Phase I dose escalation study to evaluate the safety and pharmacokinetic profile of tefibazumab in subjects with end-stage renal disease requiring hemodialysis

Two cohorts of four subjects requiring hemodialysis received tefibazumab (10 or 20 mg/kg). The mean elimination half-life was between 17 and 18 days, the average volume of distribution was 7.3 liters, and the average clearance was 12 ml/h for both dose groups. At a dose of 20 mg/kg of body weight, plasma levels were 88 microg/ml at 21 days.     

Human pharmacokinetics and safety profile of finafloxacin, a new fluoroquinolone antibiotic, in healthy volunteers

Finafloxacin is a new fluoroquinolone antibiotic with the unique property of increasing antibacterial activity at pH values lower than neutral. Whereas its antibacterial activity at neutral pH matches that of other quinolones in clinical use, it is expected to surpass this activity in tissues and body fluids acidified by the infection or inflammation processes. Pharmacokinetic parameters of oral single and multiple doses of up to 800 mg of finafloxacin and safety/tolerability observations were assessed in a phase I study including 95 healthy volunteers. Finafloxacin is well absorbed after oral administration, generating maximum concentrations (C(max)s) in plasma at least comparable to those of other fluoroquinolones, with a half-life of around 10 h. About one-third of the dose is excreted unchanged in the urine. Renal elimination appears to be a saturable process leading to slight increases of the area under the concentration-time curve extrapolated to infinity and dose normalized (AUC(∞,norm)) at dosages of 400 mg and above. Safety and tolerability data characterize finafloxacin as a drug with a favorable safety profile. In particular, adverse reactions regarded as class-typical of fluoroquinolones, such as, e.g., electrocardiogram (ECG) changes, neurotoxic effects, or hypoglycemia, were not observed in the study population.     

Multiple intravenous dose pharmacokinetic study of carumonam in healthy subjects

Steady-state pharmacokinetics of carumonam were investigated in twelve healthy adult male volunteers after 20 min intravenous infusions of three consecutive carumonam dosage regimens: 1 g every 8 h (3 g/day) from 0-72 h, 2 g every 8 h (6 g/day) from 88-120 h and 2 g every 6 h (8 g/day) from 132-216 h. Serial plasma samples were collected after the first dose of the first regimen and the last dose of all three regimens and were analysed for carumonam by a specific HPLC method. The overall mean maximal plasma concentrations were 108 and 211 mg/l at the end of infusion of 1 and 2 g, respectively. The steady-state pharmacokinetic parameters and plasma concentration-time profiles of carumonam when adjusted for dose were similar for the three regimens. The overall terminal elimination half-life was 1.4 h (range 1.1-1.8 h), the apparent volume of distribution at steady state reached 11.5 l (range 8.7-15.5 l) and the total systemic clearance amounted to 118 ml/min (range 83-158 ml/min). Considering the frequency of dosing relative to the elimination half-life, accumulation of the drug in plasma was not expected and none was found from any of the three regimens. Carumonam was well tolerated up to 8 g/day and exhibited dose-independent pharmacokinetics which were not altered upon multiple dosing.     

Multiple dose pharmacokinetics, safety, and effects on faecal microflora, of cefepime in healthy volunteers.

In a randomized, double-blind, placebo-controlled study in 12 healthy volunteers pharmacokinetics, safety and impact on the faecal microflora of cefepime were determined. For eight days eight volunteers received cefepime 1000 mg bd by constant infusion over 30 min, four volunteers received placebo. Concentrations of cefepime in serum and urine were measured by bioassay and HPLC. The correlation between the two methods was good and the bioassay results were used for pharmacokinetic calculations. The faecal flora was analysed twice before the study, twice during the study and four times after cefepime administration. There were no significant differences in the pharmacokinetic parameters between days 1 and 8. The following values (mean +/- S.D.) represent day 1. The maximum concentration of 72.69 +/- 12.2 mg/L immediately after infusion decreased to 0.56 +/- 0.17 mg/L after 12 h. The mean 12 h recovery in urine was 93.69 +/- 2.14%. Pharmacokinetic parameters based on an open two-compartment model were as follows (mean +/- S.D.): area under the curve, 142.65 +/- 18.35 mg.h/L; elimination half-life 110.3 +/- 8.3 min; steady state volume of distribution 16.0 +/- 1.9 L/70 kg; total clearance, 107.0 +/- 16.0 mL/min; renal clearance 103.0 +/- 15.2 mL/min. No accumulation was observed during the eight day study period with cefepime at this dosage; trough levels on days 2-7 ranged from 0.52 +/- 0.26 mg/L to 0.90 +/- 0.33 mg/L. In the cefepime treated group the following side-effects were noted: headache (5), fatigue (4), nausea/stomach ache (2), soft stool (2), transient scotoma (1). Side-effects in the placebo group were: headache (2) fatigue (3), nausea/stomach-ache (1), soft stool (2) and photophobia (1). During cefepime administration a decrease in the number of Escherichia coli and bifidobacteria in faeces was observed, whereas Bacteroides spp. and clostridia showed a slight increase. The numbers of faecal bacteria returned to normal 20 to 48 days after the study was completed.     

降压新药尼群洛尔片药代动力学研究的临床观察和护理

目的 探讨降压药物药代动力学研究中临床观察和护理的作用。方法 24名健康受试者分为尼群地平组、阿替洛尔组和尼群洛尔组,每组8人。观察3组健康受试者服药前和服药后的坐位、立位和卧位血压和心率变化以及任何不适主诉和体征,通过静脉留置针采得药代动力学研究的血液样本。结果 与尼群地平组和阿替洛尔组比较,尼群洛尔组的健康受试者服药前和服药后坐位、立位和卧位收缩压和舒张压以及心率均未有显著性差异。通过密切观察未发现尼群洛尔组的健康受试者有不良反应。结论 药代动力学研究中临床观察对降压药物安全性的评估是重要的,规范的护理操作和整体护理对药物临床试验的顺利完成起到重要的作用。     

Tolerability and safety profile of posaconazole: evaluation of 18 controlled studies in healthy volunteers

Background and objectives: Antifungal agent utility can be limited by safety and tolerability concerns. Posaconazole is an extended‐spectrum triazole antifungal agent for the treatment and prophylaxis of invasive fungal infection. The aim was to analyse the overall safety profile of posaconazole in healthy volunteers. Methods: Safety data from all 18 clinical pharmacology single‐ and multiple‐dose trials of posaconazole conducted in healthy volunteers plus 2 additional healthy subsets from other pharmacology trials were pooled and analysed. Four hundred and forty‐nine healthy volunteers (354 men; 95 women) were enrolled. Three hundred and twenty‐seven were white, and the mean age and weight of subjects were similar across all dosing groups. The population evaluated had no confounding factors of underlying disease or concomitant medications. Safety evaluations included spontaneously reported adverse events, clinical laboratory test results, electrocardiograms and vital sign measurements. Results: A total of 448 subjects received posaconazole, 50–1200 mg/day administered as single or multiple doses for up to 14 days. Two hundred and seventeen subjects received ≥800 mg/day posaconazole, and 188 subjects received multiple doses of posaconazole at 800 mg/day. Two hundred and thirty‐one subjects received <800 mg/day. Forty‐eight subjects from three studies received placebo. The incidence of treatment‐emergent adverse events reported with posaconazole was similar to that seen with placebo (57% vs. 63% respectively) and unrelated to dose. The most common treatment‐related adverse events (posaconazole vs. placebo) were headache (17% vs. 13%), dry mouth (9% vs. 0%) and dizziness (6% vs. 2%). No clinically significant changes in vital signs or laboratory test parameters were observed, except for transient, mild to moderate elevations in liver function test results. Posaconazole also demonstrated minimal potential to prolong corrected QT interval. Conclusions: The safety profile analysis found posaconazole to be well tolerated, and results were similar across sex, age and race.     

A single ascending dose study of epigallocatechin gallate in healthy volunteers

This randomized, double-blind, placebo-controlled study assessed the safety, tolerability and plasma kinetic behaviour of single oral doses of 94% pure crystalline bulk epigallocatechin gallate (EGCG) under fasting conditions in 60 healthy male volunteers. In each group of 10 subjects, eight received oral EGCG in single doses of 50 mg, 100 mg, 200 mg, 400 mg, 800 mg or 1600 mg, and two received placebo. Blood samples were taken at intervals until 26 h later. The area under the concentration-time curve from 0 h to infinity (AUC(0-infinity)), the maximum plasma concentration (Cmax) of EGCG, the time taken to reach the maximum concentration (Tmax), and the terminal elimination half-life (t1/2z) of EGCG were determined. Safety and tolerability were assessed. In each dosage group, the kinetic profile revealed rapid absorption with a one-peak plasma concentration versus time course, followed by a multiphasic decrease consisting of a distribution phase and an elimination phase. The mean AUC(0-infinity) of total EGCG varied between 442 and 10,368 ng.h/ml. The according mean Cmax values ranged from 130 to 3392 ng/ml and were observed after 1.3-2.2 h. The mean t1/2z values were seen between 1.9 and 4.6 h. Single oral doses of EGCG up to 1600 mg were safe and very well tolerated.     

Substantial pharmacokinetic interaction between digoxin and ritonavir in healthy volunteers

BACKGROUND: Ritonavir is a potent in vitro inhibitor of several cytochrome P450 isozymes and ABC transporters including the efflux pump P-glycoprotein (P-gp). This study assessed the effect of repetitive ritonavir administration on digoxin distribution and total and renal digoxin clearance as a marker for P-gp activity in vivo. METHODS: In a randomized, placebo-controlled crossover study, 12 healthy male participants received oral ritonavir (300 mg twice daily) for 11 days. With the assumption that ritonavir steady state had been reached, 0.5 mg digoxin was given intravenously on day 3. Digoxin concentrations were determined in plasma and urine by radioimmunoassay, and plasma ritonavir concentrations were determined by liquid chromatography-tandem mass spectrometry. Digoxin kinetics was estimated by compartmental and noncompartmental analyses, by use of the area under the plasma concentration-time curve, and the corresponding digoxin amount excreted into urine was used for digoxin clearance calculations. RESULTS: Ritonavir significantly (P <.01) increased digoxin area under the plasma concentration-time curve from time 0 to infinity by 86% and its volume of distribution by 77% and decreased nonrenal and renal digoxin clearance by 48% and 35%, respectively. Digoxin terminal half-life in plasma increased by 156% (P <.01). CONCLUSION: This inhibition of renal digoxin clearance is likely caused by ritonavir inhibition of P-gp. Its extent is considerable and similar to the effect of other potent P-gp inhibitors on digoxin disposition such as quinidine. These findings may, therefore, indicate that the pharmacokinetics of P-gp substrates sharing the renal tubular elimination pathway will be affected when combined with therapeutic doses of ritonavir in antiretroviral treatment regimens. In addition and contrarily to quinidine, these data indicate that ritonavir promotes digoxin distribution in the body.     

A phase I randomized,double‐blind,single subcutaneous dose escalation study to determine the safety,tolerability, and pharmacokinetics of rezafungin in healthy adult subjects

Rezafungin is a novel echinocandin being developed for the treatment and prevention of invasive fungal infections. The objectives of this randomized, double‐blind study in healthy adults were to determine the safety, tolerability, and pharmacokinetics of rezafungin after subcutaneous (s.c.) administration. The study design consisted of six sequential cohorts of eight subjects, except for the first cohort with four subjects. The subjects were randomized in a 3:1 ratio of rezafungin to placebo and were to receive a single dose of 1, 10, 30, 60, 100, or 200 mg. The most common adverse events (AEs) were increased alanine aminotransferase and sinus bradycardia (unsolicited) and erythema at the injection site (solicited). Unsolicited AEs were generally mild to moderate and not rezafungin‐related. Although the study was terminated after the 10 mg dose cohort due to concerns of potential increased severity of injection site reactions, no predetermined dose escalation halting criteria were met. Following the 10 mg single s.c. dose of rezafungin (n = 6), the geometric mean (GM) maximum concentration (C _max) was 105.0 ng/ml and the median time to C _max was 144 h. The GM area under the concentration‐time curve was 32,770 ng*h/ml. The median estimated terminal half‐life was 193 h. The GM apparent oral clearance was 0.255 L/h and the GM apparent volume of distribution was 68.5 L. This study demonstrates that a single s.c. dose of rezafungin in healthy adult subjects: (1) did not result in serious AEs, death, or withdrawal from the study due to an AE; and (2) produced a pharmacokinetic profile with long exposure period postadministration. In an effort to reduce the occurrence of injection site reactions, a re‐evaluation of the rezafungin s.c. formulation could be considered in the future.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Currently marketed antifungal agents of the echinocandin class are dosed by i.v. once daily and are therefore not practical for prolonged or outpatient prophylaxis. Rezafungin is an investigational echinocandin (currently in phase III trials studying once‐weekly i.v. administration) that has excellent activity against clinically relevant Candida and Aspergillus spp. and Pneumocystis jirovecii, a prolonged half‐life allowing for longer dosing intervals, and a stability/solubility profile that allows for the possibility of subcutaneous (s.c.) dosing.

• WHAT QUESTION DID THE STUDY ADDRESS?

The objectives of this randomized, double‐blind study in healthy adults were to determine the safety, tolerability, and pharmacokinetics (PKs) of rezafungin after s.c. administration.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

This study provided safety data regarding s.c. administration of rezafungin. Despite common solicited injection site reactions, s.c. administration of 10 mg of rezafungin did not result in serious adverse event (AEs), death, or withdrawals due to an AE in healthy adult subjects. The study also showed that rezafungin had a PK profile with a long exposure period.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

In an effort to reduce the occurrence of injection site reactions, these findings may lead to a future re‐evaluation of the s.c. formulation of rezafungin.     

Lack of pharmacokinetic interaction between the antimigraine compound, almotriptan, and propranolol in healthy volunteers

This study was designed to assess the pharmacokinetics of almotriptan, a 5-HT1B/1D agonist, when administered in the presence and absence of propranolol. Healthy male (n = 10) and female (n = 2) volunteers received (i) 80 mg propranolol twice daily for 7 days and 12.5 mg almotriptan on day 7, and (ii) 12.5 mg almotriptan on day 7, according to a two-way crossover design. Plasma and urinary almotriptan concentrations were measured by high performance liquid chromatography (HPLC) methods. Treatment effects on pharmacokinetic parameters were assessed by analysis of variance (ANOVA). Statistically significant differences between treatments in area under the curve (AUC), clearance, and half-life were observed (P < 0.03), but these differences were < 7%. Ninety percent confidence interval analysis of log-transformed pharmacokinetic parameters showed that the treatments were equivalent. Adverse events were mild to moderate in intensity, and no treatment effects on vital signs were observed. The results show that propranolol has no effect on the pharmacokinetics of almotriptan. Concomitant administration of the two drugs is well tolerated.     

Nonlinear pharmacokinetic properties of mildronate capsules: a randomized,open‐label,single‐ and multiple‐dose study in healthy volunteers

Mildronate has been used as antianginal drug in parts of Europe for many years, but its pharmacokinetic (PK) properties in humans remain unclear. This study was designed to assess and compare the PK properties of mildronate capsules after single escalating oral dose and multiple doses in healthy Chinese volunteers. Volunteers were randomly assigned to receive a single dose of 250, 500, 1000, 1250 or 1500 mg of mildronate capsules. Those who received the 500‐mg dose continued on the multiple‐dose phase and received 500 mg three times a day for 13 days. Plasma drug concentrations were analysed by ultraperformance liquid chromatography coupled with tandem mass spectrometry (UPLC‐MS/MS). Tolerability was assessed throughout the study. A total of 40 Chinese volunteers were enrolled in the study. No period or sequence effect was observed. Area under the concentration and C_max were increased proportionally with the dose levels, whereas t_1/2 and V_d/f were dependent on the dose. Nonlinear PK properties were found at doses of 250–1500 mg. There was an accumulation after multiple‐dose administration. No serious adverse events (AEs) were reported in the PK study. The formulation was well tolerated.     

Phase 1 safety and pharmacokinetic study of chimeric murine-human monoclonal antibody c alpha Stx2 administered intravenously to healthy adult volunteers

Hemolytic-uremic syndrome (HUS) is a serious complication of infection by Shiga toxin-producing Escherichia coli. Shiga toxin type 2 (Stx2) is responsible for the renal toxicity that can follow intestinal infection and hemorrhagic colitis due to E. coli. A chimeric mouse-human antibody, designated c alpha Stx2, that has neutralizing activity in a mouse model was produced and tested in healthy adult volunteers. In this phase I dose escalation study, c alpha Stx2 was generally well tolerated. Pharmacokinetic studies indicated that clearance was stable over the dose range of 1.0 to 10 mg/kg of body weight (0.249 +/- 0.023 ml/kg/h) but was higher for the 0.1-mg/kg dose (0.540 +/- 0.078 ml/kg/h), suggesting saturable elimination. A similar nonlinear trend was observed for the volume of distribution, where average values ranged from 0.064 +/- 0.015 liter/kg for the 1.0- to 10-mg/kg doses and 0.043 +/- 0.005 for the 0.01-mg/kg dose. The relatively small volume of distribution suggests that the antibody is limited to the vascular (plasma) compartment. The mean half-life was 165 +/- 66 h, with lowest values observed for the 0.1-mg/kg dose (56.2 +/- 9.7 h) and the highest values reported for the 10.0-mg/kg dose (206.4 +/- 12.4 h). Future studies are needed to confirm the safety of this c alpha Stx2, and innovative clinical trials will be required to measure its efficacy in preventing or treating HUS.     

A comparative pharmacokinetic and pharmacodynamic study of conventional and sustained-release preparations of acebutolol in healthy volunteers

Pharmacokinetics and the degree of beta-blockade of sustained release (SR) acebutolol (500 mg/day) and conventional acebutolol (200 mg tid) were examined after the first oral dose and after 10 days of treatment in ten healthy volunteers. After the first dose, acebutolol Cmax did not significantly differ between the two formulations; however, on day 10 acebutolol Cmax was significantly higher after SR formulation. Cmax of diacetolol, the major metabolite, did not differ between SR and conventional acebutolol neither on day 1 nor on day 10. The dose-corrected relative bio-availability of acebutolol was not different from 100% on day 1 and day 10; however the dose-corrected diacetolol AUC, SR/conventional ratio, was significantly lower than 100% on days 1 and 10. Both acebutolol preparations exerted a significant reduction in exercise tachycardia over 24 h on day 1 and day 10; however, conventional acebutolol exhibited a greater reduction 24 h after the first dose. Exercise-induced increase in systolic blood pressure was similarly inhibited by both treatments except for 24 h after the first dose when systolic blood pressure was significantly higher with SR than with conventional acebutolol. The percent reduction in heart rate during exercise was linearly correlated with log acebutolol plasma concentrations for each treatment regimen. These results suggest that beta-blockade exerted by SR acebutolol in healthy volunteers is equivalent to that of conventional acebutolol.     

Lack of pharmacokinetic interaction between linezolid and antacid in healthy volunteers

Several antibiotics show significant pharmacokinetic interactions when they are given orally concomitantly with antacids. The objective of this study was to evaluate the effects of antacid (containing magnesium) on the pharmacokinetics of linezolid. A single dose of 600 mg linezolid was given orally alone and 10 min after administration of the antacid Maalox 70mVal, which contains 600 mg magnesium hydroxide and 900 mg aluminum hydroxide, to nine healthy males and nine healthy females in a crossover and randomized study. Linezolid plasma concentrations were determined by high-performance liquid chromatography, and pharmacokinetic parameters were calculated for both treatments. Coadministration with antacids did not change the pharmacokinetics of linezolid. The ratios (90% confidence intervals) of the individual values of the area under the concentration-time curve and the maximum concentration in plasma (C(max)) (linezolid plus antacid versus linezolid alone) were 1.01 (0.99 to 1.02) and 0.99 (0.96 to 1.02), respectively. Likewise, no significant difference in any of the other pharmacokinetic parameters was observed between the treatment groups (the time to C(max), lag time, volume of distribution [V/F], and clearance [CL/F]). However, a significant sex difference was observed for AUC, C(max), V/F, and CL/F; and these differences could be almost completely explained by the differences in body weight between males and females. No clinically relevant adverse effects were detected under either condition. The coadministration of antacids had no effect on the pharmacokinetics of linezolid. This demonstrates that the oral absorption of linezolid was not affected by the presence of antacids containing magnesium hydroxide and aluminum hydroxide. Antacids can be safely administered together with linezolid.     

Safety and pharmacokinetic study with escalating doses of 3-acetyl-7-oxo-dehydroepiandrosterone in healthy male volunteers

OBJECTIVES: To evaluate the safety and pharmacokinetics of 3-acetyl-7-oxo-DHEA (3beta-acetoxyandrost-5-ene-7,17-dione) given orally. DESIGN: A randomized, double blind, placebo-controlled, escalating dose study. SETTING: The Chicago Center for Clinical Research. PARTICIPANTS: Twenty-two healthy men. STUDY METHOD: The participants received placebo (n = 6) or 3-acetyl-7-oxo-DHEA (n = 16) at 50 mg/d for 7 days followed by a 7-day washout; 100 mg/d for 7 days followed by a 7-day washout; and 200 mg/d for 28 days. OUTCOME MEASURES: Safety parameters, evaluated at each dose level, included measurement of total testosterone, free testosterone, dihydrotestosterone, estradiol, cortisol, thyroxin and insulin levels. Analyses for 7-oxo-DHEA-3beta-sulfate (DHEA-S), the only detectable metabolic product of the administered steroid, were conducted on plasma drawn from all subjects at 0.25, 0.5, 1, 2, 4, 6 and 12 hours after the final 100 mg dose of 3beta-acetyl-7-oxo-DHEA. RESULTS: There were no differences in the clinical laboratory values or in reported minor adverse experiences, between treatment and placebo groups. In general, blood hormone concentrations were unaffected by the treatment with 3beta-acetyl-7-oxo-DHEA and remained within the normal range. No changes in vital signs, blood chemistry or urinalysis occurred during treatment with 3beta-acetyl-7-oxo-DHEA compared to placebo. The administered steroid was not detected in the blood but was rapidly converted to 7-oxo-DHEA-S, the concentrations of which were proportional to dose. This steroid sulfate did not accumulate; plasma concentrations 12 hours after the 3beta-acetyl-7-oxo-DHEA dose at 7 and 28 days on the 200 mg/d dose were 15.8 and 16.3 microg/L respectively. The mean time to peak plasma level of 7-oxo-DHEA-S was 2.2 hours; the mean half life was 2.17 hours. The apparent clearance averaged 172 L/h, and the apparent mean volume of distribution was 540 L. CONCLUSION: These results indicate that 3beta-acetyl-7-oxo-DHEA is safe and well tolerated in normal healthy men at doses up to 200 mg/d for 4 weeks.     

曲美他嗪对地高辛药代动力学影响的研究

目的 :探讨曲美他嗪 (TMZ)与地高辛 (DG)合用在正常人体内对地高辛的药代动力学的影响。方法 :采用自身对照给药方法 ,实验分DG单用组和DG +TMZ合用组 ,每组为 12例健康志愿者 ,服药前取手背静脉血 2ml作为空白对照。服药后 2 0min、40min、1h、1 5h、2h、3h、4h、8h、12h、2 4h、48h取血 ,以放射免疫分析法检测血清中DG的浓度。药 时数据经3P97程序处理 ,确定单用组与合用组的药代动力学参数。结果 :经配对t检验 ,两组间主要药动学参数无显著性差异 (P>0 0 5 )。结论 :两药合用时TMZ对DG药动力学无影响。     

Pharmacokinetic profile and tolerability of indinavir-ritonavir combinations in healthy volunteers

This was a randomized, double-blind, placebo-controlled parallel study in human immunodeficiency virus type 1 (HIV-1)-uninfected healthy subjects to investigate the pharmacokinetic interaction between indinavir (IDV) and ritonavir (RTV). Subjects were allocated to treatment groups of IDV given with RTV in the following milligram doses twice daily: 800 mg of IDV-100 mg of RTV (800-100 mg), 800-200, 800-400, and 400-400 mg, placebo of IDV with RTV doses of 100, 200, and 400 mg, and placebo of both IDV and RTV. Doses of both drugs were administered for 14 days with a low-fat meal and one dose on day 15 with a high-fat meal. Blood was obtained for drug concentration measurements on days 14 and 15. Seventy-three volunteers enrolled in the study: 29 men and 44 women. Fifty-three volunteers completed the study. When compared to standard historical data for 800 mg of IDV every 8 h (q8h), the IDV area under the concentration-time curve for 24 h (AUC(24)) of IDV-RTV regimens 400-400, 800-100, and 800-200 mg were at least 1.4, 2.3, and 3.3 times higher, respectively, regardless of meal. The concentrations at the end of the dosing interval were 10 to 25 times higher than that observed in the standard regimen of 800 mg of IDV q8h for IDV-RTV 800-100 and 800-200 mg regimens, respectively. RTV at 200 mg maximally enhanced the IDV profile. Improved tolerability was associated with IDV-RTV 800-100 mg versus IDV-RTV 800-200, 800-400, and 400-400 mg q12h. The advantages of IDV-RTV twice daily over 800 mg of IDV q8h include no food restrictions and twice-daily dosing. Also, the regimens achieve levels of IDV that may be helpful in suppressing strains of HIV-1 that have reduced susceptibility to IDV or other protease inhibitors.     

Electrocardiographic profile of oral piperazine citrate in healthy volunteers

The electrocardiographic (ECG) profile of oral piperazine citrate was determined in healthy volunteers. Piperazine caused reduction in heart rate in all the subjects. The highest percentage of change was 15.7. The average pretreatment (73.6+/-6.59 beats/min) when compared with the heart rate 1 hour after piperazine was administered (64.6+/-5.21 beats/min) was statistically significant (P=0.0054). The QT and JT intervals had average increases of 9.7% and 11.1%, respectively. In contrast, piperazine did not have any effect on the QRS complex following its administration. However, the average PR interval 1 hour after ingesting oral piperazine 2 g was significantly prolonged, 0.18+/-0.0063 seconds compared with a pretreatment average of 0.16+/-0.0098 seconds. The difference between the 2 values was statistically significant (P=0.0161). No dysrhythmic phenomena were seen. Sinus rhythm was maintained in all the volunteers, with every QRS-T complex preceded by a P wave. The direction and magnitude of the mean electric axis of QRS complex and T wave were not altered by piperazine. It is concluded that oral piperazine citrate induced some changes on the ECG profile of healthy human volunteers, typical of many potent antiarrhythmic agents.