The influence of the coadministration of the p-glycoprotein modulator elacridar on the pharmacokinetics of lapatinib and its distribution in the brain and cerebrospinal fluid.

Background Lapatinib is a small-molecule tyrosine kinase inhibitor of human epidermal receptor 2 (HER2) and EGFR that has currently been approved for the treatment of HER2-positive advanced and metastatic breast cancer (BC). The ATP-binding cassette (ABC) family of transporters includes P-glycoprotein (P-gp; ABCB1) and breast cancer resistance protein (BCRP; ABCG2), which substantially restrict the penetration of drugs, including chemotherapeutics, through the blood-brain barrier and blood-cerebrospinal fluid barrier. The aim of this study was to investigate the effects of elacridar, an ABCB1 and ABCG2 inhibitor, on the brain and cerebrospinal fluid uptake of lapatinib. Methods Rats were divided into two groups: one group received 5 mg/kg elacridar and 100 mg/kg lapatinib (an experimental group), and the other group received 100 mg/kg lapatinib (a control group). Lapatinib concentrations in the blood plasma (BP), cerebrospinal fluid (CSF) and brain tissue (BT) were measured by liquid chromatography coupled with tandem mass spectrometry. Results Elacridar significantly increased lapatinib penetration into the CSF and BT (Cmax increase of 136.4% and 54.7% and AUC0-∞ increase of 53.7% and 86.5%, respectively). The Cmax of lapatinib in BP was similar in both experimental groups (3057.5 vs. 3257.5 ng/mL, respectively). Conclusion This study showed that elacridar influenced the pharmacokinetics of lapatinib. The inhibition of ABCB1 and ABCG2 transporters by elacridar substantially enhanced the penetration of lapatinib into the CSF and BT. The blocking of protein transporters could become indispensable in the treatment of patients with breast cancer and brain metastases.

The influence of cardiac output on propofol and fentanyl pharmacokinetics and pharmacodynamics in patients undergoing abdominal aortic surgery.

Cardiac output (CO) is expected to affect elimination and distribution of highly extracted and perfusion rate-limited drugs. This work was undertaken to quantify the effect of CO measured by the pulse pressure method on pharmacokinetics and pharmacodynamics of propofol and fentanyl administrated during total intravenous anesthesia (TIVA). The data were obtained from 22 ASA III patients undergoing abdominal aortic surgery. Propofol was administered via target-controlled infusion system (Diprifusor) and fentanyl was administered at a dose of 2-3 µg/kg each time analgesia appeared to be inadequate. Hemodynamic measurements as well as bispectral index were monitored and recorded throughout the surgery. Data analysis was performed by using a non-linear mixed-effect population modeling (NONMEM 7.4 software). Three compartment models that incorporated blood flows as parameters were used to describe propofol and fentanyl pharmacokinetics. The delay of the anesthetic effect, with respect to plasma concentrations, was described using a biophase (effect) compartment. The bispectral index was linked to the propofol and fentanyl effect site concentrations through a synergistic Emax model. An empirical linear model was used to describe CO changes observed during the surgery. Cardiac output was identified as an important predictor of propofol and fentanyl pharmacokinetics. Consequently, it affected the depth of anesthesia and the recovery time after propofol-fentanyl TIVA infusion cessation. The model predicted (not observed) CO values correlated best with measured responses. Patients' age was identified as a covariate affecting the rate of CO changes during the anesthesia leading to age-related difference in individual patient's responses to both drugs.

Population analysis to assess the influence of age and body weight on pharmacokinetics and pharmacodynamics of dexmedetomidine in New Zealand White rabbits.

The purpose of this work was i) to develop a population pharmacokinetic (PK) and pharmacodynamic (PD) model of dexmedetomidine (DEX) in New Zealand White rabbits, ii) to investigate the influence of the age and weight of the animals on the model parameters, and iii) to assess the linearity of DEX PKs in the examined dose range. This was a prospective, crossover study, using a total of 18 New Zealand White rabbits. DEX was administered as a single intravenous bolus injection in the doses from 25 to 300 µg kg-1 . Each New Zealand White rabbit was given the same dose of drug in its three developmental stages. To determine the DEX PK, seven blood samples were taken from each animal. The pedal withdrawal reflex was the PD response used to assess the degree of sedation. Nonlinear mixed effects modelling was used for the population PK/PD analysis. The typical value of elimination clearance was 0.061 L min-1 and was 35% higher in younger New Zealand White rabbits compared with older animals. The PK of DEX was linear in the examined concentration range. Age-related changes in sensitivity to DEX were not detected. The results suggest that due to the pharmacokinetics, younger animals will have lower DEX concentrations and a shorter duration of sedation than older animals given the same doses of DEX per kg of body weight.

The concomitant use of lapatinib and paracetamol - the risk of interaction.

Lapatinib is a tyrosine kinase inhibitor used for the treatment of breast cancer. Paracetamol is an analgesic commonly applied to patients with mild or moderate pain and fever. Cancer patients are polymedicated, which involves high risk of drug interactions during therapy. The aim of the study was to assess the interaction between lapatinib and paracetamol in rats. The rats were divided into three groups of eight animals in each. One group received lapatinib + paracetamol (IL + PA), another group received lapatinib (IIL), whereas the last group received paracetamol (IIIPA). A single dose of lapatinib (100 mg/kg b.w.) and paracetamol (100 mg/kg b.w.) was administered orally. Plasma concentrations of lapatinib, paracetamol and its metabolites - glucuronide and sulphate, were measured with the validated HPLC-MS/MS method and HPLC-UV method, respectively. The pharmacokinetic parameters of both drugs were calculated using non-compartmental methods. The co-administration of lapatinib and paracetamol increased the area under the plasma concentration-time curve (AUC) and the maximum concentration (Cmax) of lapatinib by 239.6% (p = 0.0030) and 184% (p = 0.0011), respectively. Lapatinib decreased the paracetamol AUC0-∞ by 48.8% and Cmax by 55.7%. In the IL + PA group the Cmax of paracetamol glucuronide was reduced, whereas the Cmax of paracetamol sulphate was higher than in the IIIPA group. Paracetamol significantly affected the enhanced plasma exposure of lapatinib. Additionally, lapatinib reduced the concentrations of paracetamol. The co-administration of lapatinib decreased the paracetamol glucuronidation but increased the sulphation. The findings of this study may be of clinical relevance to patients requiring analgesic therapy.

Pharmacokinetics of dexmedetomidine during analgosedation in ICU patients.

Dexmedetomidine (DEX) is a fairly new alfa2-agonist which has been increasingly used in recent years for analgosedation, mostly because it offers a unique ability of providing both moderate level of sedation and analgesia without respiratory depression. Despite of many papers published, there are still only a few concerning the PK of the drug given as long-term infusion in ICU patients. The aim of this work was to characterize the population pharmacokinetics of dexmedetomidine and to investigate the potential benefits of individualization of drug dosing based on patient characteristics in the heterogeneous group of medical and surgical patients staying in intensive care unit. This study was performed in the group of 17 males and 10 females patients with a median age of 59.5 years and median body weight of 75 kg. Blood samples for dexmedetomidine assay were collected from arterial catheter, during and after discontinuation of a standard infusion, that ranged from 24 to 102 h. The following covariates were examined to influence dexmedetomidine PK: age, sex, body weight, patients' health status described by Sequential Organ Failure Assessment Score (SOFA), inotropes usage, and infusion duration. The dexmedetomidine PK was best described by a two-compartment model. The typical values of PK parameters were estimated as 27 L for the volume of the central compartment, 87.6 L for the volume of the peripheral compartment, 38.5 L/h (9.2 mL/min/kg for a 70 kg patient) for systemic clearance and 46.4 L/h for the distribution clearance. Those values are consistent with literature findings. We were unable to show any significant relationship between collected covariates and dexmedetomidine PK. This study does not provide sufficient evidence to support the individualization of dexmedetomidine dosing based on age, sex, body weight, SOFA, and infusion duration.

Effects of Low-Dose Escherichia coli Lipopolysaccharide-Induced Endotoxemia on Morphine Pharmacokinetics in an Animal Model.

OBJECTIVE: Systemic inflammation may change the bioavailability and pharmacokinetics of opioids. However, there are insufficient data on morphine pharmacokinetics in mild inflammatory conditions. This study aimed to determine the pharmacokinetics of morphine during low-dose endotoxemia in rabbits. DESIGN: In two experiments (separated by a 14-day washout period), 10 rabbits received intravenous morphine at a dose of 3 mg/kg. In the second set of experiments, morphine infusion was preceded by low-dose endotoxemia induced with lipopolysaccharide (Escherichia coli 0111: B4) at a dose of 5 µg/kg. The kinetics of systemic morphine concentrations and chosen physiological parameters were measured at specific time intervals up to 6 hours after morphine administration. RESULTS: In endotoxemia, decreased elimination half-life (P = 0.017), mean residence time (P = 0.022), and volume of distribution (P = 0.037) as well as an increased elimination rate constant (P = 0.013) and total body clearance (P = 0.023) were noted. The inverse linear correlation between morphine clearance versus the percentage (%) change in body temperature and pulse rate observed under control conditions was abolished under endotoxemia. CONCLUSIONS: Low-dose endotoxemia is correlated with significant alterations in morphine pharmacokinetics in rabbits, leading to the faster elimination of the drug. CLINICAL IMPLICATIONS: These findings may have important implications in patients with low-grade inflammation and imply the need to modify morphine dosing regimens to ensure optimal analgesia. The issue warrants further experimental and clinical investigation.

The pharmacokinetics of dexmedetomidine during long-term infusion in critically ill pediatric patients. A Bayesian approach with informative priors.

The purpose of this study was to assess the pharmacokinetics of dexmedetomidine in the ICU settings during the prolonged infusion and to compare it with the existing literature data using the Bayesian population modeling with literature-based informative priors. Thirty-eight patients were included in the analysis with concentration measurements obtained at two occasions: first from 0 to 24 h after infusion initiation and second from 0 to 8 h after infusion end. Data analysis was conducted using WinBUGS software. The prior information on dexmedetomidine pharmacokinetics was elicited from the literature study pooling results from a relatively large group of 95 children. A two compartment PK model, with allometrically scaled parameters, maturation of clearance and t-student residual distribution on a log-scale was used to describe the data. The incorporation of time-dependent (different between two occasions) PK parameters improved the model. It was observed that volume of distribution is 1.5-fold higher during the second occasion. There was also an evidence of increased (1.3-fold) clearance for the second occasion with posterior probability equal to 62 %. This work demonstrated the usefulness of Bayesian modeling with informative priors in analyzing pharmacokinetic data and comparing it with existing literature knowledge.

Pharmacokinetics and pharmacodynamics of propofol and fentanyl in patients undergoing abdominal aortic surgery - a study of pharmacodynamic drug-drug interactions.

Propofol is routinely combined with opioid analgesics to ensure adequate anesthesia during surgery. The aim of the study was to assess the effect of fentanyl on the hypnotic effect of propofol and the possible clinical implications of this interaction. The pharmacokinetic/pharmacodynamic (PK/PD) data were obtained from 11 patients undergoing abdominal aortic surgery, classified as ASA III. Propofol was administered by a target-controlled infusion system. Fentanyl 2-3 µg/kg was given whenever insufficient analgesia occurred. The bispectral index (BIS) was used to monitor the depth of anesthesia. A population PK/PD analysis with a non-linear mixed-effect model (NONMEM 7.2 software) was conducted. Two-compartment models satisfactorily described the PK of propofol and fentanyl. The delay of the anesthetic effect in relation to PK was described by the effect compartment. The BIS was linked to propofol and fentanyl effect-site concentrations through an additive Emax model. Context-sensitive decrement times (CSDT) determined from the final model were used to assess the influence of fentanyl on the recovery after anesthesia. The population PK/PD model was successfully developed to describe simultaneously the time course and variability of propofol and fentanyl concentrations and BIS. Additive propofol-fentanyl interactions were observed and quantitated. The duration of the fentanyl infusion had minimal effect on CSDT when it was shorter than the duration of the propofol infusion. If the fentanyl infusion was longer than the propofol infusion, an almost two-fold increase in CSDT occurred. Additional doses of fentanyl administered after the cessation of the propofol infusion result in lower BIS values, and can prolong the time of recovery from anesthesia. Copyright © 2016 John Wiley & Sons, Ltd.

The pharmacokinetics of propofol in ICU patients undergoing long-term sedation.

The aim of this study was to characterize the pharmacokinetics (PK) of propofol in ICU patients undergoing long-term sedation and to assess the influence of routinely collected covariates on the PK parameters. Propofol concentration-time profiles were collected from 29 patients. Non-linear mixed-effects modelling in NONMEM 7.2 was used to analyse the observed data. The propofol pharmacokinetics was best described with a three-compartment disposition model. Non-parametric bootstrap and a visual predictive check were used to evaluate the adequacy of the developed model to describe the observations. The typical value of the propofol clearance (1.46 l/min) approximated the hepatic blood flow. The volume of distribution at steady state was high and was equal to 955.1 l, which is consistent with other studies involving propofol in ICU patients. There was no statistically significant covariate relationship between PK parameters and opioid type, SOFA score on the day of admission, APACHE II, predicted death rate, reason for ICU admission (sepsis, trauma or surgery), gender, body weight, age, infusion duration and C-reactive protein concentration. The population PK model was developed successfully to describe the time-course of propofol concentration in ICU patients undergoing prolonged sedation. Despite a very heterogeneous group of patients, consistent PK profiles were observed. Copyright © 2016 John Wiley & Sons, Ltd.

Pharmacokinetics and pharmacodynamics of propofol in cancer patients undergoing major lung surgery.

Despite the growing number of cancer cases and cancer surgeries around the world, the pharmacokinetics (PK) and pharmacodynamics (PD) of anesthetics used in this population are poorly understood. Patients operated due to cancer are usually in severe state and often require chemotherapy. It might affect the PK/PD of drugs used in this population. Therefore, in this study we explored the PK/PD of propofol in cancer patients having a major lung surgery. 23 patients that underwent a propofol-fentanyl total intravenous anesthesia were included in the analysis. A large set of demographic, biochemical and hemodynamic parameters was collected for the purpose of covariate analysis. Nonlinear mixed effect modeling in NONMEM was used to analyze the collected data. A three-compartment model was sufficient to describe PK of propofol. The anesthetic effect (AAI index) was linked to the propofol effect site concentrations through a sigmoidal E max model. A slightly higher value of clearance, a lower value of distribution clearance, and a decreased volume of peripheral compartment were observed in our patients, as compared with the literature values reported for healthy volunteers by Schnider et al. and by Eleveld et al. Despite these differences, both models led to a clinically insignificant bias of -8 and -1 % in concentration predictions, as reflected by the median performance error. The C e50 and propofol biophase concentration at the time of postoperative orientation were low and equaled 1.40 and 1.13 mg/L. The population PK/PD model was proposed for cancer patients undergoing a major lung surgery. The large body of studied covariates did not affect PK/PD of propofol significantly. The modification of propofol dosage in the group of patients under study is not necessary when TCI-guided administration of propofol by means of the Schnider model is used.

The effect of sunitinib on the plasma exposure of intravenous paracetamol and its major metabolite: paracetamol glucuronide.

The study aimed to examine the effect of sunitinib on the plasma exposure of intravenous paracetamol and its major metabolite, paracetamol glucuronide. Both drugs share metabolic pathways in the liver, and the drug interactions between sunitinib and paracetamol administered in higher doses were reported. These interactions resulted in hepatotoxicity. The adult New Zealand male rabbits were divided into three groups (6 animals each): rabbits receiving sunitinib and paracetamol (SUN + PC), rabbits receiving sunitinib (SUN), and a control group receiving paracetamol (PC). Sunitinib was administered orally (25 mg) and paracetamol was administrated intravenously (35 mg/kg). Blood samples for sunitinib and SU12662 assays were collected up to 96 h after drug administration and for paracetamol and paracetamol glucuronide up to 300 min after drug administration. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), and bilirubin were analysed before and after drug administration. A number of pharmacokinetic parameters were analysed. There were no differences in the levels of AST, ALT, and bilirubin among the groups at either time point. Significantly higher values of AUC0-t , AUC0-∞ , and C max and lower clearance and volume of distribution of paracetamol were observed in group PC vs. group SUN + PC (p < 0.01). The maximum plasma concentration of paracetamol glucuronide tended to be higher in group PC 213.27 µg/mL (90 % CI 1.06, 1.25; p = 0.0267). Statistically significant differences were revealed for paracetamol glucuronide mean residence time (MRT); MRT was higher in group SUN + PC than in group PC (p = 0.0375). The mean t max of paracetamol glucuronide was similar in both groups: SUN + PC and group PC (15 and 20 min, respectively). The mean t max of sunitinib was different in groups SUN + PC and SUN (10.0 and 7.0, respectively; p = 0.0134). At the studied doses, neither of the drugs, whether administered alone or together, had hepatotoxic effects. The present study was not able to confirm that sunitinib, administered at low doses in conjunction with paracetamol, displays a hepatoprotective effect. Significant differences were observed in some pharmacokinetic parameters of paracetamol.

The importance of rs1021737 and rs482843 polymorphisms of cystathionine gamma-lyase in the etiology of preeclampsia in the Caucasian population.

INTRODUCTION: Recently an increasing number of reports indicate the participation of genetic factors in the pathogenesis of preeclampsia (PE). The genes involved in the synthesis of nitric oxide that participates in the vasolidation, may play an important role in the development of this disorder. Hydrogen sulfide (H2S) which is produced by cystathionine gamma-lyase exhibits a similar effect to nitric oxide. It is suggested that certain polymorphisms of the CTH gene may participate in the development of chronic hypertension and preeclampsia. AIM OF THE STUDY: To evaluate the frequency of genotypes and alleles of rs1021737 and rs482843 polymorphisms of CTH gene in women with preeclampsia from Wielkopolska region. MATERIAL AND METHODS: The study group consisted of 60 patients with diagnosed preeclampsia, into the control group 120 healthy pregnant women were enrolled. The examined rs1021737 and rs482843 polymorphisms of CTH gene were determined using PCR-RFLP method. RESULTS: Analysis of rs482843 polymorphism in the CTH gene showed a statistically significant difference in the prevalence of mutated GG genotype (p<0.000001) and mutated G allele (p<0.000001) in the group of pregnant women with PE compared to the control group. There was no such correlation for the rs1021737 polymorphism. Furthermore, there are also no relationship between studied polymorphisms and selected clinical and biochemical parameters. CONCLUSIONS: The results of rs482843 polymorphism analysis suggest that mutated GG genotype predisposes to preeclampsia occurrence. There was no such relationship for the rs1021737 polymorphism of CTH gene. Hence, further studies based on the determination of CSE expression level in women with PE may confirm the observed relationship between the rs482843 polymorphism and the risk of preeclampsia.

The problems of urinary tract infections with Candida spp. aetiology in women.

Urinary tract infections (UTIs) in women are a growing clinical concern. The most frequent risk factors of UTIs with fungal aetiology in women are: antibiotic therapy (especially broad-spectrum antibiotics), immunosuppressive therapy, diabetes, malnutrition, pregnancy, and frequent intercourse. The aim of the study was to analyse urinary tract infections with Candida spp. aetiology in women hospitalised at the Clinical Hospital in Poznan, Poland, between 2009 and 2011. The investigations revealed that as many as 71% of positive urine cultures with Candida fungi came from women. The following fungi were most frequently isolated from the patients under analysis: C. albicans (47%), C. glabrata (31%), C. tropicalis (6%), C. krusei (3%). In order to diagnose a UTI the diagnosis cannot be based on a single result of a urine culture. Due to the small number of antifungal drugs and high costs of treatment, antifungal drugs should be applied with due consideration and care.

Biopharmaceutical evaluation of new slow release tablets obtained by hot tableting of coated pellets with tramadol hydrochloride.

This study was aimed at a biopharmaceutical evaluation of a new oral dosage form of tramadol hydrochloride (TH)--slow release tablets obtained by hot tableting of coated pellets, 100 mg (TP), compared to the conventional slow release tablets, Tramal Retard, 100 mg (TR). Both TP and TR formulations showed a similar release profile of TH (f2 was 71) in in vitro release studies. The in vivo study was a two-treatment, two-period, two-sequence, single-oral dose 100 mg, crossover design using rabbit model with the phases separated by a washout period of 14 days. It was shown that the amount of TH absorbed into the systemic circulation is similar for TP and TR (the 90% confidence intervals for the AUC(0-1), AUC(0-infinity) and ratios were 85-122 and 92-107%, respectively). However, after administration of slow release tablets obtained by hot tableting of coated pellets, a prolonged absorption and elimination processes and a smoother and more extended plasma profile of TH were observed. It can be assumed that the use of a new oral dosage form of TH in patients affects the extension of analgesia after single administration of the drug, with its gradual absorption into the systemic circulation.

In vitro - in vivo evaluation of a new oral dosage form of tramadol hydrochloride--controlled-release capsules filled with coated pellets.

The aim of this study was an in vitro - in vivo evaluation of a new oral dosage form of tramadol hydrochloride (TH), controlled-release capsules filled with coated pellets, 100 mg (TC), compared to the sustained release tablets, Tramal Retard, 100 mg (TR). In vitro release study of both formulations showed a similar release profile of TH over 8 h (f2 was 52). In vivo study (single oral, 100 mg dose administration in 8 rabbits) showed that the amount of TH absorbed into the systemic circulation after TC and TR administration was also similar (90% CI for AUC(0-t) and AUC(0-infinity) were 90-124% and 97-109%, respectively). However, a comparison of AUC(0-t) of pharmacokinetics of TC and TR indicates significantly prolonged absorption and elimination processes of TH when the drug is given in controlled-release capsules filled with coated pellets. It was manifested by longer: mean absorption time (p = 0.0016), mean residence time (p = 0.0268), absorption half-life (p = 0.0016), elimination half-life (p = 0.0493) and lower: absorption rate constant (p = 0.0016), elimination rate constant (p = 0.0148) and total body clearance Cl/F (p = 0.0076). It may be concluded that the new TH formulation could be expected to have a more prolonged analgesic activity than commercial sustained release tablets.

The influence of soybean extract on the expression level of selected drug transporters, transcription factors and cytochrome P450 genes encoding phase I drug-metabolizing enzymes.

OBJECTIVE: Soybean phytoestrogens, such as genistein and daidzein, reduce climacteric symptoms and the risk of certain chronic diseases such as cancer and cardiovascular diseases. Despite their widespread use in functional foods and dietary supplements, there is very little data available on their safety and herb-drug interactions, especially with antineoplastic agents. Hence, the aim of our study was to assess the effects of soybean extracts on the expression level of CYP genes and their transcriptional factors. We also investigated the effect of soybean on the mRNA level of transporters, such as P-glycoprotein (MDRI) and multidrug resistance-associated proteins (MRP1, MRP2). MATERIALS AND METHODS: Wistar rats were fed a standardized soybean extract (100 mg/kg, p.o.). cDNA was synthesized from total RNA isolated from different tissues (liver and intestinal epithelium) using reverse transcription. Gene expression level was analyzed by RT-PCR method. RESULTS: We demonstrated a significant increase of CYP1A1 mRNA level (by 89%, p = 0.002 and 125%, p = 0.004) as compared with the control group. An increase of AHR and CAR expression after 10 days was also observed (by 60%, p < 0.001 and 52%, p > 0.05, respectively). Additionally an inductive effect for CYP2D1 by 22% (p = 0.008), Mdr1a by 267% (p < 0.0001), Mdr2b by 86% (p < 0.00001), Mrp1 by 9-fold (p < 0.0001), Mrp2 by 83% (p < 0.0001) in the liver and for Mrp2 by 35% (p < 0.001) in the intestinal epithelium, was evaluated. A significant decrease of mRNA level was observed for CYP3A1 (human CYP3A4) in the liver and Mdr1b in the intestinal epithelium. Moreove, we also showed a slight decrease in the amount of mRNA for CAR, PXR and ARNT after 3 days. CONCLUSIONS: Our results suggest that Glycine max may change the expression level of CYPs, especially CYP3A4 and CYP1A 7, involved in biotransformation of xenobiotics (drugs, procarcinogens) and may participate in clinically significant interactions with drugs metabolized by these enzymes. Moreover an increase of CYP1A1 (homologue to human CYPIA 1) mRNA level may not only reduce the carcinogenicity of foreign compounds, but may also activate some compounds to their carcinogenicity In case of transporters, it is considered that an increase of their expression in the body may lead to increased fetoprotection. Also, it may reduce both, the exposure of sensitive tissues (e.g. brain, placenta) to xenobiotics and treatment effectiveness of certain diseases. Hence, the search for a safe substance that could effectively modulate transporter activity especially in the treatment of certain hormone -dependent disorders, e.g. osteoporosis and breast cancer occurring mainly in postmenopausal period, continues.

Effect of Epilobium angustifolium and Serenoa repens extracts on regulation of non-genomic signaling pathway of kinases.

OBJECTIVES: Changes of kinase activity of non-genomic cellular signaling pathway may influence the effectiveness of pharmacotherapy in case of hormone-dependent tumors. Our study investigated a possible interaction at the molecular level between an aqueous herbal extract of Epilobium angustifolium as well as a lipid-sterolic fruit extract of Serenoa repens and synthetic drugs used in the treatment of hormone-dependent cancers. MATERIAL AND METHODS: E. angustifolium and Serenoa repens extracts were orally administered to testosterone-induced rats for 21 days. Changes of RafA/Mapk3/Mapk1 mRNA levels were analyzed by real-time quantitative PCR using target specific primers. RESULTS: The level of RafA mRNA slightly increased in rats receiving Epilobium angustifolium (p = 0.076) and Serenoa repens (p = 0.016) extracts. Administration of these extracts resulted in significantly elevated Mapk1 and Mapk3 transcripts in the investigated animals (p < 0.05 for each extract). The levels of Mapk1 and Mapk3 mRNA strongly increased (p < 0.05 for each extract) in animals receiving concomitantly testosterone and the extracts, while RafA transcription slightly decreased (p < 0.05), as compared to controls. CONCLUSIONS: The results of our study may indicate a potential effect of S. repens and E. angustifolium extracts on the functioning of non-genomic cellular signaling kinases pathway. We investigated safety of these extracts to detect possible drug interactions between synthetic drugs used in the treatment of proliferative changes in hormone-dependent reproductive organs and herbal preparations.

Potential drug-drug interactions analysis in Polish pediatric pneumonology units, including cystic fibrosis patients.

The lack of data on drug-drug interactions in pediatrics represents a relevant problem in making appropriate therapeutic decisions. Our study aimed to investigate the incidence and risk factors for potential drug-drug interactions (pDDIs) in pediatric pneumonology units, including cystic fibrosis patients. We performed a 6-month prospective observational study during which clinical pharmacists, using the Lexicomp Drug Interactions checker, screened medical records to identify pDDIs. Spearman's rank coefficient, logistic regression, and the Mann-Whitney U test were used to identify correlations, analyze risk factors for pDDIs, and compare cystic fibrosis patients with the rest, respectively. Recommendations were provided for the D and X pDDIs categories. Within the 218 patients, 428 pDDIs were identified, out of which 237 were classified as clinically significant. Almost 60% of patients were exposed to at least one relevant interaction. The number of pDDIs correlated with the number of; drugs (rs = 0.53, P <  .001), hospitalization length (rs = 0.20, P <  .01), and off-label medicines (rs = 0.25, P <  .001). According to the multivariate analysis, at least 6 administered medications (OR = 4.15; 95% CI = 2.21-7.78), 4 days of hospitalization (OR = 6.41; 95% CI = 2.29-17.97), and off-label therapy (OR = 3.37; 95% CI = 1.69-6.70) were the risk factor for pDDIs. Despite significant differences in the number of medications taken, comorbidities, and off-label drugs, cystic fibrosis patients were not more exposed to pDDI. Given the lack of data on pDDIs in the pediatric population, the need for close cooperation between clinicians and clinical pharmacists to improve the safety and efficacy of pharmacotherapy is highlighted.

Bidirectional pharmacokinetic drug interactions between olaparib and metformin.

OBJECTIVE: Olaparib is a PARP (poly-ADP-ribose polymerase) inhibitor used for maintenance therapy in BRCA-mutated cancers. Metformin is a first-choice drug used in the treatment of type 2 diabetes. Both drugs are commonly co-administered to oncologic patients with add-on type 2 diabetes mellitus. Olaparib is metabolized by the CYP3A4 enzyme, which may be inhibited by metformin through the Pregnane X Receptor. In vitro studies have shown that olaparib inhibits the following metformin transporters: OCT1, MATE1, and MATE2K. The aim of the study was to assess the influence of 'the perpetrator drug' on the pharmacokinetic (PK) parameters of 'the victim drug' after a single dose. To evaluate the effect, the AUC0→∞ (area under the curve) ratio was determined (the ratio between AUC0→∞ in the presence of the perpetrator and AUC0→∞ without the presence of the perpetrator). METHODS: Male Wistar rats were assigned to three groups (eight animals in each group), which were orally administered: metformin and olaparib (IMET+OLA), vehiculum with metformin (IIMET), and vehiculum with olaparib (IIIOLA). Blood samples were collected after 24 h. HPLC was applied to measure the concentrations of olaparib and metformin. The PK parameters were calculated in a non-compartmental model. RESULTS: Metformin did not affect the olaparib PK parameters. The AUC0→∞ IMET+OLA/IIIOLA ratio was 0.99. Olaparib significantly increased the metformin Cmax (by 177.8%), AUC0→t (by 159.8%), and AUC0→∞ (by 74.1%). The AUC0→∞ IMET+OLA/IIMET ratio was 1.74. CONCLUSIONS: A single dose of metformin did not affect the PK parameters of olaparib, nor did it inhibit the olaparib metabolism, but olaparib significantly changed the metformin pharmacokinetics, which may be of clinical importance.

Pharmacokinetic interaction between regorafenib and atorvastatin in rats.

BACKGROUND: Regorafenib is used in the treatment of colorectal cancer and hepatocellular carcinoma. Due to the co-morbidity of hyperlipidemia in these conditions, statins, including atorvastatin, are used as potential adjuvant therapy agents. Both regorafenib and atorvastatin are metabolized by CYP3A4. In addition, atorvastatin is a P-gp and BCRP substrate, whereas regorafenib and its active metabolites M-2 and M-5 are inhibitors of these transporters. Hence, the concomitant use of both drugs may increase the risk of a clinically significant drug-drug interaction. Therefore, the present study aimed to assess the pharmacokinetic interactions of atorvastatin and regorafenib and their active metabolites. METHODS: Male Wistar rats were assigned to three groups (eight animals in each) and were orally administered: regorafenib and atorvastatin (IREG+ATO), a carrier with regorafenib (IIREG), and atorvastatin with a carrier (IIIATO). Blood samples were collected for 72 h. UPLC-MS/MS was the method of measurement of regorafenib and atorvastatin concentrations. The pharmacokinetic parameters were calculated with a non-compartmental model. RESULTS: A single administration of atorvastatin increased the exposure to regorafenib and its active metabolites. In the IREG+ATO group, the Cmax, AUC0-t, and AUC0-∞ of regorafenib increased 2.7, 3.2, and 3.2-fold, respectively. Atorvastatin also significantly increased the Cmax, AUC0-t, and AUC0-∞ of both regorafenib metabolites. Regorafenib, in turn, decreased the AUC0-t and AUC0-∞ of 2-OH atorvastatin by 86.9% and 67.3%, and the same parameters of 4-OH atorvastatin by 45.0% and 46.8%, respectively. CONCLUSIONS: This animal model study showed a significant pharmacokinetic interaction between regorafenib and atorvastatin. While this interaction may be clinically significant, this needs to be confirmed in clinical trials involving cancer patients.