Dose dependent pharmacokinetics of prednisone and prednisolone in man

Digital twin-enhanced three-organ microphysiological system for studying drug pharmacokinetics in pregnant women

Background

Pregnant women represent a vulnerable group in pharmaceutical research due to limited knowledge about drug metabolism and safety of commonly used corticosteroids like prednisone due to ethical and practical constraints. Current preclinical models, including animal studies, fail to accurately replicate human pregnancy conditions, resulting in gaps in drug safety and pharmacokinetics predictions. To address this issue, we used a three-organ microphysiological system (MPS) combined with a digital twin framework, to predict pharmacokinetics and fetal drug exposure.

Methods

The here shown human MPS integrated gut, liver, and placenta models, interconnected via the corresponding vasculature. Using prednisone as a model compound, we simulate oral drug administration and track its metabolism and transplacental transfer. To translate the generated data from MPS to human physiology, computational modelling techniques were developed.

Results

Our results demonstrate that the system maintains cellular integrity and accurately mimics in vivo drug dynamics, with predictions closely matching clinical data from pregnant women. Digital twinning closely aligned with the generated experimental data. Long-term exposure simulations confirmed the value of this integrated system for predicting the non-toxic metabolization of prednisone.

Conclusion

This approach may provide a potential non-animal alternative that could contribute to our understanding of drug behavior during pregnancy and may support early-stage drug safety assessment for vulnerable populations.

Rates of glucocorticoid taper in the management of polymyalgia rheumatica: the science behind the "art"

Polymyalgia rheumatica (PMR) is a common and debilitating disease for which glucocorticoids remain the therapeutic mainstay. Guideline recommendations on tapering regimens have been largely based on expert consensus. This exploratory narrative review provides a discussion on the available evidence for the rates of steroid tapering in PMR, as well as relevant pharmacology of corticosteroids. Key studies related to rates of steroid tapering are reviewed. Results favor a slow tapering regimen from a low initial steroid dose (between 10 and 20 mg) to minimize risk of relapse. This should be balanced with the risk of steroid-induced adverse events. Individualization and close monitoring have also been identified as important factors during the steroid-tapering process. There is promising data on the role of steroid-sparing agents, including methotrexate, tocilizumab, and more recently sarilumab. There is individual variability of prednisone pharmacokinetics, and the tapering of prednisone remains an "art" that would benefit from further understanding of the variables involved. Overall, glucocorticoids remain the mainstay therapy for PMR, and there continues to be a lack of robust evidence to guide steroid taper. More research is needed to optimize steroid tapering and regimens, along with the expanding role of steroid-sparing agents such as tocilizumab and sarilumab. Key Points • Polymyalgia rheumatica is a common and debilitating disease for which glucocorticoids remain the mainstay of therapy, and there is a paucity of evidence to guide steroid taper. • Limited available research favors a slow tapering regimen from a low initial steroid dose to minimize risk of relapse and steroid exposure. • The process of steroid taper should be individualized and closely monitored, with growing evidence supporting the addition of steroid-sparing agents. • More research is needed to optimize steroid tapering and regimens, along with the expanding role of steroid-sparing agents such as methotrexate, tocilizumab, and sarilumab.

A comprehensive review on glucocorticoids induced osteoporosis: A medication caused disease

Glucocorticoids (GCs) are steroid hormones that are extensively used in the treatment of autoimmune diseases, inflammation, and cancer. The major ill effect of administering GCs is that it has a deleterious effect on bone, which leads to GC-induced osteoporosis. GC therapy induces bone loss and is associated with the risk of nonvertebral and vertebral fractures, as it works in combination by increasing bone reabsorption and suppressing bone formation during the initial phase of therapy. It is seen and established that GC in excess or in low dose for 3 months or more can be a risk factor for fracture, and the risk increases with an increase in dose and duration of usage. The most common cause of secondary osteoporosis is the administration of GC inside the body to treat various diseases. The degree of bone loss is directly proportional to the GC dose and the exposure duration. The first step is to evaluate the patients' risk factors for the development of glucocorticoids that induce osteoporosis, which include the dose, duration of use, patient age, sex, previous fractures, and other medical conditions.

Emerging and legacy contaminants on the Brazilian southern coast (Santa Catarina): A multi-biomarker approach in oysters Crassostrea gasar (Adanson, 1757)

Coastal environments, such as those in the Santa Catarina State (SC, Brazil), are considered the primary receptors of anthropogenic pollutants. In this study, our objective was to evaluate the levels of emerging contaminants (ECs) and persistent organic pollutants (POPs) in indigenous Crassostrea gasar oysters from different regions of SC coast in the summer season (March 2022). Field collections were conducted in the São Francisco do Sul, Itajaí, Florianópolis and Laguna coastal zones. We analyzed the bioaccumulation levels of 75 compounds, including antibiotics (AB), endocrine disruptors (ED), non-steroidal anti-inflammatory drugs (NSAIDs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and pesticides. Furthermore, we assessed biomarker responses related to biotransformation, antioxidant defense, heat shock protection and oxidative damage in oysters' gills. Prevalence of ECs was observed in the central and southern regions, while the highest concentrations of POPs were detected in the central-northern regions of SC. Oysters exhibited an induction in biotransformation systems (cyp2au1 and cyp356a1, sult and GST activity) and antioxidant enzymes activities (SOD, CAT and GPx). Higher susceptibility to lipid peroxidation was observed in the animals from Florianópolis compared to other regions. Correlation analyses indicated possible associations between contaminants and environmental variables in the biomarker responses, serving as a warning related to climate change. Our results highlight the influence of anthropogenic activities on SC, serving as baseline of ECs and POPs levels in the coastal areas of Santa Catarina, indicating more critical zones for extensive monitoring, aiming to conserve coastal regions.

Quantitative prediction of CYP3A-mediated drug-drug interactions by correctly estimating fraction metabolized using human liver chimeric mice

BACKGROUND AND PURPOSE

Fraction metabolized (fm ) and fraction transported (ft ) are important for understanding drug-drug interactions (DDIs) in drug discovery and development. However, current in vitro systems cannot accurately estimate in vivo fm due to inability to reflect the ft by efflux transporters (ft,efflux ). This study demonstrates how CYP3A-mediated DDI for CYP3A/P-gp substrates can be predicted using Hu-PXB mice as human liver chimeric mice.

EXPERIMENTAL APPROACH

For estimating human in vitro fm by CYP3A enzyme (fm,CYP3A,in vitro ), six drugs, including CYP3A/P-gp substrates (alprazolam, cyclosporine, docetaxel, midazolam, prednisolone, and theophylline) and human hepatocytes were incubated with or without ketoconazole as a CYP3A inhibitor. We calculated fm,CYP3A,in vitro based on hepatic intrinsic clearance. To estimate human in vivo fm,CYP3A (fm,CYP3A,in vivo ), we collected information on clinical DDI caused by ketoconazole for these six drugs. We calculated fm,CYP3A,in vivo using the change of total clearance (CLtotal ). For evaluating the human DDI predictability, the six drugs were administered intravenously to Hu-PXB and SCID mice with or without ketoconazole. We calculated the change of CLtotal caused by ketoconazole. We compared the CLtotal change in humans with that in Hu-PXB and SCID mice.

KEY RESULTS

The fm,CYP3A,in vitro was overestimated compared to the fm,CYP3A,in vivo . Hu-PXB mice showed much better correlation in the change of CLtotal with humans (R2  = 0.95) compared to SCID mice (R2  = 0.0058).

CONCLUSIONS AND IMPLICATIONS

CYP3A-mediated DDI can be predicted by correctly estimating human fm,CYP3A,in vivo using Hu-PXB mice. These mice could be useful predicting hepatic fm and ft,efflux .

Fifty Years of Unraveling the Clinical Pharmacology of Corticosteroids

This review will highlight portions of Dr. William Jusko's and colleagues' work that affected the clinical use and study of corticosteroids in acute and chronic disease management. Selected publications related to corticosteroid pharmacokinetics and pharmacodynamics from the 1970s through today were included in this review, with a focus on the foundational human-based studies conducted in the 1970s-1990s. Dr. Jusko contributed significantly to early corticosteroid pharmacology across several domains including: 1) foundational corticosteroid pharmacokinetic methods and parameter development, 2) disease state-variation in corticosteroid pharmacokinetics, 3) drug interaction effects on corticosteroid pharmacokinetics, and 4) early corticosteroid pharmacodynamic studies. In an era where little was known about the pharmacokinetics and pharmacodynamics of corticosteroids, Dr. Jusko's work opened the eyes of researchers and clinicians to the potential for disease and drug interactions that could reduce or enhance the effects of corticosteroids. This significant body of work paved the way for alternative routes of administration that would be useful in concentrating the activity at the site of action and markedly reduced systemic drug exposure, minimizing the risk of adverse effects through application of the dose-sparing pharmacokinetic and pharmacodynamic principles.

The Physiological and Pharmacological Significance of the Circadian Timing of the HPA Axis: A Mathematical Modeling Approach

As a potent endogenous regulator of homeostasis, the circadian time-keeping system synchronizes internal physiology to periodic changes in the external environment to enhance survival. Adapting endogenous rhythms to the external time is accomplished hierarchically with the central pacemaker located in the suprachiasmatic nucleus (SCN) signaling the hypothalamus-pituitary-adrenal (HPA) axis to release hormones, notably cortisol, which help maintain the body's circadian rhythm. Given the essential role of HPA-releasing hormones in regulating physiological functions, including immune response, cell cycle, and energy metabolism, their daily variation is critical for the proper function of the circadian timing system. In this review, we focus on cortisol and key fundamental properties of the HPA axis and highlight their importance in controlling circadian dynamics. We demonstrate how systems-driven, mathematical modeling of the HPA axis complements experimental findings, enhances our understanding of complex physiological systems, helps predict potential mechanisms of action, and elucidates the consequences of circadian disruption. Finally, we outline the implications of circadian regulation in the context of personalized chronotherapy. Focusing on the chrono-pharmacology of synthetic glucocorticoids, we review the challenges and opportunities associated with moving toward personalized therapies that capitalize on circadian rhythms.

Prolonged glucocorticoid administration affects oocyte morphology in cats (Felis catus) undergoing an ovarian stimulation protocol

While captivity-related stress and the associated rise in baseline glucocorticoid (GC) concentrations have been linked to ovarian quiescence in some felid species, no study has examined the effects of elevated GC on oocyte quality. This study examined the effects of exogenous GC administration on the ovarian response and oocyte quality of domestic cats after an ovarian stimulation protocol. Entire mature female cats were divided into treatment (n = 6) and control (n = 6) groups. Cats in the GC treatment (GCT) group were given 1 mg kg-1 oral prednisolone daily from Day 0-45. All cats (n = 12) were given 0.088 mg kg-1 day-1 progesterone orally from Day 0-37, before treatment with 75 IU eCG im to induce follicular growth on Day 40, followed by 50 IU hCG im 80 h later to induce ovulation. Cats were ovariohysterectomised 30 h after the hCG treatment. Blood samples were collected on Days 0, 10, 30 and 40 (prior to eCG treatment), 80 h after eCG treatment, and on Day 45 for cortisol, glucose, prednisolone, oestradiol, and progesterone analysis. Cortisol concentrations did not differ between treatment groups throughout the study. Mean glucose concentrations were higher in the GCT cats (P = 0.004). Prednisolone was undetectable in all samples. Oestradiol and progesterone concentrations confirmed that the eCG treatment stimulated follicular activity and ovulation in all cats. Following ovariohysterectomy, the ovarian responses were graded (1 = excellent, 4 = poor) and oocytes retrieved from the oviducts. Each oocyte was given a total oocyte score (TOS: using an 9-point scale, 8 = best) based on four parameters: oocyte morphology, size, ooplasm uniformity and granularity, and zona pellucida (ZP) thickness and variation. Ovulation was confirmed in all cats, with a mean of 10.5 ± 1.1 ovulations per cat. Ovarian mass, ovarian response, number of ovulations, and oocyte recovery did not differ between groups. Oocyte diameter did not differ between the groups, but the ZP was thinner in the GCT group (3.1 ± 0.3 μm vs. 4.1 ± 0.3 μm, P = 0.03). The TOS was similar between treatment and control cats, but the ooplasm grade was lower (1.5 ± 0.1 vs. 1.9 ± 0.1, P = 0.01) and there was a tendency for ZP grade to be poorer (0.8 ± 0.1 vs. 1.2 ± 0.2; P = 0.08) in the treatment group. In conclusion, the GC treatment resulted in morphological changes to oocytes collected following ovarian stimulation. Whether these changes would affect fertility warrants further investigation.

In vitro and in vivo evidence that the switch from calcineurin to mTOR inhibitors may be a strategy for immunosuppression in Epstein-Barr virus-associated post-transplant lymphoproliferative disorder

Post-transplant lymphoproliferative disorder is a life-threatening complication of immunosuppression following transplantation mediated by failure of T cells to control Epstein-Barr virus (EBV)-infected and transformed B cells. Typically, a modification or reduction of immunosuppression is recommended, but insufficiently defined thus far. In order to help delineate this, we characterized EBV-antigen-specific T cells and lymphoblastoid cell lines from healthy donors and in patients with a kidney transplant in the absence or presence of the standard immunosuppressants tacrolimus, cyclosporin A, prednisolone, rapamycin, and mycophenolic acid. Phenotypes of lymphoblastoid cell-lines and T cells, T cell-receptor-repertoire diversity, and T-cell reactivity upon co-culture with autologous lymphoblastoid cell lines were analyzed. Rapamycin and mycophenolic acid inhibited lymphoblastoid cell-line proliferation. T cells treated with prednisolone and rapamycin showed nearly normal cytokine production. Proliferation and the viability of T cells were decreased by mycophenolic acid, while tacrolimus and cyclosporin A were strong suppressors of T-cell function including their killing activity. Overall, our study provides a basis for the clinical decision for the modification and reduction of immunosuppression and adds information to the complex balance of maintaining anti-viral immunity while preventing acute rejection. Thus, an immunosuppressive regime based on mTOR inhibition and reduced or withdrawn calcineurin inhibitors could be a promising strategy for patients with increased risk of or manifested EBV-associated post-transplant lymphoproliferative disorder.

Factors Associated with Rapidly Deteriorating Myelopathy in Patients with Spinal Arteriovenous Shunts

Spinal arteriovenous (AV) shunts are rare conditions that sometimes present with myelopathy symptoms. The progression of the symptoms is usually gradual; however, some cases show rapid deterioration. We retrospectively investigated the factors that induced the rapid deterioration of myelopathy symptoms in patients with spinal AV shunts. We treated 33 patients with myelopathy with spinal AV shunts at our institutions, eight of whom experienced rapid deterioration (within 24 hours: 24.2%). Of these, three were related to the body movement or particular postures associated with playing golf, 30 minutes of Japanese straight sitting, and massage care. One patient showed deterioration after embolization for a tracheal aneurysm. The remaining four patients received steroid pulse therapy (high-dose steroid infusion) shortly before the rapid deterioration. These symptoms stopped progressing after cessation of steroid use. While positional or physical factors contributing to myelopathy deterioration might exist, we could not identify specific factors in this study. Nevertheless, rapid deterioration was frequently observed after high-dose steroid use. We must take care not to administer high-dose steroids for myelopathy caused by spinal AV shunt disease.

Recent Advances in Liposomal-Based Anti-Inflammatory Therapy

Liposomes can be seen as ideal carriers for anti-inflammatory drugs as their ability to (passively) target sites of inflammation and release their content to inflammatory target cells enables them to increase local efficacy with only limited systemic exposure and adverse effects. Nonetheless, few liposomal formulations seem to reach the clinic. The current review provides an overview of the more recent innovations in liposomal treatment of rheumatoid arthritis, psoriasis, vascular inflammation, and transplantation. Cutting edge developments include the liposomal delivery of gene and RNA therapeutics and the use of hybrid systems where several liposomal bilayer features, or several drugs, are combined in a single formulation. The majority of the articles reviewed here focus on preclinical animal studies where proof-of-principle of an improved efficacy-safety ratio is observed when using liposomal formulations. A few clinical studies are included as well, which brings us to a discussion about the challenges of clinical translation of liposomal nanomedicines in the field of inflammatory diseases.

Evaluation of Physical and Chemical Parameters According to Energetic Willow (Salix viminalis L.) Cultivation

The aim of this study was the investigation of the effect of growth conditions of energy willow (Salix viminalis L.) on its physical and chemical parameters towards lignocellulosic biofuels. This work is linked to the global trend of replacing fossil fuels (coal, oil, natural gas) with energy and renewable fuels. This energy transition is dictated by the reduction of the human-induced greenhouse effect (to the greatest extent by industrial development). Changing from traditional to renewable energy sources results in industry becoming less dependent on fuels whose sources are beginning to run out, and in energy processing being broken down into smaller sectors with greater flexibility to change and less susceptibility to failure. The use of lignocellulosic raw materials such as wood, straw, food industry waste, wood, and post-consumer products such as old furniture for energy purposes allows the use of substances which bind the greenhouse gas carbon dioxide in their cellular structure during growth. In order to optimise the costs of producing such energy and minimise its impact on the environment, these plants should be located as close as possible to the source of raw materials. One of the most important characteristics for the profitability of energy production from woody biomass is a high biomass yield. For this purpose, the raw material used for this study was energy willow (Salix viminalis L.) seedlings, which are often used for energy crops. Due to the moisture-loving nature of the substrate, the effect of the addition of the active substance prednisonum as a catalyst for water adsorption from the substrate was investigated. In order to determine the substances formed during the thermal decomposition of energy willow (Salix viminalis L.) wood, a pyrolysis process was carried out at 450 °C using pyrolysis gas chromatography mass spectrometry (PY/GC-MS).

Physiologically Based Pharmacokinetic Modeling Involving Nonlinear Plasma and Tissue Binding: Application to Prednisolone and Prednisone in Rats

The pharmacokinetics (PK) of prednisolone (PNL) exhibit nonlinearity related to plasma protein binding, tissue binding, metabolic interconversion with prednisone (PN), and renal elimination. Blood and 11 tissues were collected from male Wistar rats after steady-state (SS) infusion and after subcutaneous boluses of 50 mg/kg of PNL. Concentrations of PNL and PN were measured by liquid chromatography-tandem mass spectrometry. Plasma and tissue profiles were described using a complex physiologically based pharmacokinetics (PBPK) model. Concentrations of PN and PNL were in rapid equilibrium in plasma and tissues. The tissue partition coefficients (K p ) of PNL calculated from most subcutaneously dosed tissue and plasma areas were similar to SS infusion and in silico values. The blood-to-plasma ratio of PNL was 0.71 with similar red blood cell and unbound-plasma concentrations. Plasma protein binding (60%-90%) was related to corticosteroid-binding globulin (CBG) saturation. Tissue distribution was nonlinear. The equilibrium dissociation constant (K d ) of PNL shared by all tissues was 3.01 ng/ml, with the highest binding in muscle, followed by liver, heart, intestine, and bone and the lowest binding in skin, spleen, fat, kidney, lung, and brain. Fat and bone distribution assumed access only to interstitial space. Brain PNL concentrations (K p = 0.05) were low owing to presumed P-glycoprotein-mediated efflux. Clearances of CBG-free PNL were 1789 from liver and 191.2 ml/h from kidney. The PN/PNL ratio was nonlinear for plasma, spleen, heart, intestine, bone, fat, and linear for the remaining tissues. Our PBPK model with multiple complexities well described the PK profiles of PNL and PN in blood, plasma, and diverse tissues. SIGNIFICANCE STATEMENT: Because steroids, such as prednisolone and prednisone, have similar and complex pharmacokinetics properties in various species, receptors in most tissues, and multiple therapeutic and adverse actions, this physiologically based pharmacokinetics (PBPK) model may provide greater insights into the pharmacodynamic complexities of corticosteroids. The complex properties of these compounds require innovative PBPK modeling approaches that may be instructive for other therapeutic agents.

Liposomal Delivery Improves the Efficacy of Prednisolone to Attenuate Renal Inflammation in a Mouse Model of Acute Renal Allograft Rejection

Supplemental Digital Content is available in the text.

Background.

Systemic exposure to high-dose corticosteroids effectively combats acute rejection after kidney transplantation, but at the cost of substantial side effects. In this study, a murine acute renal allograft rejection model was used to investigate whether liposomal-encapsulated prednisolone (LP) facilitates local exposure to enhance its therapeutic effect.

Methods.

Male BalbC recipients received renal allografts from male C57BL/6J donors. Recipients were injected daily with 5 mg/kg cyclosporine A and received either 10 mg/kg prednisolone (P), or LP intravenously on day 0, 3, and 6, or no additional treatment. Functional magnetic resonance imaging (fMRI) was performed on day 6 to study allograft perfusion and organs were retrieved on day 7 for further analysis.

Results.

Staining of polyethylene-glycol-labeled liposomes and high performance liquid chromatography analysis revealed accumulation in the LP treated allograft. LP treatment induced the expression of glucocorticoid responsive gene Fkbp5 in the allograft. Flow-cytometry of allografts revealed liposome presence in CD45⁺ cells, and reduced numbers of F4/80⁺ macrophages, and CD3⁺ T-lymphocytes upon LP treatment. Banff scoring showed reduced interstitial inflammation and tubulitis and fMRI analysis revealed improved allograft perfusion in LP versus NA mice.

Conclusions.

Liposomal delivery of prednisolone improved renal bio-availability, increased perfusion and reduced cellular infiltrate in the allograft, when compared with conventional prednisolone. Clinical studies should reveal if treatment with LP results in improved efficacy and reduced side effects in patients with renal allograft rejection.

Transitioning from Basic toward Systems Pharmacodynamic Models: Lessons from Corticosteroids

Technology in bioanalysis, -omics, and computation have evolved over the past half century to allow for comprehensive assessments of the molecular to whole body pharmacology of diverse corticosteroids. Such studies have advanced pharmacokinetic and pharmacodynamic (PK/PD) concepts and models that often generalize across various classes of drugs. These models encompass the "pillars" of pharmacology, namely PK and target drug exposure, the mass-law interactions of drugs with receptors/targets, and the consequent turnover and homeostatic control of genes, biomarkers, physiologic responses, and disease symptoms. Pharmacokinetic methodology utilizes noncompartmental, compartmental, reversible, physiologic [full physiologically based pharmacokinetic (PBPK) and minimal PBPK], and target-mediated drug disposition models using a growing array of pharmacometric considerations and software. Basic PK/PD models have emerged (simple direct, biophase, slow receptor binding, indirect response, irreversible, turnover with inactivation, and transduction models) that place emphasis on parsimony, are mechanistic in nature, and serve as highly useful "top-down" methods of quantitating the actions of diverse drugs. These are often components of more complex quantitative systems pharmacology (QSP) models that explain the array of responses to various drugs, including corticosteroids. Progressively deeper mechanistic appreciation of PBPK, drug-target interactions, and systems physiology from the molecular (genomic, proteomic, metabolomic) to cellular to whole body levels provides the foundation for enhanced PK/PD to comprehensive QSP models. Our research based on cell, animal, clinical, and theoretical studies with corticosteroids have provided ideas and quantitative methods that have broadly advanced the fields of PK/PD and QSP modeling and illustrates the transition toward a global, systems understanding of actions of diverse drugs. SIGNIFICANCE STATEMENT: Over the past half century, pharmacokinetics (PK) and pharmacokinetics/pharmacodynamics (PK/PD) have evolved to provide an array of mechanism-based models that help quantitate the disposition and actions of most drugs. We describe how many basic PK and PK/PD model components were identified and often applied to the diverse properties of corticosteroids (CS). The CS have complications in disposition and a wide array of simple receptor-to complex gene-mediated actions in multiple organs. Continued assessments of such complexities have offered opportunities to develop models ranging from simple PK to enhanced PK/PD to quantitative systems pharmacology (QSP) that help explain therapeutic and adverse CS effects. Concurrent development of state-of-the-art PK, PK/PD, and QSP models are described alongside experimental studies that revealed diverse CS actions.

Clinical Pharmacokinetic and Pharmacodynamic Considerations in the Treatment of Ulcerative Colitis

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) of unknown etiology, probably caused by a combination of genetic and environmental factors. The treatment of patients with active UC depends on the severity, localization and history of IBD medication. According to the classic step-up approach, treatment with 5-aminosalicylic acid compounds is the first step in the treatment of mild to moderately active UC. Corticosteroids, such as prednisolone are used in UC patients with moderate to severe disease activity, but only for remission induction therapy because of side effects associated with long-term use. Thiopurines are the next step in the treatment of active UC but monotherapy during induction therapy in UC patients is not preferred because of their slow onset. Therapeutic drug monitoring (TDM) of the pharmacologically active metabolites of thiopurines, 6-thioguanine nucleotide (6-TGN), has proven to be beneficial. Thiopurine S-methyltransferase (TMPT) plays a role in the metabolic conversion pathway of thiopurines and exhibits genetic polymorphism; however, the clinical benefit and relevance of TPMT genotyping is not well established. In patients with severely active UC refractory to corticosteroids, calcineurin inhibitors such as ciclosporin A (CsA) and tacrolimus are potential therapeutic options. These agents usually have a rather rapid onset of action. Monoclonal antibodies (anti-tumor necrosis factor [TNF] agents, vedolizumab) are the last pharmacotherapeutic option for UC patients before surgery becomes inevitable. Body weight, albumin status and antidrug antibodies contribute to the variability in the pharmacokinetics of anti-TNF agents. Additionally, the use of concomitant immunomodulators (thiopurines/methotrexate) lowers the rate of immunogenicity, and therefore the concomitant use of anti-TNF therapy with an immunomodulator may confer some advantage compared with monotherapy in certain patients. TDM of anti-TNF agents could be beneficial in patients with primary nonresponse and secondary loss of response. The potential benefit of applying TDM during vedolizumab treatment has yet to be determined.

Clinical Pharmacokinetic and Pharmacodynamic Considerations in the Treatment of Inflammatory Bowel Disease

According to recent clinical consensus, pharmacotherapy of inflammatory bowel disease (IBD) is, or should be, personalized medicine. IBD treatment is complex, with highly different treatment classes and relatively few data on treatment strategy. Although thorough evidence-based international IBD guidelines currently exist, appropriate drug and dose choice remains challenging as many disease (disease type, location of disease, disease activity and course, extraintestinal manifestations, complications) and patient characteristics [(pharmaco-)genetic predisposition, response to previous medications, side-effect profile, necessary onset of response, convenience, concurrent therapy, adherence to (maintenance) therapy] are involved. Detailed pharmacological knowledge of the IBD drug arsenal is essential for choosing the right drug, in the right dose, in the right administration form, at the right time, for each individual patient. In this in-depth review, clinical pharmacodynamic and pharmacokinetic considerations are provided for tailoring treatment with the most common IBD drugs. Development (with consequent prospective validation) of easy-to-use treatment algorithms based on these considerations and new pharmacological data may facilitate optimal and effective IBD treatment, preferably corroborated by effectiveness and safety registries.

Free prednisolone pharmacokinetics predicted from total concentrations in patients with inflammatory - immunonologic conditions

Prednisone is an anti-inflammatory drug widely used in internal medicine and rheumatology, but dosing remains empirical. The active metabolite of prednisone is free prednisolone. The aim of this work was to build a population pharmacokinetic (PK) model that can predict free prednisolone concentrations in patients with inflammatory/immunologic conditions.A total of 107 patients from the department of internal medicine of Cochin hospital provided 343 observations. Blood samples drawn for biological analyses were used for drug determination. Total plasma prednisolone concentrations were measured by liquid chromatography-mass spectrometry, and the data were modelled using Monolix. The pharmacokinetics was ascribed a one-compartment open model with three transit compartments standing for the absorption and metabolism process. The model used predicts free concentrations that served to derive total concentrations given published binding constants. Only size parameters influenced the pharmacokinetics. Free prednisolone CL_U /F and V_U /F, scaled allometrically on lean body weight, were, respectively, 26.7 L/h and 94.3 L for 50 kg LBW. CL_U /F interindividual variability was 0.20. The additive and proportional residual variabilities were, respectively, 4.3 µg/L and 0.20. The results point out some dosing issues, that is the possibility of under- or over-dosage in thin or overweight patients respectively.

Pharmacology and pharmacogenetics of prednisone and prednisolone in patients with nephrotic syndrome

Nephrotic syndrome is one of the most common glomerular disorders in childhood. Glucocorticoids have been the cornerstone of the treatment of childhood nephrotic syndrome for several decades, as the majority of children achieves complete remission after prednisone or prednisolone treatment. Currently, treatment guidelines for the first manifestation and relapse of nephrotic syndrome are mostly standardized, while large inter-individual variation is present in the clinical course of disease and side effects of glucocorticoid treatment. This review describes the mechanisms of glucocorticoid action and clinical pharmacokinetics and pharmacodynamics of prednisone and prednisolone in nephrotic syndrome patients. However, these mechanisms do not account for the large inter-individual variability in the response to glucocorticoid treatment. Previous research has shown that genetic factors can have a major influence on the pharmacokinetic and dynamic profile of the individual patient. Therefore, pharmacogenetics may have a promising role in personalized medicine for patients with nephrotic syndrome. Currently, little is known about the impact of genetic polymorphisms on glucocorticoid response and steroid-related toxicities in children with nephrotic syndrome. Although the evidence is limited, the data summarized in this study do suggest a role for pharmacogenetics to improve individualization of glucocorticoid therapy. Therefore, studies in larger cohorts with nephrotic syndrome patients are necessary to draw final conclusions about the influence of genetic polymorphisms on the glucocorticoid response and steroid-related toxicities to ultimately implement pharmacogenetics in clinical practice.

Population Pharmacokinetics of Vamorolone (VBP15) in Healthy Men and Boys With Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is an inherited neuromuscular disorder occurring in boys and caused by mutations in the dystrophin gene. Vamorolone is a first-generation delta-9,11 compound that has favorable efficacy and side effect profiles relative to classical glucocorticoids. The pharmacokinetics (PK) of oral vamorolone were assessed in parallel-group studies in healthy men (phase 1, n = 86) and boys with DMD (phase 2a, n = 48) during 14 days of once-daily dosing with a range of doses. Vamorolone exhibited moderate variability in PK, with the maximum plasma concentration usually occurring at 2-4 hours and a half-life of approximately 2 hours for all doses and days examined. Population PK modeling of all data together indicated that the PK of vamorolone can be well described by a 1-compartment model with zero-order absorption. Both men and boys showed a dose-linearity of PK parameters for the doses examined, with no accumulation of the drug during daily dosing. Ingestion with food resulted in markedly enhanced absorption of the drug, as tested in healthy men. There were similar PK of vamorolone in healthy men and DMD boys with apparent clearance averaging 2.0 L/h/kg in men and 1.7 L/h/kg in boys. Overall, vamorolone exhibited well-behaved linear PK, with similar profiles in healthy men and boys with DMD, moderate variability in PK parameters, and absorption and disposition profiles similar to those of classical glucocorticoids.

Detectable prednisolone is delayed in pericardial fluid, compared with plasma of patients with tuberculous pericarditis: A pilot study

Background

In patients with tuberculous pericarditis [TBP] adjunctive prednisolone reduces the incidence of constrictive pericarditis. It is unknown whether prednisolone permeates adequately into pericardial fluid. Drug measurements in pericardial fluid require invasive procedures, and thus less invasive methods are needed to perform full pharmacokinetic characterization of prednisolone in large numbers of patients. We sought to evaluate the relationship between prednisolone concentrations in pericardial fluid, plasma, and saliva.

Methods

Plasma, pericardial fluid, and saliva samples were collected at 7 time points from TBP patients randomized to 120 mg prednisolone or placebo. Compartmental pharmacokinetic parameters, peak concentration [C_max], and 0-24 h area under the concentration-time curve [AUC_0-24] were identified in plasma, saliva and pericardial fluid.

Results

There were five patients each in the prednisolone and placebo groups. Prednisolone concentrations were best described using a one compartment model. The absorption half-life into plasma was 1 h, while that into pericardial fluid was 9.4 h, which led to a median time-to-maximum concentration in plasma of 2.0 h versus 5.0 h in pericardial fluid [p = 0.048]. The concentration-time profiles in pericardial fluid versus plasma exhibited system hysteresis. The pericardial fluid-to-plasma C_max peak concentration ratio was 0.28 (p = 0.032), while the AUC_0-24 ratio was 0.793. The concentration-time profiles in saliva had a similar shape to those in plasma, but the saliva-to-plasma C_max was 0.59 [p = 0.032].

Conclusion

The prednisolone AUC_0-24 achieved in pericardial fluid approximates that in plasma, but the C_max is low due to delayed absorption. Saliva can be used as surrogate sampling site for pericardial fluid prednisolone.

Clinical Pharmacology in Adult and Pediatric Inflammatory Bowel Disease

This review describes the clinical pharmacology of the major drugs used for the treatment of patients with inflammatory bowel disease (IBD). Pharmacokinetics, drug metabolism, mechanism of action, efficacy, and safety profile are discussed. Some small molecules were developed to act systemically (eg, ozanimod) or locally (eg, aminosalicylates) and thus have disparate pharmacokinetic properties. In addition, locally acting compounds have been optimized to mitigate systemic exposure-eg, budesonide, which undergoes extensive first-pass metabolism-thereby reducing systemic bioavailability and side effects. Other small molecules such as thiopurines are precursors of their active metabolites and differences in genotype or phenotype of metabolizing enzymes may affect efficacy and safety, requiring therapeutic drug monitoring (TDM). Monoclonal antibodies (MAs) are large molecules administered parenterally, and their pharmacokinetics may be influenced not only by the general immunoglobulin (Ig) G metabolism and recycling pathways but also by antigen properties such as antigen distribution and antigen concentration. In addition, antibody structure, host factors, concurrent medications, and immunogenicity may contribute to the substantial inter- and intrapatient variability in drug exposure and response observed for MAs. Current guidelines recommend reactive TDM of tumor necrosis factor antagonists at the time of loss of response. Evidence for proactive TDM and for the role of TDM for biologics with a different mechanism of action is emerging. Although small molecules offer potential benefits over biologics with oral administration and lack of immunogenicity, there may be risk for more systemic side effects due to off-target binding. Understanding drug metabolism, pharmacokinetic characteristics, and mechanism of action are important in selecting the right drug at the right time at the right dose for patients with IBD.10.1093/ibd/izy189_video1izy189.video15786062223001.

Prednisone Pharmacokinetics During Pregnancy and Lactation

To evaluate the steady-state pharmacokinetics of prednisone and its metabolite prednisolone in pregnant and lactating female subjects, 19 subjects received prednisone (4-40 mg/day orally) in early (n = 3), mid (n = 9), and late (n = 13) pregnancy as well as postpartum with (n = 2) and without (n = 5) lactation. Serial blood and urine samples were collected over 1 dosing interval. Prednisone and its metabolite, prednisolone, steady-state noncompartmental pharmacokinetic parameters were estimated. During pregnancy, prednisone apparent oral clearance increased with dose (35.1 ± 11.4 L/h with 5 mg, 52.6 ± 5.2 L/h with 10 mg, and 64.3 ± 6.9 L/h with 20 mg, P = .001). Similarly, unbound prednisone apparent oral clearance increased with dose. In addition, prednisolone renal clearance increased with dose (0.3 ± 0.3 L/h with 5 mg, 0.5 ± 0.4 L/h with 10 mg, and 1.3 ± 1.1 L/h with 20 mg, P = .002). Higher prednisone (r = 0.57, P ≤ .05) and prednisolone (r = 0.75, P ≤ .05) concentrations led to a higher percentage of unbound drug. Breast-milk/plasma area under the concentration-time curve ratios were 0.5-0.6 for prednisone and 0.02-0.03 for prednisolone. Relative infant doses were 0.35% to 0.53% and 0.09% to 0.18%, for prednisone and prednisolone, respectively. Prednisone and prednisolone exhibit dose- and concentration-dependent pharmacokinetics during pregnancy, and infant exposure to these agents via breast milk is minimal.

Pharmacokinetic and pharmacodynamic modeling in BioGears

Pharmacokinetics/pharmacodynamics models were designed and integrated into the BioGears® physiology engine to address the need for real time drug effects for varying patients and injury profiles. Ten drugs were validated using experimental and subject matter expert data. The plasma concentration curves had a good fit with experimental data and 48 of 50 physiologic parameters displayed a less than 10% error compared to the validation data.

Glucocorticoid administration in athletes: Performance, metabolism and detection

It is generally acknowledged in the sporting world that glucocorticoid (GC) use enhances physical performance. This pharmacological class is therefore banned by the World Anti-Doping Agency (WADA) in in-competition samples after systemic but not local (defined as any route other than oral, intravenous, intramuscular or rectal) administration, which thus allows athletes to use GCs for therapeutic purposes. According to the 2016 WADA list, the urine reporting level for all GCs is set at 30ng/ml to distinguish between the authorized and banned routes of administration. The actual data on the ergogenic effects of GC intake are nevertheless fairly recent, with the first study showing improved physical performance with systemic GC administration dating back only to 2007. Moreover, the studies over the last decade coupling ergogenic and metabolic investigations in humans during and after GC intake have shown discrepant results. Similarly, urine discrimination between banned and authorized GC use remains complex, but it seems likely to be improved thanks to new analytical studies and the inclusion of the authorized GC uses (local routes of administration and out-of-competition samples) in the WADA monitoring program. In this review, we first summarize the current knowledge on the ergogenic and metabolic GC effects in humans during various types of exercise. We then present the antidoping legislation and methods of analysis currently used to detect GC abuse and conclude with some practical considerations and perspectives.

Population Pharmacokinetics of Prednisolone in Relation to Clinical Outcome in Children With Nephrotic Syndrome

BACKGROUND

The relapse frequency in children with nephrotic syndrome (NS) is highly variable despite standardized prednisolone treatment regimens. Existing evidence on the relationship between prednisolone pharmacokinetics (PK) and clinical response in children with NS is scarce and limited. The aim of this study was to develop a pediatric popPK model for prednisolone based on our previous model based on healthy adults using salivary measurements in children with NS and to correlate clinical outcome with between-subject variability in prednisolone exposure.

METHODS

The pharmacokinetics of prednisolone in a well-defined, prospective cohort consisting of 104 children with NS while in remission was determined. Pharmacokinetic parameters were analyzed in relation to relapse patterns and side effects. Noninvasive salivary prednisolone measurements were performed using a sparse sampling strategy. A population pharmacokinetic approach was used to derive individual estimates of apparent clearance (CL/F) and apparent volume of distribution (V/F) from the salivary concentration-time curve, followed by calculation of the area under the curve (AUC) of free prednisolone. The individual free serum prednisolone exposure from prednisolone in saliva was derived from the salivary concentration-time curves. Genetic polymorphisms of CYP3A4, CYP3A5, ABCB1, NR1L2, and POR were explored in relation to between-subject variability of CL/F.

RESULTS

Moderate interindividual variability was found for CL/F (CV, 44.7%). Unexplained random between-subject variability (eta) of CL/F was lower in patients carrying 1 or 2 ABCB1 3435C>T alleles compared to wild type: median -0.04 (interquartile range, -0.17 to 0.21) and 0.00 (-0.11 to 0.16) versus 0.17 (-0.08 to 0.47), P = 0.046. Exposure to free prednisolone was not associated with frequent relapses or adverse effects.

CONCLUSIONS

This study provides evidence for the possibility of prednisolone drug monitoring through salivary measurements and this may be of particular usefulness in pediatric patients. However, the observed variability in prednisolone exposure, in the therapeutic dose range studied, is not considered to be a major determinant of clinical outcome in children with NS.

Exploratory study of total and free prednisolone plasma exposure and cushingoid appearance, quality of life and biochemical toxicity in adult male kidney transplant recipients

BACKGROUND AND OBJECTIVE

Long-term adverse effects of oral glucocorticoids are frequent and serious. Large between-patient variability in the pharmacokinetics of prednisolone might explain why drug dose is a poor predictor of drug-related toxicity. The aim of the study was to investigate relationships between prednisolone exposure and adverse effects.

METHODS

Male kidney transplant recipients were recruited for serial blood sampling and assessment of glucocorticoid-related adverse effects including dyslipidaemia, abnormal body fat distribution, Cushingoid appearance and impaired quality of life. Total and free prednisolone plasma concentrations were determined using ultra-high-performance liquid chromatography with tandem mass spectrometric detection. Prednisolone exposure was estimated using a limited sampling strategy.

RESULTS

Fifty-six patients were recruited. Patients had a mean age of 54 years and median time post-transplantation of 75 months. Median prednisolone dose was 5 mg. Mean area under the plasma concentration-time curve was 2390 nmol h/L (±580) (SD) and 175 nmol h/L (±78) for total and free prednisolone, respectively. Waist to upper arm circumference ratio was positively associated with free prednisolone plasma exposure with a Spearman correlation coefficient of 0.30 (p value 0.02). The correlation coefficient was 0.24 (p value 0.08) for neck to upper arm circumference ratio and free prednisolone plasma exposure. The clinical Cushingoid phenotype as determined by the Visual Assessment of Cushing's Severity (VACS) score was associated with a reduced score relating to physical functioning on the SF-12, but there was no significant relationship between free prednisolone plasma exposure and quality-of-life scores. Lipid levels and haemoglobin A1c (HbA1c) were not associated with total or free prednisolone exposure.

CONCLUSIONS

There is a positive correlation between free prednisolone plasma exposure and waist to upper arm circumference ratio in adult male kidney transplant recipients on low maintenance prednisolone doses. There is no significant association between total or free prednisolone plasma exposure and plasma glucose and lipid levels in the low prednisolone dose range.

Effect of Luteolin on 11Beta-Hydroxysteroid Dehydrogenase in Rat Liver and Kidney

11Beta-hydroxysteroid dehydrogenase (11β-HSD) enzymes control the glucocorticoid (GC) signaling, which is essential in regulating homeostasis. Our previous study revealed that Eclipta prostrata (EP) affected the activity and expression of 11β-HSD enzymes which might improve the efficacy and reduce the adverse drug effects of glucocorticoid in patients undergoing combinational therapy. However, it is still unclear which composition of EP plays a major role and how it works. In this paper, we chose Luteolin which is one of the main ingredients of EP and evaluated its effect and metabolism in combination with prednisone. The effects of different concentrations of Luteolin extract on prednisone/prednisolone metabolism indicated the enzyme activity of 11β-HSD, so the production rate (pmol/min per mg protein) of metabolites was used to indicate enzyme activity. Furthermore, we explored the influence of Luteolin on gene and protein expressions of 11β-HSD I/II in rat liver and kidney tissue. Our results showed that oral administration of Luteolin significantly increased the gene and protein expressions of hepatic 11β-HSD I and renal 11β-HSD II, which may improve the efficacy and reduce the adverse drug effect of glucocorticoid in clinical application. A potential clinical value of Luteolin would also be indicated in combination therapy with prednisone for the treatment of nephrotic syndrome.

Review article: The pharmacokinetics and pharmacodynamics of drugs used in inflammatory bowel disease treatment

BACKGROUND

The following review is a compilation of the recent advances and knowledge on the behaviour of the most frequently used compounds to treat inflammatory bowel disease in an organism.

RESULTS

It considers clinical aspects of each entity and the pharmacokinetic/pharmacodynamic relationship supported by the use of plasma monitoring, tissue concentrations, and certain aspects derived from pharmacogenetics.

Competitive binding to plasma thyroid hormone transport proteins and thyroid disruption by phenylbutazone used as a probe

A model of thyroidectomized sheep intravenously supplemented with thyroid hormone (TH) was developed to mimic endogenous TH exposure and to analyze the impact on plasma TH homeostasis of xenobiotic interference with TH binding to plasma proteins. TH was displaced from plasma protein binding sites by using phenylbutazone (PBZ) as a test xenobiotic, to compare the effect of PBZ on steady state free and total plasma TH concentrations between the in vivo situation and an in vitro system. While PBZ increased free TH in vitro, PBZ administration in vivo produced an immediate reduction in both total and free plasma TH. The decrease in the total TH was consistent with a PBZ-induced displacement of TH from its plasma binding proteins, leading to an increase in total TH plasma clearance. However, this reduction in total TH was not expected to be accompanied by a parallel decrease in free plasma TH since the free TH is determined by the clearance of the free plasma TH. This suggested that PBZ may also have interfered with the clearance mechanisms of free TH. It can be concluded that our thyroidectomized sheep model enables a dual action of a xenobiotic on plasma TH to be distinguished, namely a displacement of TH from its binding proteins leading to a decrease in the total plasma concentration, which is not relevant to thyroid function versus an interference with the intrinsic TH clearance leading to a change in the free plasma TH, which has a major impact in terms of thyroid disruption.

Rapid glucocorticoid receptor-mediated inhibition of hypothalamic-pituitary-adrenal ultradian activity in healthy males

A complex dynamic ultradian rhythm underlies the hypothalamic-pituitary-adrenal (HPA) circadian rhythm. We have investigated in normal human male subjects the importance, site of action, and receptor-mediated processes involved in rapid basal corticosteroid feedback and its interaction with corticotrophin releasing hormone (CRH) drive. Pro-opiomelanocortin (POMC), ACTH, and cortisol were measured every 10 min from healthy males during the awakening period or late afternoon using an automated blood sampling system. Mathematical modeling into discrete pulses of activity revealed that intravenous infusion of the synthetic mixed glucocorticoid/mineralocorticoid agonist prednisolone produced rapid inhibition of ACTH and cortisol pulsatility within 30 min in the morning and afternoon. Any pulse that had commenced at the time of injection was unaffected, and subsequent pulsatility was inhibited. Prednisolone also inhibited ACTH and cortisol secretion in response to exogenous CRH stimulation, inferring rapid feedback inhibition at the anterior pituitary. Circulating POMC peptide concentrations were unaffected, suggesting that the rapid corticosteroid inhibitory effect specifically targeted ACTH secretion from pituitary corticotrophs. Prednisolone fast feedback was only reduced by glucocorticoid receptor antagonist pretreatment and not by mineralocorticoid receptor antagonism, suggesting a glucocorticoid receptor-mediated pathway. The intravenous prednisolone suppression test provides a powerful new tool to investigate HPA abnormalities underlying metabolic and psychiatric disease states.

Pharmacokinetics and anti-inflammatory pharmacodynamics of prednisolone in cynomolgus monkey

The purpose was to investigate whether the pharmacokinetics and pharmacodynamics of prednisolone in the non-human primate was an appropriate surrogate for man. After single intravenous doses of 0.03, 0.3, and 3 mg kg(-1), prednisolone demonstrated a dose-dependent clearance and volume of distribution. When corrected for concentration-dependent protein binding, the free clearance was linear at the tested dose levels. The protein binding-corrected volume of distribution was similar across doses. The serum half-life was estimated as being between 2 and 4 h. Prednisolone exhibits near complete inhibition of the cytokines TNF-alpha, IL-1beta, IL-6 and IL-8 with very similar IC50 estimates from 0.09 to 0.16 microg ml(-1) (from 0.24 to 0.44 microM). The monkey demonstrated a similar pharmacokinetics-pharmacodynamics profile of prednisolone when compared with man (from the literature).

Prednisone dosing per body weight or body surface area in children with nephrotic syndrome: is it equivalent?

The current guidelines recommend a dosage of prednisone of 60 mg/m(2) body surface area per day (BSA PRED) for the initial therapy of nephrotic syndrome (NS). Alternatively, a dosage of 2 mg/kg body weight per day (W PRED) can be used. We hypothesized that the BSA PRED and W PRED are not equivalent and analyzed the differences between BSA PRED calculated with various formulas for body surface area (BSA), W PRED and the dose of prednisone prescribed for our patients. We performed a retrospective chart review of the patients at their initial presentation of NS. Thirty-three children were included, of median age 3.34 years at presentation. The W PRED was significantly lower than BSA PRED (P < 0.05), with a median W PRED:BSA PRED ratio of 0.85 [interquartile range (IQR) 0.8 to 0.9]. The difference between W PRED and BSA PRED decreased proportionally to patients' weights up to 30 kg. No differences were noted between the various BSA formulas using both weight and height for the calculation of BSA. The Bland-Altman analysis showed a proportional error between W PRED and BSA PRED up to the average daily dose of 60 mg, with a mean bias of 0.86 (95% limits of agreement = 0.68 to 1.05). Ten out of the 33 patients (30%) were given a lower than recommended BSA PRED dose by more than 5 mg/day. In conclusion, the dosage of prednisone at 2 mg/kg per day versus 60 mg/m(2) per day is not equivalent for patients with weights <30 kg and/or dose <60 mg/day.

The influence of uremia on pharmacokinetics and protein binding of prednisolone

The pharmacokinetics and protein binding of prednisolone have been compared in 6 uremic patients and 6 healthy controls after intravenous injection of 20 mg prednisolone. The uremic patients had a 53% longer elimination half-time (p less than 0.01) and a 34% larger area under the time-concentration curve (AUC) (p less than 0.05) of total prednisolone than the controls. The total body clearance of total prednisolone was 26% lower and of free prednisolone 40% lower in the uremic patients than in the controls (p less than 0.01). The volume of distribution at steady state was 17% larger in the patients than in the controls, but the difference was not statistically significant. The protein binding of prednisolone was decreased in the patients, the proportion of free prednisolone being 26% higher than in the controls (p less than 0.05). The amount of free prednisolone, expressed as the AUC of free prednisolone, was 67% larger in the patients than in the controls (p less than 0.01). These results indicate that uremic patients taking prednisolone may be more prone to develop glucocorticoid side-effects because of higher concentration of free, biologically active prednisolone, secondary to a reduced rate of elimination and a decreased serum protein binding of prednisolone.

Influence of dialysis on prednisolone kinetics

Six patients with end-stage renal disease were given prednisolone, 0.7-1.0 mg/kg/b.wt. parenterally. Prednisolone kinetics were investigated during dialysis, in 3 patients on hemodialysis and in 3 on continuous peritoneal dialysis, and also on days without dialysis. Mean plasma half-life was 250 min in five patients and 690 min in one patient who also suffered from intermittent porphyria. No change was found in prednisolone kinetics when the dialysis-free period was compared to the dialysis periods.

Assessment of the impact of dosing time on the pharmacokinetics/pharmacodynamics of prednisolone

Prednisolone is widely used for the treatment of inflammation and auto-immune diseases. It exhibits nonlinear pharmacokinetics (PK); and its induced systemic effects (pharmacodynamics (PD)) are commonly evaluated with two biomarkers, cortisol and blood lymphocytes in plasma. Circadian patterns are observed in both biomarkers. Furthermore, the disease itself may show a circadian pattern. For example, in rheumatoid arthritis patients, better therapeutic outcomes have been reported when prednisolone was administered in the very early morning. The aim of this study is to evaluate the impact of dosing time on the PK/PD of prednisolone with a simulation approach using an interactive algorithm. A series of simulations were performed with either intravenous or oral administration of prednisolone or prednisone. The results showed that the initial or maximum concentration and trough concentration of total prednisolone were lower when the drug was administered in the early morning around 6 AM: . Oscillation patterns were observed in cumulative cortisol suppression (CCS) and alteration of total lymphocyte trafficking in blood. When the drug was given in the morning within the therapeutic dose range, or around 6 PM: for a small dose amount (<1 mg), the minimum CCS and maximum effect on lymphocytes were observed. These results indicated that the PK/PD of prednisolone are time- and dose-dependent, and suggested that it is necessary to consider the application of chronotherapy to achieve better clinical outcomes with fewer side effects of prednisolone, and a PK/PD simulation approach could provide a valuable tool to evaluate and predict time-dependency in the system.

Application of gastrointestinal simulation for extensions for biowaivers of highly permeable compounds

The goal of this study was to apply gastrointestinal simulation technology and integration of physiological parameters to predict biopharmaceutical drug classification. GastroPlus was used with experimentally determined physicochemical and pharmacokinetic drug properties to simulate the absorption of several weak acid and weak base BCS class II compounds. Simulation of oral drug absorption given physicochemical drug properties and physicochemical parameters will aid justification of biowaivers for selected BCS class II compounds.

Simultaneous determination of prednisolone, prednisone, cortisol, and cortisone in plasma by GC-MS: estimating unbound prednisolone concentration in patients with nephrotic syndrome during oral prednisolone therapy

Individual variability of the pharmacokinetics of prednisolone based on the unbound concentration in plasma is of significant clinical consideration. The unbound concentrations of prednisolone were measured in 10 patients with nephrotic syndrome, two patients with systemic lupus erythematosus, and one patient with dermatomyositis by examining protein bindings of prednisolone on one or more occasions during prednisolone treatment. In this study, plasma concentrations of prednisolone, prednisone, cortisol, and cortisone were simultaneously analyzed by GC-MS by using stable isotope-labeled internal standards. Equilibrium dialysis was employed to accurately estimate the unbound fractions of prednisolone in plasma. The unbound fraction of prednisolone changed depending on plasma total prednisolone concentration and plasma albumin concentration. The unbound fraction of prednisolone (Y) is calculated: Y=(-0.0101x' + 0.0736) x + 10.23, where x' is the plasma albumin concentration and x is the total prednisolone concentration. The estimated concentrations of unbound prednisolone by using the above equation were in good agreement with the measured concentrations of unbound prednisolone. Since the protein binding of prednisolone did not change in the presence of prednisone (114.0 ng/ml), it appeared that prednisone produced from the therapeutic dose of prednisolone did not affect the unbound fraction of prednisolone.

Biowaiver monographs for immediate release solid oral dosage forms: prednisone

Literature data relevant to the decision to allow a waiver of in vivo bioequivalence (BE) testing for the approval of immediate release (IR) solid oral dosage forms containing prednisone are reviewed. Due to insufficient data prednisone cannot be definitively classified according to the current Biopharmaceutics Classification System (BCS) criteria as both the solubility and the permeability of prednisone are on the borderline of the present criteria of BCS Class I. Prednisone's therapeutic indications and therapeutic index, pharmacokinetics and the possibility of excipient interactions were also taken into consideration. Available evidence indicates that a biowaiver for IR solid oral dosage forms formulated with the excipients tabulated in this article would be unlikely to expose patients to undue risks.

A Pharmacokinetic/Pharmacodynamic Approach to Predict Total Prednisolone Concentrations in Human Plasma

Prednisolone and prednisone are two widely used corticosteroids for various inflammatory and immune diseases. Prednisolone is the active form of prednisone in vivo. Total prednisolone in plasma exhibits nonlinear pharmacokinetics mainly due to its nonlinear protein binding. Other factors such as reversible metabolism (or interconversion between prednisolone and prednisone), competitive protein binding from endogenous cortisol, cortisol circadian rhythm, and prednisolone mediated cortisol suppression complicate prednisolone pharmacokinetics. This study was aimed to develop a new approach to describe the nonlinear pharmacokinetics of total prednisolone and predict total prednisolone concentrations in plasma. Based on literature datasets, a linear two-compartment pharmacokinetic model was developed to adequately describe the reversible metabolism between free prednisone and prednisolone. Cortisol and prednisolone protein binding were described via the sum of a Langmuir and linear type binding. The endogenous cortisol circadian rhythm and cortisol suppression during prednisone or prednisolone exposure were described with a previously reported linear release rate pharmacokinetic/pharmacodynamic (PK/PD) model. By combining the pharmacokinetic models for free prednisone and prednisolone, the linear release rate model for cortisol suppression, and competitive protein binding between cortisol and prednisolone, we were able to predict total prednisolone concentrations in plasma. The predicted total prednisolone concentrations in plasma were in good agreement with the literature reported data. Thus, this PK/PD approach shows that the combination of nonlinear protein binding, cortisol circadian rhythm, and cortisol suppression could account for the nonlinearity of total prednisolone. In addition, it also allows a valid prediction of total prednisolone in plasma after either prednisone or prednisolone administration.