Percutaneous absorption of methylprednisolone aceponate following topical application of Advantan lotion on intact, inflamed and stripped skin of male volunteers.

Six healthy, elderly volunteers received three topical treatments with Advantan lotion containing 0.1% of methylprednisolone aceponate (MPA, CAS 86401-95-8) on intact, inflamed and stripped skin in a consecutive fashion at weekly intervals. The lotion (O/W emulsion) containing 14C-MPA (specific radioactivity 1.8 MBq/mg MPA) was applied in an area dose of 5 mg lotion/cm2 on a marked area of 100 cm2 on the back for 24 h. Inflammation was caused by UV-B irradiation at 3 MED 6 h prior to the treatment with the test preparation. Removal of stratum corneum was performed by 20-fold adhesive tape stripping. The concentration of radioactivity was measured in the plasma and in the urine up to 7 days following each treatment. The concentration of radioactivity in the plasma did not exceed the limit of detection of 1.5 ng MPA Eq/ml at any time point. The percutaneous absorption was assessed from the cumulated excretion of radiolabelled substances in the urine corrected for biliary excretion. Less than 0.5% of the dose was percutaneously absorbed through intact skin and through inflamed skin. After removal of the penetration barrier ('stripping') the percutaneous absorption increased to 15.4 +/- 7.7% of the applied dose.

Gadolinium-ethoxybenzyl-DTPA as a hepatobiliary contrast agent for use in MR cholangiography: results of an in vivo phase-I clinical evaluation.

The purpose of this study was to investigate the time course of contrast enhancement in bile ducts and the gallbladder (GB) after injection of gadolinium-ethoxybenzyl-DTPA (Gd-EOB-DTPA). In a clinical phase-I study, MR imaging at 1.5T was performed in 16 healthy volunteers with four different doses of Gd-EOB-DTPA (10, 25, 50, and 100 micro;mol/kg b. w., four volunteers per dosage). The study protocol comprised a heavily T1-weighted fast multiplanar gradient-echo (GE) sequence before and at increasing intervals for up to 360 min after injection of Gd-EOB-DTPA. The signal enhancement was evaluated in extra- and intrahepatic bile ducts as well as in the GB. In all 16 volunteers the common bile duct showed intense signal enhancement beginning 5-16 min after injection (mean 10 min) and persisting for at least 120 min in 4 subjects and for 360 min in 12 subjects. The duration of signal enhancement was significantly (p < 0.05) longer for higher doses (50, 100 micro;mol/kg) than for lower doses (10, 25 micro;mol/kg). Intrahepatic bile ducts were hyperintense as compared with liver parenchyma in all subjects receiving 10 micro;mol/kg from approximately 50-120 min after contrast agent application. Intrahepatic bile ducts were not displayed using the higher doses, probably because of the strong enhancement of the liver parenchyma. Gallbladder contrasting was achieved in all cases beginning 7-33 min after injection (mean 19 min) and remained visible for up to 360 min in 94 %. Hyperintense visualization of normal extrahepatic bile ducts as well as the GB is regularly achieved with the hepatobiliary contrast agent Gd-EOB-DTPA. The dosage for hyperintense visualization of intrahepatic bile ducts is 10 micromol/kg.

Phase I clinical evaluation of Gd-EOB-DTPA as a hepatobiliary MR contrast agent: safety, pharmacokinetics, and MR imaging.

PURPOSE: To determine the safety, pharmacokinetics, and magnetic resonance (MR) imaging results of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) as a contrast agent for use in hepatobiliary MR imaging. MATERIALS AND METHODS: Gd-EOB-DTPA was tested at doses of 10, 25, 50, and 100 mumol per kilogram of body weight. Results of laboratory tests, clinical measurements, and pharmacokinetic data were obtained in 44 healthy volunteers in a double-blind, randomized, placebo-controlled design. MR images were obtained in another 16 healthy volunteers before and up to 6 hours after fast intravenous administration of Gd-EOB-DTPA. RESULTS: Gd-EOB-DTPA was well tolerated, with no important side effects or changes in laboratory parameters. Homogeneous enhancement of liver parenchyma was observed immediately after injection of the contrast agent. Peak liver signal intensity was noted 20 minutes after injection, followed by plateaulike enhancement over about 2 hours. The common bile duct was hyperintense within 10 minutes after injection in all volunteers. CONCLUSION: Gd-EOB-DTPA is safe and efficient for MR imaging of the liver.

Pharmacokinetics of levonorgestrel and ethinylestradiol in 14 women during three months of treatment with a tri-step combination oral contraceptive: serum protein binding of levonorgestrel and influence of treatment on free and total testosterone levels in the serum.

The pharmacokinetics of levonorgestrel (LNG) and ethinylestradiol (EE2) were determined in 14 healthy women (age 18 to 27 years) during a treatment period of three months with a tri-step combination oral contraceptive (Triquilar). Prior to this treatment period, the same women received a single administration of a coated tablet containing 0.125 mg LNG together with 0.03 mg EE2. There was a washout phase of one week between both treatments. Following single dose administration, a mean terminal half-life of 22 h was observed for LNG. The total clearance was 1.0 ml x min-1 x kg-1 and the volume of distribution was 128 l. During a treatment cycle, LNG levels in the serum accumulated by a factor of about four as compared to single dose administration. Steady-state drug levels were reached during the second half of each cycle. As compared to single dose administration, the following changes were observed for LNG at the end of treatment cycles one and three: reduced total (0.5 ml x min-1 x kg-1) and free clearance (50 ml x min-1 x kg-1) and a reduced volume of distribution (52 l). A concomitant increase in the SHBG concentrations by a factor of two as compared to pretreatment values was observed during treatment and appeared to be mainly responsible for the changes in the pharmacokinetics of LNG. Marked changes were also seen for the serum protein binding of LNG. After single dose administration, the free fraction of LNG was 1.4% and the fractions bound to SHBG and albumin were 55.0% and 43.6%, respectively. At the end of cycle one, the free fraction was only 1.0% and the fractions bound to SHBG and albumin were 69.4% and 30.0%, respectively. There was no difference in corresponding pharmacokinetic parameters and in the serum protein binding of LNG at the end of cycles one and three. On the last day of treatment cycles one and three, the AUC(0-4h) values of EE2 were 331.2 and 369.6 pg x ml-1 x h, respectively, which corresponds to an about 11-24% increase as compared to single dose administration, where an AUC(0-4h) value of 298.3 pg x ml-1 x h was found. Total and free testosterone concentrations decreased during treatment cycles one and three by about 41% and 55%, respectively, compared with the corresponding values measured prior to treatment.

PIP: In Germany, an open, intraindividual comparative study was conducted among 14 women, 18-27 years old, to examine the pharmacokinetics of levonorgestrel (LNG) and ethinyl estradiol (EE2) during a 3-month period of treatment with a tristep oral contraceptive (OC) called Triquilar. The women first received a single oral dose of 0.125 mg LNG and 0.03 mg EE2 followed by a washout period of 1 week. They received Triquilar during 3 cycles (days 1-6, 0.05 mg LNG + 0.03 EE2; days 7-11, 0.075 mg LNG + 0.04 mg EE2; and days 12-21, 0.125 LNG + 0.03 mg EE2). The mean terminal half-life for LNG was 22 hours. Total clearance of LNG was 1 ml x min-1 x kg -1. LNG volume distribution was 128.1. At the end of the treatment cycles 1 and 3, when compared to single dose administration, the total and free LNG clearance was reduced (0.5 ml x min-1 x kg-1 and 50 ml x min-1 x kg-1, respectively). LNG volume distribution was also lower after treatment cycles than after single dose administration (52 l). LNG serum levels during Triquilar treatment accumulated by a factor of 4 when compared to the level of single dose administration. Steady-state LNG levels of around 2-3 ng/ml were achieved on day 16-18 of each treatment cycle. Sex hormone binding globulin (SHBG) levels increased by a factor of 2 when compared to pretreatment levels. This simultaneous increase in SHBG likely accounted for the changes in the pharmacokinetics of LNG. After a single dose, the free fraction of LNG was 1.4% and fractions bound to SHBG and albumin were 55% and 43.6%, respectively. At the end of cycles 1 and 3, no difference in these pharmacokinetic parameters and in the serum protein binding of LNG existed. At the end of cycles 1 and 3, the 0-4 hour area under the curve (AUC) values of EE2 increased from 298.3 to 331.2 and 369.6 pg x ml-1 x h, respectively, a 11% and 24% increase, respectively. When compared to pretreatment levels, total and free testosterone levels fell during treatment cycles 1 and 3 by around 41% and 55%, respectively.

Contrast-enhanced MR imaging of liver and spleen: first experience in humans with a new superparamagnetic iron oxide.

The aim of this prospective study was to obtain the first human safety and magnetic resonance (MR) imaging results with a new formulation of superparamagnetic iron oxide (SPIO) (SHU 555 A). The SPIO was tested at four iron doses, from 5 to 40 mumol/kg. Laboratory tests and clinical measurements were done in 32 healthy volunteers for up to 3 weeks after administration. MR imaging at 1.5 T was performed before and 8 hours to 14 days after fast intravenous injection (500 mumol Fe/min) of the SPIO (six subjects per dose). Results of this phase I study demonstrate that SHU 555 A at a concentration of 0.5 mol Fe/L was well tolerated. A dose-dependent minor increase in activated partial thromboplastin time, which remained within the normal range, was seen. All doses of SPIO caused a signal loss in both liver and spleen (P < .05) with a spin-echo sequence (TR = 2,300 msec, TE = 45 msec). The signal losses in the liver 8 hours after contrast agent injection were 58%, 79%, 82%, and 87% for the 5, 10, 20, and 40 mumol Fe/kg doses, respectively. The corresponding signal losses in the spleen were 23%, 45%, 65%, and 78%, respectively. The doses that reduced signal intensity by half were 3.1 mumol Fe/kg for the liver and 12.8 mumol Fe/kg for the spleen. The results suggest that the new SPIO formulation is a safe and efficient MR contrast agent.

Pharmacokinetics, dose proportionality, and tolerability of gadobutrol after single intravenous injection in healthy volunteers.

RATIONALE AND OBJECTIVES: Gadobutrol is a new gadolinium-based hydrophilic and neutral macrocyclic contrast medium for magnetic resonance imaging. In this article, the authors report on the first application of gadobutrol in humans, up to a dose of 0.5 mmol/kg. METHODS: Gadobutrol was investigated after single intravenous administration in two phase-1 studies testing low (0.5 mol/L) and high concentrations (1 mol/L) in healthy, male volunteers using a double-blind, randomized, placebo-controlled study with n = 55 for the low concentration (0.04, 0.1, 0.2, 0.3, and 0.4 mmol/kg body weight), followed by n = 36 for the high concentration (0.3, 0.4, and 0.5 mmol/kg body weight). Vital signs and laboratory parameters were measured for all dose groups investigated, whereas for the calculation of the pharmacokinetic parameters, the dose groups 0.04, 0.1, and 0.4 mmol/kg body weight were selected. RESULTS: Gadobutrol was well tolerated up to doses of 0.5 mmol/kg, and no relevant changes in vital signs and laboratory parameters occurred. The terminal disposition half-life of gadobutrol in plasma was approximately 1.5 hours. Total clearance approximated renal clearance and approximated the value of 120 mL/min, indicating glomerular filtration as the main pathway of elimination. The steady-state volume of distribution indicated predominantly extracellular distribution of gadobutrol. No metabolites were detected. The renal excretion rate was linear over the large dose range tested, indicating dose-proportionate, first-order kinetics of gadobutrol. CONCLUSION: Single intravenous administration of gadobutrol was well tolerated up to the dose level of 0.5 mmol/kg body weight. These factors suggest that gadobutrol will be a safe magnetic resonance imaging contrast agent.

Dose proportionality of iopromide pharmacokinetics and tolerability after i.v. injection in healthy volunteers.

Twelve healthy male volunteers participated in a single-blind, randomised, placebo-controlled cross-over study of i.v. iopromide in doses of 15 g iodine or 80 g iodine infused over a period of 15 min. The volunteers were observed for three days during which time blood samples, urine and faeces were collected. The terminal disposition phase half-life of iopromide was 2 h and 1.9 h, and the total clearance was 110 and 103 ml.min-1 at the lower and at the higher dose levels, respectively. The steady state volume of distribution was 16 and 17 l, indicating predominantly extracellular distribution of iopromide. Statistical analysis (one-sided t-test) showed that all the target parameters (AUC, half-life and urinary excretion) were equivalent at both dose levels, indicating dose proportionate, first order kinetics of iopromide over the large dose range tested. Iopromide was well tolerated after both doses.

Pharmacokinetics of cyproterone acetate and ethinylestradiol in 15 women who received a combination oral contraceptive during three treatment cycles.

The pharmacokinetics of cyproterone acetate (CPA) and ethinylestradiol (EE2) were determined in 15 healthy women (age 19 to 34 years), following single dose administration of a combination oral contraceptive, containing 2.0 mg CPA together with 0.035 mg EE2 (Diane-35R). After a wash-out period of one week, the same preparation was administered during a treatment period of three months. After single dose administration, maximum concentrations of CPA in the serum were 15.2 +/- 6.6 ng/ml. Post maximum drug levels declined biphasically with half-lives of 0.8 +/- 0.4 h and 54.0 +/- 26.0 h, respectively. The apparent clearance was calculated to be 3.6 +/- 0.9 ml x min-1 x kg-1 and the volume of distribution (Vz) was 986 +/- 4371. The free fraction of CPA was 3.5 +/- 1.9% and the fractions bound to heat labile proteins and albumin were 4.6 +/- 2.2% and 92.0 +/- 3.5%, respectively. Trough levels of CPA in the serum increased during a treatment cycle, reaching a steady-state around day 16. An about two-fold accumulation of CPA was observed, which was less than expected theoretically. SHBG concentrations in the serum increased by a factor of three during a cycle, without having any effect on the protein binding of CPA. At the end of treatment cycle three, the terminal half-life of CPA had increased to a mean value of 78.6 +/- 16.0 h and the volume of distribution to a value of 1304 +/- 427 1. The apparent clearance showed a small, although significant decrease to a value of 3.0 +/- 0.4 ml x min-1 x kg-1. The observed changes Vz and t 1/2 during the treatment period were attributed to the distribution of CPA into a deep compartment and the slow release of the drug from this compartment. The AUC(0-4h) values of EE2 following single dose administration of the combination oral contraceptive were found to be 187.5 +/- 79.7 pg x ml-1 x h. On the last day of cycles one and three, the AUC(0-4h) values were 311.2 +/- 109.3 and 304.8 +/- 121.5 pg x ml-1 x h, respectively, which corresponds to an about 60% increase as compared to single dose administration. Total and free testosterone concentrations decreased during treatment cycles one and three by about 39% and 62%, respectively, compared with the corresponding values measured prior to treatment.

PIP: In Germany, 15 healthy young women received a single dose of an oral contraceptive (OC) (Diane-35R) with 2 mg cyproterone acetate (CPA) and .035 mg ethinyl estradiol (EE2) and, after a 2 week wash-out period, they received the same OC over a treatment period of 3 cycles. A drug-free interval separated each of the 3 cycles. The researchers aimed to examine the pharmacokinetics of CPA and EE2 of this OC. After 1 oral dose, CPA was rapidly absorbed and CPA serum levels rose as high as 15.2 ng/ml. 24 hours after the single dose, the free fraction of serum CPA was 3.5%. The fractions bound to albumin and heat labile proteins were 92% and 4.6%, respectively. The terminal half-life of CPA was higher at the end of treatment cycle 3 than after a single dose (78.6 hours vs. 54 hours). The apparent mean volume of distribution also increased from 986 to 1304. The apparent total clearance fell somewhat from 3.6 to 3 ml x min-1 x kg-1. Mean serum CPA trough levels rose during treatment and stabilized on day 16 of cycles 1 and 3. Accumulated CPA in the serum during treatment cycle 1 was more than 2 times higher than that expected based on data obtained after single dose administration. Serum concentration of sex hormone binding globulin increased by a factor of 3.3 during a treatment cycle due to concomitant administration of EE2. This increase did not affect the protein binding capacity of CPA. Distribution of CPA into a deep compartment (e.g., fatty tissue and skin) and the slow release of CPA from this compartment accounted for the increases in volume of distribution and the terminal half-life. The area under the curve of EE2 was about 60% higher on the last days of cycles 1 and 3 than it was after single dose administration (311.2 and 304.8, respectively vs. 187.5). When compared to baseline values, free and total testosterone levels fell during treatment cycles 1 and 3 by around 62% and 39%, respectively.

Pharmacokinetics of gestodene and ethinylestradiol in 14 women during three months of treatment with a new tri-step combination oral contraceptive: serum protein binding of gestodene and influence of treatment on free and total testosterone levels in the serum.

The pharmacokinetics of gestodene (GEST) and ethinylestradiol (EE2) were determined in 14 healthy women (age 18 to 32 years) during a treatment period of three months with a new tri-step combination oral contraceptive (Milvane). Prior to this treatment period, the same women received a single administration of a coated tablet containing 0.1 mg GEST together with 0.03 mg EE2. There was a wash-out phase of one week between both treatments. Following single dose administration, a mean terminal half-life of 18 h was observed for GEST. The total clearance was 0.9 ml x min-1 x kg-1 and the volume of distribution was 84 l. During a treatment cycle, GEST levels in the serum accumulated by a factor of 8 as compared to single dose administration. Steady-state drug levels were reached during the second half of each cycle. As compared to single dose administration, the following changes were observed for GEST at the end of treatment cycles one and three: prolonged terminal half-life (20 to 22 h), reduced total (0.16 ml x min-1 x kg-1) and free clearance (ca. 27 ml x min-1 x kg-1), reduced volume of distribution (ca. 18 l). A concomitant EE2-induced increase in the SHBG concentrations by a factor of three as compared to pretreatment values was observed during a treatment cycle and appeared to be mainly responsible for the changes in the pharmacokinetics of GEST. Marked changes were also seen for the serum protein binding of GEST. After single dose administration, the free fraction of GEST was 1.3% and the fractions bound to SHBG and albumin were 69.4% and 29.3%, respectively. At the end of cycle one, the free fraction was only 0.6% and the fractions bound to SHBG and albumin were 81.4% and 18.0%, respectively. There was no difference in corresponding pharmacokinetic parameters and in the serum protein binding of GEST at the end of cycles one and three. On the last day of treatment cycles one and three, the AUC(0-4h) values of EE2 were 299.2 and 278.1 pg x ml-1 x h, respectively, which corresponds to an about 30% increase as compared to single dose administration, where an AUC(0-4h) value of 216.1 pg x ml-1 x h was found. Total and free testosterone concentrations decreased during treatment cycles one and three by about 36% and 60%, respectively, compared with the corresponding values measured prior to treatment. The fraction of unbound testosterone thus decreased from 0.5% to 0.3% during treatment.

PIP: In Germany, researchers examined blood samples from 14 healthy young women, who first took a single oral dose of 0.1 mg gestodene and .03 mg ethinyl estradiol, then Milvane, a new tri-step combination oral contraceptive, for 3 months, to learn in detail the pharmacokinetics of gestodene. A 1-week wash-out phase occurred between the 2 treatments. The mean terminal half-life for gestodene after receiving the single dose was 18 hours. It volume of distribution stood at 84. Total clearance was 0.9 ml x min-1 x kg-1. Gestodene serum levels accumulated by a factor of 8 when compared to levels after single-dose administration. Drug levels reached a steady-state by the second part of each treatment cycle. At the end of treatment cycles 1 and 3, in comparison with single-dose administration, gestodene had a prolonged terminal half-life (20-22 h), reduced total and free clearance (0.16 ml x min-1 x kg-1 and ca. 27 ml x min-1 x kg-1, respectively), and reduced volume of distribution (ca. 18 1). When comparing single-dose administration and 3-month treatment levels, ethinyl estradiol increased sex hormone binding globulin (SHBG) levels by a factor of 3, apparently causing the changes in the pharmacokinetics of gestodene. Further, the free fraction of gestodene fell from 1.3 to 6%, and the fractions bound to SHBG increased from 69.4 to 81.4% while the fractions bound to albumin fell from 29.3 to 18%. The ethinyl estradiol values of the area under the curve stood at 299.2 pg x ml-1 x h at 0 hours of the last day of treatment cycle 1 and 3. At 4 hours, it was 278.1 pg x ml-1 s h. Between pretreatment and treatment cycles 1 and 3, total and free testosterone levels fell by almost 36% and 60%, respectively, resulting in a decrease of the fraction of unbound testosterone from 0.5 to .03% during treatment. These findings showed that pharmacokinetic parameters did not differ between cycles 1 and 3, indicating that equilibrium had been already reached after one cycle and that prolonged treatment should not result in any other changes.

Oral iloprost in healthy volunteers.

Iloprost is a potent chemically stable PGI2-mimetic. Therapeutic efficacy was shown after i.v. infusion treatment in several states of peripheral vascular disease. For out-patient therapy an oral dosage form should be developed. Based upon dissolution profiles and in vivo data of a pig model, three different film-coated pellet formulations were selected for pharmacokinetic characterization in nine healthy volunteers. In the first part of the study groups of three test subjects were treated with increasing dosages (150-300 micrograms) of iloprost. At 300 micrograms flush and headache led to the discontinuation of those titration. All formulations exhibited dose-dependent serum level profiles. The cross-over characterization in all test subjects showed that one formulation, which exhibited a modified in vitro dissolution of 60% of the dose within 1 h in pH 7.4 phosphate buffer, was optimal from the pharmacokinetic profile. After oral administration of this formulation the bioavailable dose fraction was highest and half-maximal serum levels lasted for 2.4 h (mean); therapeutic serum levels were maintained for 2.1-5.0 h. This formulation was chosen for further investigation to imitate therapeutic serum level profiles as obtained after i.v. infusion for 4-6 h with a once-a-day dosage form.

Pharmacokinetics and pharmacodynamics of cicaprost in healthy volunteers after oral administration of 5 to 20 micrograms.

In a Phase I study, the tolerability, pharmacodynamics and pharmacokinetics of cicaprost have been investigated in 6 male volunteers given 5, 10, 15 and 20 micrograms as tablets of the beta-cyclodextrin clathrate. Individual inhibition of platelet aggregation and changes in facial colour (measured by chromametry) were dose-dependent and reached a maximum 30 to 60 min post-dose. The maximum inhibition of platelet aggregation was about 40%. After 3 to 4 h pre-treatment values had returned. Blood pressure remained within the normal range. The peak plasma level of cicaprost was reached within 15 to 90 min after drug intake. Both Cmax- and AUC were individually dose-dependent. The terminal half-life in plasma of cicaprost was approx. 1 h, and its total clearance amounted to 4-7 ml.min-1.kg-1. The time courses of the plasma levels and of the pharmacodynamic actions were in agreement. Interindividual differences were observed in the occurrence of unwanted effects (e.g. headache). Thus, cicaprost is an orally available PGI2-mimetic, for which effects on platelet aggregation and vascular perfusion have been demonstrated in healthy volunteers after doses of 5 to 15 micrograms.

Successful opacification of the left heart chambers on echocardiographic examination after intravenous injection of a new saccharide based contrast agent.

A new monosaccharide microparticle based echocardiographic contrast agent (SH U 508) was injected intravenously into five healthy male volunteers following which the heart was imaged in an apical four-chamber view. Volumes of 2, 4, 8, and 16 mL of SH U 508 were incrementally injected into each volunteer. Concentrations of 50, 100, 200, 300, and 400 mg microparticles per mL of suspension were used in five successive examinations. Left heart opacification of diagnostic value was obtained during the whole cardiac cycle with concentrations of 300 and 400 mg/mL. There was no interference in imaging of the left ventricular walls due to increased attenuation. SH U 508 showed a good tolerance. No side effect was observed and no clinical relevant changes were observed in the heart rate, blood pressure, ECG, blood chemistry, hematology or urinalysis findings. This new agent may greatly extend the role of cardiac ultrasound and may also permit the examination of the arterial circulation in other organs.

Pharmacokinetics of 3H-cicaprost in healthy volunteers.

Cicaprost (5-[(E)-(1S,5S,6S,7R)-7-hydroxy-6-[(3S,4S)-3-hydroxy-4-methylnona- 1,6- diinyl]-bicyclo[3.3.0]octan-3-yliden]-3-oxapentanoic acid, ZK 96 480) is a novel PGI2-derivative, which is chemically stable and not subject to metabolic degradation in rats and cynomolgus monkeys. The pharmacokinetics of Cicaprost were studied in six healthy volunteers (age: 54-74 y) after i.v. infusion (2.1 micrograms over 60 min) and p.o. dosage (7.6 micrograms) of the tritiated compound. All treatments were well-tolerated by the test subjects. At the end of the infusion plasma levels of approximately 100 pg/ml were reached, declining biphasically with half-lives of 3-4 min and 64 +/- 21 min. Total clearance was 3.8 +/- 0.5 ml/min/kg. The oral dosage resulted in peak plasma levels of 251 +/- 90 pg/ml occurring at 23 +/- 5 min post dose. The terminal half-life in the plasma was 115 +/- 30 min. Gastro-intestinal absorption and absolute bioavailability of Cicaprost was complete. After both routes of administration approx. 60% of dose was excreted with the urine within 24 h, whereas fecal 3H-excretion lasted for several days and accounted for approx. 35%. Radiochromatography revealed that Cicaprost was metabolically stable in plasma and urine. In the feces several degradation products were observed apart from approx. 30% of the dose fraction being excreted unchanged by that route. The present results demonstrate that Cicaprost is an orally completely bioavailable, metabolically stable PGI2-mimetic which may be an ideal candidate for oral therapy because of its pharmacokinetic characteristics.

Pharmacokinetics of iotrolan after intravenous injection into healthy volunteers.

In man Iotrolan is distributed in the extravascular space after intravenous injection with a half-life of about 11 minutes, the elimination half-life being about 108 minutes. After intravenous injection 99.2 +/- 1.8% of the dose was found in the urine and 0.5 +/- 0.1% in the feces within 5 days. No metabolization occurred in man and the pharmacokinetic behavior of iotrolan is comparable to that of known nonionic contrast media (e.g., iohexol, iopromide) (7, 9, 13).

Organ-specific and general tolerance of iotrolan 280 after intravenous administration: phase I study in healthy volunteers.

Iotrolan 280, the first water-soluble, nonionic, blood-isotonic, dimeric contrast medium, was administered intravenously to 12 healthy male volunteers. In a Phase I study with an intraindividual design in comparison with placebo, four doses between 0.15 and a maximum of 0.9 g I/kg body weight were administered in accordance with the principle of dose titration. The highest volume administered was 270.6 ml. The injection rate was 10 ml/min. The observation period was 5 days, with the exception of thyroid parameters (14 days). Iotrolan displayed good general and local tolerance. The typical side effects known from x-ray contrast media either did not occur or were minor after administration of iotrolan. No allergy-like reactions and no effects on hemodynamic parameters were observed. Although one observation is under discussion no effects of iotrolan on impulse generation and propagation in the myocardium could be confirmed. The blood and laboratory and chemical parameters analyzed showed no differences in comparison with placebo. In the treatment group with the highest dose (= 0.9 g I/kg body weight) there was one subject who showed a transient increase of the urinary glucose concentration and one case of a slight transient increase of the serum chloride concentration. No such side effects were seen in the subjects of the treatment groups with lower doses. All renal functions tests were normal. In this study iotrolan showed excellent tolerance after intravenous injection up to 0.9 g I/kg body weight.