[Spectrophotometry in ultraviolet light applied to research of organic poisons in blood].
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Blood Chemical Analysis↗
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Results for “Spectrophotometry, Ultraviolet”
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Radioimmunoassay, enzyme immunoassay, spectrophotometry, and gas-liquid chromatography compared for determination of phenobarbital and diphenylhydantoin.
Sera from epileptic patients were assayed for phenobarbital and diphenylhydantoin by four different analytical procedures. Quantitative results obtained by radioimmunoassay (I) and enzyme immunoassay (II) were compared to each other and to the results obtained on aliquots of the same sample by gas-liquid chromatography (III) and ultraviolet spectrophotometry (IV). For phenobarbital the correlation coefficients were I vs. II, 0.909; I vs. III, 0.947; II vs. III, 0.917; I vs. IV, 0.950; II vs. IV, 0.953. For diphenylhydantoin the correlation coefficients were I vs. II, 0.953; I vs. III, 0.951; II vs. III, 0.957; I vs. IV, 0.862; II vs. IV, 0.898. The immunoassays can be substituted for liquid chromatography or ultraviolet spectrophotometry without changing the resulting clinical interpretations.
Chromatography, Gas↗
[Composition of nucleic acids and concentration of methylated bases in the DNA of Bifidobacterium bifidum var. Tissier].
Nucleotide composition of the sum total DNA of B. bifidum, biotype III, was determined by paper chromatography in combination with ultraviolet spectrophotometry. DNA of B. bifidum was referred to the GC-type (GC -- 62.6 mol%). Two additional nitrogen bases were present in the DNA composition; 5-methylcytosine and 6-methylaminopurine -- 0.45 mol% and 0.20 mol%, respectively. Nucleotide composition of the sum total RNA was studied with the aid of high-voltage electrophoresis in combination with ultraviolet spectrophotometry. The sum total RNA was referred to the high GC-type (GC -- 64.9 mol%). These data permit to consider it reasonable to refer bifidobacteria to the Bifidobacterium genus.
2-Aminopurine↗
Comparative determination of halofantrine tablets by titrimetry, spectrophotometry and liquid chromatography.
Comparative determination of halofantrine tablets by titrimetry, ultraviolet spectrophotometry and liquid chromatography (LC) is described. Non-aqueous titrimetry on halofantrine hydrochloride tablets was carried out using glacial acetic acid as solvent, perchloric acid as titrant and crystal violet as indicator. Simultaneous potentiometric monitoring of end point delineated an exact color shade of indicator at the end point. Direct measurement of methanol solution, at 254 nm, was adopted for UV spectrophotometric method while reversed-phase liquid chromatographic (LC) method employed a C8 column (4.6 mm x 25 cm) with mobile phase consisting of methanol / 0.05 M NaH2PO4 (76:24, v/v) containing 55 mmol/L perchloric acid (pH 3.4) at a flow rate of 1 ml / min. The three methods gave precise and accurate results. Mean percentage recovery were obtained respectively as 100.73 +/- 0.41, 100.36 +/- 0.79 and 99.93 +/- 3.74% while coefficient of variation were 0.41, 1.36 and 3.74% for non-aqueous. UV spectrophotometry and LC. The three methods were successfully applied to analysis of halofantrine tablets (Halfan) and showed no statistically significant difference in accuracy (P > 0.05, ANOVA). Validated assay methods for halofantrine tablets have been developed. The titrimetric and spectrophotometric methods are of equivalent accuracy with the liquid chromatographic method and could be used for routine quality control of halofantrine tablets where LC method is not readily available.
Antimalarials↗
Examination of steroid protein interaction by ultraviolet difference spectrophotometry.
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Androstanes↗
Biochemical and genetic aspects of nystatin resistance in saccharomyces cerevisiae.
Two phenotypically distinct sets of nystatin-resistant mutants were investigated. One set is resistant, respiratory competent, and requires no lipid for growth. The other set is more resistant, respiratory deficient, and lipid requiring (unsaturated fatty acid or sterol). Both sets show altered sterol composition as demonstrated by the Liebermann-Burchard colorimetric reaction, ultraviolet spectrophotometry, and gas-liquid chromatography. Genetic analysis indicates that all nystatin-resistant mutants can be placed into one of six distinct genetic groups. The phenotype's nystatin resistance, lipid requirement, and respiratory deficiency are recessive. There was one case of allelism for mutants from different sets. Revertants of mutants which have the tripartite phenotype retain a residual level of nystatin resistance, but they are no longer lipid requiring or respiratory deficient. Growth studies in mutants which have the tripartite phenotype reveal that the addition of ergosterol to the growth medium results in decreased resistance to nystatin.
Chromatography, Gas↗
Quantitative determination of barbital in blood serum by ultraviolet absorption spectrophotometry.
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Barbital↗
Determination of amiodarone hydrochloride in pharmaceutical formulations by derivative UV spectrophotometry and high-performance liquid chromatography (HPLC).
Assay procedures based on derivative ultraviolet spectrophotometry and high-performance liquid chromatography (HPLC) have been developed for the specific determination of amiodarone hydrochloride in pharmaceutical dosage forms. The use of first- and second-order derivative spectrophotometry was found to have suppressed the background absorption from the excipients with comparable accuracy and precision to the reversed-phased HPLC reference method. A conventional UV absorption method (lambda = 242 nm) is subject to possible interference by formulation excipients.
Amiodarone↗
[UV spectrophotometric research of drug mixture in sudden poisoning cases].
UNLABELLED: The objective of this research--to develop the methodics for analysis of amitriptyline, fluoxetine and codeine in the mixture. RESULTS: The analytical method of amitriptyline, codeine and fluoxetine in the mixture identification and quantitative determination using ultraviolet spectrophotometry was established. Preparations in the mixture can't be separated, because material ultraviolet light peaks are in insufficient distance and therefore cover one another. The maximum of ultraviolet light absorption for amitriptyline is at 217-220 and 238-240 nm; fluoxetine--at 226-228 nm; codeine--at 224-248 and 284-286 nm. Using ultraviolet spectroscopy it's possible to identify amitriptyline, fluoxetine and codeine only after separating mixture components by thin-layer chromatography, the same time executing cleaning of extracts from blood and urine. Using ultraviolet spectroscopy can be identificated at least 0.5 micro g/ml amitriptyline, 1.5 micro g/ml fluoxetine and 1.0 microg/ml codeine. The intervals of the quantitative determination: 5-25 microg/ml amitriptyline; 5-30 microg/ml fluoxetine; 100-300 microg/ml codeine; relative error of the measurement, when confidence level is 95%, is from 0.66 to 1.2% for amitriptyline; from 0.66 to 1.45% for fluoxetine; from 0.33 to 0.88% for codeine. Standard deviation is from 1.15 to 2.08% for amitriptyline; from 1.15 to 2.52% for fluoxetine; from 0.57 to 1.53% for codeine. Molar absorption coefficients for all three preparations in distillated water were determinated. CONCLUSIONS: recommended methodology suits for mixture, extracted from biological liquids, components separation, identification and quantitative determination.
Acute Disease↗
Simultaneous determination of melatonin-pyridoxine combination in tablets by zero-crossing derivative spectrophotometry and spectrofluorimetry.
Two methods have been developed for the analysis of melatonin (M) and pyridoxine hydrochloride (PH) in combination. The first method depends on first- and second-derivative ultraviolet spectrophotometry, with the zero crossing technique of measurement. First-derivative amplitudes at 296 nm and second-derivative amplitudes at 294 and 322 nm are selected for the determination of M and PH, respectively. The second method is based on the native fluorescence of both M and PH, in methanol and 0.1 M hydrochloric acid, respectively, after a preliminary solvent extraction procedure. The relative standard deviation of both methods was less than 2.0%. The two methods have been successfully applied to the determination of both drugs in laboratory-prepared mixtures and in tablets.
Melatonin↗
Determination of 2,6-dimethyl-4-(2'-nitrosophenyl)-3,5-pyridinedicarboxylic acid dimethylester in nifedipine by derivative UV-spectrophotometry in bulk material and pharmaceutical forms.
A method for the determination of 2,6-dimethyl-4-(2'-nitrosophenyl)-3,5-pyridinedicarboxylic acid dimethylester in nifedipine (bulk material and pharmaceutical formulations) by second-derivative ultraviolet spectrophotometry is described. The procedure is simple and rapid and gives accurate and precise results.
Dihydropyridines↗
Application of first-derivative UV-spectrophotometry, TLC-densitometry and liquid chromatography for the simultaneous determination of mebeverine hydrochloride and sulpiride.
Three methods are described for the simultaneous determination of mebeverine hydrochloride (MB) and sulpiride (SU) in combined pharmaceutical tablets. The first method depends on first-derivative ultraviolet spectrophotometry, with zero-crossing measurement method. The first derivative amplitudes at 214.2 and 221.6 nm were selected for the assay of MB and SU, respectively. Calibration graphs follow Beer's law in the range of 10-30 and 2-8 microg/ml(-1), and the linearity was satisfactory (r = 0.9999), for MB and SU, respectively. The second method was based on the application of the thin layer chromatographic separation of both drugs followed by the densitometric measurements of their spot areas. After separation on silica gel GF254 plates, using ethanol: diethyl ether: triethylamine (70:30:1 v/v) as the mobile phase, the chromatographic zones corresponding to the spots of MB and SU were scanned at 262 and 240 nm, respectively. The calibration function was established in the ranges of 4-12 microg for MB and 2-8 microg for SU. The third method was an internal standard procedure based on high performance liquid chromatographic separation of the two drugs on a reversed-phase, Bondapak CN column. The detection was done at 243 nm using buclizine hydrochloride as internal standard. All chromatographic methods showed good linearity, precision and reproducibility. No spectral or chromatographic interference from the tablet excipients were found. The proposed methods were successfully applied to the assay of commercial tablets and content uniformity test. The procedures were rapid, simple and suitable for quality control application.
Anticonvulsants↗
The application of derivative spectrophotometry for the simultaneous determination of cocaine and other local anesthetics.
Part I. Cocaine-Lidocaine Mixtures A rapid procedure based on second-derivative UV spectrophotometry is proposed for the simultaneous determination of cocaine and lidocaine. The optimum magnitudes are chosen in terms of response linearity, sensitivity, relative percent error, relative recovery data, and reproducibility. Part II. Cocaine-Procaine Mixtures A derivative spectrophotometric method based on second-derivative ultraviolet absorption spectra has been developed for the simultaneous determination of cocaine and procaine. Several derivative magnitudes have been investigated. A statistical analysis of the results is reported. Part III. Cocaine-Tetracaine Mixtures A simple method has been developed for the simultaneous determination of cocaine and tetracaine by measuring the amplitudes of the positive peak at 286.6 nm and the negative peak at 313.9 nm with respect to zero baseline. Part IV. Cocaine-Benzocaine Mixtures Derivative ultraviolet spectrophotometry has been used for the simultaneous determination of cocaine and benzocaine. Both cocaine and benzocaine can be assayed by measurement of, respectively, the peak-to-peak amplitude D261.4,277.4 and the peak-to-zero amplitude D299.4. The method is applied to simulated street samples of cocaine.
Anesthetics, Local↗
Isolation and identification of 24-dehydroprovitamin D3 and its photolysis to 24-dehydroprevitamin D3 in mammalian skin.
Until now it had been assumed that mammalian skin contains only one provitamin D, 7-dehydrocholesterol, that is eventually converted to vitamin D3 after the skin is exposed to sunlight. Examination by reverse phase high performance liquid chromatography of lipid extracts from young rat skin, however, led to the observation that 7-dehydrocholesterol is not the only provitamin D in rat skin. Another provitamin D, accounting for 22 +/- 3% of the total provitamin content of the skin, was resolved from 7-dehydrocholesterol, and, on the basis of ultraviolet spectrophotometry, mass spectrometry, and nuclear magnetic resonance spectrometry, was identified as 24-dehydroprovitamin D3 (cholesta-5,7,24-trien-3 beta-ol). This new cutaneous provitamin D is not unique to the rat because it was also detected in the skin of reptiles, amphibians, birds, aquatic mammals, and humans. To be certain that the cutaneous 24-dehydroprovitamin D3 was as susceptible as 7-dehydrocholesterol to ultraviolet photolysis, rat skin was exposed to ultraviolet radiation. A reverse phase high performance liquid chromatographic analysis of a lipid extract of rat skin previously exposed to ultraviolet radiation demonstrated the presence of both previtamin D3 and 24-dehydroprevitamin D3. Therefore, these observations demonstrate for the first time that mammalian skin has the capacity to produce not one but at least two different vitamin Ds.
Animals↗
Optical spectroscopic study of the ADP-myosin interaction.
The binding of ADP to heavy meromyosin, and the separated subfragment 1 components S-1(A1) and S-1 (A2), has been observed by ultraviolet spectrophotometry. The results are compatible with the presence of spectroscopically equivalent and independent sites, one per head, at both 10 degrees C and 25 degrees C. We do not observe the heterogeneity of binding and of the spectroscopic response that has been reported. The binding has also been followed by other methods sensitive to the effect of ligand on the aromatic residues of the protein, viz. intrinsic fluorescence of heavy meromyosin and changes in the near-ultraviolet Cotton effects of myosin, and its active fragments. Within the limits of our experimental precision, the binding profiles, based on concentration of myosin heads, are the same for myosin as for subfragment 1. A perturbation in the circular dichroism is also generated by pyrophosphate, which competes with ADP. The spectra suggest that subsites for the purine ring and the diphosphate can be recognized. The sensitivity of binding profiles obtained by methods of the kind used here to cooperative or antagonistic interactions between the binding sites has been analysed. It is clear that sizeable effects of this nature could be concealed by the binding curves, even for high experimental precision.
Adenosine Diphosphate↗
Application of TLC-densitometry, first-derivative UV-spectrophotometry and ratio derivative spectrophotometry for the determination of dorzolamide hydrochloride and timolol maleate.
Three methods are described for the simultaneous determination of dorzolamide hydrochloride (DORZ) and timolol maleate (TIM) in ophthalmic solutions. The first method is based on application of thin layer chromatographic separation of both drugs followed by the densitometric measurements of their spot areas. After separation on silica gel GF(254) plates, using methanol-ammonia 25% (100:1.5 v/v) as the mobile phase, the chromatographic zones corresponding to the spots were scanned at 253 and 297 nm, respectively. The calibration function was established in the ranges of 2-18 microg for DORZ and 0.5-4.5 microg for TIM. The second method depends on first derivative ultraviolet spectrophotometry, with zero-crossing measurement method. The first derivative values D(1) at 250.2 and 312.5 nm were selected for the assay of DORZ and TIM, respectively. Calibration graphs follow Beer's law in the range 10-64 and 2.5-16 microg ml(-1), respectively. The third method is based on ratio first derivative spectrophotometry. The signals in the first derivative of the ratio spectra at 244 and 306.2 nm were selected to determine DORZ and TIM in the mixture and calibration graphs are linear in the range of 5-40 and 5.0-17.5 microg ml(-1), respectively. The proposed methods were successfully applied to the determination of these compounds in synthetic mixtures and in pharmaceutical preparations. The proposed methods are simple, rapid and suitable for quality control application.
Antihypertensive Agents↗
Formation of a novel enzymatic metabolite of leukotriene A4 in tissues of Xenopus laevis.
Leukotriene-A4, hydrolase catalyzes the final step in the biosynthesis of the potent proinflammatory mediator leukotriene B4. Previously, leukotriene-A4 hydrolase has been characterized from human, mouse and rat sources, i.e. only from mammalian species. In the present investigation, expression of leukotriene-A4, hydrolase was studied in organs of Xenopus laevis. Enzyme activity was found in all nine organs tested with the highest levels in the intestine and the reproductive organs, i.e. oocytes and testes, previously unrecognized rich sources of the enzyme. No immunoreactive leukotriene-A4 hydrolase was detected in Western blots of 10000Xg supernatants of X. laevis organ homogenates, using a polyclonal antiserum raised against human leukotriene-A4 hydrolase. Likewise, Northern blot analysis of liver total RNA did not detect Xenopus leukotriene-A4 hydrolase mRNA using a human CDNA probe. These results indicate significant structural differences between the human and toad enzymes. Incubations of 10000Xg supernatants of organ homogenates with leukotriene A4 revealed the formation of a novel metabolite, denoted compound X. Conversion of leukotriene A4 into compound X was due to an enzymatic activity as judged by its protein dependence, heat sensitivity, and resistance to ultrafiltration, and this activity appeared to be linked, directly or indirectly,, to leukotriene A4 hydrolase. From data obtained by ultraviolet spectrophotometry, gas chromatography coupled to mass spectrometry, ultraviolet-induced isomerization, and comparison with a synthetic standard, compound X was assigned the structure 5S,12R-dihydroxy-6,10-trans-8,14-cis-eicosatetraenoic acid. Finally, compound X was found to exhibit contractile activity in guinea-pig lung parenchyma, apparently elicited via a leukotriene B receptor.
Animals↗
Two unusual barbiturate deaths.
The case histories and toxicological examination of two unusual fatal barbiturate poisonings are presented. One case involved the suicidal ingestion of a veterinarian euthanasia preparation containing pentobarbital which resulted in extremely high concentrations of the drug in the blood and liver. The second case involved the suicidal ingestion of vinbarbital, a drug no longer available on the american pharmaceutical market. The case exemplifies the necessity for definitive and analytical procedures for the identification of drugs in biological samples. Identification of pentobarbital and vinbarbital was by infrared spectrophotometry and thin layer chromatography. Quantitation of these drugs was by ultraviolet spectrophotometry.
Aged↗