共查询到20条相似文献,搜索用时 15 毫秒
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J. Szejtli 《Journal of inclusion phenomena and macrocyclic chemistry》1984,2(3-4):487-501
Cyclodextrins are applied to facilitate formulation problems, to improve stability and bioavailability. Following factors are determining whether or not cyclodextrins can be applied in oral pharmaceutical preparations: - properties of the selected CD: solubility, price, specific catalytic properties, - the drug to be complexed: molecular weight, polarity, solubility, - drug dose - solubility properties of the complex and the “super solubility” /temporary over-saturation/ - complex stability and possibility to shift the dissociation equilibrium toward the appropriate direction - legislative procedures 相似文献
3.
P. Speiser 《Applied biochemistry and biotechnology》1984,10(1-3):221-235
The incorporation of drugs into vesicles is one of several technological methods for the optimization of targeted drug delivery and controlled drug targeting. The main problems will always remain ? To design inert auxiliary accompanying materials in order to overcome side reactions ? To use body-friendly and biodegradable macromolecular carrier materials for the therapeutic system ? To miniaturize the dosage form dramatically in the submicroscopic size range in order to eliminate foreign body irritations ? To develop ultrafine solid and amorphous vesicular compartments (nanocapsules, nanopellets, nanoparticles) to get stable systems with good tissue transfer and organ targeting properties The actual stand of the incorporation of drugs and biologic active material into ultrafine colloidal solid capsules is reviewed here as for instance: ? Immunoactive material ? Fluorescent indicators in body fluids ? Controlled and sustained release systems ? Nonspecific drug targeting of the first-order (passage through endothelial tissues) ? Second-order targeting (a specific transparenchymal migration), and a highly specific targeting of the third-order (transcellular passage, especially lysosomal transports) Examples for some of these applications are given. It can be shown that such ultrafine vesiculated capsules offer some advantages when applied parenterally, but also partly for oral application. In the future, still more studies are necessary finally to clarify the importance and practical use of such ultrafine targeting carriers. 相似文献
4.
A. Lubecki 《Journal of Radioanalytical and Nuclear Chemistry》1969,2(1-2):3-18
Theoretical consideration concerning some possibilities for the elimination of matrix effects in non-dispersive X-ray fluorescence and absorption analysis are discussed. The theoretical treatment is concerned with the following methods:
- double-channel absorption edge analysis,
- concentration increase and dilution method in fluorescence analysis,
- fluorescence-absorption method,
- emission-transmission method,
- fluorescence-Compton scattering method,
- method of multicomponent analysis.
5.
An improvement of the signal-to-noise ratio in atomic absorption spectroscopy may be obtained by each of the following three methods of signal averaging: increase of the time constant digital signal averaging true integration of the signal The most adequate of these methods appears to be true integration. Two examples are presented to demonstrate the improved signal-to-noise ratio due to the application of this method: trace analysis of mercury in water by means of flameless AAS. The detection limit appears to be 0.2 ng which corresponds to a concentration of 2 · 10?13 g/ml. trace analysis of copper in human urine by means of flame AAS: 1,3 · 10?8 g/ml copper could be detected without any solvent extraction process. 相似文献
6.
A family of explicit linear sixth algebraic order six-step methods with vanished phase-lag and its first derivative is obtained in this paper. The investigation of the above family of methods contains: theoretical study of the new family of methods and computational study of the new family of methods. The theoretical study of the above mentioned family of methods contains:
- the development of the method,
- the computation of the local truncation error,
- the comparative local truncation error analysis. The comparison is taken place between the new family of methods with the corresponding method with constant coefficients and
- the stability analysis of the new family of methods. The stability analysis is taken place using test equation with different frequency than the frequency of the test equation used for the phase-lag analysis of the methods.
7.
I. Gutmann 《Analytical and bioanalytical chemistry》1970,252(2-3):234-236
- Determination of Maltose. Maltose is hydrolyzed by the enzyme α-glucosidase into glucose, which is determined by the enzymes hexokinase and glucose-6-phosphate-dehydrogenase. α-Glucosidase is specific for oligosaccharides with α-1,4 and α-1,2 bonds.
- Determination of Starch and Glycogen. Starch and glycogen are splitted to glucose by the enzyme amylo-glucosidase. Starch has to be dissolved before enzymatic cleavage. A comparison of different methods for preparing starch solutions is given.
- Determination of d- and l-Lactate. It is possible to determine d-lactate and l-lactate with the specific enzymes d-lactate-dehydrogenase and l-lactate-dehydrogenase. By different samples it is shown that no equal quantities of d- and l-lactate were found in the analyzed foods.
8.
Thermoanalytical and microstructural measurement techniques allow the characterization of solids, their transformation, decomposition, specific surface and pore structure. These techniques are of importance for solids with high specific surface and/or porosity. Thermoanalytical techniques are applied to detect solid state reactions, to determine reaction temperatures and to monitor the progress of the reaction. They are useful to simulate thermal processes in the industry and to receive meaningful results with small samples in a short time. Specific surface, cumulative pore volume and pore volume distribution are obtained by intrusion and absorption techniques. Here selected applications of thermoanalytical and microstructure investigations in modern fields of materials research will be presented, as: -pore analysis of sintering steps of ceramics, -secondary structure of catalyst granules, -template decomposition in zeolites, -firing process in a composide ceramic tape, -ignition of coke. 相似文献
9.
- The determination of monosubstituted acetylenic compounds was investigated at various temperatures (?60° to +95°C) by the alanate method described byMerz.
- At 90°C all active hydrogen atoms were determined with sufficient accuracy and good precision, but at 0° C the active hydrogen atom of the ethinyl group in monosubstituted acetylenes did not react. This is the basis of a method for determining the acid hydrogen in the ethinyl group: the active hydrogen reactive at 0° C is first determined, then the temperature is raised to 90° C, when all the remaining active hydrogen atoms are determined.
- The Merz method for determining active hydrogen is in our opinion the most suitable chemical method for determining ethinylcarbinols.
- It has been shown that active hydrogen atoms react faster with alanate (sodium diethyldihydridoaluminate) than with Grignard reagent. The active hydrogen atoms in certain compounds do not react quantitatively with Grignard reagent within the normal tune. The alanate method is thus more generally applicable than the Grignard method.
10.
Prof. Dr. Fritz Sauter Peter Stanetty Eike Schrom Gerhard Sengstschmid 《Monatshefte für Chemie / Chemical Monthly》1978,109(1):53-61
Derivatives of the following six ring systems were synthesized:
- 3,10-Dihydro-[1]benzothieno[2,3-d]imidazo[1,5-a]-pyrimidine (I)
- 6H-[1]Benzothieno[2,3-d]pyrazino[1,2-a]pyrimidine (II)
- 1,5-Dihydro-[1]benzothieno[2,3-d]imidazo[1,2-a]-pyrimidine (III)
- 6H-[1]Benzothieno[2,3-d]pyrimido[1,2-a]pyrimidine (IV)
- 1,5-Dihydro-imidazo[1,2-a]thieno[2,3-d]pyrimidine (V)
- 4H-Pyrimido[1,2-a]thieno[2,3-d]pyrimidine (VI)
11.
A. A. Klyosov 《Applied biochemistry and biotechnology》1986,12(3):249-300
This techno-economic study deals with the production of sugars and alcohols from cellulosic materials. It covers such key subjects as: potential raw materials; the state-of-the-art on production technologies; the economics of extant processes; and finally infers implications for developing countries from the foregoing. It is clear that a large number of cellulose-, starch-, and sugarcontaining plants can be processed to produce sugars and alcohols. Sugar-containing plants such as sugarcane, sweet sorghum, and nipa palm are the best candidates for the high-yield production of alcohol fuel. Likewise, the starch-containing crops such as cassava, sweet potatoes, yams, taro, and tannia are good candidates, but require an additional step to break down starch to sugar. However, the emphasis of this report is on the major part of biomass containing cellulose and which, therefore, needs special treatment before it can be used to produce glucose and alcohols. To utilize cellulosic containing raw materials the following steps are necessary: ? Increase self-sufficiency since alcohols can to a great part substitute for petroleum fuels. ? Achieve a better balance of trade. ? Be able to increase employment, especially in rural areas. ? Achieve a higher level of technical competence in biotechnology and related areas. ? Be in a position to expand chemical industries. ? Establish an improved agricultural base by being able to utilize alternative crops and by being able to use what was previously termed agricultural wastes. 相似文献
- Growth, harvest, and delivery of raw materials to processing plants; or, alternatively, the collection and delivery of cellulosic “waste” products.
- Pretreatment or conversion of the raw material by mechanical, physical, chemical, or enzymatic methods to break down the cellulose to sugars and to modify or remove unwanted side-products, usually lignin and hemicellulose.
- Recovery and purification of sugars from reaction mixture.
- Fermentation of sugars to alcohol and purification by distillation.
- Treatment of process residues to reduce pollution and to recover potentially valuable side-products.
12.
M. Wiedemann L. Raith A. Wirtz H. J. Karl 《Analytical and bioanalytical chemistry》1972,261(4-5):382-385
Amberlite IRA 400-coated resin strips were tested with regard to their capability to separate free from protein-bound steroids, and as such to act as an adsorbant for the determination of testosterone by protein binding methods. Results showed
- Tritium labelled testosterone, dihydrotestosterone, cortisol, progesterone and estradiol are adsorbed to the Amberlite in aqueous media.
- Adsorbed are mainly the free steroids and not the steroid hormones which are bound to their specific proteins.
- Through the quantitative determination of testosterone, results show a coefficient of variation of 1.3–3.9% in the range from 1–8 ng per sample.
- The standard curves performed on different days fit well. The percentage error calculated for curves performed on 5 successive days was 5.7% for 8 ng of testosterone and 1.7% for 2 ng.
13.
Two methods for the determination of the active ingredient of Eulan WA neu in textile industry waste waters are described:
- Gas chromatographic method. The waste water is acidified and extracted with toluene. The active ingredient is determined in the extract with ECD (63Ni)-indication by external standards.
- Thin-layer chromatographic method. After having splitted the active ingredient—directly in the waste water or after extraction with toluene—the resulting aromatic amines are separated by TLC. The spots are coloured by diazotizing and coupling with 1-N-naphthylethylene-diamine. Evaluation is made by comparison with standards. Taking 500 ml of waste water per analysis the detection limit is 0.05 ppm for both the methods.
14.
D. L. Massart L. Buydens C. Armanino I. Broeckaert D. Coomans W. H. Dekker M. P. Derde M. Detaevernier K. H. Esbensen M. Forina M. Jonckheer L. Kaufman A. M. Massart-Leën J. Smeyers-Verbeke J. C. Den Hartog 《Analytical and bioanalytical chemistry》1982,311(4):448-448
This poster illustrates the lecture on Pattern Recognition and gives recently published and unpublished examples, mainly from the laboratory from the first author. The applications concern: - the determination of metabolic pathways of branched chain fatty acids (by clustering), - the development of a genetic classification of meteorites (by clustering), - the classification of cholinergic agents according to their interaction with different receptors (by clustering), - the structure of a data set consisting of gaschromatographic profiles in samples collected in pollution monitoring stations (by factor analysis and pattern recognition), - factors determining GLC behaviour of solutes (by factor analysis and multiple regression), - the classification of olive oils according to geographic origin (by principal components and pattern recognition), - the diagnosis of thyroid status (by pattern recognition). 相似文献
15.
A. Lubecki 《Journal of Radioanalytical and Nuclear Chemistry》1970,4(2):337-345
A way of graphical estimation of sensitivity is presented for the following methods:
- X-ray fluorescent analysis without the elimination of matrix effects,
- fluorescence-Compton-scattering method,
- dilution method.
16.
- The equilibrium spreading pressures were studied as a function of composition of the following binary systems by use of the Wilhelmy-method atT=295 K on aqueous substrate:
- The equilibrium spreading pressures of the pure components of the systems I und II, respectively, decrease due to addition of the corresponding components of mixture. A minimum occurs at the mole fractionx=0,50. The equilibrium spreading pressures of mixtures of system III rise with increasing mole fraction of octadecyldiethylphosphine oxide.
- The three spreading diagrams are based on one general type. The phase rule is applied and shows that the components of the 3 systems must be immiscible in the monolayer but miscible in the bulk phase.
17.
Holm Pauschmann 《Analytical and bioanalytical chemistry》1972,258(5):358-363
Separation processes, based on different migration speeds of components in mixtures can be reduced to combinations of 3 elements:
- Migrations, defined by different speeds of components,
- Shifts, which move all components at the same speed,
- Gradients, which influence the speed of components in migrations or shifts.
18.
The aim of this contribution is to draw attention to the following problems:
- boundary conditions of kinetic models,
- distortion of kinetic data by cutting-off the peak ends,
- regression analysis involved in the evaluation of kinetic data.
19.
W. Klötzer R. Franzmair H. Bretschneider 《Monatshefte für Chemie / Chemical Monthly》1970,101(5):1263-1270
Three methods for the synthesis of various substituted 2-amino-1-pyrrolines are described:
- Cyclization of 2.2-disubstituted 4-bromobutyronitriles with ammonia to yield 3.3-disubstituted 2-amino-1-pyrrolines.
- Reduction of 2-aminopyrrolin-5-ones or 2-iminosuccinimides with LiAlH4, a route leading especially to 3.3.4-substituted 2-aminopyrrolines.
- Chlorination of 4.4-disubstituted pyrrolidones with POCl3 followed by treatment with NH3 gives 4.4-disubstituted 2-amino-1-pyrrolines.
20.
As has been demonstrated, mass spectrometry provides a powerful analytical tool for the accurate measurement of small amounts of substances in a complex biological matrix. In our laboratory this technique is used as a reference method for measuring the routine clinical chemical parameters creatinine, uric acid, cholesterol, total glycerol and the hormones cortisol, testosterone, oestradiol-17β, oestriol, progesterone, aldosterone and thyroxine in human serum. In general, the analytical procedure for measuring a substance by isotope dilution mass spectrometry (IDMS) consists of the following steps:
- Addition of a certain amount of the isotopically labeled analyte to the serum sample.
- Isolation and purification of the labeled and the non-labeled endogenous analyte from the biological matrix.
- Derivative formation of the isolated and purified labeled and non-labeled compound.
- Selected ion recording of characteristicm/z values of the labeled and non-labeled analyte using combined gas chromatography-mass spectrometry (GCMS).
- Calculation of the concentration of the analyte from the isotope ratio measured by GCMS.