide. Inhibition by thiourea was noncompetitive with respect to ethanol in the absence of azide but was competitive in the presence of azide. Urea, a compound which does not react with hydroxyl radicals or H2O2, was without effect. Thiourea had no effect on NADH- and NADH-cytochrome c reductase, NADPH oxidase, and NADH- and NADPH-dependent oxygen uptake. Thiourea inhibited the activities of aniline hydroxylase and aminopyrine demethylase. Thiourea, but no other hydroxyl radical scavengers, e.g., dimethyl sulfoxide, mannitol, and benzoate, reacted directly with H202 and decreased H2O2 accumulation in the presence of azide. Therefore the actions of thiourea are complex because it can react with both hydroxyl radicals and H2O2. Differences between the actions of thiourea and those previously reported for dimethyl sulfoxide, mannitol, and benzoate, e.g., effects on drug metabolism, effectiveness of inhibition in the absence of azide, or kinetics of the inhibition, probably reflect the fact that thiourea reacts directly with H2O2 whereas the other agents do not. The current results remain consistent with the concept that microsomal oxidation of alcohols involves interactions of the alcohols with hydroxyl radicals generated from microsomal electron transfer.
A model system for the partitioning of peripheral membrane proteins into membranes by ligand binding has been examined experimentally. Both bovine serum albumin and lysozyme partition between water and 1-butanol by the addition of sodium p-toluene sulfonate at pH 2.4. The partitioning is characterized by high orders of reaction: 25 and 10, respectively. Theory indicates that these high orders of reaction need not result from cooperative ligand binding in either phase, but depend primarily upon the number N of protein sites at which the transfer-promoting ligant binds, and on the difference in free energy of formation delta F0s of the protein--ligand complexes in the two phases. From the reaction orders and the experimental values of N, 80 for albumin and 11 for lysozyme, delta F0s was calculated to be --0.5 kcal/mol (--2.1 kJ/mol) and --0.8 kcal/mol (--2.5 kJ/mol) per ligand bound, respectively. Experiments measuring the dependence on ligand concentration of the rate of protein electrophoresis across the water/butanol interface are described. These rates increase by more than two orders of magnitude as the ligand concentration approaches the critical value for partition and are inversely dependent on the number of ligant sites for the two proteins studied.
A family of five antibiotic substances was isolated from the slime mold Physarum gyrosum by high pressure liquid chromatography (HPLC). For this purpose, mold was cultured for two weeks in a liquid medium. Soluble products were harvested by rotary evaporation of medium and extraction with 1-butanol. Paper chromatography in ethyl acetate:pyridine:water (2:2:1 v/v) was used for preliminary fractionation. Active components were separated by HPLC with a reverse-phase column packed with Bondapack C18/Porasil B (Waters Associates) and were eluted with a linear gradient of methanol:water increasing from 70 to 100% methanol over 90 minutes. Purification was completed by rechromatographing individual fractions. Purity of the active components was verified by HPLC and thin layer chromatography. Activity assays against Bacillus cereus showed these materials to be bacteriostatic rather than bacteriocidal.
The organic hydroperoxide cumene hydroperoxide is capable of oxidizing ethanol to acetaldehyde in the presence of either catalase, purified cytochrome P-450 or rat liver microsomes. Other hemoproteins like horseradish peroxidase, cytochrome c or hemoglobin were ineffective. In addition to ethanol, higher alcohols like 1-propanol, 1-butanol and 1-pentanol are also oxidized to their corresponding aldehydes to a lesser extent. Other organic hydroxyperoxides will replace cumene hydroperoxide in oxidizing ethanol but less effectively. The cumene-hydroperoxide-dependent ethanol oxidation in microsomes was inhibited partially by cytochrome P-450 inhibitors but was unaffected by catalase inhibitors. Phenobarbital pretreatment of rats increased the specific activity of the cumene-hydroperoxide-dependent ethanol oxidation per mg of microsomes about seven-fold. The evidence suggests that cytochrome P-450 rather than catalase is the enzyme responsible for hydroperoxide-dependent ethanol oxidation. However, when H2O2 is used in place of cumene hydroperoxide, the microsomal ethanol oxidation closely resembles the catalase system.
The isolation of erythrocytes of high purity from human blood was achieved by a combination of the two well established methods cells in erythrocyte preparations of different purities was studied. The acid protease activity was recovered to a level comparable with the recovery of erythrocytes, while the neutral protease activity as detected by the release of acid-soluble peptides from hemoglobin or casein disappeared in proportion to the removal of white blood cells. An acid protease was solubilized from the membranes of the purified erythrocytes by the extraction with 1-butanol. The enzyme was active in a pH range from 2 to 4, and sensitive to pepstatin. It was named pH-3 protease after its pH optimum. Sealed ghosts with right-side-out membranes and inside-out vesicles with reverted membranes were prepared from the purified erythrocytes and compared with respect to pH-3 protease activity for its latency as well as its inactivation by tryptic digestion. The results obtained indicate that pH-3 protase is localized on the inner surface of erythrocyte membranes. The self-digestion experiments at pH 4 using the sealed ghosts showed higher availability to pH-3 protease of spectrin and IVa protein than the other membrane proteins, also suggesting the localization of an acid protease in the inner membranes of erythrocytes.
Positive patch test reactions to isopropyl alcohol in connection with proved allergy to ethyl alcohol have already been published. A case of allergy to isopropyl alcohol with positive reactions to isopropanol (unpurified test material) and negative reactions to ethanol and methanol has also been reported. We report a case of a occupationally acquired sensitivity to isopropyl alcohol in which, on testing with gas chromatographically purified material, positive patch test reactions were found to 1-propanol, 1-butanol, 2-propanol, 2-butanol and methanal (formaldehyde) but not to the primary alcohols methanol, ethanol and amyl alcohol; not to the aldehydes acetal (acetaldehyde) and butanal; nor to the ketones acetone, butanon and isobutyl ketone, nor to methanoic (formic)acid. A tentative explanation for this peculiar pattern of reactions is given.
During the initial stages of intraperiplasmic growth of Bdellovibrio bacteriovorus on Escherichia coli, the peptidoglycan of the E. coli becomes acylated with long-chain fatty acids, primarily palmitic acid (60%) and oleic acid (20%). The attachment of the fatty acids to the peptidoglycan involves a carboxylic-ester bond, i.e., they were removed by treatment with alkaline hydroxylamine. Their linkage to the peptidoglycan does not involve a protein molecule. When the bdelloplast peptidoglycan was digested with lysozyme, the fatty acid-containing split products behaved as lipopeptidoglycan, i.e., they were extracted into the organic phase of 1-butanol:acetic acid:water (4:15) two-phase system; all of the lysozyme split products generated from normal E. coli peptidoglycan were extracted into the water phase. It is suggested that the function of the acylation reaction is to help stabilize the bdelloplast outer membrane against osmotic forces. In addition, a model is presented to explain how a bdellovibrio penetrates, stabilizes, and lyses a substrate cell.
The glucuronide of 7-hydroxychlorpromazine (CPOH), formed by incubation with hepatic microsomes and UDP-[U-14C]glucuronic acid, was isolated by extraction into 1-butanol at pH 1 and assayed by liquid scintillation counting. Although concentrations of CPOH greater than 3 X 10(-4) M stimulated its conjugation, the apparent KM of the transferase in microsomes from guinea pig liver for CPOH was 9.5 X 10(-5) M. The apparent activation of glucuronyltransferase by high concentrations of CPOH was prevented when preparations were maximmally stimulated by Triton X-100. The rate of conjugation of CPOH by preparations of guinea pig liver was almost twice that measured with those of rat liver. However, the maximal stimulation of the conjugation of CPOH by Triton with preparations of rat liver was almost twice that observed with microsomes from guinea pig liver. The conjugation of CPOH by microsomes from rat and guinea pig liver was inhibited about 25% by SKF 525-A (1 X 10(-4) M). The inhibitory action of SKF 525-A decreased at concentrations greater than 5 X 10(-4) M and no inhibition was observed at 1 X 10(-3) M.
A heat stable toxin present in needles of ponderosa pine was found to be soluble in methanol, ethanol, chloroform hexanes and 1-butanol. The embryotoxic effects of fresh green pine needles and a chloroform/methanol extract were determined by measuring embryo resorption in pregnant mice. Autoclaving the needles and extract for 1 hour prior to feeding enhanced the embryoresorptive effect by 28% and 32%, respectively. The results of this study revealed that the embryo resorptive dose (ERD50) of heat stable toxin for 1 mouse was 8.95 gms. for fresh green pine needles and 6.46 gms. for autoclaved green pine needles. In addition to embryocidal effects, feeding of the toxin resulted in significant weight loss in adult mice.