Effects of a new cardiotonic phosphodiesterase III inhibitor, olprinone, on cardiohemodynamics and plasma hormones in conscious pigs with heart failure

Population pharmacokinetics of olprinone in healthy male volunteers

BACKGROUND

Olprinone decreases the cardiac preload and/or afterload because of its vasodilatory effect and increases myocardial contractility by inhibiting phosphodiesterase III.

PURPOSE

The objective of this study was to characterize the population pharmacokinetics of olprinone after a single continuous infusion in healthy male volunteers.

METHODS

We used 500 plasma concentration data points collected from nine healthy male volunteers for the study. The population pharmacokinetic analysis was performed using the nonlinear mixed effect model (NONMEM®) software.

RESULTS

The time course of plasma concentration of olprinone was best described using a two-compartment model. The final pharmacokinetic parameters were total clearance (7.37 mL/minute/kg), distribution volume of the central compartment (134 mL/kg), intercompartmental clearance (7.75 mL/minute/kg), and distribution volume of the peripheral compartment (275 mL/kg). The interindividual variability in the total clearance was 12.4%, and the residual error variability (exponential and additive) were 22.2% and 0.129 (standard deviation). The final pharmacokinetic model was assessed using a bootstrap method and visual predictive check.

CONCLUSION

We developed a population pharmacokinetic model of olprinone in healthy male adults. The bootstrap method and visual predictive check showed that this model was appropriate. Our results might be used to develop the population pharmacokinetic model in patients.

Population pharmacokinetics of olprinone in patients undergoing cardiac surgery with cardiopulmonary bypass

PURPOSE

Olprinone, a phosphodiesterase type III inhibitor, is a strong inotrope and vasodilator that does not increase oxygen consumption and is often used during weaning from cardiopulmonary bypass (CPB). To control the pharmacological effects of olprinone, pharmacokinetic information is essential; however, there is little published information on the pharmacokinetics of olprinone in a large population. Therefore, the purpose of this study was to determine olprinone pharmacokinetic parameters in a large population undergoing cardiac surgery with CPB.

METHODS

Olprinone was infused at a rate of 0.2 μg/kg/min when weaning from CPB was started. Whole blood samples were periodically obtained to determine the olprinone concentrations using high-performance liquid chromatography. Measured olprinone concentrations were analyzed with a one-compartment model via a population approach.

RESULTS

A total of 86 blood samples from 26 patients were used for pharmacokinetic analysis. The calculated clearance, volume of distribution (V(d)), and elimination half-life were 378 ml/min, 40.7 l, and 97.1 min, respectively. Olprinone clearance depended on weight and creatinine clearance, whereas V(d) depended only on weight.

CONCLUSION

We investigated the pharmacokinetic parameters of olprinone in patients undergoing cardiac surgery with CPB. Olprinone clearance depended on weight and creatinine clearance, whereas V(d) depended only on weight. When olprinone is infused according to the recommended dosing regimen, it takes more than 60 min to reach the target concentration (20 ng/ml). However, there is a possibility that a lower concentration is sufficient for weaning from CPB in combination with a continuous infusion of dopamine.

The phosphodiesterase III inhibitor olprinone inhibits hippocampal glutamate release via a cGMP/PKG pathway

Olprinone, an inhibitor of cyclic nucleotide phosphodiesterase III, inhibited an increase in intracellular Ca(2+) concentrations for acutely dissociated rat hippocampal pyramidal neurons induced by extracellular high K(+) (35 mM) depolarization. Olprinone (100 microM) significantly reduced spontaneous glutamate release from rat hippocampal slices. Furthermore, olprinone significantly decreased the rate of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor-mediated miniature excitatory postsynaptic currents (AMPA-mEPSCs) monitored from CA1 pyramidal neurons of rat hippocampal slices, and the effect was blocked by KT5823, an inhibitor of protein kinase G (PKG), but not by H-89, an inhibitor of protein kinase A (PKA). In the PKA assay using PC-12 cells, olprinone did not activate PKA. Taken together, the results of the present study show that olprinone attenuates intracellular Ca(2+) rise through voltage-sensitive Ca(2+) channels and inhibits presynaptic glutamate release via a cGMP/PKG pathway.

The enhancement of cellular cAMP with olprinone protects autotransplanted rat kidney against cold ischemia-reperfusion injury

The administration of a cyclic nucleotide analog improves cold ischemia/reperfusion injury in several organs. The type 3 phosphodiesterase inhibitor olprinone is a potent stimulus that enhances cellular cAMP levels. The present study was performed to investigate the protective effects of enhanced intracellular cAMP levels by olprinone in rat orthotopic kidney transplantation. Autotransplantation and immediate contralateral nephrectomy were performed in Lewis rats after 18 hours of graft storage at 4 degrees C in University of Wisconsin (UW) solution with or without 25 microg/mL olprinone hydrochloride. At 2 hours after reperfusion, serum and urinary biochemical indicators of renal dysfunction and injury were measured: serum creatinine, fractional excretion of Na+ and urinary N-acetyl-D-glucosaminidase. Additionally, intracellular cAMP in kidney tissues was measured by a radioimmunology method. Compared to the only UW solution group, olprinone hydrochloride significantly reduced the increased in serum creatinine, FENa and NAG caused by renal ischemia/reperfusion injury, after 2 hours of reperfusion. The content of cAMP at the endpoint of 18 hours cold preservation was significantly greater in the UW plus olprinone hydrochloride group than that in the UW group. Two hours after reperfusion, the content of cAMP in the UW plus olprinone hydrochloride group was still significantly higher than that in the UW group without containing olprinone hydrochloride. These results support a beneficial effect of olprinone against cold ischemia and reperfusion injury via an increased intracellular cAMP levels.

Effects of a phosphodiesterase 3 inhibitor, olprinone, on rhythmical change in tension of human gastroepiploic artery

The gastroepiploic artery, used widely as a conduit in coronary artery bypass grafting, has high vasospasticity. The aims of this study were to examine the vasorelaxant effects of three phosphodiesterase 3 (PDE3) inhibitors, olprinone, milrinone and amrinone, on isolated gastroepiploic arterial preparations in comparison with a calcium channel blocker diltiazem, and to confirm the mRNA expression of PDE3A isoenzyme using reverse transcription-polymerase chain reaction (RT-PCR) in the human gastroepiploic artery isolated from stomach removed in cancer surgery. In endothelium-denuded gastroepiploic arterial preparations, phenylephrine (100 microM) produced spontaneous, rhythmical changes in tension consisting of repeated contraction and relaxation. Olprinone at a concentration of 10 microM (n=6) significantly inhibited the frequency (2.7+/-1.1 times/30 min vs. 6.2+/-0.7 times/30 min in the vehicle group), maximum tension (1.7+/-0.6 g vs. 3.6+/-0.6 g in the vehicle group) and minimum tension (0.6+/-0.2 g vs. 1.7+/-0.3 g in the vehicle group) of rhythmical changes. Such potency is comparable to that of diltiazem, but is stronger than milrinone and amrinone. RT-PCR using PDE3A- or PDE3B-specific oligonucleotide primer demonstrated the existence of PDE3A sequence in the gastroepiploic artery. These results suggest that olprinone, a potent PDE3A inhibitor, would be suitable for protecting against perioperative spasm during coronary artery bypass graft surgery.

Olprinone, a phosphodiesterase III inhibitor, does not affect hypoxia-induced pial arteriolar dilatation in rabbits

PURPOSE

Olprinone, a phosphodiesterase III inhibitor, is used for the treatment of heart failure or asthma. Such patients may suffer from hypoxia. However, the effect of olprinone on the cerebral vasodilator response to hypoxia remains unclear.

METHODS

Rabbits were anesthetized and ventilated mechanically. The pial arteriolar diameter was determined using a cranial window and intravital microscopy. Hypoxia was induced twice in the same animal by reducing FIO(2) to 0.1. The first episode was induced during an infusion of saline, and the second during an infusion of saline (saline group; n = 8) or olprinone (1 microg x kg(-1) x min(-1), OLP1 group; n = 8 or 10 microg x kg(-1) x min(-1), OLP10 group; n = 8). The pial arteriolar responses to hypoxia were recorded and compared between the two episodes of hypoxia in each group.

RESULTS

Blood gas data in the first hypoxic challenge were identical to those in the second challenge in each group. Pial arteriolar diameter increased significantly during hypoxia. In arterioles between 50-100 microm diameter, first and second hypoxia-induced pial arteriolar dilatation in OLP1 were 13 +/- 6% and 10 +/- 7% respectively (P = 0.574 ) and those in OLP10 were 16 +/- 6% and 15 +/- 7% respectively (P = 0.606). In arterioles between 25-50 microm, the results were the same as in arterioles between 50-100 microm.

CONCLUSION

Olprinone does not affect the hypoxia-induced dilatation of pial arterioles in pentobarbital anesthetized rabbits.

Heterocyclization of functionalized vinylic derivatives of imidazo

Heterocyclization of functionalized vinylic derivatives of imidazo[1,2-a]pyridines was explored experimentally and theoretically using semiempirical AM1 and ab initio methods. A range of functionalized vinylic derivatives (azido, amino, and carbodiimide groups) were prepared for conversion into pyrroloazaindoles 19-22, imidazo[1,x]-, (x = 5, 6, 7, 8), [2,6]-, and [2,7]naphthyridines 28-30, 35-38 by thermal reaction. In the case of vinylic groups in the 5 position, peri annulation also was observed. The experimental and theoretical data are compared and discussed.

The effects of olprinone (a phosphodiesterase III inhibitor) on hepatic vascular bed in a porcine model of endotoxemia

Decreased hepatic blood flow, and impaired hepatic oxygen delivery caused by endotoxin, result in hepatic metabolic deterioration followed by liver dysfunction and multiple organ failure. Among phosphodiesterase III inhibitors, only olprinone increases hepatosplanchnic blood flow. We evaluated the effects of olprinone on systemic hemodynamics, hepatic circulation, and hepatic oxygen delivery in a porcine model of endotoxemia. Fifteen pigs received a continuous infusion (1.7 microg. kg(-1). h(-1)) of endotoxin (lipopolysaccharide [LPS]) via the portal vein for 240 min. Seven of these pigs received olprinone infusion (0.3 microg. kg(-1). min(-1)) via a central vein from t = 150 min to t = 240 min, whereas the eight remaining pigs served as LPS controls. Continuous infusion of LPS caused significant reductions in hemodynamic variables and a significant increase in arterial lactate. After the administration of olprinone during the LPS infusion, portal venous flow and hepatic oxygen delivery were increased and were higher than in the LPS group. Furthermore, olprinone prevented any further increase in arterial lactate. We conclude that the administration of olprinone halted the disturbances in the hepatic circulation, especially in portal venous flow and hepatic oxygen delivery, in a porcine model of endotoxemia.

IMPLICATIONS

Endotoxin is a causative factor in peripheral vascular failure, resulting in a hemodynamic depression that includes a reduction in liver blood flow. The administration of olprinone (phosphodiesterase III inhibitor) improves the liver blood flow circulation in a porcine model of endotoxemia.

Comparison of the effects of amrinone, milrinone and olprinone in reversing bupivacaine-induced cardiovascular depression

BACKGROUND

Increasing evidence indicates that amrinone, a phosphodiesterase fraction III (PDE-III) inhibitor, has relative efficacy as an initial treatment for cardiovascular depression after bupivacaine in an experimental setting. This study was performed to compare the cardiovascular effects of the other new PDE-III inhibitors, milrinone and olprinone, with those of amrinone in reversing bupivacaine-induced cardiovascular depression.

METHODS

In sevoflurane-anaesthetized dogs, bupivacaine was infused intravenously at 1 mg x kg(-1) x min(-1) until mean arterial pressure fell to 60 mmHg or less. The dogs received either amrinone (2 mg x kg(-1)), milrinone (0.2 mg x kg(-1)), olprinone (0.12 mg x kg(-1)) or 0.9% saline (0.5 ml x kg(-1)).

RESULTS

Amrinone, milrinone and olprinone improved left ventricular systolic and diastolic function, resulting in an increase in cardiac index. The most significant difference observed among the three drugs was the change in heart rate (HR) after treatment. Milrinone significantly increased HR, but olprinone did not.

CONCLUSION

Milrinone and olprinone are as effective as amrinone in reversing bupivacaine-induced cardiovascular depression.

Phosphodiesterase III inhibitor olprinone chlorate is not significantly removed by continuous venovenous hemodiafiltration

The study objective was to determine whether a phosphodiesterase III inhibitor, olprinone chlorate, is effectively removed by continuous venovenous hemodiafiltration (CVVHDF) in a patient with cardiac and renal failure. The patient was a 73 year old man who had undergone coronary artery bypass grafting for ischemic heart disease and who developed cardiac and renal failure postoperatively. A 0.2 microg/kg per minute dosage of olprinone chlorate was administered intravenously for 120 minutes while the patient was treated with CVVHDF. Samples from the arterial and venous blood catheters and those from the ultradiafiltrate for 12 hours were collected to calculate pharmacokinetic parameters and clearance of hemodiafiltration. The calculated parameters were as follows: half-life of elimination phase: 4.96 hours; total clearance 3.40 ml/min per kg. The clearance of CVVHDF was 0.33 ml/min per kg. The olprinone chlorate clearance of CVVHDF approximates only 10% of total clearance in this case. CVVHDF may not produce significant reduction in the serum olprinone chlorate level. It is recommended that the infusion dosage of olprinone chlorate should be reduced when given to patients with renal failure even if treated with CVVHDF.

Vasorelaxant effect of a phosphodiesterase 3 inhibitor, olprinone, on isolated human radial artery

The radial artery is currently used as a viable arterial conduit for myocardial revascularization. The aims of this study were to identify phosphodiesterase 3 isoenzyme in the human radial artery isolated for coronary artery bypass grafting, and to examine the vasorelaxant effect of a cardiotonic and vasodilating phosphodiesterase 3 inhibitor, 1, 2-dihydro-6-methyl-2-oxo-5-(imidazo[1,2-a]pyridin-6-yl)-3-pyridine carbonitrile hydrochloride monohydrate (olprinone). The phosphodiesterase 3 isoenzyme was separated from the radial artery by DEAE-Sepharose chromatography. Olprinone inhibited the phosphodiesterase 3 activity with an IC(50) value of 1.25 microM. Olprinone relaxed the phenylephrine-induced contractions of endothelium-denuded arterial strips with an EC(50) value of 0. 107+/-0.029 microM (n=5). These findings indicate that the human radial artery possesses phosphodiesterase 3 isoenzyme activity and olprinone causes potent relaxation of the arterial strip in vitro through inhibition of phosphodiesterase 3 isozyme activity.

Hemodynamic effects of phosphodiesterase III inhibitor in patients with a large ventricular left-to-right shunt

The hemodynamic effects of olprinone, a newly synthesized phosphodiesterase (PDE) III inhibitor, were assessed in patients with a large cardiac left-to-right shunt. Ten patients with a large ventricular septal defect (VSD) were evaluated during cardiac catheterization. Olprinone was administered as a bolus, 20 microg/kg body weight, and hemodynamic data were obtained before and after the administration. Heart rate and systemic flow increased significantly after administration. On the other hand, olprinone significantly reduced left and right atrial pressure, the systolic pulmonary/arterial pressure ratio, and systemic vascular resistance. However, pulmonary flow and pulmonary vascular resistance were not changed. These results suggested that olprinone had a positive inotropic effect and selective vasodilator effect on patients with a large ventricular left-to-right shunt. Thus, PDE inhibitors may be beneficial for the treatment of patients with a large VSD.