硝酸异山梨酯类药品理化常数与分离定量的研究

本研究报导了硝酸山梨酯、５－单硝酸异山梨酯、２－单硝酸异山梨酯理化常数测试，ＴＬＣ法对相关物质的分离及ＨＰＬＣ法分离定量的研究。优选了ＨＰＬＣ条件，确立了以Ｃ１８柱及不同比例甲醇－水为流动相系统对５－ＩＳＭＮ、ＩＳＤＮ的定量分析方法。经过方法认证研究表明该法优于国内外报导方法、专属性强，灵敏度高，并对不同批号样品进行了检测。     

Saliva concentrations of isosorbide dinitrate, isosorbide 2-mononitrate and isosorbide 5-mononitrate.

Correlations between saliva and plasma concentrations of isosorbide dinitrate (ISDN), and its active metabolites, isosorbide 2-mononitrate (2-ISMN) and isosorbide 5-mononitrate (5-ISMN) were examined. In the case of 5-ISMN (r = 0.98, P less than 0.01), saliva concentrations are probably reliable indices of the plasma concentrations of this drug and their measurement should provide a useful non-invasive procedure to assess compliance during the clinical use of products containing either ISDN or 5-ISMN: it may also be helpful in assessing the clinical pharmacokinetics of 5-ISMN. Less satisfactory correlations were obtained for ISDN (r = 0.84) and 2-ISMN (r = 0.83).     

Plasma disposition and hemodynamic effects of a single oral dose of isosorbide dinitrate in human males and females.

The goal of the present work was to determine the plasma disposition and hemodynamic effects of isosorbide dinitrate (ISDN) in human males and females. Fourteen healthy human volunteers took part in the study; seven males, 21.7 +/- 2.5 y (SD), and seven females, 20.7 +/- 3.4 y. Measurements of forearm blood flow (FBF), vascular conductance (FVC), and venous capacitance (Cv) were obtained by venous occlusion plethysmography, whereas blood pressure was measured by automatic sphygmomanometry. Blood samples were taken through a catheter placed in the antecubital vein at 0, 15, 30, 45, 60, 90, 120, 360, 480, 720, and 1440 min following a single 10 mg oral dose of ISDN. Plasma concentrations of ISDN and its mononitrate metabolites, isosorbide-2-mononitrate (2-ISMN) and isosorbide-5-mononitrate (5-ISMN), were determined by large bore capillary column gas-liquid chromatography. Hemodynamic measurements were made at corresponding experimental times up to 480 min. No differences were observed in the disposition of ISDN, 2-ISMN or 5-ISMN between the male and female volunteers. In addition, the plasma concentrations of ISDN and its mononitrate metabolites did not consistently correlate with the hemodynamic changes of the individual subjects. Diastolic blood pressure was significantly decreased for a 0.5 h period starting at 30 min, which was the time at which plasma ISDN concentrations peaked, and which preceded the time when the plasma concentrations of 2-ISMN and 5-ISMN were maximal. These observations indicate that, for a single 10 mg oral dose of ISDN, there were no gender-dependent differences in the plasma disposition of the parent drug or its mononitrate metabolites, and the vascular changes responsible for the decrease in diastolic blood pressure in these volunteers occurred in vascular beds other than those of skeletal muscle as represented by forearm blood flow.     

Contribution of isosorbide-5-mononitrate, a major metabolite of isosorbide dinitrate (ISDN), to the hemodynamic effect of ISDN administered orally in conscious dogs

This study was designed to determine the extent, to which isosorbide-5-mononitrate (5-ISMN) contributes to the hemodynamic effect of isosorbide dinitrate (ISDN) in conscious dogs. Test drugs (ISDN or 5-ISMN) were given orally. Either ISDN or 5-ISMN produced a decrease in blood pressure dose-dependently, the decrease in pulse pressure being specific; the pattern of blood pressure change induced by ISDN or 5-ISMN was different from that induced by nifedipine or prazosin. The effect of ISDN (2 mg/kg) was almost equivalent to that of 5-ISMN (4 mg/kg) and the effect of ISDN (4 mg/kg) to that of 5-ISMN (8 mg/kg). After administration of ISDN, both ISDN and 5-ISMN appeared in the plasma, and the effect of ISDN well-correlated with the increase in the plasma concentration of 5-ISMN. Contribution of 5-ISMN to the effect of ISDN was estimated to be about 30% from the value of the plasma concentration of 5-ISMN at 3 to 4 hr after administration, when the maximal response to ISDN occurred. Based on the data of the area under the plasma concentration curve of 5-ISMN (from 0 to 10 hr after administration), the fraction of biotransformation to 5-ISMN from ISDN was calculated to be 73.6 to 76.6% (based on moles). Because the ability of 5-ISMN to decrease pulse pressure was about 1/2 (or 41% based on moles) of that of ISDN, the contribution of 5-ISMN to the effect of ISDN was estimated to be about 30% in total, the value being similar with that estimated at 3 to 4 hr after administration.     

反相高效液相色谱梯度洗脱法测定制剂中的硝酸异山梨酯及其降解产物

硝酸异山梨酯(ISDN)为血管扩张药物,用于治疗心绞痛。其降解产物5-硝酸异山梨酯(5-ISMN)比其它冠状血管扩张剂更有效,且毒性小。Mizuno等用HPLC法研究了ISDN及其降解产物在水溶液中的稳定性,但分离时间较长。Dimov等报道用梯度HPLC法在18min内分离了硝酸单取代异山梨酯、醋酸单取代异山梨酯和硝酸、醋酸异山梨     

Differential Inhibitory Effects of Isosorbide Dinitrate and its Mononitrate Metabolites on Platelet Aggregation and Thromboxane Formation

The effects of isosorbide dinitrate (ISDN) and its 2- and 5-mononitrate metabolites (2-ISMN and 5-ISMN) against platelet aggregation and thromboxane release were investigated by analysis of platelet aggregation curves. ISDN, 2-ISMN and 5-ISMN (isosorbide nitrates, ISN) inhibited both ADP- and epinephrine (EPI)-induced platelet aggregation. ISN affected specifically the extent of ADP-induced aggregation and the velocity of EPI-induced effects. 2-ISMN was more potent against platelet aggregation compared to ISDN and 5-ISMN. The isosorbide nitrates were poor inhibitors of both arachidonic acid-induced aggregation and platelet TxB2 release. The differential inhibition by the three isosorbide nitrates of endogenous TxB2 release during ADP-induced aggregation further indicates that 2-ISMN is a significantly more potent platelet inhibitor than either ISDN or 5-ISMN. These studies suggest a role of the metabolites in modulating the pharmacological effects of ISDN on platelet activity.     

Determination of isosorbide dinitrate biotransformation in various tissues of the rabbit by capillary column gas-liquid chromatography

A selective and sensitive capillary column gas-liquid chromatographic procedure has been developed for the simultaneous determination of isosorbide dinitrate (ISDN) and its mononitrate metabolites in rabbit blood and tissue homogenates. The method has a limit of detection of 0.1 ng ml-1 for ISDN, 1 ng ml-1 for isosorbide 5-mononitrate (5-ISMN), and 2 ng ml-1 for isosorbide 2-mononitrate (2-ISMN). The day-to-day coefficients of variation were 2.5, 6.8, and 11.3 per cent for ISDN, 5-ISMN, and 2-ISMN, respectively. The within-day coefficients of variation were 2.7, 4.9 and 6.5 per cent for ISDN, 5-ISMN, and 2-ISMN, respectively. The procedure was used to determine the biotransformation of ISDN (2 X 10(-7) M) to 5-ISMN and 2-ISMN by various rabbit tissue homogenates. The relative rate of biotransformation of ISDN was liver greater than lung approximately equal to intestine greater than kidney greater than blood approximately equal to skeletal muscle, with the lung and intestine homogenates being about two-thirds as active as liver homogenates. These results indicate that extrahepatic biotransformation of ISDN, especially by lung and intestine, may contribute to the systemic clearance of ISDN in the rabbit.     

Cutaneous metabolism of isosorbide dinitrate after transdermal administration in isolated perfused porcine skin

The purpose of this study was to determine whether isosorbide dinitrate (ISDN) was metabolized by the skin during transdermal delivery. In order to assess this, the isolated perfused porcine skin flap (IPPSF) was utilized since this in vitro model possesses a viable epidermis and intact vasculature, two attributes ideal for studying the biotransformation of a vasoactive drug. ISDN transdermal systems (20 cm²) were applied onto IPPSFs and the venous efflux sampled repeatedly over 16 h. ISDN, isosorbide-2-mononitrate (IS-2-MN), and isosorbide-5-mononitrate (IS-5-MN) fluxes were determined using gas chromatography. Approximately 14% of parent ISDN was metabolized to IS-2-MN and 10% to IS-5-MN. These observations are important as they indicate that a fraction of ISDN is biotransformed during transdermal delivery.     

Pharmacokinetics of low-dose isosorbide dinitrate and metabolites after buccal or oral administration]

The kinetics of isosorbide dinitrate (ISDN; CAS 87-33-2) and its metabolites isosorbide-5-mononitrate (IS-5-MN) and isosorbide-2-mononitrate (IS-2-MN) were examined after buccal and oral administration of 5 mg ISDN. Twelve healthy volunteers were included in a randomized cross-over study. The mean dose-corrected AUCs for total nitrate in serum after the two different preparations were in the same range. The relative bioavailability of ISDN applied buccally, however, was more than twice that after oral application. The metabolism of ISDN differed depending on the route of administration, where the AUC-ratios ISDN: IS-2-MN: IS-5-MN were 1:2.7:19.4 after buccal and 1:5.7:53.4 after oral application respectively. The absorption rate constants Ka for ISDN and the MRT after buccal and oral application did not differ significantly. The same holds for the mean residence time.     

Comparison of the effect of isosorbide-5-mononitrate and isosorbide dinitrate in a slow-release form on exercise-induced myocardial ischemia

A randomized, double blind, placebo-controlled crossover study on 20 patients with exercise-induced angina pectoris and reproducible ST-segment depression during exercise-stress test was performed to compare the effect of a single dose of 120 mg of isosorbide dinitrate in a slow-release form with that of a twice-daily application of 20 mg of isosorbide-5-mononitrate. Symptom-limited exercise tests were done, and nitrate plasma levels were measured in the subjects 6, 10, and 24 hours after the first administration of the drug. Both drugs produced a highly significant reduction in the size of exercise-induced ST-depressions (P less than .001) 6 and 10 hours after the first administration of isosorbide dinitrate as well as 6 hours after the first and 4 hours after the second dose of isosorbide-5-mononitrate. The effect was still significant (P less than .05) 24 hours after the administration of isosorbide dinitrate in a slow-release form and 18 hours after the second dose of isosorbide-5-mononitrate. In the case of the drug isosorbide dinitrate, nitrate plasma levels for its metabolite, isosorbide-5-mononitrate, were highest 10 hours after first application. In the case of the drug isosorbide-5-mononitrate, nitrate plasma levels were highest 4 hours after the second dose. Two 20 mg doses of isosorbide-5-mononitrate and a single dose of 120 mg isosorbide dinitrate in a slow release form have a comparable effect on the reduction of exercise-induced ST-segment depressions.     

Pharmacokinetics of three organic nitrates in Chinese healthy male volunteers

Eighteen Chinese male subjects completed a single-blind, randomized, three-treatment, three-period, cross-over study. In each treatment phase, subjects received a single dose of 20 mg isosorbide dinitrate (CAS 87-33-2, ISDN) intravenous infusion, 20 mg isosorbide 5-mononitrate (CAS 16051-77-7, 5-ISMN) tablet or 20 mg isosorbide 5-mononitrate intravenous infusion. Each consecutive dosing was separated by a washout period of 7 days. Following each dosing, venous blood samples were collected over a period of 16 h. Plasma concentrations of ISDN and its two active metabolites isosorbide 2-mononitrate (2-ISMN), 5-ISMN had been measured by a validated gas chromatographic method. Various pharmacokinetic parameters including AUC0-t, AUC0-infinity, Cmax, tmax, t1/2, Kelm and MRT were determined for the three formulations and found to be in good agreement with literature values. AUC0-t and AUC0-infinity of 5-ISMN tablet and intravenous infusion were 2694 +/- 496 ng x ml(-1) x h vs. 2548 +/- 556 ng x ml(-1) x h and 3266 +/- 624 ng x ml(-1) x h vs. 3178 +/- 769 ng x ml(-1) x h, respectively, and the relative bioavailability of 5-ISMN tablet was 105 +/- 20%. As compared with 5-ISMN intravenous infusion, ISDN can rapidly reach the plateau concentration and metabolize to its active metabolites 5-ISMN and 2-ISMN, which both have vasodilator effect. The results of this study suggest that as evaluated from the pharmacokinetic profiles of the three formulations, 5-ISMN tablet and ISDN intravenous infusion are ideal vasodilators and anti-angina drugs especially in acute conditions due to their rapid onset and long duration of action.     

Assay of glyceryl trinitrate, isosorbide dinitrate, and their metabolites in plasma by large-bore capillary column gas-liquid chromatography

Two large-bore capillary columns, one with dimethyl polysiloxane (HP-1) as the stationary phase and the other with phenyl (50 per cent) methyl (50 per cent) polysiloxane (DB-17), were used to develop gas-liquid chromatographic (GLC) assays for measuring isosorbide dinitrate (ISDN), glyceryl trinitrate (GTN), and their metabolites. ISDN, isosorbide-2-mononitrate (2-ISMN), and isosorbide-5-mononitrate (5-ISMN) in plasma, ranging in concentration from 1 to 300 nM, and GTN, glyceryl-1,2-dinitrate (1,2-GDN), and glyceryl-1,3-dinitrate (1,3-GDN), ranging in concentration from 3 to 60 nM in plasma, were analysed on both columns. GLC analysis yielded baseline resolution of the analytes. The method using the dimethyl polysiloxane column gave a lower limit of detectability for GTN of 0.75 nM (signal/noise (s/n) = 2), and the procedure using the phenyl-methyl column provided a lower limit of detectability for ISDN of 81 pM (s/n = 2). The large-bore column GLC procedures exhibited shorter retention times for both ISDN and GTN than those previously reported for capillary-column assays. The chromatographic resolution of analytes and column efficiency of the large-bore capillary columns were comparable to the results previously found using capillary-column GC. The assays for ISDN and GTN have been shown to be appropriate for pharmacokinetic studies in volunteers and patients. We determined that the HP-1 column is appropriate for the analysis of GTN and metabolites, and the DB-17 column is suitable for analysis of ISDN and its metabolites. We conclude that the use of large-bore capillary columns provides rapid and reliable GLC assays for organic nitrates.     

Lack of effect of asymmetrical dosage timing of isosorbide-5-mononitrate on nitrate tolerance during long-term administration

Summary Isosorbide 5-mononitrate is an active metabolite of isosorbide dinitrate and possesses many theoretical advantages over its parent drug. However, the development of partial tolerance has been demonstrated when the drug is given 12 hourly or 8 hourly. We have therefore evaluated the acute and sustained (2 weeks) effects of isosorbide-5-mononitrate 40 mg given twice daily (08.00 h and 14.00 h, allowing an 18-h dose-free period) in 19 patients with stable chronic angina, using computerized exercise testing and a placebo-controlled, double-blind, randomized trial protocol. There were two phases of 2 weeks each in which patients received placebo or active isosorbide-5-mononitrate. Acute testing was performed 2 h after the first dose and chronic testing 2 h after the morning dose on Day 14. Acute testing showed an increase in exercise time from a mean (SD) of 6.7 (2.2) min to 10.1 (2.95) min (P<0.01) after a single dose of isosorbide-5-mononitrate 40 mg. The time to 1 mm of ST depression, and rest and peak exercise heart rates increased significantly during acute testing with isosorbide-5-mononitrate; resting and peak exercise systolic blood pressures fell significantly. Due to drop outs cross-over analysis was performed on 11 patients who completed both chronic phases and 13 patients were assessed for the comparison of acute isosorbide-5-mononitrate with chronic isosorbide-5-mononitrate. After 2 weeks of therapy exercise time did not show a sustained increase 8.01 (2.14) min chronic placebo to 8.58 (1.93) min chronic isosorbide-5-mononitrate. The improvement in ST segment variables seen acutely was not sustained. These data suggest that the attenuation of the effect of isosorbide-5-mononitrate due to partial tolerance is not mitigated by using an asymmetrical dose regimen.     

Concentrations of isosorbide dinitrate,isosorbide-2-mononitrate and isosorbide-5-mononitrate in human vascular and muscle tissue under steady-state conditions

Summary The concentrations of isosorbide dinitrate (ISDN), isosorbide-5-mononitrate (IS-5-MN) and isosorbide-2-mononitrate (IS-2-MN) were determined in plasma (PL), saphenous vein wall (SV) and pectoral muscle (PM) from 8 patients undergoing coronary bypass surgery.The patients were pretreated for 2 days with ISDN 240 mg per day (standard release formulation) in 4 doses of 40 mg and one dose of 80 mg. The plasma and tissue samples were obtained during the operation, 10–12 h after the last dose.Isosorbide-2-mononitrate and isosorbide-5-mononitrate were present in plasma and tissues in the same concentration ranges with molar concentration ratios of 0.88 (IS-2-MN: PM/PL), 0.85 (IS-5-MN: PM/PL), 0.99 (IS-2-MN: SV/PL) and 1.06 (IS-5-MN: SV/PL). Mean ISDN concentrations in tissue were considerably higher than in plasma; the molar concentration ratios were 4.9 (SM/PL) and 7.21 (SV/PL).The accumulation of ISDN in vessel walls may contribute to its greater vascular action compared to the mononitrates, but it may also facilitate the development of tolerance during long-term treatment.     

Metabolic fact of 14C-isosorbide 5-mononitrate in humans

Single oral doses of 20 mg of the carbon-14 labelled form of the antianginal drug isosorbide 5-mononitrate (5-ISMN, Elantan) were essentially completely absorbed and excreted fairly rapidly in the urine. Means of 24, 52, 78, 93 and 96% dose were excreted during 6, 12, 24, 48 and 120 h, respectively. Concentrations of 14C reached peak levels at about 1-2 h when about 86% of the 14C was associated with the parent drug, 5-ISMN (peak mean level 430 ng/ml), and the remainder mainly with the pharmacologically-inactive denitrated product isosorbide. Because the plasma (and urinary) half-life of isosorbide was longer (about 8-9 h) than that of 5-ISMN (about 4.5 h), the proportions of the former in plasma increased relative to the latter. Concentrations of 14C in whole-blood and plasma were similar, implying that 5-ISMN diffused into blood cells. Concentrations of 5-ISMN in saliva and plasma were almost identical, presumably because of the almost negligible plasma protein binding of the drug (less than 5%). At least five metabolites of 5-ISMN were detected in urine - these were isosorbide (about 37% dose), conjugated material (about 25% dose) presumably mainly 5-ISMN-glucuronide, sorbitol (about 7% dose), the parent drug 5-ISMN (about 2% dose) and two unidentified metabolites (about 7 and 4% dose, respectively). The conjugated material was excreted in the urine relatively more rapidly than the denitrated product, isosorbide.     

Effects and pharmacokinetics of isosorbide dinitrate in normal man

Summary 18 subjects were given isosorbide dinitrate (ISDN) 5 mg sublingually and serum concentrations of ISDN, 2-isosorbide mononitrate (2-ISMN) and 5-isosorbide mononitrate (5-ISMN) were measured, as well as changes in digital plethysmographic amplitude, heart rate, ECG, blood pressure and Schellong's test. ISDN was rapidly absorbed and metabolized, having an elimination half-life of 29 min. Its metabolites 2-ISMN and 5-ISMN had longer half-lives of 1.75 and 7.6 h respectively. The amplitude of the -wave of the digital plethysmograph did not change significantly either in the predrug period or after placebo administration. It increased within 4 min of administration of ISDN, and reached a maximum after 14 min; the effect lasted for about 2 h. ISDN lowers blood pressure and increases heart rate in most volunteers, but in 3 of the 18 subjects severe hypotension occurred, accompanied by severe, reversible bradycardia, which was probably due to vagal reflexes initiated by the markedly diminished ventricular enddiastolic volume (LVEDV) and pressure (LVEDP). No correlation could be demonstrated between the serum concentration of ISDN and/or its vasoactive metabolites and changes in plethysmographic amplitude.     

Pharmacokinetics of isosorbide dinitrate and its mononitrate metabolites after intravenous infusion

Plasma concentrations of isosorbide dinitrate (ISDN) and its two active metabolites 2-isosorbide mononitrate (2-ISMN) and 5-isosorbide mononitrate (5-ISMN) have been measured during and for 6 hr after intravenous infusion at a rate of 2.5 mg/hr during 1.75 hr in six cardiac patients, by a capillary gas chromatographic method. Data were analyzed by simultaneous modeling of the observed kinetics of the three compounds. Two or three phases were detected on the postinfusion ISDN concentration-time curves. ISDN concentrations declined with a mean terminal half-life of 2.81 hr +/- 0.7 SD. The mean systemic clearance of ISDN (2.9 L/min +/- 0.7 SD) and its mean total volume of distribution (259 L +/- 48 SD) were relatively high. Plasma 5-ISMN concentrations were 5- to 6-fold greater than those of 2-ISMN during the whole observation period. Maximum levels of 2-ISMN (6.7 ng/ml +/- 0.9 SD) and of 5-ISMN (27 ng/ml +/- 6 SD) occurred within a few minutes after the end of infusion. The mean half-lives of 2-ISMN (1.59 hr +/- 0.19 SD) and of 5-ISMN (3.78 hr +/- 0.79 SD) estimated by the model were smaller than those calculated by a model-independent method (2.95 hr +/- 0.41 SD and 5.98 hr +/- 2.22, respectively), but were in good agreement with those reported in the literature following separate administration of both metabolites to man. This study shows how such modeling can distinguish between metabolite formation and elimination processes and allow the determination of metabolite half-lives after administration of the precursor drug.     

5-单硝酸异山梨酯血药浓度测定及其在人的药代动力学

采用气相色谱-电子捕获检测法测定 5-单硝酸异山梨酯的血药浓度。样品经乙醚—正己烷混合溶剂提取,三氟醋酐进行衍生化后,用5% SE-30硅烷化玻璃填充柱分离,以硝酸异山梨酯为内标,⁶³Ni电子捕获检测器检测。此法操作简便,日内、日间误差分别小于4%和6.5%,平均回收率为99.62%±1.19%。在20～800ng·mL^-1血浆浓度范围内呈线性关系(γ=0.9995)。最低检测浓度为2.0ng·mL^-1。应用此法研究了10名健康志愿者单次口服20mg 5-单硝酸异山梨酯片后的药代动力学。     

单硝酸异山梨酯胶囊溶出度比较

目的 :考察同类产品内在质量 ,为临床用药提供参考。方法 :采用HPLC法 ,按《中国药典》溶出度测定法测定单硝酸异山梨酯胶囊的溶出度。结果与结论 :10min平均累积溶出百分率产品C>D>F>A>E>B。6个厂家供试品45min时的溶出量均大于标示量的85 % ,但其溶出度参数m、T50、Td 的差别均有非常显著意义     

Absorption of Isosorbide Dinitrate after Administration as Spray,Ointment and Microemulsion Patch. An In-vitro Study Using the Isolated Perfused Bovine Udder

The isolated perfused bovine udder is an in-vitro model, which maintains bovine udder skin with an isolated vasculature in a viable state. Using this in-vitro model, the percutaneous absorption and metabolism of isosorbide dinitrate (ISDN) was studied. The organ was perfused with gassed Tyrode solution for up to 6 h. A region of udder skin was treated topically with 60 mg ISDN as a spray, 60 mg ISDN as an ointment and with 120mg ISDN as a microemulsion patch of 30 cm². Spray and ointment were applied onto a skin region of 400 cm². The concentrations of ISDN and its metabolites isosorbide-2-mononitrate and isosorbide-5-mononitrate were measured in perfusate fractions by capillary column gas-liquid chromatography with electron capture detection. Following topical administration of the different formulations, ISDN as well as its metabolites were detected in the perfusate fractions, thus demonstrating that ISDN is metabolized by the udder skin in-vitro. A maximum amount of ISDN was absorbed after administration as a spray followed by ointment and microemulsion (5, 2·5 and 1·8 μmol total organic nitrate, respectively). In contrast, the ISDN flux per cm² skin was significantly higher after administration of the microemulsion (64·4 pmol cm^?2 min^?1 for the microemulsion compared with 21·9 and 10·2 pmol cm^?2 min^?1 for spray and ointment).