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81.
Development and validation of a stability-indicating HPLC method for the determination of degradation products in dipyridamole injection 总被引:1,自引:0,他引:1
Summary The development and subsequent validation of an isocratic high-performance liquid chromatographic (HPLC) procedure employing
ultraviolet (UV) detection for the determination of degradation products in Dipyridamole Injection is reported. The development
of this assay involved the evaluation of several factors including buffer type, ionic strength, pH, organic composition, and
column type. The described method is simple, reproducible, accurate, and selective. The precision, relative standard deviation
(RSD), amongst five sample preparations for total degradation products was not more than (NMT) 10.2 %, while the individual
degradation products were NMT 12.1%. Intermediate precision, as determined from fifteen sample preparations, generated by
two Analysts on different HPLC systems over three days, exhibited an RSD for total and individual degradation products of
8.2 % and NMT 27.5 %, respectively. The mean absolute recovery of dipyridamole using the described method is 102.1±1. 9%,
(mean±SD, n=12) over the concentration range of 0.03 % to 5.0 % of its label claim of 5 mg mL−1. The limit of detection and limit of quantitation were 0.1 and 0.3 μg mL−1, respectively. The linearity of the peak response was verified with respect to dipyridamole concentration over a range of
0.3 and 50 μg mL−1 (0.03 % to 5.0 % label claim). The Standard and Assay Preparations are stable for up to 48 hours at room temperature. The
selectivity was evaluated by subjecting the finished product (Dipyridamole Injection) to thermal, acidic, basic, oxidative
and fluorescent radiation stress conditions. No interference in the analysis of degradation products was observed, showing
the method is stability-indicating. 相似文献
82.
Laser induced fluorescence excitation and resolved emission spectra of 1,3-C6H4F+2 are obtained in a Ne matrix with high signal/noise despite the ion's low emission quantum yield. The ground state vibrational structure is mostly regular but that of the upper is very irregular suggesting nearly degenerate, mutually perturbing, excited states. 相似文献
83.
A two-dimensional (2-D) model of the atmosphere including photochemistry as complete as that in advanced 1-D models, parameterized transport, diurnal effects and rayleigh scattering has been used to calculate present day altitude profiles of trace species mixing ratios.The structure and content of the model will be described and a comparison of model results with atmospheric measurements will be presented.In particular, while there had been some expectation that inclusion of latitudinal and seasonal effects would resolve certain major discrepancies for atmospheric chlorine species, the current profiles for 30 degrees latitude are qualitatively similar to 1-D model results and seasonal variations are relatively small. The principle discrepancies between 1-D model results and measurements including overstimation by the model of ClO concentrations below 30 km and understimation of HCl above 30 km are still present in the 2-D model results.The absence of change in HCl also imploies that over-estimation of HF/HCl ratio above 20 km remains a problem.The implications for model validation and ozone depletion calculations, in the view of the effect of chlorofluorocarbons, will be discussed. 相似文献
84.
E Wenkert E W Hagaman B Lal G E Gutowski A S Katner J C Miller N Neuss 《Helvetica chimica acta》1975,58(6):1560-1567
The total assignment of the 13C-shifts of the complex Vinica rosea L. alkaloids vincaleucoblastine, leurosidine and leurosine and of a synthetic isomer of the latter is presented. The structure of leurosidine is corrected and a tentative structure for the acid-catalyzed product of isomerization of leurosine is proposed. 相似文献
85.
[reaction: see text] Metalation of oxazoles at the 4 and 5 position was achieved after regioselective C-2 silyl protection. Removal of the protecting group was then accomplished under mild conditions allowing for a straightforward preparation of C-5 monosubstituted and C-4,5 disubstituted oxazoles. The first practical C-2 protecting group of oxazoles has been demonstrated. 相似文献
86.
R. Miller 《Colloid and polymer science》1983,261(5):441-444
Relations are given describing the compression of adsorption layers of soluble surfactants, using models of pure diffusion, pure kinetic, and mixed diffusion-kinetic-controlled adsorption. For the compression of the adsorption layer of a mixture of soluble surfactants all models predict a relativ enrichment of the most surface active substance. 相似文献
87.
C.A. Cody R.C. Levitt R.K. Khanna Philip J. Miller 《Journal of solid state chemistry》1978,26(3):293-309
The infrared and Raman spectra of NaH3(SeO3)2 and NaD3(SeO3)2 have been recorded from 24 to 300°K. The interpretation, assignments, and analysis of the spectral studies are presented on the paraelectric α phase (proton disordered), ferroelectric β phase (proton ordered) and ferroelectric γ phase (proton ordered). A discussion of a newly proposed proton-triggered phase transition mechanism and a possible origin of the hydrogen-bonded OH stretching region of KH2PO4-type ferroelectrics is given. 相似文献
88.
89.
Kenji Maeda Ross A. Miller Ali Shafiee Joseph D. Armstrong III 《Tetrahedron letters》2005,46(9):1545-1549
Highly diastereoselective (>20:1) bromo-lactonization of N-sulfonyl-2-allyl-2-phenylglycine methyl ester (11) was observed. Successive treatment of the chiral lactone with MeONa gave the desired (2S,4R)-4-hydroxy-2-phenylproline derivative in high yield without erosion of the diastereoselectivity. The starting chiral non-racemic compound (5) was prepared from the racemic 2-phenylglycine using a classical kinetic resolution (crystallization), an asymmetric phase transfer alkylation, and an enzyme-catalyzed kinetic resolution. 相似文献
90.
Summary A colorimetric method for the determination of 2,2-dihydroxy-biphenyl in rat urine is described. The ether extract is subjected to thin-layer chromatography on silica gel-G plates in the solvent system benzene-methanol (8020) and spots corresponding to 2,2-dihydroxybiphenyl and its glucuronide derivative are eluted with ethanol. The glucuronide is hydrolysed with HCl and the 2,2-di-hydroxybiphenyl content is determined after colour development with sodium cobaltinitrite, the absorbance being read at 410 nm. The method is sensitive and reproducible. It obeys the Lambert-Beer law in the concentration range 0.7–8.9g/ml.
Eine empfindliche kolorimetrische Methode zur Bestimmung von 2,2 -Dihydroxybiphenyl
Zusammenfassung Eine kolorimetrische Methode zur Bestimmung von 2,2-Dihydroxy-biphenyl in Rattenharn wurde beschrieben. Der ätherische Extrakt wird auf Silikagel-G-Platten dünnschicht-chromatographisch mit dem Lösungsmittelsystem Benzol-Methanol (8020) getrennt. Die dem genannten Stoff und seinem Glucuronid entsprechenden Flecken werden mit äthanol eluiert. Das Glucuronid wird mit Salzsäure hydrolysiert und der Gehalt an 2,2-Di-hydroxybiphenyl nach Ausführung der Farbreaktion mit Natriumkobalti-nitrit und Messung bei 410 nm bestimmt. Das Verfahren ist empfindlich und gut reproduzierbar. Es entspricht dem Lambert-Beerschen Gesetz zwischen 0,7 und 8,9g/ml.相似文献