Advancing alternative methods to reduce animal testing.

Emerging approaches show promise for regulatory use.

A metagenomic analysis for combination therapy of multiple classes of antibiotics on the prevention of the spread of antibiotic-resistant genes.

Antibiotics used systemically to treat infections may have off-target effects on the gut microbiome, potentially resulting in the emergence of drug-resistant bacteria or selection of pathogenic species. These organisms may present a risk to the host and spread to the environment with a risk of transmission in the community. To investigate the risk of emergent antibiotic resistance in the gut microbiome following systemic treatment with antibiotics, this metagenomic analysis project used next-generation sequencing, a custom-built metagenomics pipeline, and differential abundance analysis to study the effect of antibiotics (ampicillin, ciprofloxacin, and fosfomycin) in monotherapy and different combinations at high and low doses, to determine the effect on resistome and taxonomic composition in the gut of Balb/c mice.

New science, drug regulation, and emergent public health issues: The work of FDA's division of applied regulatory science.

The U.S. Food and Drug Administration (FDA) Division of Applied Regulatory Science (DARS) moves new science into the drug review process and addresses emergent regulatory and public health questions for the Agency.

A Bioanalytical Method for Quantification of N-nitrosodimethylamine (NDMA) in Human Plasma and Urine with Different Meals and following Administration of Ranitidine.

Control of N-nitrosoamine impurities is important for ensuring the safety of drug products. Findings of nitrosamine impurities in some drug products led FDA to develop new guidance providing recommendations for manufacturers towards prevention and detection of nitrosamine impurities in pharmaceutical products. One of these products, ranitidine, also had a published in vivo study, which has since been retracted by its authors, suggesting a potential for in vivo conversion of ranitidine to the probable human carcinogen, N-nitrosodimethylamine (NDMA).

Determination of five positive control drugs in hERG external solution (buffer) by LC-MS/MS to support in vitro hERG assay as recommended by ICH S7B.

ICH S7B recommends screening for hERG channel block using patch clamp recordings to assess a drug's proarrhythmic risk. Block of the hERG channel has been associated with clinical QT prolongation as well as the rare, but potentially fatal ventricular tachyarrhythmia Torsade de Pointes (TdP). During recording, drug concentrations perfused to the cells can deviate from nominal concentrations due to molecule-specific properties (such as non-specific binding), thereby introducing error when assessing drug potency.

Effect of Paroxetine or Quetiapine Combined With Oxycodone vs Oxycodone Alone on Ventilation During Hypercapnia: A Randomized Clinical Trial.

Importance: Opioids can cause severe respiratory depression by suppressing feedback mechanisms that increase ventilation in response to hypercapnia. Following the addition of boxed warnings to benzodiazepine and opioid products about increased respiratory depression risk with simultaneous use, the US Food and Drug Administration evaluated whether other drugs that might be used in place of benzodiazepines may cause similar effects.

Objective: To study whether combining paroxetine or quetiapine with oxycodone, compared with oxycodone alone, decreases the ventilatory response to hypercapnia.

Effect of Oral Ranitidine on Urinary Excretion of N-Nitrosodimethylamine (NDMA): A Randomized Clinical Trial.

Importance: In 2019, the US Food and Drug Administration (FDA) received a citizen petition indicating that ranitidine contained the probable human carcinogen N-nitrosodimethylamine (NDMA). In addition, the petitioner proposed that ranitidine could convert to NDMA in humans; however, this was primarily based on a small clinical study that detected an increase in urinary excretion of NDMA after oral ranitidine consumption.

Objective: To evaluate the 24-hour urinary excretion of NDMA after oral administration of ranitidine compared with placebo.

Effects of sedative psychotropic drugs combined with oxycodone on respiratory depression in the rat.

Following a decision to require label warnings for concurrent use of opioids and benzodiazepines and increased risk of respiratory depression and death, the US Food and Drug Administratioin (FDA) recognized that other sedative psychotropic drugs may be substituted for benzodiazepines and be used concurrently with opioids. In some cases, data on the ability of these alternatives to depress respiration alone or in conjunction with an opioid are lacking. A nonclinical in vivo model was developed that could detect worsening respiratory depression when a benzodiazepine (diazepam) was used in combination with an opioid (oxycodone) compared to the opioid alone based on an increased arterial partial pressure of carbon dioxide (pCO ).

Emergence of nosocomial associated opportunistic pathogens in the gut microbiome after antibiotic treatment.

Introduction: According to the Centers for Disease Control's 2015 Hospital Acquired Infection Hospital Prevalence Survey, 1 in 31 hospital patients was infected with at least one nosocomial pathogen while being treated for unrelated issues. Many studies associate antibiotic administration with nosocomial infection occurrence. However, to our knowledge, there is little to no direct evidence of antibiotic administration selecting for nosocomial opportunistic pathogens.

The effect of antibiotics on the gut microbiome: a metagenomics analysis of microbial shift and gut antibiotic resistance in antibiotic treated mice.

Background: Emergence of antibiotic resistance is a global public health concern. The relationships between antibiotic use, the gut community composition, normal physiology and metabolism, and individual and public health are still being defined. Shifts in composition of bacteria, antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) after antibiotic treatment are not well-understood.

Developing an animal model to detect drug-drug interactions impacting drug-induced respiratory depression.

Opioids and benzodiazepines were frequently co-prescribed to patients with pain and psychiatric or neurological disorders; however, co-prescription of these drugs increased the risk for severe respiratory depression and death. Consequently, the U.S.

A high-throughput bioanalytical assay to support pharmacokinetic interaction study of oxycodone and diazepam in Sprague Dawley rats.

Benzodiazepines potentiate respiratory depression when combined with an opioid leading the U.S Food and Drug Administration (FDA) to recommend updating the labels of these products with a boxed warning for respiratory depression with co-use. Potential respiratory depression upon co-administration of opioids with some psychotropic drugs is not well understood.

Quantitative analysis of underivatized 17 β-estradiol using a high-throughput LC-MS/MS assay - Application to support a pharmacokinetic study in ovariectomized guinea pigs.

Difference in female sex hormone, β-estradiol (E), levels can contribute to sex differences in biological processes that underlie target tissue functions (QT interval), vulnerability to diseases (hepatitis or HIV), and response toward therapies. Accurate quantification of plasma E level is thus an important aspect in both basic science research examining hormone-regulated physiological mechanisms and in clinical settings to support patient care associated with altered E levels. Due to lack of a high-throughput high-sensitivity analytical method, we developed and validated a LC-MS/MS assay for accurate low-level quantification of E and demonstrated its application to a guinea pig pharmacokinetic study in which guinea pigs were treated with 10 or 40 μg/kg E subcutaneously and blood samples collected at 0 (pre-dose), 0.

Evaluation of Immunocompetent Urinary Tract Infected Balb/C Mouse Model For the Study of Antibiotic Resistance Development Using CFT073 Infection.

Urinary tract infections (UTI) are common worldwide and are becoming increasingly difficult to treat because of the development of antibiotic resistance. Immunocompetent murine models of human UTI have been used to study pathogenesis and treatment but not for investigating resistance development after treatment with antibiotics. In this study, intravesical inoculation of uropathogenic CFT073 in immunocompetent Balb/c mice was used as a model of human UTI.

Detection of Reg3γ by Immunohistochemistry in Cerulein-Induced Model of Acute Pancreatic Injury in Mice and Rats.

Objective: In a continuation of previous work, Reg3γ protein was further evaluated as a biomarker of pancreatic injury using immunohistochemistry in an additional species.

Methods: Mice and rats were treated with intraperitoneal cerulein injections, creating acute pancreatic injury. Mice received 2, 4, or 6 doses, and rats received 1, 2, or 3 doses of cerulein creating low, medium, and high treatment groups.

Application of Mechanistic Ocular Absorption Modeling and Simulation to Understand the Impact of Formulation Properties on Ophthalmic Bioavailability in Rabbits: a Case Study Using Dexamethasone Suspension.

Developing mathematical models to predict changes in ocular bioavailability and pharmacokinetics due to differences in the physicochemical properties of complex topical ophthalmic suspension formulations is important in drug product development and regulatory assessment. Herein, we used published FDA clinical pharmacology review data, in-house, and literature rabbit pharmacokinetic data generated for dexamethasone ophthalmic suspensions to demonstrate how the mechanistic Ocular Compartmental Absorption and Transit model by GastroPlus™ can be used to characterize ocular drug pharmacokinetic performance in rabbits for suspension formulations. This model was used to describe the dose-dependent (0.

An alternating polarity switching assay for quantification of oxycodone and topiramate: An application of LC-MS/MS method in support to PK/PD study in rodents.

In mass spectrometry, compounds that have different ionization properties experience challenges in simultaneous analysis. In the present paper, the authors proposed a polarity switching (+ve and -ve) LC-MS/MS method to analyze oxycodone and topiramate in a single run. The developed method was validated in the range of 5-1000 ng/mL for oxycodone and 20-5000 ng/mL for topiramate as per the US FDA guidelines.

Protocol for evaluation of topical ophthalmic drug products in different compartments of fresh eye tissues in a rabbit model.

Topical ophthalmic drugs are the most commonly used dosage form to treat diseases of the anterior segment of the eye. Although this dosage form has the advantages of ease of application, small volume dose, and rapid action and is largely devoid of systemic adverse effects, the bioavailability is low due to pre-corneal anatomical barriers and the nature of the drug formulation itself. Some complex generic formulations (suspensions, ointments, gels) for topical ophthalmic products face impediments to rapid regulatory approval because of the complex nature of the formulations and difficulties in determining bioequivalence with the innovator product.

Biomarkers of drug-induced acute kidney injury: a regulatory perspective.

Biomarkers are one of the drug development tools that are being developed through collaborative efforts among multiple stakeholder communities to enhance the drug development process. Biomarkers of acute drug-induced renal injury as used in drug development are more commonly referred to as renal safety biomarkers, the focus of this manuscript. Areas covered: This manuscript provides an overview of the history and evolution of the United States Food and Drug Administration's Center for Drug Evaluation and Research's Biomarker Qualification Program.

Co-sequencing and novel delayed anti-correlation identify function for pancreatic enriched microRNA biomarkers in a rat model of acute pancreatic injury.

Background: Co-sequencing of messenger ribonucleic acid (mRNA) and micro ribonucleic acid (miRNA) across a time series (1, 3, 6, 24, and 48 h post injury) was used to identify potential miRNA-gene interactions during pancreatic injury, associate serum and tissue levels of candidate miRNA biomarkers of pancreatic injury, and functionally link these candidate miRNA biomarkers to observed histopathology. RNAs were derived from pancreatic tissues obtained in experiments characterizing the serum levels of candidate miRNA biomarkers in response to acute pancreatic injury in rats.

Results: No correlation was discovered between tissue and serum levels of the miRNAs.

Translating New Science Into the Drug Review Process: The US FDA's Division of Applied Regulatory Science.

In 2011, the US Food and drug Administration (FDA) developed a strategic plan for regulatory science that focuses on developing new tools, standards, and approaches to assess the safety, efficacy, quality, and performance of FDA-regulated products. In line with this, the Division of Applied Regulatory Science was created to move new science into the Center for Drug Evaluation and Research (CDER) review process and close the gap between scientific innovation and drug review. The Division, located in the Office of Clinical Pharmacology, is unique in that it performs mission-critical applied research and review across the translational research spectrum including in vitro and in vivo laboratory research, in silico computational modeling and informatics, and integrated clinical research covering clinical pharmacology, experimental medicine, and postmarket analyses.

Determination of Non-Transferrin Bound Iron, Transferrin Bound Iron, Drug Bound Iron and Total Iron in Serum in a Rats after IV Administration of Sodium Ferric Gluconate Complex by Simple Ultrafiltration Inductively Coupled Plasma Mass Spectrometric Detection.

A rapid, sensitive and specific ultrafiltration inductively-coupled plasma mass spectrometry (UF-ICP-MSICP-MS) method was developed and validated for the quantification of non-transferrin bound iron (NTBI), transferrin bound iron (TBI), drug bound iron (DI) and total iron (TI) in the same rat serum sample after intravenous (IV) administration of iron gluconate nanoparticles in sucrose solution (Ferrlecit). Ultrafiltration with a 30 kDa molecular cut-off filter was used for sample cleanup. Different elution solvents were used to separate each form of iron from sample serum.

Regulatory Science - An Underappreciated Component of Translational Research.

Translational science refers to translating basic scientific findings to practical application (i.e., 'bench-to-bedside').