Isosorbide 5-mononitrate pharmacokinetics in humans

When isosorbide 5-mononitrate was intravenously infused at a rate of 4 mg h ^?1 for 2.5 h to five human subjects, its concentrations in plasma increased slowly to 185 ng ml^?1 ± 5 per cent C.V. at 2.5 h and a steady-state plasma level was not reached during the infusion. When the infusion was discontinued, plasma drug concentrations declined with an elimination half-life of 4.2 h ± 6 per cent C.V. The systemic clearance after the infusion doses was 132 ml min^?1 ± 18 per cent C.V. and the volume of distribution was 48.4 1 ± 16 per cent C. V. After equal oral doses of 10 mg, the peak plasma isosorbide 5-mononitrate concentration of 191 ng ml^?1 ±16 per cent C.V. was reached at 1.1 h ± 30 per cent C.V., and plasma levels declined with a terminal half-life of 4.9 h. The complete systemic availability of isosorbide 5-mononitrate indicated that pre-systemic elimination after the oral doses was negligible. A one-compartment open model appeared adequate to describe the plasma level data after intravenous infusion and oral doses. After single oral doses of 10 mg isosorbide dinitrate, the peak plasma concentration of the 5-mononitrate metabolite of 72 ng ml^?1 ± 27 per cent C. V. occurred at l.7h.41 per cent C.V. Approximately 50 per cent (range 22–68 per cent) of the oral dose of isosorbide dinitrate circulated in plasma as the 5-mononitrate metabolite. The pharmacokinetics of isosorbide mononitrates are markedly different to those of the parent dinitrate and these differences follow from the greater systemic availability and volume of distribution of the mononitrates.     

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.     

人血浆中单硝酸异山梨酯的LC-MS/MS法测定及其药动学

建立了液相色谱-串联质谱法测定人血浆中的单硝酸异山梨酯.采用Venusil ASB C8色谱柱,以甲醇-5 mmol/L乙酸铵溶液(60∶40)为流动相,电喷雾离子源,负离子模式,多反应监测(MRM).监测离子为m/z 249.9→58.2(单硝酸异山梨酯)和m/z 149.9→106.4(内标,对乙酰氨基酚).单硝酸异山梨酯在5～1 000 ng/ml范围内线性关系良好,低、中、高浓度组的提取回收率分别为69.6％、58.9％和64.6％.志愿者单剂量U服20 mg单硝酸异山梨酯口崩片后的主要药动学参数为:cmax (343.0±87.3) ng/ml,tmax (1.11±0.67)h,t1/2 (6.01±1.29)h,AUC0-0→t(2 578±605) ng·h·ml-1,AUC0→∞(2 785±653) ng·h·ml-1.     

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.     

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.     

Simultaneous determination of isosorbide dinitrate and its mononitrates in human plasma by capillary column GLC.

A previously described electron-capture GLC method for determination of isosorbide dinitrate in human plasma was adapted for the simultaneous determination of isosorbide dinitrate, isosorbide 2-mononitrate, and isosorbide 5-mononitrate using a capillary column. Quantitation was done with two internal standards. The lower limits of detection were approximately 0.5 ng/ml of plasma for isosorbide dinitrate, 2 ng/ml for isosorbide 2-mononitrate, and 20 ng/ml for isosorbide 5-mononitrate.     

Sex-related difference in the metabolism of isosorbide dinitrate following incubation in human blood

Isosorbide dinitrate (ISDN) (at a concentration of 100 ng/ml) was incubated aerobically at 37° in whole blood from five male and five female normal volunteers. Following incubation of the blood samples for 0, 30, 60, 120, 240 and 360 min, the samples were centrifuged and the plasma was assayed for ISDN. A linear relationship was observed between the logarithm of the concentration of ISDN remaining and incubation time, and there was a significant difference between the $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ of ISDN in blood from males (90.6 min) and females (161.4 min). Very little ISDN metabolism was observed when ISDN was incubated with plasma rather than whole blood. When erythrocytes, resuspended in saline, were incubated with ISDN, there was a time-dependent loss of ISDN from the saline incubation medium. Investigation of the soluble fraction obtained after hemolysis of these erythrocytes also showed a time-dependent loss of ISDN. The saline incubation medium contained sufficient concentrations of the two major ISDN metabolites (isosorbide 2- and 5-mononitrate) to account for the observed disappearance of ISDN. The results indicate that ISDN is metabolized in the cellular compartment of blood and that the metabolic rate in males is greater than that in females.     

单次用硝酸异山梨酯透皮贴剂在健康志愿者的药代动力学

目的 研究健康受试者单次用硝酸异山梨酯透皮贴剂(抗心绞痛药)的药代动力学及安全性.方法 28名健康志愿者随机分为3个剂量组,分别单次用硝酸异山梨酯透皮贴剂40、80和120 mg,用HPLC-GC测定血浆硝酸异山梨酯及代谢物2-单硝基异山梨酯和5-单硝基异山梨酯的浓度,用WinNonLin 5.0计算其主要药代动力学参数.密切观察不良事件.结果 3个剂量组分别单次用不同剂量的硝酸异山梨酯透皮贴剂后的主要药代动力学参数,硝酸异山梨酯:Cmax分别为(4.56±0.64)、(7.85±1.59)和(12.75±2.57)ng·mL-1;AUC0-tn分别为(301.14±52.93)、(530.83±124.51)和(790.33±201.10)ng·mL-1·h.2-单硝基异山梨酯:Cmax分别为(4.00±0.49)、(6.72±0.97)和(10.45±1.74)ng·mL-1;AUC0-tn分别为(250.89±33.78)、(435.21±85.14)和(625.93±140.44)ng·mL-1·h.5-单硝基异山梨酯:Cmax分别为(10.57±1.17)、(20.35±1.54)和(30.31±4.58)ng·mL-1;AUC0-tn分别为(661.783±80.773)、(1335.46±164.85)和(1905.14±330.69)ng·mL-1·h.本试验共发生10件与研究药有关的不良事件,主要为转氨酶一过性升高(7.1%)、头痛(21.4%)和贴皮处瘙痒(7.1%).结论 在40～120 mg内,硝酸异山梨酯的体内过程呈线性药代动力学特征.     

Concentrations of the vasodilator isosorbide dinitrate and its metabolites in the blood of human subjects

Summary An oral dose of 5 mg of¹⁴C-isosorbide dinitrate was rapidly absorbed, biotransformed and excreted by human subjects. Peak whole blood concentrations of radioactivity were reached after 1.5 to 2 hours and declined relatively slowly. The radioactivity in whole blood mainly represented metabolites, isosorbide mononitrates. The peak concentrations found were 4.5, 11.7 and 34.3 ng/ml of isosorbide dinitrate, isosorbide 2-mononitrate and isosorbide 5-mononitrate, respectively, in the blood of one subject and 5.9, 15 and 61.3 ng/ml, respectively, in the blood of another subject. However, concentrations of the metabolites declined relatively slowly during 6 h after the oral dose. Up to 99% of an oral dose of isosorbide dinitrate was excreted during 5 days, mainly in the urine of the first day (ca. 78%). The results showed that isosorbide mononitrates were available to contribute to the pharmacological action.     

5-单硝酸异山梨醇酯的合成

山梨醇经脱水得到异山梨醇,用硅胶-活性炭过滤后,再经硝化、氢氧化钠成盐反应及中和反应等制得5-单硝酸异山梨醇酯,总收率约16%,纯度不低于99%。     

Isosorbide dinitrate in plasma and dialysate during haemodialysis

Summary In 10 patients with end stage renal disease on regular haemodialysis the plasma concentrations and dialyzer clearance of isosorbide dinitrate (ISDN) were determined after an oral dose of a retarded release formulation of 60 mg ISDN. The maximal plasma concentration of ISDN 2–7 h after oral administration was higher (14 ng/ml) than has been reported in healthy volunteers. The haemodialyzer clearance of ISDN was 92.4 ml/min at a blood flow of 200 ml/min and dialysate flow of 500 ml/min. During a 5-h haemodialysis an average of 0.3 mg ISDN was removed from the patient's circulation, representing about 0.5% of the administered dose and about 3% of the available drug in the circulation. No influence of haemodialysis on the plasma level of ISDN was found.     

5-单硝酸酯联合卡维地洛治疗老年单纯性收缩期高血压疗效观察

目的观察联合使用5-单硝酸酯和卡维地洛治疗部分老年单纯性收缩期高血压患者的疗效,尤其脉压(PP)的变化,推论它们对大动脉弹性改变的程度。方法对37例100≥脉压≥80 mmHg的老年单纯性收缩期高血压患者采用5-单硝酸酯联合卡维地洛治疗,观察治疗前、治疗后1、3、6个月的血压、脉压、血脂、血糖、心率及心电图P-R的改变,分析脉压的变化及副作用的发生。结果治疗后3月脉压下降(P<0.05),而副作用及对代谢的影响轻微(P>0.05)。结论5-单硝酸酯联合卡维地洛治疗部分老年单纯性收缩期高血压有效,是改善大动脉弹性的手段之一。     

甲氧氯普胺与心痛定治疗肾绞痛的疗效比较

目的:观察甲氧氯普胺治疗肾绞痛的疗效。方法:对43例肾绞痛患者应用甲氧氯普胺0.4mg/kg,肌内注射。对照组41例用心痛定10mg,嚼碎含化。结果:甲氧氯普胺治疗肾绞痛的总有效率(86.0％)明显高于心痛定(75.6％)。结论:甲氧氯普胺治疗肾绞痛有效、安全。     

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).     

生物样品中5-单硝酸异山梨酯色谱法检测研究进展

5-单硝酸异山梨酯（5-ISMN）由于无明显紫外吸收且热不稳定,在生物样品中的检测具有一定难度。为满足5-ISMN生物样品中检测的灵敏度和专属性等要求,国内外学者建立了其高效液相色谱、气相色谱-电子捕获、气相色谱-质谱、高效液相色谱-质谱等检测方法。本文就相关色谱方法的研究进展进行综述。     

First data on effects and pharmacokinetics of isosorbide-5-mononitrate in normal man

Summary Isosorbide-5-mononitrate (IS-5-MN) 5, 10, 20, 30, 40 and 50 mg were administered orally to 2 healthy male volunteers. The pharmacological effect was determined using digital pulse plethysmography and the orthostatic tilting test, and at the same time side effects were monitored. The threshold of oral activity of IS-5-MN was found to be 5 mg. The maximum response was reached with doses of 20–30 mg. The duration of action of this dose was approximately 8 h. Higher doses did not lead to any further increase, but rather to a decrease in the pharmacological response, while the side-effects, such as headaches, dizziness and nausea, became more prominent. In a randomized, double-blind, three-way cross-over study in 11 female volunteers IS-5-MN 30 mg proved to be more potent with respect to pharmacological activity than sustained released ISDN 20 mg (isosorbide dinitrate), whereas there was no difference in side-effects. Thus, it can be estimated that IS-5-MN 20 mg is approximately equivalent to 20 mg sustained released ISDN. IS-5-MN is rapidly absorbed after oral administration and the maximum concentration in serum was reached 1.2±0.2 h after doses of 10 to 50 mg. The pharmacokinetics showed dose-linearity. The compound was eliminated with an average half life of 4.04±0.16 h, which is appropriate for a reasonably prolonged duration of action without the need for a sustained release formulation.     

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.     

Comparative study of the bioavailability and pharmacokinetics of isosorbide dinitrate formulations in retard form and in standard preparations by determination of isosorbide-5-mononitrate

The aim of the study was to determine the relative bioavailability and the pharmacokinetic parameters following administration of a slow-release formulation of isosorbide dinitrate (ISDN, Isdin) capsules (20, 40 and 60 mg). A gas chromatographic method was used to determine the plasma concentrations of ISDN and isosorbide-5-mononitrate (IS-5-MN). All of the required pharmacokinetic parameters were ascertained. The study was performed on 12 healthy volunteers in a steady-state crossover design. A comparison of the areas under the plasma concentration/time curves of the test preparations and the commercial preparations showed higher values for the test preparations in all of the investigations. However, these values were only statistically significant for the 40 and 60 mg formulations ISDN and the 60 mg formulation IS-5-MN.     

Pharmacokinetics of intravenous and oral isosorbide-5-mononitrate

Summary The pharmacokinetics of isosorbide-5-mononitrate (IS-5-MN) has been studied in two groups of healthy volunteers after oral (n=20) and intravenous (n=11) administration of 20 mg, which had previously been proved to be as effective as 20 mg sustained-release isosorbide dinitrate (ISDN). IS-5-MN in serum was measured by gas chromatography using capillary columns. The kinetic calculations were carried out with a newly developed model, which assumes a virtual volume of distribution dependent on time. IS-5-MN is rapidly (invasion half-life 4.1 min) and completely absorbed from the gastro-intestinal tract without any first pass metabolism. The maximum concentration of 480 µg/l was reached 1.2 h after oral administration of 20 mg. The substance was distributed throughout the total body water (distribution coefficient: 0.62), and was eliminated with a terminal t_1/2 of 4.1 and 4.6 h after oral and intravenous administration, respectively. Total body clearance was 115 ml/min. Thus, IS-5-MN is unlike ISDN with respect to the absence of first-pass metabolism and an 8-times longer half-life. The consequences for therapy are discussed.     

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 2.5mg/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.