Assessment of adherence to diuretics and ß-blockers by serum drug monitoring in comparison to urine analysis.

Purpose: Toxicological screenings for identifying antihypertensive drugs proved to be a useful tool for assessing adherence. However, misinterpretation may occur in case of highly metabolised drugs with low renal excretion, as well as for drugs with a prolonged detectability. The aim of the present study was to compare a recently developed therapeutic drug monitoring (TDM) method based on serum concentrations to an urine drug detection method for assessing adherence in outpatients.Materials and methods: Corresponding urine and blood samples were obtained at the same time from 26 outpatients without supervised medication. Urine and serum analyses were performed using established high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) methodologies. Adherence was assumed if drugs were detectable in urine or if serum concentrations were above individually calculated lower dose-related concentrations (DRC) or literature-based therapeutic reference ranges (TRR) used as cut-off, respectively.Results: The identification of analytes in urine as well as the quantitative serum assay were performed for atenolol (n = 6 patients), bisoprolol (n = 8), nebivolol (n = 6), canrenone (n = 6, metabolite of spironolactone), hydrochlorothiazide (n = 12) and furosemide (n = 2). On the basis of drug detectability in urine, adherence was assumed in 88% of prescriptions. In 81% (DRC) and 50% (TRR) of the serum analyses the cut-off value was exceeded, which confirms patients' adherence in a lower number. Differences in adherence rates were found in five patients, mainly for ß-blockers.Conclusion: This study suggests that assessment of adherence can be performed more precisely on the basis of serum drug concentrations with individually calculated lower DRC than by using the TRR or qualitative urinalysis.

Determination of diuretics in human urine using HPLC coupled with magnetic solid-phase extraction based on a metal-organic framework.

Magnetic solid-phase extraction (MSPE) employing a metal-organic framework (Fe3 O4 @UiO-66-OH) combined with high-performance liquid chromatography was developed for the determination of trace diuretics in urine. The structure and properties of Fe3 O4 @UiO-66-OH were investigated using X-ray diffraction, infrared spectroscopy, scanning electron microscopy and vibrating sample magnetometry. Magnetic solid-phase extraction conditions, such as adsorbent amount and solution pH, were optimized using response surface methodology. Under the optimal conditions, the method resulted in excellent linearity with a high correlation coefficient (r > 0.99), satisfactory intraday repeatability (1.78-2.99%), low limits of detection (0.08-0.23 ng/ml), and good recoveries in urine samples (between 93.5 and 103%). Fe3 O4 @UiO-66-OH based on MSPE is a novel pretreatment technique for the detection of trace diuretics in urine.

A biochemometrics strategy for tracing diuretic components of crude and processed Alisma orientale based on quantitative determination and pharmacological evaluation.

We proposed a biochemometrics strategy for tracing diuretic components of herbs based on quantitative determination and pharmacological evaluation. First, a sensitive and robust liquid chromatography coupled with tandem mass spectrometry approach was established for simultaneous quantification of six major triterpenoids in crude and salt-processed Alisma orientale. The separation of triterpenoids was achieved on a BEH C18 column with a mobile phase consisting of acetonitrile and water spiked with 0.1% formic acid. Six major triterpenoids were detected by multiple reaction monitoring in the negative ion mode. Glycyrrhetinic acid was used as the internal standard. The approach showed good linearity. Intra- and inter-day precisions were all within 2.9%. The recovery rates of each triterpenoid ranged from 97.9% to 103.2%. The approach was then successfully employed for quantitative analysis of six triterpenoids in ten batches of crude and salt-processed A. orientale. Second, the diuretic effects of crude and salt-processed A. orientale were evaluated in mice. Third, principal component analysis and canonical correlation analysis were used to uncover the relationship between the contents of six major triterpenoids and the diuretic effect of different crude and salt-processed samples. Alisol B, alisol F, and alisol A have a close positive correlation with the diuretic effect.

Effect of the angiotensin receptor-neprilysin inhibitor sacubitril/valsartan on the pharmacokinetics and pharmacodynamics of a single dose of furosemide.

AIMS: Sacubitril/valsartan is indicated for the treatment of heart failure and reduced ejection fraction (HFrEF). Furosemide, a loop diuretic commonly used for the treatment of HFrEF, may be coadministered with sacubitril/valsartan in clinical practice. The effect of sacubitril/valsartan on the pharmacokinetics and pharmacodynamics of furosemide was evaluated in this open label, two-period, single-sequence study in healthy subjects. METHODS: All subjects (n = 28) received 40 mg oral single-dose furosemide during period 1, followed by a washout of 2 days. In period 2, sacubitril/valsartan 200 mg (97/103 mg) was administered twice daily for 5 days and a single dose of 40 mg furosemide was coadministered on day 6. Serial plasma and urine samples were collected to determine the pharmacokinetics of furosemide and sacubitril/valsartan and the pharmacodynamics of furosemide. The point estimates and the associated 90% confidence intervals for pharmacokinetic parameters were evaluated. RESULTS: Coadministration of furosemide with sacubitril/valsartan decreased the maximum observed plasma concentration (Cmax ) [estimated geometric mean ratio (90% confidence interval): 0.50 (0.44, 0.56)], area under the plasma concentration-time curve (AUC) from time 0 to infinity [0.72 (0.67, 0.77)] and 24-h urinary excretion of furosemide [0.74 (0.69, 0.79)]. When coadministered with sacubitril/valsartan, 0-4-h, 4-8-h and 0-24-h diuresis in response to furosemide was reduced by ~7%, 21% and 0.2%, respectively, while natriuresis was reduced by ~ 28.5%, 7% and 15%, respectively. Post hoc analysis of the pivotal phase III Prospective comparison of ARNI with ACEI to Determine Impact on Global Mortality and morbidity in Heart Failure trial (PARADIGM-HF) indicated that the median furosemide dose was similar at baseline and at the end of the study in the sacubitril/valsartan group. CONCLUSIONS: Sacubitril/valsartan reduced plasma Cmax and AUC and 24-h urinary excretion of furosemide, while not significantly affecting its pharmacodynamic effects in healthy subjects.

Pharmacokinetics of furosemide administered 4 and 24 hours prior to high-speed exercise in horses.

Furosemide is a diuretic agent used commonly in racehorses to attenuate the bleeding associated with exercise-induced pulmonary hemorrhage (EIPH). The current study describes serum and urine concentrations and the pharmacokinetics of furosemide following administration at 4 and 24 hrs prior to maximal exercise. Eight exercised adult Thoroughbred horses received a single IV administration of 250 mg of furosemide at 4 and 24 hrs prior to maximal exercise on a high-speed treadmill. Blood and urine samples were collected at time 0 and at various times for up to 72 hrs and furosemide concentrations determined using liquid chromatography-tandem mass spectrometry. Serum furosemide concentrations remained above the LOQ (0.05 ng/ml) for 36 hrs in 3/8 and 1/8 horses in the 4- and 24-hrs groups, respectively. Serum concentration data were best fit by a two-compartment model. There was not a significant difference in the volume of distribution at steady-state (0.594 ± 0.178 [4 hrs] and 0.648 ± 0.147 [24 hrs] L/kg) or systemic clearance (0.541 ± 0.094 [4 hrs] and 0.617 ± 0.114 [24 hrs] L/hrs/kg) between horses that were exercised at 4- and 24 hrs postdrug administration. The mean ± SD elimination half-life was 3.12 ± 0.387 and 3.23 ± 0.407 hrs following administration at 4 and 24 hrs prior to exercise, respectively.

Two-phase and three-phase liquid-phase microextraction of hydrochlorothiazide and triamterene in urine samples.

This paper reports the applicability of two-phase and three-phase hollow fiber based liquid-phase microextraction (HF-LPME) for the extraction of hydrochlorothiazide (HYD) and triamterene (TRM) from human urine. The HYD in two-phase HF-LPME is extracted from 24 mL of the aqueous sample into an organic phase with microliter volume located inside the pores and lumen of a polypropylene hollow fiber as acceptor phase, but the TRM in three-phase HF-LPME is extracted from aqueous donor phase to organic phase and then back-extracted to the aqueous acceptor phase, which can be directly injected into HPLC for analysis. Under optimized conditions preconcentration factors of HYD and TRM were obtained as 128 and 239, respectively. The calibration curves were linear (R(2) ≥ 0.995) in the concentration range of 1.0-100 µg/L for HYD and 2.0-100 µg/L for TRM. The limits of detection for HYD and TRM were 0.5 µg/L. The intra-day and inter-day RSD based on four replicates were obtained as ≤5.8 and ≤9.3%, respectively. The methods were successfully applied for determining the concentration of the drugs in urine samples. Copyright © 2015 John Wiley & Sons, Ltd.

Population-based meta-analysis of furosemide pharmacokinetics.

Furosemide is a loop diuretic frequently used to treat fluid overload conditions such as hepatic cirrhosis and congestive heart failure (CHF). A population-based meta-analysis approach in NONMEM® was used to develop a PK model characterizing the time-course of furosemide in plasma and excretion into the urine for healthy subjects and fluid overload patients. Furosemide PK data from healthy subjects receiving 80 mg of oral furosemide were supplemented with additional individual and aggregate plasma concentration and urinary excretion versus time data from the literature after intravenous (i.v.) or oral furosemide administration (10-500 mg) to healthy subjects or fluid overload patients. A three-compartment model with zero-order input following i.v. administration (or first-order absorption using a Weibull function after oral administration) and first-order elimination best described furosemide PK. A covariate analysis identified creatinine clearance (CL(CR)) as a statistically significant predictor of renal clearance (CL(R)), with a population mean CL(R) of 4.67, 3.11, 1.95 and 1.17 l/h for a subject with normal renal function (CL(CR) = 120 ml/min) or mild (CL(CR) = 80 ml/min), moderate (CL(CR) = 50 ml/min) or severe (CLCR = 30 ml/min) renal impairment. Oral bioavailability was 59.1% and non-renal clearance was 2.02 l/h. A PC-VPC and other model diagnostics demonstrated that the population PK model can reasonably predict the rate of urinary furosemide excretion over time using dosing history and commonly available demographic data, allowing for convenient assessment of PK-PD relationships for furosemide when given alone or in combination with other agents used to treat fluid overload conditions.

Pharmacokinetic and pharmacodynamic alterations in the Roux-en-Y gastric bypass recipients.

OBJECTIVE: We conducted a pharmacokinetic (PK) study and a pharmacodynamic (PD) study to assess whether Roux-en-Y gastric bypass (RYGB) surgery is associated with significant changes to PK and PD of oral medications. BACKGROUND: The effect of RYGB on oral drug disposition is not well understood. METHODS: An oral cocktail of probe drugs for major drug-metabolizing enzymes (caffeine, tolbutamide, omeprazole, dextromethorphan, and oral and intravenous midazolam) was administered to 18 RYGB recipients and 18 controls. Timed blood and urine samples were obtained for PK analyses. Forty mg of oral furosemide was administered to 13 RYGB recipients and 14 controls, and urine and blood samples were collected for assessing furosemidePK, and urine volume and urine sodium excretion for PD analyses. RESULTS: Compared with controls, the RYGB group had significantly lower time to maximum plasma concentration (tmax) for caffeine (0.58 ± 0.5 vs 2.1 ± 2.2 hours, P < 0.0001), tolbutamide (1.4 ± 1.8 vs 2.1 ± 2.2 hours, P = 0.0001), omeprazole (1.1 ± 1.1 vs 4.4 ± 1.3 hours, P < 0.0001), and oral midazolam (0.5 ± 0.2 vs 0.7 ± 0.4 hours, P < 0.01). However, maximum plasma concentration, half-life, area under the curve, and oral bioavailability were not different. Compared with controls, the RYGB group had brisk natriuresis, with significantly lower tmax for urine sodium (1.3 ± 0.5 vs 3.1 ± 2.3 hours, P < 0.02) and correspondingly lower tmax for furosemide (1.8 ± 0.3 vs 4.2 ± 1.2 hours, P = 0.006). However, 6-hour urine sodium and 6-hour urine volume were not different between the two groups. CONCLUSIONS: RYGB recipients have significantly shorter tmax for the studied orally administered medications, but otherwise no other significant changes in PK were reported.

Magnetic resonance imaging finding of empty sella in obesity related idiopathic intracranial hypertension is associated with enlarged sella turcica.

INTRODUCTION: Empty sella in MRI is an important finding associated with idiopathic intracranial hypertension (IIH). This study assesses the sensitivity and reproducibility of several morphological measures of the sella and pituitary gland to indentify the measure that best differentiates IIH from controls. Additionally, the study assesses reversal in gland compression following treatment. METHODS: Sagittal 3D-T1W sequence with 1 mm isotropic resolution was obtained from ten newly diagnosed IIH patients and 11 matched healthy controls. Follow-up MRI scans were obtained from eight patients at 1-week post-lumbar puncture and acetazolamide treatment. 1D and 2D measures of absolute and normalized heights and cross-sectional areas of the gland and sella were obtained to identify the measure that best differentiates IIH patients and controls. RESULTS: Overall area-based measurements had higher sensitivity than length with p < 0.0001 for sella area compared with p = 0.004 for normalized gland height. The gland cross-sectional areas were similar in both cohorts (p = 0.557), while the sella area was significantly larger in IIH, 200 ± 24 versus 124 ± 25 mm(2), with the highest sensitivity and specificity, 100% and 90.9%, respectively. Absolute gland area was the most sensitive measure for assessing post treatment changes, with 100% sensitivity and 50 % specificity. Average post-treatment gland area was 18% larger (p = 0.016). Yet, all eight patients remained within the empty sella range based on a normalized gland area threshold of 0.41. CONCLUSIONS: Sellar area is larger in IIH, and it demonstrated highest sensitivity for differentiating IIH from control subjects, while absolute gland area was more sensitive for detecting post treatment changes.

Population-based meta-analysis of hydrochlorothiazide pharmacokinetics.

Hydrochlorothiazide (HCTZ) is a thiazide diuretic used for the treatment of hypertension and edema associated with fluid overload conditions such as congestive heart failure (CHF). A population-based meta-analysis approach in NONMEM® was used to develop a PK model to characterize the time-course of HCTZ concentrations in plasma and excretion into the urine for healthy subjects and CHF patients. Data from healthy subjects receiving 100 mg of oral HCTZ were supplemented with additional plasma concentration and urinary excretion versus time data published in the literature following administration of oral HCTZ doses ranging from 10 to 500 mg to healthy subjects or patients with renal failure, CHF or hypertension. A two-compartment model with first-order oral absorption, using a Weibull function, and first-order elimination best described HCTZ PK. Creatinine clearance (CLCR ) was a statistically significant predictor of renal clearance (CLR ). Non-renal clearance was estimated to be 2.44 l/h, CLR was 18.3 l/h and T1/2,α was 1.6 h and T1/2,ß was 14.8 h for a typical individual with normal renal function (CLCR = 120 ml/min). However, CLR was reduced to 10.5, 5.47 and 2.70 l/h in mild (CLCR = 80 ml/min), moderate (CLCR = 50 ml/min) and severe (CLCR = 30 ml/min) renal impairment, respectively. Model diagnostics helped to demonstrate that the population PK model reasonably predicts the rate of urinary HCTZ excretion over time using dosing history and estimated CLCR , allowing for the convenient assessment of PK-PD relationships for HCTZ when given alone or in combination with other agents used to treat fluid overload conditions.

Simultaneous determination of aliskiren and hydrochlorothiazide in tablets and spiked human urine by ion-pair liquid chromatography.

An alternative method for analysis of aliskiren (ALI) and hydrochlorothiazde (HCT) in combined dosage forms by ion-pair reversed phase high performance liquid chromatography was developed and validated. The pharmaceutical preparations were analyzed using a C18 column (250 mm x 4.6 mm, 3 microm) with a mobile phase consisting of 25% methanol, 50% sodium monobasic phosphate aqueous solution containing 6 mM tetrabutylammonium bromide and 25% water at pH 7.2. Isocratic analysis was performed at a flow rate of 1 mL/min and a column temperature of 30 degrees C under direct UV detection at 210 nm. Paracetamol was used as internal standard. The validation was performed according to the ICH guidelines. The proposed method was linear over the concentration range of 0.250 to 60 and 0.1 to 10 microg/mL for ALI and HCT, respectively. The limits of detection and quantitation (LOD and LOQ) were 0.075 and 0.198 microg/mL, respectively, for ALI and 0.04 and 0.062 microg/mL, respectively, for HCT. The method proved to be specific, sensitive, precise and accurate with mean recovery values of 101.1 +/- 0.32% and 100.9 +/- 0.41% for ALI and HCT, respectively. The method robustness was evaluated by means of an experimental design. The proposed method was applied successfully to spiked human urine samples with mean recoveries of 98.8 +/- 0.36% and 98.1 +/- 0.21% for ALI and HCT, respectively.

A comprehensive and high-throughput screening method for multiple prohibited substances by UPLC-QE Plus-HRMS and HPLC-QQQ-MS in human urine for doping control.

Since the World Anti-Doping Agency's (WADA) Prohibited List is updated on an annual basis, screening methods must be continually adapted to align with these changes. In accordance with Technical Document-MRPL 2022, a newly combined, comprehensive, rapid and high-throughput doping control screening method has been developed for the analysis of 350 substances with different polarities in human urine using ultra-high performance liquid chromatography coupled with Q Exactive Plus Hybrid Quadrupole-Orbitrap mass spectrometer (UPLC-QE Plus-HRMS) and ultra-high performance liquid chromatography coupled with triple quadrupole mass spectrometer (UPLC-QQQ-MS). The limits of detection were in the range of 0.12-50 ng mL-1 for beta-2 agonists, hormone and metabolic modulators, narcotics, cannabinoids and glucocorticoids, 0.1-14 ng mL-1 for the manipulation of blood and blood components, beta blockers, anabolic agents and hypoxia-inducible factor (HIF) activating agents, and 2.5-100 000 ng mL-1 for substances of Appendix A, diuretics & masking agents and stimulants. The sample preparation consisted of two parts: one is the dilute & shoot part analyzed in UPLC-QQQ-MS, another is a mixture of the dilute & shoot part and a liquid-liquid extraction part of hydrolyzed human urine analyzed in UPLC-QE Plus-HRMS in full scan mode with polarity switching and parallel reaction monitoring (PRM) mode. The method has been fully validated for doping control purposes. All the substances were compliant with WADA's required 1/2 minimum requirement performance level (MRPL) or minimum reporting level (MRL), and this method was successfully used in the 2022 Beijing Winter Olympic Games and Winter Paralympic Games for anti-doping purpose.

Pharmacokinetics and pharmacodynamics of single-dose oral tolvaptan in fasted and non-fasted states in healthy Caucasian and Japanese male subjects.

PURPOSE: To compare the pharmacokinetics and pharmacodynamics of tolvaptan in Caucasian and Japanese healthy male subjects under fasting and non-fasting conditions. METHODS: This was a single-center, parallel-group, randomized, open-label, three-period crossover trial of single oral doses of tolvaptan 30 mg under fasting and non-fasting [a high-fat, high-calorie meal (HFM) or Japanese standard meal] conditions in 25 healthy male Caucasian subjects and 24 healthy male Japanese subjects. Pharmacodynamic endpoints were urine volume and fluid balance for 0 to 24 h postdose. RESULTS: In the fasted state, the plasma tolvaptan C(max) and AUC(∞) geometric mean ratios (90 % confidence interval) were 1.105 (0.845-1.444) and 1.145 (0.843-1.554) for Japanese compared to Caucasian subjects. A HFM increased the C(max) and AUC(∞) values by about 1.15-fold in both Japanese and Caucasian subjects.. Twenty-four-hour urine volumes paralleled pharmacokinetic changes, but the increases were not clinically significant. Fluid balance in the Japanese men was 1.4- to 2.0-fold more negative than that in the Caucasian men. CONCLUSION: Tolvaptan pharmacokinetics is not clinically significantly affected by race. Body weight is a factor that affects exposure. Tolvaptan can be administered with or without food.

Pharmacokinetics, pharmacodynamics and safety of tolvaptan, a novel, oral, selective nonpeptide AVP V2-receptor antagonist: results of single- and multiple-dose studies in healthy Japanese male volunteers.

PURPOSE: Single- and multiple-dose studies were conducted to assess the pharmacokinetics, pharmacodynamics and safety of tolvaptan in healthy Japanese subjects. METHODS: All studies were single-center, randomized, placebo-controlled, single-blind or double-blind. In an ascending single-dose study, subjects were given a single oral dose of 15-120 mg tolvaptan or placebo. In multiple-dose studies, subjects were given 30, 60, 90 or 120 mg tolvaptan or placebo once daily for 7 days. RESULTS: After a single dose of 15-120 mg tolvaptan, the maximum plasma concentration (C(max)) and the area under the plasma concentration-time curve from zero to time t (AUC(t)) increased dose-dependently, and increases in AUC(t) were dose-proportional. Increases in 24-hour cumulative urine volume were dose- and AUC(24hr)-dependent. Urine excretion rates reached a maximum within 2-4 h after dosing. The maximal urine excretion rates increased dose-dependently, and appeared to reach a plateau at doses ≥ 60 mg. A decrease in urine osmolality and an increase in free water clearance indicated an aquaretic effect of tolvaptan. Serum sodium concentrations were increased by tolvaptan and were higher than that with placebo, even 24 h after dosing, while serum potassium concentrations were unchanged. No tolvaptan accumulation was found after multiple dosing for 7 days. Although 24-hour cumulative urine volume following multiple dosing slightly decreased, a sustained diuretic effect was observed throughout the dosing period. The most common adverse event was mild thirst. CONCLUSIONS: Single and multiple oral doses of tolvaptan exhibited dose-dependent aquaretic effects. Tolvaptan was well tolerated at all doses tested.

Synthesis and in vivo diuretic activity of some novel pyrimidine derivatives.

A series of 1,6-dihydropyrimidine-2-amine derivatives and 1,6-dihydropyrimidine-2-thiol derivatives were synthesized by the reaction of substituted 1,3-diphenylprop-2-en-1-one (chalcones) with guanidine hydrochloride and thiourea, respectively. All the synthesized compounds were in good agreement with elemental and spectral data. The synthesized compounds were screened in vivo for diuretic activity. The four compounds 2d, 2e, 3d and 3e, which showed moderate to good diuretic activity, were evaluated for their toxicity studies and none of the compounds showed any toxicity of the liver as compared with control. However, compounds 3e and 3d showed diuretic properties more than that of standard (acetazolamide) and were long acting. Overall, compound 3e, 6-(2,6-dichlorophenyl)-4-(pyridin-2-yl)-1,6-dihydropyrimidine-2-thiol, was found to be the most promising candidate of the series.

Subtherapeutic Acetazolamide Doses as a Noninvasive Method for Assessing Medication Adherence.

Adherence monitoring is a vital component of clinical efficacy trials, as the regularity of medication consumption affects both efficacy and adverse effect profiles. Pill-counts do not confirm consumption, and invasive plasma assessments can only assist post hoc assessments. We previously reported on the pharmacokinetics of a potential adherence marker to noninvasively monitor dosage consumption during a trial without breaking a blind. We reported that consumption cessation of subtherapeutic 15 mg acetazolamide (ACZ) doses showed a predictable urinary excretion decay that was quantifiable for an extended period. The current study describes the clinical implementation of 15 mg ACZ doses as an adherence marker excipient in distinct cohorts taking ACZ for different "adherence" durations. We confirm that ACZ output did not change (accumulate) during 18-20 days of adherence, and developed and assessed urinary cutoffs as nonadherence indicators. We demonstrate that whereas an absolute concentration cutoff (989 ng/mL) lacked sensitivity, a creatinine normalized equivalent (1,376 ng/mg ACZ) was highly accurate at detecting nonadherence. We also demonstrate that during nonadherent phases of three trials, creatinine-normalized urinary ACZ elimination was reproducible within and across trials with low variability. Excretion was first order, with a decay half-life averaging ~ 2.0 days. Further, excretion remained quantifiable for 14 days, providing a long period during which the date of last consumption might be determined. We conclude that inclusion of 15 mg ACZ as a dosage form adherence marker excipient, provides a reliable and sensitive mechanism to confirm medication consumption and detect nonadherence during clinical efficacy trials.

A Pilot Study of the Maternal-Fetal Pharmacokinetics of Furosemide in Plasma, Urine, and Amniotic Fluid of Hypertensive Parturient Women Under Cesarean Section.

The third trimester of pregnancy is related to physiological changes that can modify the process of absorption, distribution, metabolism, and excretion and, consequently, the efficacy and toxicity of drugs. However, little is known about furosemide pharmacokinetics and placental transfer in pregnancy. This study evaluated the maternal-fetal pharmacokinetics and distribution to amniotic fluid of furosemide in hypertensive parturient women under cesarean section. Twelve hypertensive parturient women under methyldopa (250 mg/8 h) and/or pindolol (10 mg/12 h) treatment received a 40-mg single oral dose of furosemide 1 to 10 hours before delivery by cesarean section. Blood and urine samples were collected for 12 hours after furosemide administration. At delivery, samples were obtained from maternal and umbilical cord blood (n = 8) to assess the transplacental transfer. Amniotic fluid (n = 4) was collected at the time of delivery. The following furosemide pharmacokinetic parameters were obtained as median (interquartile range): Cmax , 403 ng/mL (229 to 715 ng/mL); Tmax , 2.00 hours (1.50 to 4.83 hours); elimination half-life (t1/2 ), 2.50 hours (1.77 to 2.97 hours); AUC0-12 h , 1366 ng⋅h/mL (927 to 2531 ng⋅h/mL); AUC0-∞ , 1580 ng⋅h/mL (1270 to 2881 ng⋅h/mL); CL/F 25.3 L/h (13.8 to 31.4 L/h); CLR, 2.50 L/h (1.77 to 2.97 L/h); CLNR, 22.7 L/h (12.1 to 25.6 L/h); and Vd /F 82.8 L (34.4 to 173 L). The transplacental transfer of furosemide was 0.43 (0.10 to 0.73), and the amniotic fluid concentration was 11.0 ng/mL (5.51 to 14.6 ng/mL). From a clinical point of view, these results suggest that substrates of uridine diphosphate-glucuronosyltransferase isoenzymes such as furosemide may have increased clearance during pregnancy and could require dose adjustment in this population.

Rats with congenital hydronephrosis show increased susceptibility to renal ischemia-reperfusion injury.

Many drug candidates have shown significant renoprotective effects in preclinical models; however, there is no clinically used effective pharmacotherapy for acute kidney injury. The failure to translate from bench to bedside could be due to misleading results from experimental animals with undetected congenital kidney defects. This study was performed to assess the effects of congenital hydronephrosis on the functional capacity of tubular renal transporters as well as kidney sensitivity to ischemia-reperfusion (I-R)-induced injury in male Wistar rats. Ultrasonography was used to distinguish healthy control rats from rats with hydronephrosis. L-carnitine or furosemide was administered, and serial blood samples were collected and analyzed to assess the effects of hydronephrosis on the pharmacokinetic parameters. Renal injury was induced by clamping the renal pedicles of both kidneys for 30 min with subsequent 24 hr reperfusion. The prevalence of hydronephrosis reached ~30%. The plasma concentrations after administration of L-carnitine or furosemide were similar in both groups. I-R induced more pronounced renal injury in the hydronephrotic rats than the control rats, which was evident by a significantly higher kidney injury molecule-1 concentration and lower creatinine concentration in the urine of the hydronephrotic rats than the control rats. After I-R, the gene expression levels of renal injury markers were significantly higher in the hydronephrotic kidneys than in the kidneys of control group animals. In conclusion, our results demonstrate that hydronephrotic kidneys are more susceptible to I-R-induced damage than healthy kidneys. Unilateral hydronephrosis does not affect the pharmacokinetics of substances secreted or absorbed in the renal tubules.

A bioavailability/bioequivalence and pharmacokinetic study of two oral doses of torasemide (5 and 10 mg): prolonged-release versus the conventional formulation.

1. The main objective of the present study was to compare the bioavailability/bioequivalence of a new prolonged-release (PR) formulation of torasemide with an immediate-release (IR) formulation. In addition, we assessed the pharmacokinetics of both formulations, as well as the urine pharmacodynamics. 2. Two doses (5 and 10 mg) of PR torasemide were compared with the same doses of IR torasemide in a single-blind, single-dose, two-treatment, two-period, cross-over, sequence-randomized clinical trial in 20 healthy volunteers (two groups; n = 10 in each group). Torasemide plasma concentrations were measured by high-pressure liquid chromatography-electrospray ionization mass spectrometry. Torasemide urine concentrations, the diuretic effect of torasemide, urine electrolytes and urine density were also determined. 3. Plasma bioequivalence parameters, based on logged values, were as follows: (i) in the 5 mg group, the area under the plasma drug concentration-time curve from t = 0 to last measurable drug concentration at time t (AUC(0-t)) tablet ratio was 1.03 (90% confidence interval (CI) 0.91-1.17) and C(max) was 0.82 (90% CI: 0.68-0.98); and (ii) in the 10 mg group, the AUC(0-t) was 1.07 (90% CI 0.99-1.14) and C(max) was 0.68 (90% CI 0.60-0.78). The PR formulation showed a significantly prolonged t(max) compared with the IR formulation. The amount of torasemide recovered in the urine 24 h after administration was higher with the PR formulation for both doses. The natriuretic rate versus torasemide excretion rate for the PR and IR formulations were successfully regressed to a sigmoid E(max) model. Pharmacodynamic urine evaluations were similar with both formulations, although urine volume and urine electrolyte excretion were lower for the PR formulation in the first hour after administration. However, the PR formulation showed higher natriuretic efficiency. No significant adverse events were reported. 4. In conclusion, both formulations of torasemide showed similar systemic exposure (AUC). However, the PR formulation had a lower rate of absorption (lower C(max) and prolonged t(max)). The PR formulation had urinary excretion rates that were associated with a higher natriuretic efficiency and more constant diuresis.

Sample preparation development and matrix effects evaluation for multianalyte determination in urine.

The development of a generic analytical method remains difficult when a high number of compounds has to be simultaneously considered. This study proposes an innovative strategy for the development of a solid phase extraction (SPE) procedure before liquid chromatography-mass spectrometry analysis of 34 diuretics and beta-blockers in urine samples. These compounds have been selected since they are often encountered in anti-doping control. The principle is based on the selection of representative analytes during SPE protocol optimization, allowing a drastic reduction of generated data and development time. To select the representative compounds, all substances were classified based on their SPE behavior with a generic method and groups were formed with the help of a chemometric tool, namely hierarchical cluster analysis (HCA). One representative analyte per group was selected and used for subsequent SPE method development. Once the SPE method was developed, compounds were analyzed by LC-MS and matrix effects were evaluated to determine the influence of the matrix on the SPE process and MS signal alteration due to endogenous compounds. As a result, matrix effects evaluation must be performed on all analytes; representative compounds previously selected for SPE development were unable to predict matrix effects.