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PLOS ONETitle - Optimization of the flash extraction of flavonoids from the leaves of Salix babylonica using the response surface method and an evaluation of the leaves high antioxidant activity

Many biological activities of Salix babylonica leaves are attributed to the plants high total flavonoid content. Flash extraction has the advantages of high efficiency and maximum retention of the active ingredient. In this study, flash extraction was used to extract the total flavonoids, and a Box-Behnken design was used to optimize the extraction conditions for the first time. The effects of four independent variables, including ethanol concentration, extraction voltage, time, and ratio of liquid to material on flavonoid yield, was determined, and the optimal conditions for flavonoid extraction were evaluated using response surface methodology. Statistical analyses showed that the linear and quadratic terms of these four variables had significant effects. The fitted second-order model revealed that the optimal conditions consisted of an ethanol concentration of 67.91%, extraction time of 87 s, extraction voltage of 116 V and ratio of liquid to material of 42.79. Under the optimum conditions, the experimental value of 66.40{+/-}0.80% nearly coincided with that predicted by the model. In the ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH.) assays, the extracts showed significant antioxidant and scavenging capacity for free radicals, respectively. This study helps to better exploit the resources of Salix babylonica leaves and provides new insights for effective extraction of flavonoids.

pharmacology and toxicology

Repeated Δ9-tetrahydrocannabinol (THC) vapor inhalation during adolescence: Sex differences inacute thermoregulatory tolerance and in feeding during adulthood

Adolescents are regularly exposed to {Delta}9-tetrahydrocannabinol (THC) via smoking, and, more recently, vaping, cannabis / extracts. Growing legalization of cannabis for medical and recreational purposes, combined with decreasing perceptions of harm, makes it increasingly important to determine the consequences of frequent adolescent exposure for motivated behavior and lasting tolerance in response to THC. Male and female rats inhaled THC vapor, or that from the propylene glycol (PG) vehicle, twice daily for 30 minutes from postnatal day (PND) 35-39 and PND 42-45 using an e-cigarette system. Thermoregulatory responses to vapor inhalation were assessed by radio-telemetry during adolescence and from PND 86-94; chow intake was assessed in adulthood. Blood samples were obtained from additional adolescent groups following initial THC inhalation and after four days of twice daily exposure. Additional groups exposed repeatedly to THC or PG during adolescence were evaluated for intravenous self-administration of oxycodone as adults. Female, not male, adolescents developed tolerance to the hypothermic effects of THC inhalation in the first week of repeated exposure despite similar plasma THC levels. Each sex exhibited tolerance to THC hypothermia in adulthood after repeated adolescent THC with THC greater potency exhibited in females. Repeated-THC male rats consumed more food than their PG treated control group, in the absence of a significant bodyweight difference. Adolescent THC did not alter oxycodone self-administration in either sex, but increased fentanyl self-administration in females. Repeated THC vapor inhalation in adolescent rats results in lasting consequences observable in adulthood.\n\nAbbreviationsPG, propylene glycol; THC, {Delta}9tetrahydrocannabinol;

pharmacology and toxicology

Commensal gut bacteria convert the immunosuppressant tacrolimus to less potent metabolites

Tacrolimus exhibits low and variable drug exposure after oral dosing, but the contributing factors remain unclear. Based on our recent report showing a positive correlation between fecal abundance of Faecalibacterium prausnitzii and oral tacrolimus dose in kidney transplant patients, we tested whether F. prausnitzii and other gut abundant bacteria are capable of metabolizing tacrolimus. Incubation of F. prausnitzii with tacrolimus led to production of two compounds (the major one named M1), which was not observed upon tacrolimus incubation with hepatic microsomes. Isolation, purification, and structure elucidation using mass spectrometry and nuclear magnetic resonance spectroscopy indicated that M1 is a C-9 keto-reduction product of tacrolimus. Pharmacological activity testing using human peripheral blood mononuclear cells demonstrated that M1 is 15-fold less potent than tacrolimus as an immunosuppressant. Screening of 22 gut bacteria species revealed that most Clostridiales bacteria are extensive tacrolimus metabolizers. Tacrolimus conversion to M1 was verified in fresh stool samples from two healthy adults. M1 was also detected in the stool samples from kidney transplant recipients who had been taking tacrolimus orally. Together, this study presents gut bacteria metabolism as a previously unrecognized elimination route of tacrolimus, potentially contributing to the low and variable tacrolimus exposure after oral dosing.

pharmacology and toxicology

Effects of a complex mixture of persistent organic pollutants (POPs) on steroidogenesis in H295R cells under 10 μM forskolin stimulation - results from a pilot study

This study describes the utilization of an LC-MS/MS based H295R assay to assess an environmentally relevant mixture of persistent organic pollutants (POPs). H295R cells were exposed to the POP mixture in two conditions stimulated with 10 M forskolin and unstimulated. Most importantly, the unstimulated cells responded to the low concentration of the mixture with a significant down-regulation of dehydroepiandrosterone (DHEA). This response was not observed in forskolin-stimulated cells. In stimulated H295R cells, exposure to the highest concentration showed a trend towards induced production of mineralocorticoids and glucocorticoids, although this was not significant. On the other hand, in the same exposure concentration and condition, estrogen and androgen production tended to be down-regulated. In addition to these patterns of responses being different in the stimulated vs unstimulated condition, four steroids were not detectable in the unstimulated condition.

pharmacology and toxicology

The High-throughput WAFFL System for Treating and Monitoring Individual Drosophila melanogaster Adults

Non-mammalian model organisms have been essential for our understanding of the mechanisms and control of development, disease, and physiology, but are underutilized in pharmacological phenotypic screening assays due to low throughput compared to cell-based systems. To increase the utility of using Drosophila melanogaster in screening, we have designed the whole animal feeding flat (WAFFL), a novel, flexible, and complete system for feeding, monitoring, and assaying flies in a high throughput format. Our system was conceived keeping in mind the use of off-the-shelf, commercial, 96-well consumables and equipment in order to be amenable to experimental needs. Here we provide an overview of the design and 3-D printing manufacture specifications.

pharmacology and toxicology

Microplastic-mediated transport of PCBs? A depuration study with Daphnia magna

The role of microplastic (MP) as a carrier of persistent organic pollutants (POPs) to aquatic organisms has been a topic of debate. However, theoretically, the reverse POP transport can occur at higher relative contaminant concentrations in the organism than in the microplastic. The effect of microplastic on the PCB removal in planktonic animals was evaluated using the cladoceran Daphnia magna with a high body burden of polychlorinated biphenyls (PCB 18, 40, 128 and 209) exposed to a mixture of microplastic and algae (with 77% MP by mass); daphnids exposed to only algae served as the control. As the endpoints, we used PCB body burden, growth, fecundity and elemental composition (%C and %N) of the daphnids. We found that PCB 209 was removed more efficiently in the daphnids fed with microplastic, while there was no difference for the {Sigma}PCBs between the microplastic-exposed and control animals. Effects of the microplastic exposure on fecundity were of low biological significance, even though both the starting PCB body burden and the microplastic exposure concentrations were high and greatly exceeding environmentally relevant concentrations.

pharmacology and toxicology

The chemistry and pharmacology of putative synthetic cannabinoid receptor agonist (SCRA) new psychoactive substances (NPS) 5F-PY-PICA, 5F-PY-PINACA, and their analogues

The structural diversity of synthetic cannabinoid receptor agonist (SCRA) new psychoactive substances (NPS) has increased since the first examples were reported a decade ago. 5F-PY-PICA and 5F-PY-PINACA were identified in 2015 as putative SCRA NPS, although nothing is known of their pharmacology. 5F-PY-PICA, 5F-PY-PINACA, and analogues intended to explore structure-activity relationships within this class of SCRAs were synthesized and characterized by nuclear magnetic resonance spectroscopy and liquid chromatography-quadrupole time-of-flight-mass spectrometry. Using competitive binding experiments and fluorescence-based plate reader membrane potential assays, the affinities and activities of all analogues at cannabinoid type 1 and type 2 receptors (CB1 and CB2) were evaluated. All ligands showed minimal affinity for CB1 (pKi < 5), although several demonstrated moderate CB2 binding (pKi = 5.45-6.99). At 10 M none of the compounds produced an effect > 50% of CP55,950 at CB1, while several compounds showed a slightly higher relative efficacy at CB2. Unlike other SCRA NPS, 5F-PYPICA and 5F-PY-PINACA did not produce cannabimimetic effects in mice at doses up to 10 mg/kg.

pharmacology and toxicology

Proteomic Profile of TGF-β1 treated Lung Fibroblasts identifies Novel Markers of Activated Fibroblasts in the Silica Exposed Rat Lung

We performed liquid chromatography-tandem mass spectrometry (LC-MS/MS) on control and TGF-{beta}1-exposed rat lung fibroblasts to identify proteins differentially expressed between cell populations. A total of 1648 proteins were found to be differentially expressed in response to TGF-{beta}1 treatment and 196 proteins were expressed at [&ge;] 1.2 fold relative to control. Guided by these results, we next determined whether similar changes in protein expression were detectable in the rat lung after chronic exposure to silica dust. Of the five proteins selected for further analysis, we found that levels of all proteins were markedly increased in the silica-exposed rat lung, including the proteins for the very low density lipoprotein receptor (VLDLR) and the transmembrane (type I) heparin sulfate proteoglycan called syndecan 2 (SDC2). Because VLDLR and SDC2 have not, to our knowledge, been previously linked to the pathobiology of silicosis, we next examined whether knockdown of either gene altered responses to TGF-{beta}1 in MRC-5 lung fibroblasts. Interestingly, we found knockdown of either VLDLR or SDC2 dramatically reduced collagen production to TGF-{beta}1, suggesting that both proteins might play a novel role in myofibroblast biology and pathogenesis of silica-induced pulmonary fibrosis. In summary, our findings suggest that performing LC-MS/MS on TGF-{beta}1 stimulated lung fibroblasts can uncover novel molecular targets of activated myofibroblasts in silica-exposed lung.\n\nHighlightsWe identified 196 proteins differentially expressed between control and TGF-{beta}1 treated fibroblastsby LC-MS/MS.\n\nSeveral proteins identified by LC-MS/MS were also found to be differentially expressed in whole lung tissues and isolated fibroblasts after chronic exposure to silica dust, including the very low density lipoprotein receptor (VLDLR) and the transmembrane type I heparan sulfate proteoglycan called syndecan 2\n\nKnockdown of SDC2 or VLDLR markedly inhibited collagen production in MRC-5 fibroblasts, suggesting a novel pathogenic role for these proteins in myofibroblast biology.

pharmacology and toxicology

Guiding dose selection of monoclonal antibodies using a new parameter (AFTIR) for characterizing ligand binding systems

Guiding the dose selection for monoclonal antibody oncology drugs is often done using methods for predicting the receptor occupancy of the drug in the tumor. In this manuscript, previous work on characterizing target inhibition at steady state using the AFIR metric [1] is extended to include a \"target-tissue\" compartment and the shedding of membrane-bound targets. A new potency metric AFTIR (Averarge Free Tissue target to Initial target ratio at steady state) is derived, and it depends on only four key quantities: the equilibrium binding constant, the fold-change in target expression at steady state after binding to drug, the biodistribution of target from circulation to target tissue, and the average drug concentration in circulation. The AFTIR metric is useful for guiding dose selection, for efficiently performing sensitivity analyses, and for building intuition for more complex target mediated drug disposition models. In particular, reducing the complex, physiological model to four key parameters needed to predict target inhibition helps to highlight specific parameters that are the most important to estimate in future experiments to guide drug development.\n\nGraphical Abstract\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=145 SRC=\"FIGDIR/small/432500_fig1.gif\" ALT=\"Figure 1\">\nView larger version (30K):\norg.highwire.dtl.DTLVardef@6895d7org.highwire.dtl.DTLVardef@4566e0org.highwire.dtl.DTLVardef@6515e8org.highwire.dtl.DTLVardef@8168ea_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFig. 1C_FLOATNO Graphical Abstract\n\nC_FIG

pharmacology and toxicology

Rubsicolins are naturally occurring G-protein-biased delta opioid receptor peptides

The impact that {beta}-arrestin proteins have on G-protein-coupled receptor trafficking, signaling and physiological behavior has gained much appreciation over the past decade. A number of studies have attributed the side effects associated with the use of naturally occurring and synthetic opioids, such as respiratory depression and constipation, to excessive recruitment of {beta}-arrestin. These findings have led to the development of biased opioid small molecule agonists that do not recruit {beta}-arrestin, activating only the canonical G-protein pathway. Similar G-protein biased small molecule opioids have been found to occur in nature, particularly within kratom, and opioids within salvia have served as a template for the synthesis of other G-protein-biased opioids. Here, we present the first report of naturally occurring peptides that selectively activate G-protein signaling pathways with minimal {beta}-arrestin recruitment. We find that rubiscolin peptides, which are produced as cleavage products of the plant protein rubisco, bind to and activate G-protein signaling at {delta} opioid receptors. However, unlike the naturally occurring {delta} opioid peptides leu-enkephalin and deltorphin II, the rubiscolin peptides only very weakly recruit {beta}-arrestin 2 and have undectable recruitment of {beta}-arrestin 1 at the {delta} opioid receptor.

pharmacology and toxicology

Comprehensive proteomic and metabolomic profiling of mcr-1 mediated colistin resistance in Escherichia coli

The spread of mcr-1 in human and veterinary medicine has jeopardized the use of polymyxins, the last-resort antibiotics against life-threatening multidrug-resistant Gram-negative bacteria. As a lipid-modified gene, whether mcr-1 brings proteomic and metabolomic changes in the bacteria and affects the corresponding metabolic pathway is largely unknown. Herein, we used label-free quantitative proteomics and untargeted metabolomics to profile comprehensive proteome and metabolome characteristics of mcr-1-mediated colistin-resistant and -sensitive Escherichia coli and further insight the resistant mechanism of colistin. We identified large sets of differential expression proteins and metabolites that contributed to mcr-1-mediated antibiotic resistance predominantly in the different growth conditions with and without colistin. mcr-1 could cause the down-regulated expression of most proteins to adapt drug pressure. Pathway analysis showed that metabolic process was significantly affected, mainly related to glycerophospholipid metabolism, thiamine metabolism, and lipopolysaccharide biosynthesis. The substrate phosphatidylethanolamine for mcr-1 to mediate colistin resistance is accumulated in colistin-resistant E. coli. Notably, mcr-1 can not only cause the phosphoethanolamine modification of bacterial cell membrane lipid A, but also affect the biosynthesis and transport of lipoprotein in colistin resistance through disturbing the expression of efflux pump proteins involved in cationic antibacterial peptide resistance pathway. Overall, the disturbed glycerophospholipid metabolism, lipopolysaccharide biosynthesis and the accumulation of the substrate phosphatidylethanolamine is closely related with mcr-1-mediated colistin resistance and these findings can further provide valuable information to inhibit colistin resistance by blocking this metabolic process.

pharmacology and toxicology

Enhancing acute kidney injury regeneration by promoting cellular dedifferentiation in zebrafish

Acute kidney injury (AKI) is a serious disorder for which there is no approved pharmaceutical treatment. Following injury, native nephrons display limited regenerative capabilities, relying on the dedifferentiation and proliferation of renal tubular epithelial cells (RTECs) that survive the insult. Previously, we identified 4-(phenylthio)butanoic acid (PTBA), a histone deacetylase inhibitor (HDI) that enhances renal recovery and showed that PTBA treatment increased RTEC proliferation and reduced renal fibrosis. Here, we investigated the regenerative mechanisms of PTBA in zebrafish models of larval renal injury and adult cardiac injury. With respect to renal injury, we showed that delivery of PTBA using an esterified prodrug (UPHD25) increases the reactivation of the renal progenitor gene Pax2a, enhances dedifferentiation of RTECs, reduces Kidney injury molecule-1 expression, and lowers the number of infiltrating macrophages. Further, we find that the effects of PTBA on RTEC proliferation depend upon retinoic acid signaling and demonstrate the therapeutic properties of PTBA are not restricted to the kidney but also increase cardiomyocyte proliferation and decrease fibrosis following cardiac injury in adult zebrafish. These studies provide key mechanistic insights into how PTBA enhances tissue repair in models of acute injury and lay the groundwork for translating this novel HDI into the clinic.\n\nSUMMARY STATEMENTMortality associated with acute kidney injury (AKI) is in part due to limited treatments available to ameliorate kidney injury. We identified a compound that enhances AKI recovery by promoting cellular dedifferentiation.

pharmacology and toxicology

Cannabichromene is a cannabinoid CB2 receptor agonist

BACKGROUNDCannabichromene (CBC) is one of the most abundant phytocannabinoids in Cannabis spp. It has modest anti-nociceptive and anti-inflammatory effects and potentiates some effects of {Delta}9-tetrahydrocannabinol (THC) in vivo. How CBC exerts these effects is poorly defined and there is little information about its efficacy at cannabinoid receptors. We sought to determine the functional activity of CBC at CB1 and CB2 receptors.\n\nEXPERIMENTAL APPROACHAtT20 cells stably expressing HA-tagged human CB1 and CB2 receptors were used. Assays of cellular membrane potential and loss of cell surface receptors were performed.\n\nKEY RESULTSCBC activated CB2 but not CB1 receptors to produce a hyperpolarization of AtT20 cells. Activation of CB2 receptors was antagonised by the CB2 antagonist AM630 and sensitive to pertussis toxin. Co-application of CBC reduced activation of CB2 receptors CP55,940, a potent CB1 and CB2 agonist. Continuous CBC application induced loss of cell surface CB2 receptors and desensitisation of the CB2-induced hyperpolarization.\n\nCONCLUSIONS AND IMPLICATIONSCannabichromene is a selective CB2 receptor agonist displaying higher efficacy than THC in hyperpolarising AtT20 cells. CBC may contribute to the potential therapeutic effectiveness of some cannabis preparations, potentially through CB2-mediated modulation of inflammation.

pharmacology and toxicology

Sacubitril/valsartan (LCZ696) Significantly Reduces Aldosterone and Increases cGMP Circulating Levels in a Canine Model of RAAS Activation

Simultaneous blockade of angiotensin receptors and enhancement of natriuretic peptides (NP) by the first-in-class angiotensin receptor neprilysin (NEP) inhibitor sacubitril/valsartan constitutes an effective approach to treating heart failure. This study examined the effects of sacubitril/valsartan (225 and 675mg/day) vs. placebo, sacubitril (360mg/day), valsartan (900mg/day), and benazepril (5mg/day) on the dynamics of the renin-angiotensin-aldosterone system (RAAS) and the NP system in dogs. Beagle dogs (n=18) were fed a low-salt diet (0.05% Na) for 15 days to model RAAS activation observed in clinical heart failure. Drugs were administered once daily during the last 10 days, while the effects on the RAAS and NPs were assessed on days 1, 5, and 10. Steady-state pharmacokinetics of the test agents were evaluated on day 5. Compared with placebo, sacubitril/valsartan (675mg) substantially increased cGMP circulating levels, while benazepril and valsartan showed no effect. Additionally, sacubitril/valsartan (675mg) and valsartan significantly increased plasma renin activity, angiotensin I and angiotensin II concentrations. Finally, sacubitril/valsartan (both doses), and valsartan significantly decreased plasma aldosterone vs. placebo. Systemic exposure to valsartan following sacubitril/valsartan 675mg administration was similar to that observed with valsartan 900mg administration alone. Sacubitril/valsartan favorably modulates the dynamics of the renin and NP cascades through complementary NEP and RAAS inhibition.

pharmacology and toxicology

Characterization of the gastric motility response to human motilin and erythromycin in human motilin receptor-expressing transgenic mice

Motilin is a gastrointestinal peptide hormone that stimulates gastrointestinal motility. Motilin is produced primarily in the duodenum and jejunum. Motilin receptors (MTLRs) are G protein-coupled receptors that may represent a clinically useful pharmacological target as they can be activated by erythromycin. The functions of motilin are highly species-dependent and remain poorly understood. As a functional motilin system is absent in rodents such as rats and mice, these species are not commonly used for basic studies. In this study, we examine the usefulness of human MTLR-overexpressing transgenic (hMTLR-Tg) mice by identifying the mechanisms of the gastric motor response to human motilin and erythromycin.\n\nThe distribution of hMTLR was examined immunohistochemically in male wild-type (WT) and hMTLR-Tg mice. The contractile response of gastric strips was measured isometrically in an organ bath, while gastric emptying was determined using phenol red.\n\nhMTLR expression was abundant in the gastric smooth muscle layer but more potently expressed in the myenteric plexus of hMTLR-Tg mice but not WT mice. hMTLR was not co-localized with vesicular acetylcholine transporter, a marker of cholinergic neurons in the myenteric plexus. Treatment with human motilin and erythromycin caused concentration-dependent contraction of gastric strips obtained from hMTLR-Tg mice but not from WT mice.\n\nThe contractile response to human motilin and erythromycin in hMTLR-Tg mice was affected by neither atropine nor tetrodotoxin and was totally absent in Ca2+-free conditions. Furthermore, intraperitoneal injection of erythromycin significantly promoted gastric emptying in hMTLR-Tg mice but not in WT mice.\n\nHuman motilin and erythromycin stimulate the gastric motor response in hMTLR-Tg mice. This action is mediated by direct contraction of smooth muscle via the influx of extracellular Ca2+. Thus, hMTLR-Tg mice may be useful for the evaluation of MTLR agonists as gastric prokinetic agents.

pharmacology and toxicology

Initiation of droxidopa during hospital admission for management of refractory neurogenic orthostatic hypotension in severely ill patients

IntroductionOrthostatic hypotension (OH) is a common cause of hospitalization, particularly in the elderly. Hospitalized patients with OH are often severely ill, with complex medical comorbidities and high rates of disability. Droxidopa is a norepinephrine precursor approved for the treatment of neurogenic OH (nOH) associated with autonomic failure that is commonly used in the outpatient setting, but there is currently no data regarding the safety and efficacy of droxidopa initiation in medically complex patients.\n\nMethodsWe performed a retrospective review of patients started on droxidopa for refractory nOH while hospitalized at Vanderbilt University Medical Center between October 2014 and May 2017. Primary outcome measures were safety, change in physician global impression of illness severity from admission to discharge, and persistence on medication after 180-day follow-up.\n\nResultsA total of 20 patients were identified through chart review. Patients were medically complex with high rates of cardiovascular comorbidities and a diverse array of underlying autonomic diagnoses. Rapid titration of droxidopa was safe and well-tolerated in this cohort, with no cardiovascular events or new onset arrhythmias. Supine hypertension requiring treatment occurred in four patients. One death occurred during hospital admission due to organ failure associated with end-stage amyloidosis. Treating physicians noted improvements in presyncopal symptoms in 80% of patients. After 6 months, 13 patients (65%) continued on droxidopa therapy.\n\nConclusionIn a retrospective cohort of hospitalized, severely ill patients with refractory nOH, supervised rapid titration of droxidopa was safe and effective. Treatment persistence was high, suggesting that symptomatic benefit extended beyond acute intervention.

pharmacology and toxicology

Exploring the Correlation between the Cognitive Benefits of Drug Combinations in a Clinical Alzheimer Disease Database and the Efficacies of the Same Drug Combinations Predicted from a Computational Model

INTRODUCTIONIdentification of drug combinations that could be effective in Alzheimers treatment is made difficult by the number of possible combinations. This analysis identifies as potentially therapeutic those drug combinations that rank highest when their efficacy is determined jointly from two independent data sources.\n\nMETHODSEstimates of the efficacy of the same drug combinations were derived from a clinical dataset and from pre-clinical data, in the form of a computational model of neuroinflammation. Standard linear regression was used to show that the two sets of estimates were correlated, and to rule out possible confounds.\n\nRESULTSThe ten highest ranking, jointly determined drug combinations most frequently consisted of COX2 inhibitors and aspirin, along with various antihypertensive medications.\n\nDISCUSSIONTen combinations of from five to nine drugs, and the three-drug combination of a COX2 inhibitor, aspirin, and a calcium-channel blocker, are discussed as candidates for consideration in future clinical and pre-clinical studies.

pharmacology and toxicology

Ceftolozane-tazobactam pharmacokinetics during extracorporeal membrane oxygenation in a lung transplant recipient

Ceftolozane-tazobactam pharmacokinetics during extracorporeal membrane oxygenation (ECMO) has not been previously studied. In this work we report on the ceftolozane and tazobactam plasmatic levels in a lung transplant recipient during ECMO, treated with ceftolozane-tazobactam (2g/1g, intravenously every 8 h, 1 h infusion) for a Pseudomonas aeruginosa pulmonary infection. Ceftolozane Cmax and Cmin, monitored during 96 hrs, remained above 60 and 20 g/mL, respectively, with optimal drug exposure (100% %TMIC). Tazobactam levels were above 1.9 g/mL.

pharmacology and toxicology