Solvent Effects on the Chemo- and Site-Selectivity of Transition Metal-Catalyzed Nitrene Transfer Reactions: Alternatives to Chlorinated Solvents

Transition metal-catalyzed, non-enzymatic nitrene transfer (NT) reactions to selectively transform C-H and C=C bonds to new C-N bonds are a powerful strategy to streamline the preparation of valuable amine building blocks. However, many catalysts for these reactions use environmentally unfriendly solvents that include dichloromethane, chloroform, 1,2-dichloroethane and benzene. We developed a high-throughput experimentation (HTE) protocol for heterogeneous NT reaction mixtures to enable rapid screening of a broad range of solvents for this chemistry. Coupled with the American Chemical Society Pharmaceutical Roundtable (ACSPR) solvent tool, we identified several attractive replacements for chlorinated solvents. Selected catalysts for NT were compared and contrasted using our HTE protocol, including silver supported by N-dentate ligands, dinuclear Rh complexes and Fe/Mn phthalocyanine catalysts.

CDC Guidelines for the Prevention and Treatment of Anthrax, 2023

This report updates previous CDC guidelines and recommendations on preferred prevention and treatment regimens regarding naturally occurring anthrax. Also provided are a wide range of alternative regimens to first-line antimicrobial drugs for use if patients have contraindications or intolerances or after a wide-area aerosol release of

Bacillus anthracis spores if resources become limited or a multidrug-resistant B. anthracis strain is used (Hendricks KA, Wright ME, Shadomy SV, et al.; Workgroup on Anthrax Clinical Guidelines. Centers for Disease Control and Prevention expert panel meetings on prevention and treatment of anthrax in adults. Emerg Infect Dis 2014;20:e130687; Meaney-Delman D, Rasmussen SA, Beigi RH, et al. Prophylaxis and treatment of anthrax in pregnant women. Obstet Gynecol 2013;122:885-900; Bradley JS, Peacock G, Krug SE, et al. Pediatric anthrax clinical management. Pediatrics 2014;133:e1411-36). Specifically, this report updates antimicrobial drug and antitoxin use for both postexposure prophylaxis (PEP) and treatment from these previous guidelines best practices and is based on systematic reviews of the literature regarding 1) in vitro antimicrobial drug activity against B. anthracis; 2) in vivo antimicrobial drug efficacy for PEP and treatment; 3) in vivo and human antitoxin efficacy for PEP, treatment, or both; and 4) human survival after antimicrobial drug PEP and treatment of localized anthrax, systemic anthrax, and anthrax meningitis.

Changes from previous CDC guidelines and recommendations include an expanded list of alternative antimicrobial drugs to use when first-line antimicrobial drugs are contraindicated or not tolerated or after a bioterrorism event when first-line antimicrobial drugs are depleted or ineffective against a genetically engineered resistant

B. anthracis strain. In addition, these updated guidelines include new recommendations regarding special considerations for the diagnosis and treatment of anthrax meningitis, including comorbid, social, and clinical predictors of anthrax meningitis. The previously published CDC guidelines and recommendations described potentially beneficial critical care measures and clinical assessment tools and procedures for persons with anthrax, which have not changed and are not addressed in this update. In addition, no changes were made to the Advisory Committee on Immunization Practices recommendations for use of anthrax vaccine (Bower WA, Schiffer J, Atmar RL, et al. Use of anthrax vaccine in the United States: recommendations of the Advisory Committee on Immunization Practices, 2019. MMWR Recomm Rep 2019;68[No. RR-4]:1-14). The updated guidelines in this report can be used by health care providers to prevent and treat anthrax and guide emergency preparedness officials and planners as they develop and update plans for a wide-area aerosol release of B. anthracis.

Mapping the Evidence for Opioid-Mediated Changes in Malignancy and Chemotherapeutic Efficacy: Protocol for a Scoping Review

BACKGROUND

Numerous reports contend opioids can augment or inhibit malignancy. At present, there is no consensus on the risk or benefit posed by opioids on malignancy or chemotherapeutic activity. Distinguishing the consequences of opioid use from pain and its management is challenging. Additionally, opioid concentration data is often lacking in clinical studies. A scoping review approach inclusive of preclinical and clinical data will improve our understanding of the risk-benefit relationship concerning commonly prescribed opioids and cancer and cancer treatment.

OBJECTIVE

The aim of the study is to map diverse studies spanning from preclinical to clinical regarding opioids with malignancy and its treatment.

METHODS

This scoping review will use the Arksey six stages framework to (1) identify the research question; (2) identify relevant studies; (3) select studies meeting criteria; (4) extract and chart data; (5) collate, summarize, and report results; and (6) conduct expert consultation. An initial pilot study was undertaken to (1) parameterize the extent and scale of existing data for an evidence review, (2) identify key factors to be extracted in systematic charting efforts, and (3) assess opioid concentration as a variable for its relevance to the central hypothesis. Six databases will be searched with no filters: MEDLINE, Embase, CINAHL Complete, Cochrane Library, Biological Sciences Collection, and International Pharmaceutical Abstracts. Trial registries will include ClinicalTrials.gov, Cochrane CENTRAL, International Standard Randomised Controlled Trial Number Registry, European Union Clinical Trials Register, and World Health Organization International Clinical Trials Registry. Eligibility criteria will include preclinical and clinical study data on opioids effects on tumor growth or survival, or alteration on the antineoplastic activity of chemotherapeutics. We will chart data on (1) opioid concentration from human subjects with cancer, yielding a "physiologic range" to better interpret available preclinical data; (2) patterns of opioid exposure with disease and treatment-related patient outcomes; and (3) the influence of opioids on cancer cell survival, as well as opioid-related changes to cancer cell susceptibility for chemotherapeutics.

RESULTS

This scoping review will present results in narrative forms as well as with the use of tables and diagrams. Initiated in February 2021 at the University of Utah, this protocol is anticipated to generate a scoping review by August 2023. The results of the scoping review will be disseminated through scientific conference proceedings and presentations, stakeholder meetings, and by publication in a peer-reviewed journal.

CONCLUSIONS

The findings of this scoping review will provide a comprehensive description of the consequences of prescription opioids on malignancy and its treatment. By incorporating preclinical and clinical data, this scoping review will invite novel comparisons across study types that could inform new basic, translational, and clinical studies regarding risks and benefits of opioid use among patients with cancer.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/38167.

Drug exposure during pregnancy: Current understanding and approaches to measure maternal-fetal drug exposure

Prescription drug use is prevalent during pregnancy, yet there is limited knowledge about maternal-fetal safety and efficacy of this drug use because pregnant individuals have historically been excluded from clinical trials. Underrepresentation has resulted in a lack of data available to estimate or predict fetal drug exposure. Approaches to study fetal drug pharmacology are limited and must be evaluated for feasibility and accuracy. Anatomic and physiological changes throughout pregnancy fluctuate based on gestational age and can affect drug pharmacokinetics (PK) for both mother and fetus. Drug concentrations have been studied throughout different stages of gestation and at or following delivery in tissue and fluid biospecimens. Sampling amniotic fluid, umbilical cord blood, placental tissue, meconium, umbilical cord tissue, and neonatal hair present surrogate options to quantify and characterize fetal drug exposure. These sampling methods can be applied to all therapeutics including small molecule drugs, large molecule drugs, conjugated nanoparticles, and chemical exposures. Alternative approaches to determine PK have been explored, including physiologically based PK modeling, in vitro methods, and traditional animal models. These alternative approaches along with convenience sampling of tissue or fluid biospecimens can address challenges in studying maternal-fetal pharmacology. In this narrative review, we 1) present an overview of the current understanding of maternal-fetal drug exposure; 2) discuss biospecimen-guided sampling design and methods for measuring fetal drug concentrations throughout gestation; and 3) propose methods for advancing pharmacology research in the maternal-fetal population.

A Tribute to the Pioneers of Fetal Pharmacology

Clinical pharmacology is a branch of the field of pharmacology that evolved following the recognition that the nature, duration, and intensity of drug action depend on both the intrinsic properties of the drug and an interaction with the host to whom the drug is given. Advances in drug development have placed highly specific and extremely potent therapeutic agents in the marketplace. While these advances have progressed rapidly in adult medicine, pediatric clinical pharmacology has not kept pace and until very recently has lagged behind the research and attention paid to the proper use of therapeutic and diagnostic drugs in adults. Recognition that advances in the science of developmental pharmacology and pediatric clinical pharmacology were essential in the development of new drugs to treat children came in the 1950s and 1960s mostly through the work of 2 pioneering scientists in fetal and perinatal clinical pharmacology, Drs Sumner Yaffe and Bernard Mirkin. Here we pay a tribute to these most influential pioneers in the United States who were instrumental in paving the path for advancing the field of fetal and perinatal pharmacology concepts and their incorporation into pediatric drug development programs.

Treatment optimization of maintenance immunosuppressive agents in pediatric renal transplant recipients

Introduction: Graft survival in pediatric kidney transplant patients has increased significantly within the last three decades, correlating with the discovery and utilization of new immunosuppressants as well as improvements in patient care. Despite these developments in graft survival for patients, there is still improvement needed, particularly in long-term care in pediatric patients receiving grafts from deceased donor patients. Maintenance immunosuppressive therapies have narrow therapeutic indices and are associated with high inter-individual and intra-individual variability.Areas covered: In this review, we examine the impact of pharmacokinetic variability on renal transplantation and its association with age, genetic polymorphisms, drug-drug interactions, drug-disease interactions, renal insufficiency, route of administration, and branded versus generic drug formulation. Pharmacodynamics are outlined in terms of the mechanism of action for each immunosuppressant, potential adverse effects, and the utility of pharmacodynamic biomarkers.Expert opinion: Acquiring abetter quantitative understanding of immunosuppressant pharmacokinetics and pharmacodynamic components should help clinicians implement treatment regimens to maintain the balance between therapeutic efficacy and drug-related toxicity.

Allene Trifunctionalization via Amidyl Radical Cyclization and TEMPO Trapping

Radical-mediated trifunctionalizations of allenes are virtually unknown, in contrast to well-studied radical difunctionalizations of alkenes and alkynes. In this article, we describe a light-promoted reaction that transforms all three allene carbons to new carbon-heteroatom bonds in one pot with no expensive transition-metal catalyst. Formation of an electron donor-acceptor complex between an electron-deficient aryl and K₂CO₃, followed by photochemical generation of an amidyl radical and cyclization, yields a vinyl radical that can be trapped by TEMPO to ultimately furnish the product. Insights into the impact of the allene substitution pattern, radical source, and donor are presented, along with studies to unravel the mechanism of this unusual transformation.

Development of a severity scale to assess chronic lung disease after extremely preterm birth

OBJECTIVE

Chronic lung disease of prematurity (CLDP) is a frequent complication of prematurity. We aimed to identify what clinicians believe are the most important factors determining the severity of CLDP in extremely preterm infants (<28 weeks gestational age) after discharge from the neonatal intensive care unit (NICU) through 12 months corrected age (CA), and to evaluate how these factors should be weighted for scoring, to develop a CLDP severity scale.

STUDY DESIGN

Clinicians completed a three-round online survey utilizing Delphi methodology. Clinicians rated the importance of various factors used to evaluate the severity of CLDP, from 0 (not at all important) to 10 (very important) for the period between discharge home from the NICU and 12 months CA. Fourteen factors were considered in Round 1; 13 in Rounds 2 and 3. The relative importance of factors was explored via a set of 16 single-profile tasks (i.e., hypothetical patient profiles with varying CLDP severity levels).

RESULTS

Overall, 91 clinicians from 11 countries who were experienced in treating prematurity-related lung diseases completed Round 1; 88 completed Rounds 2 and 3. Based on Round 3, the most important factors in determining CLDP severity were mechanical ventilation (mean absolute importance rating, 8.89), supplemental oxygen ≥2 L/min (8.49), rehospitalizations (7.65), and supplemental oxygen <2 L/min (7.56). Single-profile tasks showed that supplemental oxygen had the greatest impact on profile classification.

CONCLUSION

The most important factors for clinicians assigning CLDP severity during infancy were mechanical ventilation, supplemental oxygen ≥2 L/min, and respiratory-related rehospitalizations.

Regioselective Intramolecular Allene Amidation Enabled by an EDA Complex*

The addition of radicals to unsaturated precursors is a powerful tool for the synthesis of both carbo- and heterocyclic organic building blocks. The recent advent of mild ways to generate N-centered radicals has reignited interest in exploiting highly regio-, chemo-, and stereoselective transformations that employ these reactive intermediates. While the additions of aminyl, iminyl, and amidyl radicals to alkenes and alkynes have been well-studied, analogous additions to allenes are scarce. Allenes offer several attractive features, including potential for selective amidation at three distinct sites via judicious choice of precursor or radical source, the opportunity for axial-to-point chirality transfer, and productive trapping of vinyl or allyl radical intermediates to diversify functionality in the products. In this article, we report a regioselective addition of amidyl radicals to allenes to furnish an array of valuable N-heterocycle scaffolds.

Supportive care medications coinciding with chemotherapy among children with hematologic malignancy

Pharmacokinetic (PK) conflicts can arise between supportive care medications (SCM) and chemotherapy in children with hematologic malignancy (HM). In this retrospective study, medical records for children (28 days-18 years) diagnosed with HM and receiving an SCM antimicrobial were collected from a hospital network between 1 May 2000 and 31 December 2014. PK drug-gene associations were obtained from a curated pharmacogenomics database. Among 730 patients (median age of 7.5 (IQR 3.7-13.9) years), primarily diagnosed with lymphoid leukemia (52%), lymphoma (28%), or acute myeloid leukemia (16%), chemotherapy was administered in 2846 hospitalizations. SCM accounted for 90.5% (n = 448) of distinct drugs with 93% (n = 679) of children, receiving ≥5 different SCM/hospitalization. Same-day SCM/chemotherapeutic PK gene overlap occurred in 48.3% of hospitalizations and was associated with age (p = 0.026), number of SCM, HM subtype, surgery, and hematopoietic stem cell transplant (p < 0.0001). A high and variable SCM burden among children with HM receiving chemotherapy poses a risk for unanticipated PK conflicts.

Development of the PREMature Infant Index (PREMII™), a clinician-reported outcome measure assessing functional status of extremely preterm infants

Background: Comprehensive measures to evaluate the effectiveness of medical interventions in extremely preterm infants are lacking. Although length of stay is used as an indicator of overall health among preterm infants in clinical studies, it is confounded by nonmedical factors (e.g. parental readiness and availability of home nursing support).Objectives: To develop the PREMature Infant Index (PREMII^™), an electronic content-valid clinician-reported outcome measure for assessing functional status of extremely preterm infants (<28 weeks gestational age) serially over time in the neonatal intensive care unit. We report the development stages of the PREMII, including suggestions for scoring.Methods: We developed the PREMII according to US Food and Drug Administration regulatory standards. Development included five stages: (1) literature review, (2) clinical expert interviews, (3) Delphi panel survey, (4) development of items/levels, and (5) cognitive interviews/usability testing. Scoring approaches were explored via an online clinician survey.Results: Key factors reflective of functional status were identified by physicians and nurses during development of the PREMII, as were levels within each factor to assess functional status. The resulting PREMII evaluates eight infant health factors: respiratory support, oxygen administration, apnea, bradycardia, desaturation, thermoregulation, feeding, and weight gain, each scored with three to six gradations. Factor levels are standardized on a 0-100 scale; resultant scores are 0-100. No usability issues were identified. The online clinician survey identified optimal scoring methods to capture functional status at a given time point.Conclusions: Our findings support the content validity and usability of the PREMII as a multifunction outcome measure to assess functional status over time in extremely preterm infants. Psychometric validation is ongoing.

Dose-escalation trial of budesonide in surfactant for prevention of bronchopulmonary dysplasia in extremely low gestational age high-risk newborns (SASSIE)

BACKGROUND

Initial trials of lung-targeted budesonide (0.25 mg/kg) in surfactant to prevent bronchopulmonary dysplasia (BPD) in premature infants have shown benefit; however, the optimal safe dose is unknown.

METHODS

Dose-escalation study of budesonide (0.025, 0.05, 0.10 mg/kg) in calfactatant in extremely low gestational age neonates (ELGANs) requiring intubation at 3-14 days. Tracheal aspirate (TA) cytokines, blood budesonide concentrations, and untargeted blood metabolomics were measured. Outcomes were compared with matched infants receiving surfactant in the Trial Of Late SURFactant (TOLSURF).

RESULTS

Twenty-four infants with mean gestational age 25.0 weeks and 743 g birth weight requiring mechanical ventilation were enrolled at mean age 6 days. Budesonide was detected in the blood of all infants with a half-life of 3.4 h. Of 11 infants with elevated TA cytokine levels at baseline, treatment was associated with sustained decrease (mean 65%) at all three dosing levels. There were time- and dose-dependent decreases in blood cortisol concentrations and changes in total blood metabolites. Respiratory outcomes did not differ from the historic controls.

CONCLUSIONS

Budesonide/surfactant had no clinical respiratory benefit at any dosing levels for intubated ELGANs. One-tenth the dose used in previous trials had minimal systemic metabolic effects and appeared effective for lung-targeted anti-inflammatory action.

Mechanistic Aspects and Synthetic Applications of Radical Additions to Allenes

More than 50 years have passed since Haszeldine reported the first addition of a trifluoromethyl radical to an allene; in the intervening years, both the chemistry of allenes and the reactivity of single-electron species have become topics of intense interest. In this Review, we provide an overview of the fundamentals of radical additions to allenes and highlight the emergence of theoretical and experimental evidence that reveals unique reactivity patterns for radical additions to allenes as compared with other unsaturated compounds. Factors capable of exerting control over the chemo-, regio-, and stereoselectivities of the attack of carbon- and heteroatom-based radicals at each of the three potential reactive sites in an allene substrate are described. These include reaction conditions, the nature of the attacking radical, the substitution pattern of the allene, and the length of the linker between the radical center and the proximal allene carbon in the substrate. Cycloaddition reactions between allenes and partners containing π-bonds, which are likely to proceed through radical pathways, are presented to highlight their ability to rapidly access complex polycyclic scaffolds. Finally, the synthetic utility of the products arising from these chemistries is described, including their applications to the construction of complex molecules.

Development of a neonatal adverse event severity scale through a Delphi consensus approach

BACKGROUND

Assessment of the seriousness, expectedness and causality are necessary for any adverse event (AE) in a clinical trial. In addition, assessing AE severity helps determine the importance of the AE in the clinical setting. Standardisation of AE severity criteria could make safety information more reliable and comparable across trials. Although standardised AE severity scales have been developed in other research fields, they are not suitable for use in neonates. The development of an AE severity scale to facilitate the conduct and interpretation of neonatal clinical trials is therefore urgently needed.

METHODS

A stepwise consensus process was undertaken within the International Neonatal Consortium (INC) with input from all relevant stakeholders. The consensus process included several rounds of surveys (based on a Delphi approach), face-to-face meetings and a pilot validation.

RESULTS

Neonatal AE severity was classified by five grades (mild, moderate, severe, life threatening or death). AE severity in neonates was defined by the effect of the AE on age appropriate behaviour, basal physiological functions and care changes in response to the AE. Pilot validation of the generic criteria revealed κ=0.23 and guided further refinement. This generic scale was applied to 35 typical and common neonatal AEs resulting in the INC neonatal AE severity scale (NAESS) V.1.0, which is now publicly available.

DISCUSSION

The INC NAESS is an ongoing effort that will be continuously updated. Future perspectives include further validation and the development of a training module for users.

Antibiotic Treatment of Suspected and Confirmed Neonatal Sepsis Within 28 Days of Birth: A Retrospective Analysis

Neonatal sepsis causes significant mortality and morbidity worldwide. Diagnosis is usually confirmed via blood culture results. Blood culture sepsis confirmation can take days and suffer from contamination and false negatives. Empiric therapy with antibiotics is common. This study aims to retrospectively describe and compare treatments of blood culture-confirmed and unconfirmed, but suspected, sepsis within the University of Utah Hospital system. Electronic health records were obtained from 1,248 neonates from January 1, 2006, to December 31, 2017. Sepsis was categorized into early-onset (≤3 days of birth, EOS) and late-onset (>3 and ≤28 days of birth, LOS) and categorized as culture-confirmed sepsis if a pathogen was cultured from the blood and unconfirmed if all blood cultures were negative with no potentially contaminated blood cultures. Of 1,010 neonates in the EOS cohort, 23 (2.3%) were culture-confirmed, most with Escherichia coli (42%). Treatment for unconfirmed EOS lasted an average of 6.1 days with primarily gentamicin and ampicillin while confirmed patients were treated for an average of 12.3 days with increased administration of cefotaxime. Of 311 neonates in the LOS cohort, 62 (20%) were culture-confirmed, most culturing coagulase negative staphylococci (46%). Treatment courses for unconfirmed LOS lasted an average of 7.8 days while confirmed patients were treated for an average of 11.4 days, these patients were primarily treated with vancomycin and gentamicin. The use of cefotaxime for unconfirmed EOS and LOS increased throughout the study period. Cefotaxime administration was associated with an increase in neonatal mortality, even when potential confounding factors were added to the logistic regression model (adjusted odds ratio 2.8, 95%CI [1.21, 6.88], p = 0.02). These results may not be generalized to all hospitals and the use of cefotaxime may be a surrogate for other factors. Given the low rate of blood culture positive diagnosis and the high exposure rate of empiric antibiotics, this patient population might benefit from improved diagnostics with reevaluation of antibiotic use guidelines.

Development of a neonatal adverse event severity scale through a Delphi consensus approach

BACKGROUND

Assessment of the seriousness, expectedness and causality are necessary for any adverse event (AE) in a clinical trial. In addition, assessing AE severity helps determine the importance of the AE in the clinical setting. Standardisation of AE severity criteria could make safety information more reliable and comparable across trials. Although standardised AE severity scales have been developed in other research fields, they are not suitable for use in neonates. The development of an AE severity scale to facilitate the conduct and interpretation of neonatal clinical trials is therefore urgently needed.

METHODS

A stepwise consensus process was undertaken within the International Neonatal Consortium (INC) with input from all relevant stakeholders. The consensus process included several rounds of surveys (based on a Delphi approach), face-to-face meetings and a pilot validation.

RESULTS

Neonatal AE severity was classified by five grades (mild, moderate, severe, life threatening or death). AE severity in neonates was defined by the effect of the AE on age appropriate behaviour, basal physiological functions and care changes in response to the AE. Pilot validation of the generic criteria revealed κ=0.23 and guided further refinement. This generic scale was applied to 35 typical and common neonatal AEs resulting in the INC neonatal AE severity scale (NAESS) V.1.0, which is now publicly available.

DISCUSSION

The INC NAESS is an ongoing effort that will be continuously updated. Future perspectives include further validation and the development of a training module for users.

Pediatric Age Groups and Approach to Studies

Pediatric clinical trials are often requested according to specific age ranges. In the past and still today, these ages may correspond to developmental stages, such as newborn, infancy, childhood, and adolescence. Selection of ages for pediatric participation in medication studies should correspond to ages of rapid changes in pharmacokinetics and pharmacodynamics. Age-related changes in several enzymes involved in drug metabolism and glomerular filtration are described as examples of optimal ages for study of specific drugs according to their pathways of disposition.

Principles of Pharmacokinetics in the Pregnant Woman and Fetus

Pregnancy profoundly alters a woman's physiology. These changes alter drug absorption, distribution, metabolism, and elimination and emphasize the pharmacologic complexity of pregnancy. They also emphasize the dangers of extrapolating pharmacologic expectations from nonpregnant populations to pregnant women and their fetuses. Although concerns about fetal safety have historically limited pharmacokinetic studies during pregnancy, it is important to recognize that many medications are clinically indicated for various maternal or fetal conditions, and it is particularly important that these therapies be evidence-based with appropriate study, including short-term and long-term outcomes data.

Pharmacometrics in Pediatrics

Pharmacometrics have advanced from compartmental analysis to noncompartmental analysis and population pharmacokinetics that require complicated mathematical programs. These sophisticated mathematical analyses determine not only the usual pharmacometric measures of clearance and volume of distribution but also the effects of covariates on these measures. Although these analyses are very suitable to studies of small patient populations often encountered in pediatric studies, most pediatric clinicians have not been trained in how these analyses are conducted or the meaning of the results of these analyses expressed in terms of error measures and fixed and variable effects. In addition, clinicians may not be able to evaluate whether their patient population is adequately represented in the analysis. Thorough and clear descriptions of the methodology and the strengths and weaknesses of these analyses need to be published in journals read by clinicians.

Administration of Inhaled Pulmonary Vasodilators to the Mechanically Ventilated Neonatal Patient

Pulmonary hypertension is a life-threatening condition that affects people of all ages that can occur as an idiopathic disorder at birth or as part of a variety of cardiovascular and infectious disorders. It is commonly treated with inhaled pulmonary vasodilators such as nitric oxide and less frequently using formulations and analogs of prostacyclin. To minimize systemic effects and preserve pulmonary vasodilation, vasodilators are often administered directly into the airway. Nitric oxide is the only USA Food and Drug Administration-approved inhaled pulmonary vasodilator that can be used during mechanical ventilation. Over the past two decades, interest has grown in the use of aerosolized prostacyclin and prostacyclin analogs for the treatment of pulmonary hypertension during mechanical ventilation. Clinicians who administer inhaled prostacyclin may not have a clear understanding of its risks because of the lack of data from large clinical trials examining safety and efficacy; moreover, its safe use remains poorly documented. The off-label use of drugs is legitimate, but prescribers must recognize the potential complications and liability in doing so. This manuscript aims to address potential problems related to the aerosol administration of pulmonary vasodilators in the mechanically ventilated neonatal patient.

Pharmacokinetics of Budesonide Administered with Surfactant in Premature Lambs: Implications for Neonatal Clinical Trials

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of premature human infants, which may persist through adulthood. Airway inflammation has been firmly established in the pathogenesis of BPD. Previous studies to reduce airway inflammation with high-dose dexamethasone demonstrated adverse neurological outcomes, despite lower incidences of BPD. Instillation of budesonide and surfactant can facilitate early extubation and reduce the incidence of BPD and death among very low birth weight infants. However, the pharmacokinetics of budesonide and its distribution into the lung and brain are unknown. Therefore, 5 premature lambs were administered 0.25 mg/kg budesonide, with surfactant as the vehicle. Plasma and tissue samples were taken from the lambs for measurement of budesonide, 16α- hydroxy prednisolone, and budesonide palmitate using LC/MS/MS. Peak plasma budesonide concentrations were inversely correlated with the oxygenation index (correlation coefficient of -0.75). plasma budesonide concentrations were extremely low (~10% of expected) for two lambs that had high oxygenation indices and were excluded from further analyses. For the remaining 5 premature lambs, a non-compartmental analysis demonstrated an AUCinf of 148.77 ± 28.16 h*μg/L, half-life of 4.76 ± 1.79 h, and Cmax of 46.17 ± 17.71 µg/L. Using population pharmacokinetic methods, a onecompartment model with exponential residual error and first-order absorption adequately described the data. The apparent clearance and apparent volume of distribution of budesonide were estimated at 6.29 L/h (1.99 L/h/kg) and 29.1 L (9.2 L/kg), respectively. Budesonide and budesonide palmitate, but not 16α-hydroxy prednisolone, were detected in lung tissue. In this study, budesonide and its metabolites were not detected in the brain, which suggests that intratracheal instillation suggests that after local pulmonary deposition, there is no evidence of budesonide accumulation in the central nervous system. Overall, these results show that peak plasma budesonide concentrations are inversely correlated with the oxygenation index and that lung-specific delivery of budesonide avoids accumulation of budesonide in the brain.

Characterization of Transient Receptor Potential Vanilloid-1 (TRPV1) Variant Activation by Coal Fly Ash Particles and Associations with Altered Transient Receptor Potential Ankyrin-1 (TRPA1) Expression and Asthma

Transient receptor potential (TRP) channels are activated by environmental particulate materials. We hypothesized that polymorphic variants of transient receptor potential vanilloid-1 (TRPV1) would be uniquely responsive to insoluble coal fly ash compared with the prototypical soluble agonist capsaicin. Furthermore, these changes would manifest as differences in lung cell responses to these agonists and perhaps correlate with changes in asthma symptom control. The TRPV1-I315M and -T469I variants were more responsive to capsaicin and coal fly ash. The I585V variant was less responsive to coal fly ash particles due to reduced translation of protein and an apparent role for Ile-585 in activation by particles. In HEK-293 cells, I585V had an inhibitory effect on wild-type TRPV1 expression, activation, and internalization/agonist-induced desensitization. In normal human bronchial epithelial cells, IL-8 secretion in response to coal fly ash treatment was reduced for cells heterozygous for TRPV1-I585V. Finally, both the I315M and I585V variants were associated with worse asthma symptom control with the effects of I315M manifesting in mild asthma and those of the I585V variant manifesting in severe, steroid-insensitive individuals. This effect may be due in part to increased transient receptor potential ankyrin-1 (TRPA1) expression by lung epithelial cells expressing the TRPV1-I585V variant. These findings suggest that specific molecular interactions control TRPV1 activation by particles, differential activation, and desensitization of TRPV1 by particles and/or other agonists, and cellular changes in the expression of TRPA1 as a result of I585V expression could contribute to variations in asthma symptom control.

Population Pharmacokinetics of Darbepoetin Alfa in Conjunction with Hypothermia for the Treatment of Neonatal Hypoxic-Ischemic Encephalopathy

AIM

The aim of this study was to determine the population pharmacokinetics of darbepoetin alfa in hypothermic neonates with hypoxic-ischemic encephalopathy treated with hypothermia.

METHODS

Neonates ≥36 weeks gestation and <12 h postpartum with moderate to severe hypoxic-ischemic encephalopathy who were undergoing hypothermia treatment were recruited in this randomized, multicenter, investigational, new drug pharmacokinetic study. Two intravenous darbepoetin alfa treatment groups were evaluated: 2 and 10 µg/kg. Serum erythropoietin concentrations were measured using an enzyme-linked immunosorbent assay. Monolix 4.3.1 was used to estimate darbepoetin alfa clearance and volume of distribution. Covariates tested included: birthweight, gestational age, postnatal age, postmenstrual age, sex, Sarnat score, and study site.

RESULTS

Darbepoetin alfa pharmacokinetics were well described by a one-compartment model with exponential error. Clearance and the volume of distribution were scaled by birthweight (centered on the mean) a priori. Additionally, gestational age (also centered on the mean) significantly affected darbepoetin alfa clearance. Clearance and volume of distribution were estimated as 0.0465 L/h (95% confidence interval 0.0392-0.0537) and 1.58 L (95% confidence interval 1.29-1.87), respectively.

CONCLUSIONS

A one-compartment model successfully described the pharmacokinetics of darbepoetin alfa among hypothermic neonates treated for hypoxic-ischemic encephalopathy. Clearance decreased with increasing gestational age.

Incorporating pharmacodynamic considerations into caffeine therapeutic drug monitoring in preterm neonates

Background

This study sought to assess the pharmacokinetic and pharmacodynamic relationships of caffeine citrate therapy in preterm neonates who had therapeutic drug monitoring (TDM) in the post-extubation period.

Methods

A retrospective observational study was conducted in preterm neonates who received caffeine citrate therapy for apnea of prematurity and had TDM done in the post-extubation period between January 2006 and October 2011. The relationships between pharmacodynamic effects (heart rate, respiratory rate, episodes of apnea, adverse events) and caffeine serum concentrations were explored.

Results

A total of 177 blood samples were obtained from 115 preterm neonates with a median (range) gestational age of 29 (24 – 33) weeks and birth weight of 1230 (607 – 2304) kg. Caffeine citrate therapy was initiated at a median (interquartile range) postnatal age of 1 (1 – 3) day and TDM was performed at a postnatal age of 15 (10 – 24) days. No direct correlations were found between respiratory rate or apneic episodes and caffeine serum concentrations; however, heart rate and caffeine serum concentrations were significantly correlated (p < 0.05). Dosing regimen of 40/5 mg/kg q12h (loading dose/maintenance dose, time interval) led to similar endotracheal re-intubation rate but increased percentage of patients experiencing tachycardia compared to the standard regimen of 20/5 mg/kg q24h (44.7 % vs 10.2 %, p < 0.001).

Conclusion

Based on this retrospective study, no correlation between episodes of apnea and caffeine serum concentrations was found in neonates who had TDM of caffeine citrate therapy in the post-extubation period, whereas a significant association between tachycardia and concentrations existed. Notwithstanding the absence of severe adverse reactions, TDM should be considered in critically ill neonates with unexplained adverse effects, such as tachycardia.

Electronic supplementary material

The online version of this article (doi:10.1186/s40360-016-0065-x) contains supplementary material, which is available to authorized users.

Salivary caffeine concentrations are comparable to plasma concentrations in preterm infants receiving extended caffeine therapy

AIMS

Caffeine concentrations in preterm infants are usually measured in the blood. However, salivary assays may provide a valid and practical alternative. The present study explored the validity and clinical utility of salivary caffeine concentrations as an alternative to blood concentrations and developed a novel plasma/salivary caffeine distribution model.

METHODS

Paired salivary and plasma samples were obtained in 29 infants. Salivary samples were obtained using a commercially available salivary collection system. Caffeine concentrations in the saliva and plasma were determined using high-performance liquid chromatography. A population pharmacokinetic (PK) model was developed using NONMEM 7.3.

RESULTS

The mean (± standard deviation) gestational age (GA) at birth and birth weight were 27.9 ± 2.1 weeks and 1171.6 ± 384.9 g, respectively. Paired samples were obtained at a mean postmenstrual age (PMA) of 35.5 ± 1.1 weeks. The range of plasma caffeine concentrations was 9.5-54.1 μg ml(-1) , with a mean difference (95% confidence interval) between plasma and salivary concentrations of -0.18 μg ml(-1) (-1.90, 1.54). Salivary and plasma caffeine concentrations were strongly correlated (Pearson's correlation coefficient = 0.87, P < 0.001). Caffeine PK in plasma and saliva was simultaneously described by a three-compartment recirculation model. Current body weight, birth weight, GA, PMA and postnatal age were not significantly correlated with any PK parameter.

CONCLUSIONS

Salivary sampling provides an easy, non-invasive method for measuring caffeine concentrations. Salivary concentrations correlate highly with plasma concentrations. Caffeine PK in saliva and plasma are well described by a three-compartment recirculation model.

A propensity-matched cohort study of vancomycin-associated nephrotoxicity in neonates

BACKGROUND

The incidence of nephrotoxicity among vancomycin-treated neonates has been reported to range from 2% to 20%. These widely varying estimates have led to confusion and controversy regarding the safety of vancomycin among neonates.

OBJECTIVE

Evaluate the incidence of nephrotoxicity among neonates receiving vancomycin concomitantly with gentamicin.

DESIGN

Retrospective observational cohort study using propensity score matching to provide covariate balance between neonates who did or did not receive vancomycin based on factors known to be related to the development of renal dysfunction.

SETTING

Hospitals (n=22) throughout the Intermountain West, including a quaternary care children's hospital.

PATIENTS

Neonates ≤44 postmenstrual weeks (median gestational age: 31 (IQR 28-36) weeks) receiving intravenous gentamicin with or without exposure to vancomycin from January 2006 to December 2012.

MAIN OUTCOME MEASURES

Nephrotoxicity based on the modified Acute Kidney Injury Network criteria for acute kidney injury (AKI) or serum creatinine concentration ≥1.5 mg/dL persisting for ≥48 h.

RESULTS

The final cohort was comprised of 1066 neonates (533 receiving vancomycin and gentamicin vs 533 receiving gentamicin). In a propensity score-matched cohort that was well balanced across 16 covariates, AKI was not associated with vancomycin use (16 neonates receiving vancomycin vs 7 controls experienced AKI; OR 1.5; 95% CI 0.6 to 4.0). However, the presence of a patent ductus arteriosus, concomitant non-steroidal anti-inflammatory drug use, ≥1 positive blood cultures, low birth weight and higher severity of illness and risk of mortality scores were associated with an increased risk of nephrotoxicity.

CONCLUSIONS

These results corroborate several earlier reports and much anecdotal evidence describing the infrequent occurrence of nephrotoxicity in neonates receiving concomitant vancomycin and gentamicin.

Activation of Transient Receptor Potential Ankyrin-1 by Insoluble Particulate Material and Association with Asthma

Inhaled irritants activate transient receptor potential ankyrin-1 (TRPA1), resulting in cough, bronchoconstriction, and inflammation/edema. TRPA1 is also implicated in the pathogenesis of asthma. Our hypothesis was that particulate materials activate TRPA1 via a mechanism distinct from chemical agonists and that, in a cohort of children with asthma living in a location prone to high levels of air pollution, expression of uniquely sensitive forms of TRPA1 may correlate with reduced asthma control. Variant forms of TRPA1 were constructed by mutating residues in known functional elements and corresponding to single-nucleotide polymorphisms in functional domains. TRPA1 activity was studied in transfected HEK-293 cells using allyl-isothiocynate, a model soluble electrophilic agonist; 3,5-ditert butylphenol, a soluble nonelectrophilic agonist and a component of diesel exhaust particles; and insoluble coal fly ash (CFA) particles. The N-terminal variants R3C and R58T exhibited greater, but not additive, activity with all three agonists. The ankyrin repeat domain-4 single nucleotide polymorphisms E179K and K186N exhibited decreased response to CFA. The predicted N-linked glycosylation site residues N747A and N753A exhibited decreased responses to CFA, which were not attributable to differences in cellular localization. The pore-loop residue R919Q was comparable to wild-type, whereas N954T was inactive to soluble agonists but not CFA. These data identify roles for ankyrin domain-4, cell surface N-linked glycans, and selected pore-loop domain residues in the activation of TRPA1 by insoluble particles. Furthermore, the R3C and R58T polymorphisms correlated with reduced asthma control for some children, which suggest that TRPA1 activity may modulate asthma, particularly among individuals living in locations prone to high levels of air pollution.

Inositol Analysis by HPLC and Its Stability in Scavenged Sample Conditions

Inositol is a 6-carbon sugar alcohol that has been shown in limited studies to reduce retinopathy of prematurity and chronic lung disease in premature newborns. Developmentally it has a high concentration in the fetus that decreases with gestational age. It is transported from the fetus to the mother across the placenta. Although studies are underway to determine inositol kinetics in premature newborns treated therapeutically, the effects of gestational age, age after birth, and feeding on inositol concentrations after birth have not been studied adequately in premature newborns. Such studies would minimize blood removal and trauma in preterm newborns by using plasma samples scavenged from the clinical laboratory to measure inositol after birth, if they remain stable. This report describes a new high pressure liquid chromatographic assay for inositol and its use to study the stability of inositol in conditions of storage that might be encountered within the clinical laboratory. The assay is linear from 0 to 1000 Mm with a lower limit of quantitation of 50 μM. Inositol in human plasma remains stable in refrigeration and at room temperature for up to 14 days and is not affected by storage in red blood cells that are intact or lysed. Anticoagulants encountered in clinical blood samples do not interfere with the chromatograms. Thus, it is feasible to measure the changes in inositol concentrations in plasma from preterm newborns that is scavenged from the clinical laboratory after storage for as long as 14 days.

Darbepoetin administration to neonates undergoing cooling for encephalopathy: a safety and pharmacokinetic trial

BACKGROUND

Despite therapeutic hypothermia, neonates with encephalopathy (NE) have high rates of death or disability. Darbepoetin alfa (Darbe) has comparable biological activity to erythropoietin, but has extended circulating half-life (t(1/2)). Our aim was to determine Darbe safety and pharmacokinetics as adjunctive therapy to hypothermia.

STUDY DESIGN

Thirty infants (n = 10/arm) ≥36 wk gestation undergoing therapeutic hypothermia for NE were randomized to receive placebo, Darbe low dose (2 μg/kg), or high dose (10 μg/kg) given intravenously within 12 h of birth (first dose/hypothermia condition) and at 7 d (second dose/normothermia condition). Adverse events were documented for 1 mo. Serum samples were obtained to characterize Darbe pharmacokinetics.

RESULTS

Adverse events (hypotension, altered liver and renal function, seizures, and death) were similar to placebo and historical controls. Following the first Darbe dose at 2 and 10 μg/kg, t(1/2) was 24 and 32 h, and the area under the curve (AUC(inf)) was 26,555 and 180,886 h*mU/ml*, respectively. In addition, clearance was not significantly different between the doses (0.05 and 0.04 l/h). At 7 d, t(1/2) was 26 and 35 h, and AUC(inf) was 10,790 and 56,233 h*mU/ml*, respectively (*P < 0.01).

CONCLUSION

Darbe combined with hypothermia has similar safety profile to placebo with pharmacokinetics sufficient for weekly administration.

Optimal design in pediatric pharmacokinetic and pharmacodynamic clinical studies

It is not trivial to conduct clinical trials with pediatric participants. Ethical, logistical, and financial considerations add to the complexity of pediatric studies. Optimal design theory allows investigators the opportunity to apply mathematical optimization algorithms to define how to structure their data collection to answer focused research questions. These techniques can be used to determine an optimal sample size, optimal sample times, and the number of samples required for pharmacokinetic and pharmacodynamic studies. The aim of this review is to demonstrate how to determine optimal sample size, optimal sample times, and the number of samples required from each patient by presenting specific examples using optimal design tools. Additionally, this review aims to discuss the relative usefulness of sparse vs rich data. This review is intended to educate the clinician, as well as the basic research scientist, whom plan on conducting a pharmacokinetic/pharmacodynamic clinical trial in pediatric patients.

The pharmacokinetics of methadone and its metabolites in neonates, infants, and children

BACKGROUND

The lack of methadone pharmacokinetic data in children and neonates restrains dosing to achieve the target concentration in these populations. A minimum effective analgesic concentration of methadone in opioid naïve adults is 0.058 mg·l(-1) , while no withdrawal symptoms were observed in neonates suffering opioid withdrawal if plasma concentrations of methadone were above 0.06 mg·l(-1) . The racemate of methadone which is commonly used in pediatric and anesthetic care is metabolized to 2-ethylidine-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) and 2-ethyl-5-methyl-3,3-diphenylpyrroline (EMDP).

METHODS

Data from four studies (age 33-week PMA-15 years) were pooled (n = 56) for compartment analysis using nonlinear mixed effects modeling. Parameter estimates were standardized to a 70-kg person using an allometric model approach. Investigation was made of the racemate and metabolite (EDDP and EMDP) dispositions. In addition, neonatal data (n = 7) allowed further study of R- and S-enantiomer pharmacokinetics.

RESULTS

A three-compartment linear disposition model best described the observed time-concentration profiles with additional compartments for metabolites. Population parameter estimates (between-subject variability) were central volume (V1) 21.5 (29%) l.70 kg(-1) , peripheral volumes of distribution V2 75.1 (23%) l.70 kg(-1) and V3 484 (8%) l.70 kg(-1) , clearance (CL) 9.45 (11%) l·h(-1) .70 kg(-1) , and intercompartment clearances Q2 325 (21%) l·h(-1) .70 kg(-1) and Q3 136 (14%) l·h(-1) .70 kg(-1) . EDDP formation clearance was 9.1 (11%) l·h(-1) .70 kg(-1) , formation clearance of EMDP from EDDP 7.4 (63%) l·h(-1) .70 kg(-1) , elimination clearance of EDDP was 40.9 (26%) l·h(-1) .70 kg(-1) and the rate constant for intermediate compartments 2.17 (43%) h(-1) .

CONCLUSIONS

Current pharmacokinetic parameter estimates in children and neonates are similar to those reported in adults. There was no clearance maturation with age. Neonatal enantiomer clearances were similar to those described in adults. A regimen of 0.2 mg·kg(-1) per 8 h in neonates achieves a target concentration of 0.06 mg·l(-1) within 36 h. Infusion, rather than intermittent dosing, should be considered if this target is to be achieved in older children after cardiac surgery.

Pharmacokinetics and safety of a single intravenous dose of myo-inositol in preterm infants of 23-29 wk

BACKGROUND

Myo-inositol given to preterm infants with respiratory distress has reduced death, increased survival without bronchopulmonary dysplasia, and reduced severe retinopathy of prematurity in two randomized trials. Pharmacokinetic (PK) studies in extremely preterm infants are needed before efficacy trials.

METHODS

Infants born in 23-29 wk of gestation were randomized to a single intravenous (i.v.) dose of inositol at 60 or 120 mg/kg or placebo. Over 96 h, serum levels (sparse sampling population PK) and urine inositol excretion were determined. Population PK models were fit using a nonlinear mixed-effects approach. Safety outcomes were recorded.

RESULTS

A single-compartment model that included factors for endogenous inositol production, allometric size based on weight, gestational age strata, and creatinine clearance fit the data best. The central volume of distribution was 0.5115 l/kg, the clearance was 0.0679 l/kg/h, endogenous production was 2.67 mg/kg/h, and the half-life was 5.22 h when modeled without the covariates. During the first 12 h, renal inositol excretion quadrupled in the 120 mg/kg group, returning to near-baseline value after 48 h. There was no diuretic side effect. No significant differences in adverse events occurred among the three groups (P > 0.05).

CONCLUSION

A single-compartment model accounting for endogenous production satisfactorily described the PK of i.v. inositol.

Regulation of CYP3A genes by glucocorticoids in human lung cells

Inhaled glucocorticoids are the first-line treatment for patients with persistent asthma.  However, approximately thirty percent of patients exhibit glucocorticoid insensitivity, which may involve excess metabolic clearance of the glucocorticoids by CYP3A enzymes in the lung.  CYP3A4, 3A5, and 3A7 enzymes metabolize glucocorticoids, which in turn induce CYP3A genes.  However, the mechanism of CYP3A5 mRNA regulation by glucocorticoids in lung cells has not been determined.  In hepatocytes, glucocorticoids bind to the glucocorticoid receptor (GR), which induces the expression of the constitutive androstane receptor or pregnane X receptor; both of which bind to the retinoid X receptor alpha, leading to the induction of CYP3A4, 3A5, and 3A7.  There is also evidence to suggest a direct induction of CYP3A5 by GR activation in liver cells. In this study, these pathways were evaluated as the mechanism for CYP3A5 mRNA induction by glucocorticoids in freshly isolated primary tracheal epithelial, adenocarcinomic human alveolar basal epithelial (A549), immortalized bronchial epithelial (BEAS-2B), primary normal human bronchial/tracheal epithelial (NHBE), primary small airway epithelial (SAEC), and primary lobar epithelial lung cells. In A549 cells, beclomethasone 17-monopropionate ([M1]) induced CYP3A5 mRNA through the glucocorticoid receptor. CYP3A5 mRNA induction by five different glucocorticoids was attenuated by inhibiting the glucocorticoid receptor using ketoconazole, and for beclomethasone dipropionate, using siRNA-mediated knock-down of the glucocorticoid receptor. The constitutive androstane receptor was not expressed in lung cells. SAEC cells, a primary lung cell line, expressed CYP3A5, but CYP3A5 mRNA was not induced by glucocorticoid treatment despite evaluating a multitude of cell culture conditions. None of the other lung cells expressed CYP3A4, 3A5 or 3A7 mRNA. These studies demonstrate that CYP3A5 mRNA is induced by glucocorticoids in A549 cells via the glucocorticoid receptor, but that additional undefined regulatory processes exist in primary lung cells.

Fluticasone propionate pharmacogenetics: CYP3A4*22 polymorphism and pediatric asthma control

OBJECTIVE

To determine the relationship between allelic variations in genes involved in fluticasone propionate (FP) metabolism and asthma control among children with asthma managed with inhaled FP.

STUDY DESIGN

The relationship between variability in asthma control scores and genetic variation in drug metabolism was assessed by genotyping 9 single nucleotide polymorphisms in the CYP3A4, CYP3A5, and CYP3A7 genes. Genotype information was compared with asthma control scores (0=well controlled to 15=poorly controlled), determined using a questionnaire modified from the National Heart Lung and Blood Institute's Expert Panel 3 guidelines.

RESULTS

Our study cohort comprised 734 children with asthma (mean age, 8.8±4.3 years) and was predominantly male (61%) and non-Hispanic white (53%). More than one-half of the children (56%; n=413) were receiving an inhaled glucocorticoid daily, with FP the most frequently prescribed agent (65%). Among the children receiving daily FP, single nucleotide polymorphisms in CYP3A5 and CYP3A7 were not associated with asthma control scores. In contrast, asthma control scores were significantly improved in the 20 children (7%) with the CYP3A4*22 allele (median, 3; range, 0-6) compared with the 201 children without the CYP3A4*22 allele (median, 4; range, 0-15; P=.02). The presence of CYP3A4*22 was associated with improved asthma control scores by 2.1 points (95% CI, 0.5-3.8).

CONCLUSION

The presence of CYP3A4*22, which is associated with decreased hepatic CYP3A4 expression and activity, was accompanied by improved asthma control in the FP-treated children. Decreased CYP3A4 activity may improve asthma control with inhaled FP.

Effect of decreased parenteral soybean lipid emulsion on hepatic function in infants at risk for parenteral nutrition-associated liver disease: a pilot study

PURPOSE

We performed a pilot trial to compare reduced dose versus standard soybean lipid emulsion in neonates at risk for parenteral nutrition-associated liver disease.

METHODS

A prospective randomized controlled trial was performed (2009-2011) enrolling surgical patients ≥ 26 weeks' gestation anticipated to require >50% of daily caloric intake from parenteral nutrition (PN) for at least 4 weeks. Randomization occurred into either reduced (1.0 g/kg/day) or standard (3g/kg/day) groups. Co-primary outcomes for interpretation of the results were conjugated bilirubin and total bile acids. Additional outcomes included ALT, AST, GGT, alkaline phosphatase, growth, and essential fatty acid levels. Outcomes were compared between treatment groups using Wilcoxon rank sums tests.

RESULTS

Twenty-eight patients (47% enrollment rate) were included in the study with an average treatment duration of 5.4 weeks. Groups had similar PN calories and protein intake throughout the study. Total increase from baseline was smaller in the reduced vs. standard group for conjugated bilirubin (p=0.04) and total bile acids (p=0.02). Weight z-score increased more in the standard group, and no patient experienced essential fatty acid deficiency.

CONCLUSION

Markers of cholestasis rose at a slower rate using reduced lipid doses. This pilot study demonstrates feasibility and need for a larger study evaluating the effects of reduced lipids in patients at risk for developing parenteral nutrition-associated liver disease.

Characteristics of antimicrobial studies registered in the USA through ClinicalTrials.Gov

Increasing rates of antimicrobial-resistant infections and the dwindling pipeline of new agents necessitate judicious, evidence-based antimicrobial prescribing. Clinical trials represent a vital resource for establishing evidence of safety and efficacy, which are crucial to guiding antimicrobial treatment decisions. The objective of this study was to comprehensively evaluate the characteristics of antimicrobial research studies registered in ClinicalTrials.gov. Primary outcome measures, funding sources, inclusion criteria and the reporting of study results were evaluated for 16055 antimicrobial studies registered in ClinicalTrials.gov as of mid 2012. Interventional studies accounted for 93% of registered antimicrobial studies. Clinical trials of drugs (82%) and biologics (9%) were most common. Antibacterial, antiviral and antifungal studies accounted for 43%, 41% and 16% of drug trials, respectively. Among interventional drug trials, 73% featured randomised allocation to study arms and 71% included measures of safety and/or efficacy as primary endpoints. Children were eligible for enrolment in 26% of studies. Among the studies, 60% were sponsored primarily by non-profit organisations, 30% by industry and 10% by the federal government. Only 7% of studies reported results; however, 71% of these were sponsored primarily by industry. Antimicrobial studies commonly incorporated elements of high-quality trial design, including randomisation and safety/efficacy endpoints. Publication of study results and updating of ClinicalTrials.gov should be encouraged for all studies, with particular attention paid to research sponsored by non-profit organisations and governmental agencies. Leveraging the application of these data to guide the careful selection of antimicrobial agents will be essential to preserve their utility for years to come.

Metabolism of beclomethasone dipropionate by cytochrome P450 3A enzymes

Inhaled glucocorticoids, such as beclomethasone dipropionate (BDP), are the mainstay treatment of asthma. However, ≈ 30% of patients exhibit little to no benefit from treatment. It has been postulated that glucocorticoid resistance, or insensitivity, is attributable to individual differences in glucocorticoid receptor-mediated processes. It is possible that variations in cytochrome P450 3A enzyme-mediated metabolism of BDP may contribute to this phenomenon. This hypothesis was explored by evaluating the contributions of CYP3A4, 3A5, 3A7, and esterase enzymes in the metabolism of BDP in vitro and relating metabolism to changes in CYP3A enzyme mRNA expression via the glucocorticoid receptor in lung and liver cells. CYP3A4 and CYP3A5 metabolized BDP via hydroxylation ([M4] and [M6]) and dehydrogenation ([M5]) at similar rates; CYP3A7 did not metabolize BDP. A new metabolite [M6], formed by the combined action of esterases and CYP3A4 hydroxylation, was also characterized. To validate the results observed using microsomes and recombinant enzymes, studies were also conducted using A549 lung and DPX2 liver cells. Both liver and lung cells produced esterase-dependent metabolites [M1-M3], with [M1] correlating with CYP3A5 mRNA induction in A549 cells. Liver cells produced both hydroxylated and dehydrogenated metabolites [M4, M5, and M6], but lung cells produced only the dehydrogenated metabolite [M5]. These studies show that CYP3A4 and CYP3A5 metabolize BDP to inactive metabolites and suggest that differences in the expression or function of these enzymes in the lung and/or liver could influence BDP disposition in humans.

An algorithm to detect adverse drug reactions in the neonatal intensive care unit

Critically ill newborns in neonatal intensive care units (NICUs) are at greater risk of developing adverse drug reactions (ADRs). Differentiation of ADRs from reactions associated with organ dysfunction/immaturity is difficult. Current ADR algorithm scoring was established arbitrarily without validation in infants. The study objective was to develop a valid and reliable algorithm to identify ADRs in the NICU. Algorithm development began with a 24-item questionnaire for data collection on 100 previously suspected ADRs. Five pediatric pharmacologists independently rated cases as definite, probable, possible, and unlikely ADRs. Consensus "gold standard" was reached via teleconference. Logistic regression and iterative C programs were used to derive the scoring system. For validation, 50 prospectively collected ADR cases were assessed by 3 clinicians using the new algorithm and the Naranjo algorithm. Weighted kappa and intraclass correlation coefficient (ICC) were used to compare validity and reliability of algorithms. The new algorithm consists of 13 items. Kappa and ICC of the new algorithm were 0.76 and 0.62 versus 0.31 and 0.43 for the Naranjo algorithm. The new algorithm developed using actual patient data is more valid and reliable than the Naranjo algorithm for identifying ADRs in the NICU population. Because of the relatively small and nonrandom samples, further refinement and additional testing are needed.

Proton pump inhibitors in pediatrics : mechanism of action, pharmacokinetics, pharmacogenetics, and pharmacodynamics

Proton pump inhibitors (PPIs) have become some of the most frequently prescribed medications for treatment of adults and children. Their effectiveness for treatment of peptic conditions in the pediatric population, including gastric ulcers, gastroesophageal reflux disease (GERD), and Helicobacter pylori infections has been established for children older than 1 year. Studies of the preverbal population of neonates and infants have identified doses that inhibit acid production, but the effectiveness of PPIs in the treatment of GERD has not been established except for the recent approval of esomeprazole treatment of erosive esophagitis in infants. Reasons that have been proposed for this are complex, ranging from GERD not occurring in this population to a lack of histologic identification of esophagitis related to GERD to questions about the validity of symptom scoring systems to identify esophagitis when it occurs in infants. The effectiveness of PPIs relates to their structures, which must undergo acidic activation within the parietal cell to allow the PPI to be ionized and form covalent disulfide bonds with cysteines of the H(+)-K(+)-adenosine triphosphatase (H(+)-K(+)-ATPase). Once the PPI binds to the proton pump, the pump is inactivated. Some PPIs, such as omeprazole and rabeprazole bind to cysteines that are exposed, and their binding can be reversed. After irreversible chemical inhibition of the proton pump, such as occurs with pantoprazole, the recovery of the protein of the pump has a half-life of around 50 h. Cytochrome P450 (CYP) 2C19 and to a lesser degree CYP3A4 clear the PPIs metabolically. These enzymes are immature at birth and reach adult levels of activity by 5-6 months after birth. This parallels studies of the maturation of CYP2C19 to adult levels by roughly the same age after birth. Specific single nucleotide polymorphisms of CYP2C19 reduce clearance proportionally and increase exposure and prolong proton pump inhibition. Prolonged treatment of pediatric patients with PPIs has not caused cancer or significant abnormalities.

Metabolic pathways of inhaled glucocorticoids by the CYP3A enzymes

Asthma is one of the most prevalent diseases in the world, for which the mainstay treatment has been inhaled glucocorticoids (GCs). Despite the widespread use of these drugs, approximately 30% of asthma sufferers exhibit some degree of steroid insensitivity or are refractory to inhaled GCs. One hypothesis to explain this phenomenon is interpatient variability in the clearance of these compounds. The objective of this research is to determine how metabolism of GCs by the CYP3A family of enzymes could affect their effectiveness in asthmatic patients. In this work, the metabolism of four frequently prescribed inhaled GCs, triamcinolone acetonide, flunisolide, budesonide, and fluticasone propionate, by the CYP3A family of enzymes was studied to identify differences in their rates of clearance and to identify their metabolites. Both interenzyme and interdrug variability in rates of metabolism and metabolic fate were observed. CYP3A4 was the most efficient metabolic catalyst for all the compounds, and CYP3A7 had the slowest rates. CYP3A5, which is particularly relevant to GC metabolism in the lungs, was also shown to efficiently metabolize triamcinolone acetonide, budesonide, and fluticasone propionate. In contrast, flunisolide was only metabolized via CYP3A4, with no significant turnover by CYP3A5 or CYP3A7. Common metabolites included 6β-hydroxylation and Δ(6)-dehydrogenation for triamcinolone acetonide, budesonide, and flunisolide. The structure of Δ(6)-flunisolide was unambiguously established by NMR analysis. Metabolism also occurred on the D-ring substituents, including the 21-carboxy metabolites for triamcinolone acetonide and flunisolide. The novel metabolite 21-nortriamcinolone acetonide was also identified by liquid chromatography-mass spectrometry and NMR analysis.