Gender differences in pharmacokinetics and pharmacodynamics of azosemide in rats

Gender Medicine and Pharmacology

Gender-specific medicine consists of a transversal methodological approach that aims to study the influence of sex and gender on diseases [...].

Evaluation of Sex Differences in Preclinical Pharmacology Research: How Far Is Left to Go?

Until the last quarter of the 20th century, sex was not recognized as a variable in health research, nor was it believed to be a factor that could affect health and illness. Researchers preferred studying male models for a variety of reasons, such as simplicity, lower costs, hormone confounding effects, and fear of liability from perinatal exposure in case of pregnancy. Equitable representation is imperative for determining the safety, effectiveness, and tolerance of therapeutic agents for all consumers. Decades of female models' underrepresentation in preclinical studies has resulted in inequality in the understanding, diagnosis, and treatment of disease between the sexes. Sex bias has been highlighted as one of the contributing factors to the poor translation and replicability of preclinical research. There have been multiple calls for action, and the inclusion of sex as a biological variable is increasingly supported. However, although there has been substantial progress in the efforts to include more female models in preclinical studies, disparities today remain. In the present review, we consider the current standard practice of the preclinical research setting, why the sex bias exists, why there is the need to include female models, and what risks may arise from continuing this exclusion from experimental design.

The search for brain-permeant NKCC1 inhibitors for the treatment of seizures: Pharmacokinetic-pharmacodynamic modelling of NKCC1 inhibition by azosemide, torasemide, and bumetanide in mouse brain

Because of its potent inhibitory effect on the Na⁺-K⁺-2Cl^- symporter isotype 1 (NKCC1) in brain neurons, bumetanide has been tested with varying results for treatment of seizures that potentially evolve as a consequence of abnormal NKCC1 activity. However, because of its physicochemical properties, bumetanide only poorly penetrates into the brain. We previously demonstrated that NKCC1 can be also inhibited by azosemide and torasemide, which lack the carboxyl group of bumetanide and thus should be better brain-permeable. Here we studied the brain distribution kinetics of azosemide and torasemide in comparison with bumetanide in mice and used pharmacokinetic-pharmacodynamic modelling to determine whether the drugs reach NKCC1-inhibitory brain concentrations. All three drugs hardly distributed into the brain, which seemed to be the result of probenecid-sensitive efflux transport at the blood-brain barrier. When fractions unbound in plasma and brain were determined by equilibrium dialysis, only about 6-17% of the brain drug concentration were freely available. With the systemic doses (10 mg/kg i.v.) used, free brain concentrations of bumetanide and torasemide were in the NKCC1-inhibitory concentration range, while levels of azosemide were slightly below this range. However, all three drugs exhibited free plasma levels that would be sufficient to block NKCC1 at the apical membrane of brain capillary endothelial cells. These data suggest that azosemide and torasemide are interesting alternatives to bumetanide for treatment of seizures involving abnormal NKCC1 functionality, particularly because of their longer duration of action and their lower diuretic potency, which is an advantage in patients with seizures.

The pharmacokinetics of orally administered fudosteine in healthy Chinese volunteers

The pharmacokinetics of fudosteine in healthy Chinese volunteers was investigated for the first time after single- and multiple-dose administration. Five male and five female volunteers were enrolled in this study. Each subject received 400 mg fudosteine capsules (the therapeutic dose) on day 1 after overnight fasting for the single-dose study and three times daily oral administration (400 mg) for 5 consecutive days until the sixth morning for the multiple-dose study. Serial blood samples were collected at specified time intervals up to 16 hours following the first and last doses of fudosteine. Plasma harvested from the blood was separated and analyzed for fudosteine levels by a validated high-performance liquid chromatography-electrospray ionization mass spectrometry (HPLC/ESI/MS) method employing percolumn derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl). Noncompartmental analysis was used for the calculation of the total area under the plasma concentration-time curve (AUC) from time zero to time infinity and the terminal half-life (t1/2) of fudosteine. The pharmacokinetic parameters for single- and multiple-dose administration were estimated as follows: Cmax amounted to 10.13+/-4.39 microg/mL and 11.75+/-6.51 microg/mL, tmax to 0.69+/-0.36 h and 0.53+/-0.12 h and t1/2 to 2.33+/-0.63 h and 2.40+/-0.37 h, respectively. No significant differences were found between single- and multiple-dose oral administration, although gender differences were observed.

Gender differences in the pharmacokinetics of DA-6034, a derivative of flavonoids, in rats

Gender differences in the pharmacokinetics of DA-6034 were evaluated after intravenous and oral administration at a dose of 50 mg/kg to male and female Sprague-Dawley rats. After intravenous administration to male rats, although the total area under the plasma concentration-time curve from time zero to time infinity of DA-6034 was not significantly different between male and female rats, the plasma concentrations of DA-6034 were lower from 30 min to 480 min, the mean residence time was significantly shorter (6.28 versus 12.2 min), the percentage of intravenous dose of DA-6034 excreted in 24 h urine as unchanged drug was significantly greater (14.4% versus 10.5% of intravenous dose). After oral administration, the pharmacokinetic parameters of DA-6034 were not significantly different between male and female rats.

Pharmacokinetics and pharmacodynamics of azosemide

Azosemide is used in the treatment of oedematous states and hypertension. The exact mechanism of action is not fully understood, but it mainly acts on both the medullary and cortical segments of the thick ascending limb of the loop of Henle. Delayed tolerance was demonstrated in humans by homeostatic mechanisms (principally an increase in aldosterone secretion and perhaps also an increase in the reabsorption of solute in the proximal tubule). After oral administration to healthy humans in the fasting state, the plasma concentration of azosemide reached its peak at 3-4 h with an absorption lag time of approximately 1 h and a terminal half-life of 2-3 h. The estimated extent of absolute oral bioavailability in humans was approximately 20.4%. After oral administration of the same dose of azosemide and furosemide, the diuretic effect was similar between the two drugs, but after intravenous administration, the effect of azosemide was 5.5-8 times greater than that in furosemide. This could be due to the considerable first-pass effect of azosemide. The protein binding to 4% human serum albumin was greater than 95% at azosemide concentrations ranging from 10 to 100 microg/ml using an equilibrium dialysis technique. The poor affinity of human tissues to azosemide was supported by the relatively small value of the apparent post-pseudodistribution volume of distribution (Vdbeta), 0.262 l/kg. Eleven metabolites (including degraded products) of azosemide including M1, glucuronide conjugates of both M1 and azosemide, thiophenemethanol, thiophencarboxylic acid and its glycine conjugate were obtained in rats. Only azosemide and its glucuronide were detected in humans. In humans, total body clearance, renal clearance and terminal half-life of azosemide were 112 ml/min, 41.6 ml/min and 2.03 h, respectively. Azosemide is actively secreted in the renal proximal tubule possibly via nonspecific organic acid secretory pathway in humans. Thus, the amount of azosemide that reaches its site of action could be significantly modified by changes in the capacity of this transport system. This capacity, in turn, could be predictably changed in disease states, resulting in decreased delivery of the diuretic to the transport site, as well as in the presence of other organic acids such as nonsteroidal anti-inflammatory drugs which could compete for active transport of azosemide. The urinary excretion rate of azosemide could be correlated well to its diuretic effects since the receptors are located in the loop of Henle. The diuretic effects of azosemide were dependent on the rate and composition of fluid replacement in rabbits; therefore, this factor should be considered in the evaluation of bioequivalence assessment.