Study On Photochemical Reaction Kinetics Of Sodium Nitroprusside

Sodium nitroprusside（Na₂[Fe（CN）₅NO]·2H₂O,SNP）has been used clinically for more than 40 years as an arterial and venous vasodilator.In vivo,SNP,as a prodrug,reacts with physiological thiols to release NO,resulting in rapid vasodilation and a sharp reduction in blood pressure.It is commonly used clinically for cardiac surgery,hypertensive emergencies,heart failure,vascular surgery,pediatric surgery and other acute hemodynamic applications.The release of cyanide anions associated with SNP is associated with potential cyanide accumulation and severe toxicity.SNP releases cyanide anions when acting in the body,which can lead to the accumulation and poisoning of severely toxic cyanides in the body.However,as SNP can rapidly depressurization during the operation,it will continue to be used as a antihypertensive drug in clinical practice.In this paper,we explored the kinetics of photochemical reaction of SNP through experiments.The electron spin resonance（EPR）technique proved that SNP could release NO after photoinduced.The three splitting characteristic signal peaks of NO radicals were measured by NO free radical capture technique.Different irradiated wavelengthes can control the release of NO,a basic method to control NO release quantitatively was developed.The mechanism of binding of SNP and three proteins was analyzed by investigating the change of fluorescence intensity at the maximum fluorescence emission wavelength of human serum albumin,lysozyme and bovine hemoglobin after adding SNP.By studying the photodynamic process of SNP in different solvents under different wavelength conditions,and the basic process of light reaction of SNP was clarified.The two-dimensional infrared correlation spectra of SNP were studied.It was confirmed that the order of change of each functional group in the SNP molecule was CN bond vibration before the NO bond began to change,and the peak at 2074 cm^-11 occurred last.Finally,the effects of SNP on the growth of tumor cells under xenon illumination and without illumination were also studied.The main contents of this paper mainly include five parts:First:the physicochemical properties,history and clinical function of SNP,the physiological functions of NO and the common exogenous NO donor and photodynamic therapy were introduced.Second:the electron spin resonance technique was used to measure and record the NO releasing from SNP solution under photo irradiation at different wavelength.The experimental data showed that the exicited wavelength can control the NO release quantitatively.Third:the vibrational peak position of the characteristic functional groups of SNP was detected by Fourier transform infrared spectroscopy.Using NO stretching vibration of SNP as a probe,the one-dimensional IR spectra kinetics under white light and 420 nm light were analyzed respectively.Thetwo-dimensionalinfraredspectraofsodium nitroprusside in H₂O and DMSO solutions were determined.The positions of the characteristic absorption peaks and the order of the changes were determined,and each absorption peak was assigned.Fourth:the changes of the characteristic peaks of SNP after addition of human serum albumin,lysozyme and hemoglobin were detected by Fourier transform infrared spectroscopy,the combination of three kinds of protein and SNP was studied.The binding modes of human serum albumin,lysozyme and bovine hemoglobin were determined by observing the change of fluorescence spectrum after adding SNP,followed by static quenching analysis and calculation of the size of the binding constant between them,and finally concluded that the strength of three proteins and SNP binding order:human serum albumin>lysozyme>bovine hemoglobin.Fifth:the CCK-8 method was used to study the inhibition effect of sodium nitroprusside against Hela and HepG-2 tumor cells,under the light conditions and without light.The effection of photo irradiation were compared and discussed.Sixth:all the work was summarized,and the next work plan was made.