Pharmacokinetics of Hydroxytyrosol and Its Sulfate and Glucuronide Metabolites after the Oral Administration of Table Olives to Sprague-Dawley Rats

The pharmacokinetics (PK) of hydroxytyrosol and its metabolites were characterized following oral administration to Sprague-Dawley rats of 3.85 and 7.70 g of destoned Arbequina table olives/kg. Plasma samples were analyzed using a fully validated method consisting of liquid extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Noncompartmental PK analysis of hydroxytyrosol demonstrated linear PK between doses of 2.95 and 5.85 mg hydroxytyrosol/kg. Half-life was approximately 2.5 h, while mean residence time was around 4 h. Clearance occurred by conversion to two sulfate and two glucuronide conjugates. The area under the plasma concentration-time curve (AUC) ratios of metabolites versus parent hydroxytyrosol was approximately 7-9-fold for the sulfate and below 0.25 for the glucuronide, indicating sulfation as the predominant metabolic pathway. Despite extensive metabolism, hydroxytyrosol remained in plasma for up to 8 h with AUCs of 4293 and 8919 min·nmol/L for the doses of 3.85 and 7.70 g/kg, respectively. Therefore, table olives provide a more sustained plasma profile than other foods containing hydroxytyrosol, which may enhance its health-protecting activities.

Fostering Animal Welfare and Advancing 3Rs Principles through the Establishment of a 3Rs Advisory Group

Based on the current state of science, the use of animals remains essential in bringing safe and effective medicines to patients. Respect for laboratory animal welfare and the application of 3Rs principles (the replacement, reduction, and refinement of animal use in research) are a priority throughout the pharmaceutical industry. Given the rapid pace of development, technological progress, and the emergence of new-approach methodologies (NAMs) in the field of biomedical research, maintaining a leading position in scientific advancements with a focus on the principles of replace, reduce, and refine (3Rs) can be quite challenging. To effectively address these challenges and sustain a prominent position in the scientific community, organizations can derive significant advantages from establishing an internal 3Rs advisory group (3Rs AG). The primary objective of a 3Rs AG is to stay at the forefront of the knowledge of best practices related to the 3Rs principles in the industry. This group plays a crucial role in fostering innovation and facilitating the seamless integration and implementation of 3Rs principles into a company's policies and procedures. The thoughtful reduction in and replacement of animal studies and the refinement of study designs and practices, enabled by a 3Rs AG, can minimize animal use as well as guide resources and positively impact study and data quality. This article provides guidance on how to establish a successful and impactful 3Rs AG.

Impact of repeated micro and macro blood sampling on clinical chemistry and haematology in rats for toxicokinetic studies

Non-clinical rodent safety studies are essential in the development of new medicines to assess for potential adverse effects. Typically, toxicokinetic samples are collected from a satellite group. AstraZeneca implemented repeated microsampling of main study animals as standard in the one-month small molecule regulatory toxicology studies. A retrospective analysis of the clinical chemistry and haematology data collected in 52 independent studies from the adult rat controls explored the impact of micro and macro sampling of main study animals. For the majority of variables, the blood sampling technique had no significant impact on the mean or range. For microsampling, a few variables had statistically significant effects on the mean signal but these were considered to have limited biological relevance and would therefore not introduce a meaningful bias to any toxicological evaluation. The macrosampling had the expected effects on the red cell parameters of haemoglobin, haematocrit and red blood count due to the larger blood volume draw. In contrast, microsampling showed no such changes. In conclusion, this large-scale retrospective analysis supports the use of microsampling, for toxicokinetics, of main study animals and enables us to conduct rodent toxicology studies without satellite animals and further reduce the number of animals used in toxicological assessments.

Pharmacokinetics of Single-Dose Intramuscular and Subcutaneous Injections of Buprenorphine in Common Marmosets (Callithrix jacchus)

Although buprenorphine is the most frequently used opioid analgesic in common marmosets (Callithrix jacchus), there is limited information in the literature supporting current dosing regimens used for this species. The purpose of this study was to determine the pharmacokinetic profiles of single-dose buprenorphine HCl administered intramuscularly (IM) at 0.01 mg/kg in 6 adult marmosets (1.8 to 12.8 y old; 2 males, 4 females) and subcutaneously (SQ) at 0.01 mg/kg in 6 adult marmo- sets (2.3-4.4 y old; 3 males, 3 females) by mass spectrometry. Blood was collected at multiple time points from 0.25 to 24 h from unsedated animals following a hybrid sparse-serial sampling design. The maximal observed plasma concentration of buprenorphine (Cmax ) administered IM (2.57 ± 0.95 ng/mL) was significantly higher than administered SQ (1.47 ± 0.61 ng/mL). However, the time to Cmax (Tmax) was not statistically different between routes (17.4 ± 6 min for IM and 19.8 ± 7.8 min for SQ). The time of the last quantifiable concentration of buprenorphine was 5 ± 1.67 h for IM compared with 6.33 ± 1.51 h for SQ, which was not statistically different. The mean buprenorphine plasma concentration-time curves were used to propose a dosing frequency of 4 to 6 h for buprenorphine at 0.01 mg/kg IM or SQ based on a theoretical therapeutic plasma concentration threshold of 0.1 ng/mL. Based on the mean pharmacokinetic parameters and plasma-concentration time curves, both IM and SQ routes of buprenorphine at this dose provide a rapid increase in the plasma concentration of buprenorphine above the therapeutic threshold, and may be more effective for acute rather than long-lasting analgesia. Further studies are needed to examine repeated dosing regimens and the efficacy of buprenorphine in common marmosets.

Guidelines for the experimental design of pharmacokinetic studies with nanomaterials in preclinical animal models

A shared feature in the value proposition of every nanomaterial-based drug delivery systems is the desirable improvement in the disposition (or ADME) and pharmacokinetic profiles of the encapsulated drug being delivered. Remarkable progress has been made towards understanding the complex and multifactorial relationships between pharmacokinetic profiles and nanomaterial physicochemical properties, biological interactions, species physiology, etc. These advances have fuelled the rational design of numerous nanomaterials with long-circulation times and improved tissue accumulation (e.g., in tumours). Unfortunately, a central weakness in many of these research efforts has been the inconsistent and insufficient characterisation of the pharmacokinetic profiles of nanomaterials in scientific reporting-a problem affecting the majoirty of of contemporary nanomaterials literature and innovative nanomaterials in early stages of preclinical development especially. Given the significant role of pharmacokinetic assessments to serve as guideposts for deciding whether to continue with the preclinical development and clinical translation of drug delivery systems, the prevalence of poor pharmacokinetic characterisations in nanomaterials research is particularly alarming. A conspicuous problem in many reports is the inappropriate selection of experimental designs and methodologies for studying nanomaterial pharmacokinetics, the consequences of which are increased uncertainty over the accurate interpretation of reported pharmacokinetic data and diminished experimental reproducibility throughout the field. Thus, there is renewed interest in the establishment of consistent and comprehensive strategies for designing preclinical experiments to assess the pharmacokinetics of nanomaterials with diverse physicochemical properties. Towards this end, herein are proposed simple guidelines for the experimental design of pharmacokinetic studies with nanomaterials drawn from the best research practices, principle strategies, and important considerations used in industry for collecting pharmacokinetic data in preclinical animal models. Specifically, key experimental design factors in these studies are identified and examined in the context of nanomaterials for optimality, including blood sampling strategy and technique, sample allocation and sampling time window, test species selection, experimental sources of pharmacokinetic variability, etc. Methods for noninvasive imaging-derived pharmacokinetic assessments of theranostic nanomaterials are also explored with particular focus on emission tomography imaging modalities. Taken together, this review will provide nanomaterial researchers with practical knowledge and pragmatic recommendations for selecting the best designs and methodologies for assessing the pharmacokinetic profiles of their nanomaterials, and hopefully maximise the chances of translational success of these innovative products into humans.

A Proof of the Low Speed Centrifugation Concept in Rodents: New Perspectives for In Vivo Research

IMPACT STATEMENT

This study evaluated for the first time the composition and bioactivity of platelet-rich fibrin (PRF) produced from small animal blood by reducing the initial blood volume needed for the preparation of PRF from 10 to 3 mL. The results showed that different preparation protocols of PRF produced using 3 mL of animal blood exhibit the same composition, properties, and bioactivity as PRF prepared using 10 mL human blood.

Multiwell three-dimensional systems enable in vivo screening of immune reactions to biomaterials: a new strategy toward translational biomaterial research

In vivo experiments are accompanied by ethical issues, including sacrificing a large number of animals as well as large costs. A new in vivo 3D screening system was developed to reduce the number of required animals without compromising the results. The present pilot study examined a multiwell array system in combination with three different collagen-based biomaterials (A, B and C) using subcutaneous implantation for 10 days and histological and histomorphometrical evaluations. The tissue reaction towards the device itself was dominated by mononuclear cells. However, three independent biomaterial-specific tissue reactions were observed in three chambers. The results showed a mononuclear cell-based tissue reaction in one chamber (A) and foreign body reaction by multinucleated giant cells in the other two chambers (B and C). Statistical analysis showed a significantly higher number of multinucleated giant cells in cases B and C than in case A (A vs. B; ***P < 0.001), (A vs. C; P < 0.01). These outcomes were comparable to previously published observations with conventional biomaterial implantation. The present data lead to the conclusion that this 3D screening system could be an alternative tool to enhance the effectiveness of in vivo experiments, thus offering a more economic strategy to screen biomaterial-related cellular reactions, while saving animals, without influencing the final outcome.

Semi-mechanistic Pharmacokinetic/Pharmacodynamic model of three pegylated rHuEPO and ior®EPOCIM in New Zealand rabbits

Marketed formulations of erythropoietin (EPO) ior®EPOCIM, MIRCERA® and two newly developed pegylated-EPO analogues (PEG-EPO 32 and 40 kDa) formulations were intravenously administered to New Zealand rabbits. A semi-mechanistic Pharmacokinetic/Pharmacodynamic (PK/PD) model describing in a simultaneous and integrated form the time course of reticulocytes, red blood cells and hemoglobin was built to account for the time course of hematopoiesis stimulation after erythropoietin administration. Data analysis was performed based on the population approach with the software NONMEM version 7.3. Erythropoietin disposition of each of the administered formulations was best described with a two compartment model and linear elimination. Different formulations show different clearance and apparent volume of distribution of the central compartment but share estimates of inter-compartmental clearance and apparent peripheral volume of distribution. A semi-mechanistic model including cell proliferation, maturation, and homeostatic regulation provided a good description of the data regardless the type of erythropoietin formulation administered. The system-, and drug-related parameters showed consistency and differed across formulations, respectively. A single IV administration of PEG-EPO 32 and 40 kDa formulations in New Zealand rabbits achieves a median change of 27% and 22% on RET levels, and of 47% and 63% on RBC and HGB levels, respectively compared to MIRCERA®. The administration of new branched PEG-chains formulations improves PK and PD properties of EPO, in terms of increasing elimination half-lives and pharmacological activity on RET, RBC and HGB compared to commercially available formulations (ior®EPOCIM and MIRCERA®).

Opportunities to Apply the 3Rs in Safety Assessment Programs

Before a potential new medicine can be administered to humans it is essential that its safety is adequately assessed. Safety assessment in animals forms an integral part of this process, from early drug discovery and initial candidate selection to the program of recommended regulatory tests in animals. The 3Rs (replacement, reduction, and refinement of animals in research) are integrated in the current regulatory requirements and expectations and, in the EU, provide a legal and ethical framework for in vivo research to ensure the scientific objectives are met whilst minimizing animal use and maintaining high animal welfare standards. Though the regulations are designed to uncover potential risks, they are intended to be flexible, so that the most appropriate approach can be taken for an individual product. This article outlines current and future opportunities to apply the 3Rs in safety assessment programs for pharmaceuticals, and the potential (scientific, financial, and ethical) benefits to the industry, across the drug discovery and development process. For example, improvements to, or the development of, novel, early screens (e.g., in vitro, in silico, or nonmammalian screens) designed to identify compounds with undesirable characteristics earlier in development have the potential to reduce late-stage attrition by improving the selection of compounds that require regulatory testing in animals. Opportunities also exist within the current regulatory framework to simultaneously reduce and/or refine animal use and improve scientific outcomes through improvements to technical procedures and/or adjustments to study designs. It is important that approaches to safety assessment are continuously reviewed and challenged to ensure they are science-driven and predictive of relevant effects in humans.