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Purpose Efficacy of treosulfan, used in the treatment of marrow disorders, depends on the activity of its monoepoxy—(EBDM) and diepoxy compounds. The study aimed to describe the pharmacokinetics of treosulfan and EBDM in the rat plasma and brain by means of mixed-effects modelling. Methods The study had a one-animal-per-sample design and included ninty-six 10-week-old Wistar rats of both sexes. Treosulfan and EBDM concentrations in the brain and plasma were measured by an HPLC–MS/MS method. The population pharmacokinetic model was established in NONMEM software with a first-order estimation method with interaction. Results One-compartment pharmacokinetic model best described changes in the concentrations of treosulfan in plasma, and EBDM concentrations in plasma and in the brain. Treosulfan concentrations in the brain followed a two-compartment model. Both treosulfan and EBDM poorly penetrated the blood–brain barrier (ratio of influx and efflux clearances through the blood–brain barrier was 0.120 and 0.317 for treosulfan and EBDM, respectively). Treosulfan plasma clearance was significantly lower in male rats than in females (0.273 L/h/kg vs 0.419 L/h/kg). Conclusions The developed population pharmacokinetic model is the first that allows the prediction of treosulfan and EBDM concentrations in rat plasma and brain. These results provide directions for future studies on treosulfan regarding the contribution of transport proteins or the development of a physiological-based model.

Summary Introduction: Rhodiola rosea (RR) and Rhodiola kirilowii (RK) are well known for their influence on central nervous system, however their impact on the development of alcohol tolerance has not yet been proven. Objective: The aim of this study was to determine the ability of RR and RK roots extracts to inhibit the development of alcohol tolerance in vivo, both, peripheral (metabolic) and central ones. Methods: Male Wistar rats were treated with RR and RK extracts (p.o.) and ethanol (i.p.) for ten consecutive days. On the first, third, fifth and eighth days the hypothermic action of ethanol was measured, while on the ninth day the loss of righting reflex was examined. On the tenth day rats were treated with assigned extract and sacrificed 1 h after the ethanol injection. Results: Both extracts inhibited development of tolerance to the hypothermic action of ethanol. The observed effect seems to be specific since none of the extracts affected body temperature in water-treated animals. RK extract also prolonged the hypnotic action of ethanol. RR-treated rats had higher blood-ethanol concentrations, in contrast to RK ones. Conclusions: RR and RK extracts inhibited the development of tolerance to the hypothermic action of ethanol. Prolongation of the hypnotic action of ethanol by RK extract may be associated with influence on the central nervous system, while the RR one also inhibited the development of metabolic tolerance.

Treosulfan is a prodrug applied in the treatment of ovarian cancer and conditioning prior to stem cell transplantation. So far, the bioanalysis of treosulfan in either whole blood or red blood cells (RBC) has not been carried out. In this work, the RBC/plasma partition coefficient (Ke/p) of treosulfan and its active monoepoxide was determined for the first time. Male and female 10-week-old Wistar rats (n = 6/6) received an intraperitoneal injection of treosulfan at the dose of 500 mg/kg body weight. The concentrations of treosulfan and its monoepoxide in plasma (Cp) and RBC were analyzed with a validated HPLC–MS/MS method. The mean Ke/p of treosulfan and its monoepoxide were 0.74 and 0.60, respectively, corresponding to the blood/plasma partition coefficient of 0.88 and 0.82. The Spearman test demonstrated that the Ke/p of the prodrug correlated with its Cp, but no correlation between the Ke/p and Cp of the active monoepoxide was observed. Treosulfan and its monoepoxide achieve higher concentrations in plasma than in RBC; therefore, the choice of plasma for bioanalysis is rational as compared to whole blood. The distribution of treosulfan into RBC may be a saturable process at therapeutic concentrations.

Hydrochloride of 10-{2-hydroxy-3-[N,N-bis-(2-hydroxyethyl)amino]propyl}-2-trifluoromethylphenothiazine (Flu-A) is a analogue of neuroleptic fluphenazine. Flu-A exhibits anti-multidrug resistance, antimutagenic, proapoptopic, and cancer-chemopreventive activities in screening studies. To define identity, quality, and purity of new active substance it is necessary to develop a appropriate analytical method and to establish a degradation profile. Thus, a stability-indicating reversed-phase high-performance liquid chromatography method was developed and validated for quantitative determination of Flu-A in the presence of its degradation products generated under stress conditions. The compound was subjected to oxidation, photolysis, and degradation in aqueous solutions (neutral and acidic), and solid state according to the International Council for Harmonisation Guidelines. The method was also found to be suitable for intermediate and accelerated studies and for the evaluation of kinetic mechanism of Flu-A degradation in aqueous solutions (pH 5.1–7.5, 353 K). The structures of main potential degradation products were established using high-performance liquid chromatography-Electrospray Ionization-mass spectrometry method.

In this paper the decomposition product of levofloxacin was identified. Levofloxacin was dissolved in 0.9% NaCl, 5% glucose, and Ringer’s solution. The solutions were divided into two batches: the first one was exposed to daylight and the second one was protected from it. The solutions were stored at the room temperature. The qualitative analysis of the degradation product was performed using MS and TOF detectors. The quantitative assay was done by a validated HPLC method. Visual inspection and pH assessment were done. Levofloxacin protected from daylight remained stable in 0.9% NaCl, 5% dextrose, and Ringer’s solution. A slight decomposition of the analyte was observed in the solutions exposed to daylight with the fastest decomposition rate in Ringer’s solution as compared with 0.9% NaCl and 5% dextrose solutions. The degradation product of levofloxacin detected with MS was levofloxacin N-oxide. Levofloxacin solutions should be protected from direct daylight to maintain drug stability. Levofloxacin N-oxide is formed regardless of the solvent used.

Rationale & objective: Midazolam is one of top three drugs used in palliative care. Its use increases in the last days of hospice patients’ lives while safe dosage can be challenging. Equations currently used to estimate glomerular filtration rate, e.g: the Cockroft-Gault (eGFRCR) and the Modification of Diet in Renal Disease (eGFRMDRD) ones, do not generate precise calculations, especially in palliative patients exhibiting variations in body parameters. Our aim was to seek new relationships between mean midazolam (Mavg) and alfahydroxymidazolam (OH-Mavg) concentrations in plasma, and selected biochemical and physiological parameters of palliative patients, to enable optimal midazolam pharmacotherapy. Study design, participants and interventions: The pilot study included 11 Caucasians, aged 42–95, with advanced cancer disease, receiving midazolam in a hospice in-patient unit. We tested correlations among Mavg, BMI, eGFRMDRD, midazolam clearance (CL), OH-Mavg, bilirubin (Bil) and blood creatinine concentration (Cr). F test and leave-one out (LOO) validation was applied to verify the correlations’ significance and predictive ability. Results: We found ten statistically significant (p < 0.05) correlations related to midazolam pharmacokinetics and physiological factors. We formulated two equations with high degree of predictive ability, based on the eGFRMDRD→CL and the (Bil + BMI × Ln(Cr))→Mavg-(OH-Mavg) correlations.The limitations of the study mainly revolve around its pilot nature and the need to continue testing the results on a bigger population.No funding to disclose. Conclusions: The significance of correlations corresponding to the arithmetic expressions confirms that Bil, BMI, Ln(Cr) analyzed simultaneously report a series of processes on which midazolam metabolism depends. Two of ten correlations proposed came close to meet all LOO validation criteria. Current findings can help optimize midazolam treatment in palliative therapy.

Objective. Development of midazolam (MDZ) pharmacokinetic model is pivotal for predicting drug response and determining appropriate dosing in patients who undergo surgical procedures. The aim of this study was to provide population pharmacokinetic analysis describing MDZ and its main metabolite 1-OH-midazolam (1-OH-MDZ) used during oral premedication in surgical paediatric patients. The influence of gender, age, and body weight on MDZ pharmacokinetics was also investigated. Material and Methods The analyzed data set included 27 patients, aged 1 to 17 years, who received oral midazolam syrup before various surgical procedures. The 1‑OH‑MDZ concentration was approximated by a proportional relationship to MDZ concentration. Population nonlinear mixed-effect modeling was done using NONMEM 7.2. Non-parametric bootstrap and VPC were conducted to evaluate the adequacy of the model to describe the observations. Results Midazolam pharmacokinetic model was developed to describe the time course of MDZ and 1-OH-MDZ concentrations. High inter-individual variability in volume of central compartment (93%) and clearance (60%) of MDZ w ere observed. The effect of body weight was accounted for by the allometric scaling. Significant differences in MDZ pharmacokinetics due to the age and gender were not found. Conclusions The population MDZ pharmacokinetic model was successfully developed for paediatric patients. Age, gender do not explain inter-individual variation in the pharmacokinetics of MDZ. No effect of maturation was detected.

Efficacy of treosulfan, used in the treatment of marrow disorders, depends on the activity of its monoepoxy-(EBDM) and diepoxy compounds. The study aimed to describe the pharmacokinetics of treosulfan and EBDM in the rat plasma and brain by means of mixed-effects modelling.The study had a one-animal-per-sample design and included ninty-six 10-week-old Wistar rats of both sexes. Treosulfan and EBDM concentrations in the brain and plasma were measured by an HPLC-MS/MS method. The population pharmacokinetic model was established in NONMEM software with a first-order estimation method with interaction.One-compartment pharmacokinetic model best described changes in the concentrations of treosulfan in plasma, and EBDM concentrations in plasma and in the brain. Treosulfan concentrations in the brain followed a two-compartment model. Both treosulfan and EBDM poorly penetrated the blood-brain barrier (ratio of influx and efflux clearances through the blood-brain barrier was 0.120 and 0.317 for treosulfan and EBDM, respectively). Treosulfan plasma clearance was significantly lower in male rats than in females (0.273 L/h/kg vs 0.419 L/h/kg).The developed population pharmacokinetic model is the first that allows the prediction of treosulfan and EBDM concentrations in rat plasma and brain. These results provide directions for future studies on treosulfan regarding the contribution of transport proteins or the development of a physiological-based model.

Background Recently the number of new psychoactive substances have significantly increased, becoming popular among experienced users of designer drugs. A significant group includes benzodiazepine derivatives, which have not been introduced as medications but are abused by people experimenting with new and classical psychoactive substances. Case presentation The aim of this paper was to present the case of a clonazolam ingestion by a person who was not habituated to benzodiazepines. The intake caused only prolonged coma, decreased muscle tone, and deep tendon reflexes without any other concomitant toxicity and cardio-respiratory failure. Conclusions Clonazolam concentrations in patient’s blood, measured three times were 0.077 mg/L, 0.015 mg/L, 0.009 mg/L after 4, 8 and 12 h, respectively. Clonazolam’s human toxicity has not been well established, so any case of poisoning should be closely monitored.

Pro-drug treosulfan (TREO) is currently evaluated in randomized phase III clinical trials as a conditioning agent prior to HSCT. In the present paper pharmacokinetics of both TREO and its biologically active monoepoxide (S,S-EBDM) was investigated in pediatric patients for the first time. The studies were carried out in 16 children (median age 7.5 years) undergoing TREO-based preparative regimen prior to HSCT, who received 10, 12 or 14 g/m(2) of the drug as a 1h or 2h intravenous infusion. Plasma concentrations of TREO as well as S,S-EBDM were determined using the validated HPLC-MS/MS method. The changes in S,S-EBDM concentration over time followed TREO levels. The area under the curve (AUC) of TREO was 100-fold higher than AUC of S,S-EBDM. No statistically significant dependency of the dose-normalized AUC of either TREO or S,S-EBDM on the patients' age and body surface area was stated. Moreover, plasma C(max) as well as AUC of S,S-EBDM demonstrated linear correlation with the C(max) and AUC of TREO, respectively. The biological half-lives of TREO and S,S-EBDM were similar. This indicates that S,S-EBDM was completely eliminated from the patients' blood within relatively short time, comparable to TREO.

The aim of this study was to optimize the process of tablets compression and identification of film-coating critical process parameters (CPPs) affecting critical quality attributes (CQAs) using quality by design (QbD) approach. Design of experiment (DOE) and regression methods were employed to investigate hardness, disintegration time, and thickness of uncoated tablets depending on slugging and tableting compression force (CPPs). Plackett-Burman experimental design was applied to identify critical coating process parameters among selected ones that is: drying and preheating time, atomization air pressure, spray rate, air volume, inlet air temperature, and drum pressure that may influence the hardness and disintegration time of coated tablets. As a result of the research, design space was established to facilitate an in-depth understanding of existing relationship between CPPs and CQAs of intermediate product (uncoated tablets). Screening revealed that spray rate and inlet air temperature are two most important factors that affect the hardness of coated tablets. Simultaneously, none of the tested coating factors have influence on disintegration time. The observation was confirmed by conducting film coating of pilot size batches.

This study evaluates possible circadian rhythms during prolonged midazolam infusion in 27 pediatric intensive care unit (PICU) children under mechanical ventilation.Blood samples for midazolam and 1-OH-midazolam assay were collected throughout the infusion at different times of the day. The blood pressure, heart rate and body temperature were recorded every hour for the rhythms analysis. Population nonlinear mixed-effect modeling with NONMEM was used for data analysis.A two-compartment model for midazolam pharmacokinetics and a one-compartment model for midazolam metabolite adequately described the data. The 24 h profiles of all monitored physiological parameters were greatly disturbed/abolished in comparison with the well-known 24 h rhythmic patterns in healthy subjects. There was no significant circadian rhythm detected with respect to midazolam pharmacokinetics, its active metabolite pharmacokinetics and all monitored parameters.We concluded that the light-dark cycle did not influence midazolam pharmacokinetics in intensive care units children. Also, endogenous rhythms in critically ill and sedated children are severely disturbed and desynchronized. Our results confirmed that it is necessary to adjust the dose of midazolam to the patient's body weight. The low value of midazolam clearances observed in our study was probably caused by mechanical ventilation, which was shown to decrease the cardiac output.

Background A vast majority of people who abuse alcohol are also defined as “heavy smokers”. Tobacco smokes induces CYP1A1, CYP1A2, CYP2A6 isoenzymes, but on the other hand, ethanol activates CYP2E1, which can be important during combined, chronic use of both of them. The aim of the study was to evaluate the influence of tobacco smoke xenobiotics on ethanol pharmacokinetics and the level of its metabolites in alcohol preferring and non-preferring rats. Methods Ethanol, acetaldehyde, methanol, n -propanol and n -butanol were determined in whole blood by means of gas chromatography. Cotinine in serum was determined by LC–MS/MS. A non-compartmental analysis (cotinine, acetaldehyde) and Widmark equation (ethanol) were used for pharmacokinetic parameters calculation. Results Ethanol levels were lower in animals exposed to tobacco smoke compared to rats receiving this xenobiotic, without a prior exposure to tobacco smoke. Lower values of the studied pharmacokinetic parameters were observed in the alcohol preferring males compared to the non-alcohol preferring rats. Both n -propanol and n -butanol had higher values of the pharmacokinetic parameters analyzed in the animals exposed to tobacco smoke and ethanol compared to those, which ethanol was administered only once. Conclusions An increase in maximum concentration and the area under concentration–time curve for ethanol after its administration to rats preferring alcohol and exposed to tobacco smoke are accompanied by a decrease in the volume of distribution. The changes in the volume of distribution may be caused by an increase in the first-pass effect, in the intestinal tract and/or in the liver. The acetaldehyde elimination rate constant was significantly higher in alcohol-preferring animals.

Lethal intoxications with phosphine belong to rare cases in Poland. Most frequently they involve suicidal intake of metal phospidesand accidental intoxications due to gas inhalation. The case of acute intoxication with phosphine in presented, affecting two persons:a 14-month-old child, who died, and the surviving mother. The intoxication took place on a farm and phosphine was released fromtoxic aluminium phosphide, a component of Quickphos Pellets 56GE preparation, widely used for disinsection of empty facilities for storage of grain and other alimentary products. Autopsy of the 14-month-old child demonstrated cerebral edema and pulmonaryedema and excluded other pathology as the cause of death. Toxicological tests demonstrated only elevated levels of phosphorus. Theentire clinical pattern of intoxication permitted to conclude that the cause of 14-month-old child’s death involved acute intoxication with phosphine, in the mother a subacute intoxication with phosphine was diagnosed. The survival of the mother and death of her14-month-old child reflected their very different body weight and distinct resistance to toxic effect of phosphine.

The aim of this study was to examine the ability of extracts from root of Rhodiola rosea (RR) and Rhodiola kirilowii (RK) to inhibit the development of acute ethanol tolerance. The ethanol-water (1:1) extracts were standardized on phenylpropanoids (rosavin, rosin, rosarin) and phenylethanoids (salidroside, p-tyrosol) contents. The experiments were performed …