High-performance liquid chromatographic determination of sodium nitroprusside

Baaske, David M.; Smith, Marilyn Dix; Karnatz, Nancy N.; Carter, James E.

doi:10.1016/s0021-9673(01)84047-4

Cited by 18 publications

(7 citation statements)

References 7 publications

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“…Because of the instability of SNP in the presence of light (Baaske et al, 1981), all the perfusions were conducted under a safelight (Delta 1/CPM, Inc. Dallas, TX). The study consisted of 32 IPRLs, divided into eight experimental groups (n ϭ 4/group).…”

Section: Methodsmentioning

confidence: 99%

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Hepatic Disposition and Effects of Nitric Oxide Donors: Rapid and Concentration-Dependent Reduction in the Cytochrome P450-Mediated Drug Metabolism in Isolated Perfused Rat Livers

Vuppugalla

Mehvar²

2004

J Pharmacol Exp Ther

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Various mechanisms, including high levels of cytokines and nitric oxide (NO), have been proposed as mediators for inflammation-induced cytochrome 450 down-regulation. However, the contribution of each of these mediators to the observed effects is controversial. We used an isolated perfused rat liver (IPRL) model to test the direct effects of NO donors on CYP450 down-regulation in the absence of cytokines or other confounding in vivo factors. Our hypothesis was that NO rapidly and concentration-dependently decreases CYP450 activities in IPRL. Livers were perfused (60 min) with 50 to 500 M sodium nitroprusside (SNP) or 100 to 500 M isosorbide dinitrate (ISDN) as NO donors, and the perfusate and biliary disposition of SNP, ISDN, and generated nitrate/nitrite (NO x ) were determined. Additionally, at the end of perfusion, catalytic activities and protein levels of various cytochrome isoenzymes were measured. Both SNP and ISDN exhibited linear hepatic disposition with extraction ratios of ϳ0.30 and 0.50, respectively. Furthermore, although in small amounts, both NO donors and NO x were found in the bile. Except for CYP2D1, the catalytic activities of all the studied isoenzymes were substantially (up to 85%) decreased by both NO donors. However, the apoprotein levels of isoenzymes remained largely unchanged. Additionally, the inhibitory effects of NO donors were concentration-dependent, with the concentrations of SNP producing one-half of maximum inhibition being in the order of 2C11 Ͼ 2B1/2 Ͼ 2E1 ϭ 3A2 Ͼ 1A1/2. These studies indicate that the effects of NO on the down-regulation of cytochrome 450 catalytic activity are rapid, concentration-dependent, and isoenzyme-selective.

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Section: Methodsmentioning

confidence: 99%

“…Perfusate and biliary SNP or ISDN concentrations were estimated using previously reported HPLC methods (Baaske et al, 1981;Pramar et al, 1991). For SNP, samples were prepared under a safelight and transferred to an HPLC autosampler that prevented exposure to light.…”

Section: Methodsmentioning

confidence: 99%

Hepatic Disposition and Effects of Nitric Oxide Donors: Rapid and Concentration-Dependent Reduction in the Cytochrome P450-Mediated Drug Metabolism in Isolated Perfused Rat Livers

Vuppugalla

Mehvar²

2004

J Pharmacol Exp Ther

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“…For each group, periodical samples (5-to 30-min intervals) were taken from the outlet perfusate. Because SNP degrades on exposure to light (Baaske et al, 1981), the perfusion experiments were carried out under the Safelight (Delta 1 CPM, Inc. Dallas, TX). The collected samples were then wrapped in aluminum foil and stored at Ϫ80°C for further analysis of nitrate/nitrite (NO x ) levels.…”

Section: Methodsmentioning

confidence: 99%

Short-Term Inhibitory Effects of Nitric Oxide on Cytochrome P450-Mediated Drug Metabolism: Time Dependency and Reversibility Profiles in Isolated Perfused Rat Livers

Vuppugalla

Mehvar

2004

Drug Metab Dispos

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ABSTRACT:Nitric oxide (NO) is implicated as a mediator in the decreased catalytic activities of cytochrome P450 (P450) enzymes during inflammation or infection. Here, we examined the time course and the reversibility of the NO effect on P450s using isolated perfused rat livers. Livers were perfused at a constant rate with the NO donor sodium nitroprusside (SNP) for 0.5 or 1 h, followed by washout periods of 0 to 2.5 h. At the end of perfusion, microsomes were prepared and analyzed for P450 activities and other metabolic markers. Whereas 0.5 h of NO exposure caused an irreversible decline (ϳ30%) in total P450 content, a greater decline after 1 h of NO (ϳ55%) was mostly (ϳ30%) reversible, a pattern identical to that observed for the microsomal heme content. NO exposure also caused an enzyme-selective and time-dependent decline in P450 activities. Whereas the pattern of decline and reversibility of activities were qualitatively similar for CYP3A2, 2C11, 2E1, and 1A1/2, they differed for 2B1/2 and 2D1 in that the decline in the activity was delayed (1 h) for 2B1/2 and not observed for 2D1. This may be attributed to the accessibility of heme or cysteine thiolate and/or the presence/reactivity of critical cysteinyl amino acid residues in various P450 enzymes. Additionally, for most enzymes, the activity showed a biphasic decline, one within 1 h of SNP perfusion and another after 2 h of washout. This was associated with an identical biphasic decline in the microsomal free thiols, presumably due to the rapid and slow reaction of NO and peroxynitrite, respectively, with critical P450 thiols. The short-term effects of NO on P450 are time-dependent and enzyme-selective, with both reversible and irreversible mechanisms.

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“…1.09×10 -8 18 1.02 ×10 -8 3 1.12×10 -8 21 1.04×10 -8 6 1.15×10 -8 24 1.12×10 -8 9 1.14×10 -8 27 1.05×10 -8 12…”

Section: Ip (A) Time (Minute) Ip (A) Time (Minute)unclassified

“…Several methods are available for measuring SNP. The spectrophotometric method of analysis for SNP developed utilizing the molar absorptivity values at the maxima absorbency appearing in the electronic spectrum at 394 and 498 nm (5,6) .…”

Section: Introductionmentioning

confidence: 99%

Using The Interaction of Sodium Nitroprusside With Modecate And Tegretol, As an Indirect Method For Their Determination Using S.W.V. Technique

Abdul-Razzak¹

1999

J.Edu.Sci.

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A square wave voltammetric (S.W.V.) method has been developed for the quantitative analysis of sodium nitroprusside (SNP), sodium nitroprusside gives a peak at (-0.592) volt against the reference electrode (Ag/AgCl/sat KCl) in phosphate buffer (pH= 7.0). A calibration curve was constructed for the range [(0.99 x 10 -7 -(14.77 x 10 -7 )]M the method was applied for indirect determination of medicate and tegretol individually via the interaction of SNP with these drugs. So, a calibration curve was constructed by adding appropriate amounts of modecate of the Using The Interaction of Sodium Nitroprusside With Modecate And Tegretol, …

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High-performance liquid chromatographic determination of sodium nitroprusside

Cited by 18 publications

References 7 publications

Hepatic Disposition and Effects of Nitric Oxide Donors: Rapid and Concentration-Dependent Reduction in the Cytochrome P450-Mediated Drug Metabolism in Isolated Perfused Rat Livers

Hepatic Disposition and Effects of Nitric Oxide Donors: Rapid and Concentration-Dependent Reduction in the Cytochrome P450-Mediated Drug Metabolism in Isolated Perfused Rat Livers

Short-Term Inhibitory Effects of Nitric Oxide on Cytochrome P450-Mediated Drug Metabolism: Time Dependency and Reversibility Profiles in Isolated Perfused Rat Livers

Using The Interaction of Sodium Nitroprusside With Modecate And Tegretol, As an Indirect Method For Their Determination Using S.W.V. Technique

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