Related compound standard

Related compound standard. These standards are typically characterized fully, but not to the same extent as the primary reference standard of the active... 

Related compound standard These standards are typically characterized fully, but not to the same extent as the primary reference standard of the active drug substance. Because quantities of these standards are typically limited, response factors for these standards can be assigned to eliminate routine use in FIPLC purity determination. 

P-Keto-sulphoxides and Related Compounds.—Standard syntheses have been illustrated in the recent literature methyl benzenesulphinate reacts with an active methylene compound in the presence of NaH to give a j8-keto-sulphoxide, and preparations from cyanohydrins have been described. pKa, Values of a series of substituted a-phenylsulphinylacetophenones are readily correlated with Hammett -values. ... 

Compiled from Daubert, T. E., R. R Danner, H. M. Sibiil, and C. C. Stebbins, DIPPR Data Compilation of Pure Compound Properties, Project 801 Sponsor Release, July, 1993, Design Institute for Physical Property Data, AlChE, New York, NY and from Thermodynamics Research Center, Selected Values of Properties of Hydrocarbons and Related Compounds, Thermodynamics Research Center Hydrocarbon Project, Texas A M University, College Station, Texas (extant 1994). The compounds are considered to be formed from the elements in their standard states at 298.15 K and 101,325 P. These include C (graphite) and S (rhombic). Enthalpy of combustion is the net value for the compound in its standard state at 298.15K and 101,325 Pa. 

Particularly for direct microanalytical techniques using <10 mg of sample for analysis, it is highly desirable to obtain quantitative information on element- and compound-specific homogeneity in the certificates for validation and quality control of measurements. As the mean concentration in a CRM is clearly material-related, the standard deviation of this mean value should represent the element s distribution in this matrix rather than differences in the analytical procedures used. 

Beasley et al. developed a panel of immunoassays to monitor DDT, its metabolites, and structurally related compounds, but they found that milk has a severe effect on the assay performance. They found that when directly utilizing whole milk, color development was completely inhibited. Even when using 1 100 dilutions of whole milk, the assay sensitivity was reduced by 90% (based on the IC50 shift, not simply the dilution factor). A number of procedures were evaluated to eliminate the interferences from the fat-soluble analytes. However, many of the procedures that removed interferences also removed the analytes. Extraction with a mixture of solvents and the use of similarly processed blank milk to prepare the standards ultimately yielded more accurate results. This article demonstrates the difficulties encountered in analyzing lipid-soluble analytes. 

Spectrophotometric determination with 4-hexylresorcinol and a fluorometric method with m-aminophenol are the most commonly used procedures for the determination of acrolein. However, gas chromatography and high-performance liquid chromatography procedures are also used (USEPA 1980 Kissel etal. 1981 Nishikawa and Hayakawa 1986). Acrolein concentrations in rainwater between 4 and 200 pg/L can be measured rapidly (less than 80 min) without interference from related compounds the method involves acrolein bromination and analysis by gas chromatography with electron capture detection (Nishikawa and Hayakawa 1986). Kissel etal. (1981) emphasize that water samples from potential acrolein treatment systems require the use of water from that system in preparing blanks, controls, and standards and that acrolein measurements should be made at the anticipated use concentrations. 

High performance liquid chromatography is used to determine the purity of calcitriol, and to separate it from related compounds. Using a 10 micron silica column of 25 cm length, and a mobile phase of spectroquality heptane ethyl acetate. methanol (50 50 1) at a flow rate of 1.7 ml/ minute, separation and quantitation are achieved. p-Dimethyl-aminobenzaldehyde may be used as an internal standard to compensate for variations in injection technique and instrumental conditions. With a 254 nm ultraviolet absorbance detector, 0.01 ug of calcitriol may be detected (3). 

The logarithm for the capacity factor correlates well with known log P values obtained by the shake flask method. In practice, the k values are determined isocratically from 70 to 30% organic mobile phase and then extrapolated to 0%. Prior to determining the log P for an unknown compound, a set of structurally related molecules (standards) are analyzed to construct a correlation model between the logarithm of the retention factor and known log P values. The process is then repeated for the test compounds and their log P values determined from the mathematical relationship established for the standard compounds. 

From the measured electron-transfer equilibrium constant and the known standard potential for the reference D /D- couple it has been possible to determine E for the PhO /PhO- couple. The method, however, is non-trivial and does not lend itself to the rapid determination of standard potentials for a large series of related compounds. 

From the examination of structure-activity relationships, it has been concluded that a phenyl moiety at C-6 as well as a 4-hydroxypiperidine side-chain attached to C-3 of the pyridazine system is essential for anticonvulsant activity in this class of compounds [184], Compounds (54) and (55) have been found to have similar anticonvulsant profiles in animals (mice, rats and baboons) [165, and literature cited therein] and to represent potent broad-spectrum antiepileptic drugs. Their potency with regard to antagonizing seizures (induced by electro-shock or various chemicals) has been compared with standard anticonvulsants like carbamazepine and phenobarbitone [185, 186], A quantitative electroencephalographic analysis of (55) has been published [187]. From in vitro studies it has been concluded that the anticonvulsant activities of these compounds are not mediated by an enhancement of GABAergic transmission or by an interaction with benzodiazepine receptor sites [ 165,186,187], On the other hand, in vivo experiments showed that (54), at anticonvulsant doses, increases the affinity of flunitrazepam for its central receptor site [ 186], Investigations of (54) and (55) in a behavioural test predictive of antianxiety activity revealed a marked difference in the pharmacological profiles of these structurally closely related compounds the dichloro compound SR 41378 (55) has also been found to possess anxiolytic (anticonflict) properties [165],... 

For the quantification of alkylphenol ethoxylates (APEOs), several related compounds have been used as internal standard, e.g. for recovery determination, decylphenol monoethoxylate [20]. Octylphenol nonaethoxylate (t-0PE09) was synthesised by reacting octylphenol (OP) with 1,2-6j.s(2-chloroethoxy)ethane to give the chloro derivative, followed by reaction with the sodium salt of hexaethylene glycol [21,22], Another approach used the synthetic standard l-(4,-methoxyphenyl)-hexan-l-ol as a surrogate to monitor the efficiency of the extraction for... 

Samuel, J.B., E.C. Penski, and J.J. Callahan, 1983. Physical Properties of Standard Agents, Candidate Agents, and Related Compounds at Several Temperatures, ARCSL-SP-83015, Unclassified Report, June. Aberdeen Proving Ground, Md. Army Armament Research and Development Command. 

In addition to the amiodarone-related compounds, (81) and (82), described above, BASF has been exploring some novel heterocyclic compounds as Class III antiarrhythmic agents. A series of imidazo[l,2-c]pyrro-lo[l,2-a]quinazoline derivatives have been patented which are several times more potent than (-I- )-sotalol in lengthening QT interval of the electrocardiogram in the anaesthetized guinea-pig model [230], One of the most potent compounds is (85), which was 17-times more potent than the standard. These compounds represent one of the unique Class III structural types described to date. 

This concept is in essence a chromatographic effect similar to that observed in gas chromatography (GC), with the conjugated polymer film acting as the stationary phase. It is possible that like in GC and other candidate technologies for explosive detection, these responses could be empirically standardized for expected analytes of interest and sensory devices caHbrated to deconvolute temporal quenching signals to determine which analytes are present. This would further enhance the selectivity of what is already a very selective sensor for TNT and related compounds. 

If measurements are to be carried out at low activities (for example in studying complexation equilibria), standard solutions cannot be prepared by simple dilution to the required value because the activities would irreproducibly vary as a result of adsorption effects, hydrolysis and other side reactions. Then it is useful to use well-defined complexation reactions to maintain the required metal activity value [14, 50, 132]. EDTA and related compounds are very well suited for this purpose, because they form stable 1 1 complexes with metal ions, whose dissociation can be controlled by varying the pH of the solution. Such systems are often termed metal-ion buffers [50] (cf. also p. 77) and permit adjustment of metal ion activities down to about 10 ° m. (Strictly speaking, these systems are defined in terms of the concentration, but from the point of view of the experimental precision, the difference between the concentration and activity at this level is unimportant.)... 

Phenol and phenolic derivatives, cresol and related compounds were analyzed by Folin-Ciocalteau reagent at 700 m/i, standardizing each compound separately by its Folin response. Their slopes (molar absorption coefficients) were 8000-10,000 M-1cm-1. Interestingly, methoxyl aromatics with no free hydroxyl groups were not reactive. 

Structurally related compounds demonstrate different extraction behaviours in a ternary liquid-liquid extraction system composed of methylene chloride, chloroform and methyl ter/.-butyl ether. In investigations for finding proper internal standards, one should take into account the extraction liquid used for extraction of both analyte and internal standard. 

National Bureau of Standards, Preliminary Report on Thermodynamic Properties of Selected Light Elements and Some Related Compounds, Rept. 8628 (Jan. 1, 1965). 

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