Bioavailability and reversible metabolism of prednisone and prednisolone in man

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.

Biotransformation of Δ1-Progesterone Using Selected Entomopathogenic Filamentous Fungi and Prediction of Its Products' Bioactivity

This research aimed at obtaining new derivatives of pregn-1,4-diene-3,20-dione (Δ1-progesterone) (2) through microbiological transformation. For the role of catalysts, we used six strains of entomopathogenic filamentous fungi (Beauveria bassiana KCh J1.5, Beauveria caledonica KCh J3.3, Isaria fumosorosea KCh J2, Isaria farinosa KCh KW1.1, Isaria tenuipes MU35, and Metarhizium robertsii MU4). The substrate (2) was obtained by carrying out an enzymatic 1,2-dehydrogenation on an increased scale (3.5 g/L) using a recombinant cholest-4-en-3-one Δ1-dehydrogenase (AcmB) from Sterolibacterium denitrificans. All selected strains were characterized by the high biotransformation capacity for the used substrate. As a result of the biotransformation, six steroid derivatives were obtained: 11α-hydroxypregn-1,4-diene-3,20-dione (3), 6β,11α-dihydroxypregn-1,4-diene-3,20-dione (4), 6β-hydroxypregn-1,4-diene-3,11,20-trione (5), 6β,17α-dihydroxypregn-1,4-diene-3,20-dione (6), 6β,17β-dihydroxyandrost-1,4-diene-3-one (7), and 12β,17α-dihydroxypregn-1,4-diene-3,20-dione (8). The results show evident variability of the biotransformation process between strains of the tested biocatalysts from different species described as entomopathogenic filamentous fungi. The obtained products were tested in silico using cheminformatics tools for their pharmacokinetic and pharmacodynamic properties, proving their potentially high biological activities. This study showed that the obtained compounds may have applications as effective inhibitors of testosterone 17β-dehydrogenase. Most of the obtained products should, also with a high probability, find potential uses as androgen antagonists, a prostate as well as menopausal disorders treatment. They should also demonstrate immunosuppressive, erythropoiesis-stimulating, and anti-inflammatory properties.

Urinary Free Cortisol Determination and Interferences Studies Using Liquid Chromatography Coupled to Tandem Mass Spectrometry after On-Line Solid Phase Extraction Based on TurboflowTM Chromatography

(1) A 24 h urinary free cortisol (UFF) is one of the first-line exams recommended for the diagnosis of Cushing's syndrome. In a hospital hormonology department, this activity can exceed several hundred dosages per week. The UFF is generally determined via an immunoassay with an automate using a chemiluminescence or electrochemiluminescence detection system. To increase the cortisol concentration in the analyzed sample, the automated analysis is preceded by urine extraction, which does not prevent there from being some interferences due to other steroids with close structures. (2) This paper describes the development of on-line solid phase extraction coupled to liquid chromatography and mass spectrometry for the analysis of urinary free cortisol. The on-line extraction was based on the TurboflowTM chromatography coupled to the analytical column by two valves, easily available for the laboratories. (3) The choice of the Accucore Polar Premium® analytical column made it possible to avoid analytical interferences with exogenous or endogenous molecules having the same SRM transition (363 → 121) as cortisol. (4) The method was fully validated in the range of clinically relevant concentrations from the lower limit of quantification (LLOQ) to 411.75 nmol·L-1.

Interventions for bullous pemphigoid

BACKGROUND

Bullous pemphigoid (BP) is the most common autoimmune blistering disease. Oral steroids are the standard treatment. We have updated this review, which was first published in 2002, because several new treatments have since been tried.

OBJECTIVES

To assess the effects of treatments for bullous pemphigoid.

SEARCH METHODS

We updated searches of the following databases to November 2021: Cochrane Skin Specialised Register, CENTRAL, MEDLINE, and Embase. We searched five trial databases to January 2022, and checked the reference lists of included studies for further references to relevant randomised controlled trials (RCTs).

SELECTION CRITERIA

RCTs of treatments for immunofluorescence-confirmed bullous pemphigoid.

DATA COLLECTION AND ANALYSIS

At least two review authors, working independently, evaluated the studies against the review's inclusion criteria and extracted data from included studies. Using GRADE methodology, we assessed the certainty of the evidence for each outcome in each comparison. Our primary outcomes were healing of skin lesions and mortality.

MAIN RESULTS

We identified 14 RCTs (1442 participants). The main treatment modalities assessed were oral steroids, topical steroids, and the oral anti-inflammatory antibiotic doxycycline. Most studies reported mortality but adverse events and quality of life were not well reported. We decided to look at the primary outcomes 'disease control' and 'mortality'. Almost all studies investigated different comparisons; two studies were placebo-controlled. The results are therefore based on a single study for each comparison except azathioprine. Most studies involved only small numbers of participants. We assessed the risk of bias for all key outcomes as having 'some concerns' or high risk, due to missing data, inappropriate analysis, or insufficient information. Clobetasol propionate cream versus oral prednisone Compared to oral prednisone, clobetasol propionate cream applied over the whole body probably increases skin healing at day 21 (risk ratio (RR 1.08, 95% confidence interval (CI) 1.03 to 1.13; 1 study, 341 participants; moderate-certainty evidence). Skin healing at 21 days was seen in 99.8% of participants assigned to clobetasol and 92.4% of participants assigned to prednisone. Clobetasol propionate cream applied over the whole body compared to oral prednisone may reduce mortality at one year (RR 0.73, 95% CI 0.53 to 1.01; 1 study, 341 participants; low-certainty evidence). Death occurred in 26.5% (45/170) of participants assigned to clobetasol and 36.3% (62/171) of participants assigned to oral prednisone. This study did not measure quality of life. Clobetasol propionate cream may reduce risk of severe complications by day 21 compared with oral prednisone (RR 0.65, 95% CI 0.50 to 0.86; 1 study, 341 participants; low-certainty evidence). Mild clobetasol propionate cream regimen (10 to 30 g/day) versus standard clobetasol propionate cream regimen (40 g/day) A mild regimen of topical clobetasol propionate applied over the whole body compared to the standard regimen probably does not change skin healing at day 21 (RR 1.00, 95% CI 0.97 to 1.03; 1 study, 312 participants; moderate-certainty evidence). Both groups showed complete healing of lesions at day 21 in 98% participants. A mild regimen of topical clobetasol propionate applied over the whole body compared to the standard regimen may not change mortality at one year (RR 1.00, 95% CI 0.75 to 1.32; 1 study, 312 participants; low-certainty evidence), which occurred in 118/312 (37.9%) participants. This study did not measure quality of life. A mild regimen of topical clobetasol propionate applied over the whole body compared to the standard regimen may not change adverse events at one year (RR 0.94, 95% CI 0.78 to 1.14; 1 study, 309 participants; low-certainty evidence). Doxycycline versus prednisolone Compared to prednisolone (0.5 mg/kg/day), doxycycline (200 mg/day) induces less skin healing at six weeks (RR 0.81, 95% CI 0.72 to 0.92; 1 study, 213 participants; high-certainty evidence). Complete skin healing was reported in 73.8% of participants assigned to doxycycline and 91.1% assigned to prednisolone. Doxycycline compared to prednisolone probably decreases mortality at one year (RR 0.25, 95% CI 0.07 to 0.89; number needed to treat for an additional beneficial outcome (NNTB) = 14; 1 study, 234 participants; moderate-certainty evidence). Mortality occurred in 2.4% (3/132) of participants with doxycycline and 9.7% (11/121) with prednisolone. Compared to prednisolone, doxycycline improved quality of life at one year (mean difference 1.8 points lower, which is more favourable on the Dermatology Life Quality Index, 95% CI 1.02 to 2.58 lower; 1 study, 234 participants; high-certainty evidence). Doxycycline compared to prednisolone probably reduces severe or life-threatening treatment-related adverse events at one year (RR 0.59, 95% CI 0.35 to 0.99; 1 study, 234 participants; moderate-certainty evidence). Prednisone plus azathioprine versus prednisone It is unclear whether azathioprine plus prednisone compared to prednisone alone affects skin healing or mortality because there was only very low-certainty evidence from two trials (98 participants). These studies did not measure quality of life. Adverse events were reported in a total of 20/48 (42%) participants assigned to azathioprine plus prednisone and 15/44 (34%) participants assigned to prednisone. Nicotinamide plus tetracycline versus prednisone It is unclear whether nicotinamide plus tetracycline compared to prednisone affects skin healing or mortality because there was only very low-certainty evidence from one trial (18 participants). This study did not measure quality of life. Fewer adverse events were reported in the nicotinamide group. Methylprednisolone plus azathioprine versus methylprednisolone plus dapsone It is unclear whether azathioprine plus methylprednisolone compared to dapsone plus methylprednisolone affects skin healing or mortality because there was only very low-certainty evidence from one trial (54 participants). This study did not measure quality of life. A total of 18 adverse events were reported in the azathioprine group and 13 in the dapsone group.

AUTHORS' CONCLUSIONS

Clobetasol propionate cream applied over the whole body is probably similarly effective as, and may cause less mortality than, oral prednisone for treating bullous pemphigoid. Lower-dose clobetasol propionate cream applied over the whole body is probably similarly effective as standard-dose clobetasol propionate cream and has similar mortality. Doxycycline is less effective but causes less mortality than prednisolone for treating bullous pemphigoid. Other treatments need further investigation.

Investigation of the urinary excretion of prednisolone and metabolites after nasal administration: Relevance to doping control

Glucocorticosteroid use in sport is restricted to non-systemic (nasal/ophtamological/dermatological/intra-articular) use. Systemic use is prohibited because of strong inflammatory suppressing effects. Prednisolone is a GC proven to be very effective in the treatment of nasal congestions and allergic rhinitis and its therapeutic use is allowed. To establish normal urinary concentration ranges for nasally administered prednisolone, an excretion study was performed with Sofrasolone® (nasal-inhaler). Six volunteers were administered a high dose (4.5 mg prednisolone in four gifts over a 9-h period). Samples were analysed using a validated LC-MS/MS method monitoring prednisolone (PRED) and the metabolites prednisone (PREDON), 20β-dihydroprednisolone (20βPRED) and 20α-dihydroprednisolone (20αPRED) in the total fraction (glucuroconjugated and free). Maximum concentrations were 266, 500, 350 and 140 ng/ml for PRED, PREDON, 20βPRED and 20αPRED, respectively. These results show that the current reporting limit of 30 ng/ml in urine can be easily exceeded after therapeutic use. Hence, to avoid false-positive findings related to nasal application, this limit should be increased. To investigate the degree of glucuronidation of PRED and its metabolites also the free fraction was investigated. This shows that PREDON has the highest glucuroconjugation (50%). PRED, 20βPRED and 20αPRED only show less than 20% conjugation.

Elimination profiles of prednisone and prednisolone after different administration routes: Evaluation of the reporting level and washout periods to ensure safe therapeutic administrations

Prednisolone (PRED) and prednisone (PSONE) are prohibited in sports competitions when administered by systemic routes, and they are allowed by other routes for therapeutic purposes. There is no restriction of use in out-of-competition periods. The present study aimed to evaluate the urinary excretion of PRED, PSONE, and their most important metabolites after systemic and nonsystemic treatments in order to verify the suitability of the current reporting level of 30 ng/ml used to distinguish allowed and prohibited administrations and to establish washout periods for oral treatments performed in out-of-competition periods. PRED was studied after dermatological administration (5 mg/day for 5 days, n = 6 males) and oral administration (5 mg, n = 6 males; 10 mg, n = 2 males). PSONE was studied after oral administration (10 mg, n = 2 males; 30 mg, n = 1 male and 1 female). Concentrations in urine were measured using an LC-MS/MS method. Concentrations after dermatological treatment were low for all metabolites. After oral administration, concentrations were very high during the first 24 h after administration ranging from 1.6 to 2261 ng/ml and from 4.6 to 908 ng/ml for PRED and PSONE, respectively. Concentrations of most of the metabolites measured were lower than 30 ng/ml from 24 h after all oral administrations. New reporting levels are proposed for PRED and PSONE considering data of our study and other information published after nonsystemic administrations of the compounds. Washout periods of at least 24 h are recommended to ensure no false positives when oral treatments need to be performed in out-of-competition periods.

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.

How can we minimise the use of regular oral corticosteroids in asthma?

Options to achieve oral corticosteroid (OCS)-sparing have been triggering increasing interest since the 1970s because of the side-effects of OCSs, and this has now become achievable with biologics. The Société de Pneumologie de Langue Française workshop on OCSs aimed to conduct a comprehensive review of the basics for OCS use in asthma and issue key research questions. Pharmacology and definition of regular use were reviewed by the first working group (WG1). WG2 examined whether regular OCS use is associated with T2 endotype. WG3 reported on the specificities of the paediatric area. Key “research statement proposals” were suggested by WG4. It was found that the benefits of regular OCS use in asthma outside episodes of exacerbations are poorly supported by the existing evidence. However, complete OCS elimination couldn’t be achieved in any available studies for all patients and the panel felt that it was too early to conclude that regular OCS use could be declared criminal. Repeated or prolonged need for OCS beyond 1 g·year⁻¹ should indicate the need for referral to secondary/tertiary care. A strategic sequential plan aiming at reducing overall exposure to OCS in severe asthma was then held as a conclusion of the workshop.

A yearly cumulative OCS dose above 1 g should be considered unacceptable in severe asthma and should make the case for referralhttp://bit.ly/34GAYLX

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.

Hepatic clearance concepts and misconceptions: Why the well-stirred model is still used even though it is not physiologic reality?

The liver is the most important drug metabolizing organ, endowed with a plethora of metabolizing enzymes and transporters to facilitate drug entry and removal via metabolism and/or biliary excretion. For this reason, much focus surrounds the development of clearance concepts, which are based on normalizing the rate of removal to the input or arterial concentration. By so doing, some authors have recently claimed that it implies one specific model of hepatic elimination, namely, the widely used well-stirred or venous equilibration model (WSM). This commentary challenges this claim and aims to provide a comprehensive discussion of not only the WSM but other currently applied hepatic clearance models - the parallel tube model (PTM), the dispersion model (DM), the zonal liver model (ZLM), and the heterogeneous capillary transit time model of Goresky and co-workers (GM). The WSM, PTM, and DM differ in the patterns of internal blood flow, assuming bulk, plug, and dispersive flows, respectively, which render different degrees of mixing within the liver that are characterized by the magnitudes of the dispersion number (D_N), resulting in different implications concerning the (unbound) substrate concentration in liver (Cu_H). Early models assumed perfusion rate-limited distribution, which have since been modified to include membrane-limited transport. The recent developments associated with the misconceptions and the sensitivity of the models are hereby addressed. Since the WSM has been and will likely remain widely used, the pros and cons of this model relative to physiological reality are further discussed.

Glucocorticoids dosing in obese subjects: A systematic review

Glucocorticoids (GCs) are amongst the most widely used and effective treatments to control inflammatory and autoimmune diseases. In obese subjects, drug dosing adjusted by body weight is problematic, all the more so as patients are at higher risk of GC metabolic side effects. We propose here to describe the determinants of drug pharmacokinetics (PK) in obese subjects and GC pharmacology, and to identify the existing PK studies that may help discussing the best size descriptor for GC dosing in obese subjects. A clinician and a pharmacist screened PubMed using the MeSH Terms: "glucocorticoids" OR "steroidal agents" AND "pharmacokinetics" AND "obesity" OR "overweight". The search was limited to the publications written in English language and to those performed in humans. A systematic search using the MeSH terms was performed until August 31st, 2017. Only three such PK studies have been published so far that compare dexamethasone, prednisolone and methylprednisolone in obese and normal weight subjects. The studies concur that GC partially distribute in the excess of body weight and that adjustment by total body weight (TBW) or by body weight (BW) excess would increase the initial plasma GC concentration after a loading dose and would thus be inappropriate. Contradictory results are observed regarding GC exposure or clearance according to the GC studied. Behind this overwhelming lack of conclusive evidence for adjusting GC by body weight, further PK studies are clearly needed for guiding their dosing. Furthermore, studies demonstrated an increased sensibility to GC, even when GC exposure was reduced, suggesting that adjustment by body weight may not only be unnecessary but also dangerous.

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.

The availability of drug by liposomal drug delivery : Individual kinetics and tissue distribution of encapsulated and released drug in mice after administration of PEGylated liposomal prednisolone phosphate

Lately, the usefulness of liposomal drug delivery systems has been debated. To better understand the underlying pharmacokinetics of the targeted drug delivery by liposomes, individual encapsulated and non-encapsulated drug concentrations in blood, tumor, liver, spleen and kidneys were quantified after i.v. administration of liposomal prednisolone phosphate in mice. Kinetic analysis shows that the tumor influx of encapsulated drug is not dominant compared to the uptake by the other tissues. Further, from a quantitative point of view, the availability of non-encapsulated drug in the tumor tissue after liposomal delivery is not pronounced as compared to the other tissues studied. However, drug release in the tumor seems more extended than in the other tissues and the non-encapsulated drug concentration decreases more slowly in the tumor than in the liver and spleen. The spleen shows a high affinity for the uptake of encapsulated drug as well as the release of drug from the liposomes. Subsequently, released drug in the spleen, and possibly also in other tissues, is probably quickly redistributed towards the blood and other tissues. This also impairs the drug delivery effect of the liposomes. In contrast to the released drug in the central circulation, liver and spleen, the released drug concentration in the tumor remains at a fairly constant level likely due to the extended release kinetics from the liposomes. These extended release characteristics in the tumor most probably contribute to the beneficial effect. Nevertheless, it should be noted that larger released drug concentrations are formed in healthy tissues.

Evaluation of interconversion pharmacokinetics of 16α-hydroxycleroda-3,13(14)Z-dien-15,16-olide - a novel HMG-CoA reductase inhibitor and its acid metabolite using multi-compartmental pharmacokinetic model in mice

16α-Hydroxycleroda-3,13(14)Z-dien-15,16-olide (4655K-09 or K-09) is a novel clerodane diterpene lactone reported for its anti-hyperlipidemic efficacy. The objective of the present study was to investigate the probable reversible metabolism of 4655K-09 and evaluate its effects on pharmacokinetic (PK) properties. The PK studies were carried out through intravenous (IV) bolus administration of 4655K-09 and K-9T in mice at a dose of 3, 6 and 12 mg/kg separately. The oral PK study of 4655K-09 was carried out at therapeutic dose of 25 mg/kg. The % AUC of metabolite converted to parent upon its administration % AUCK-09K-9T was found to be 27.28 ± 2.67. The multi-compartmental interconversion model defined reversible and irreversible clearances along with volumes of distribution for parent and metabolite. The results emphasized that hydrolysis of lactone to acid was more efficient than back conversion to parent due to greater extent of irreversible elimination of acid. Further, the role of interconversion in pharmacokinetics of 4655K-09 was evaluated through secondary parameters like conversion coefficients of parent to metabolite ( KK-9TK-09:0.08 ± 0.02 ), metabolite to parent ( KK-09K-9T : 0.019 ± 0.001), exposure enhancement (EE: 1.04 ± 0.006), and recycled fraction (RF: 0.042 ± 0.007), highlighted the minimal role of interconversion. The estimation of oral bioavailability remains unaffected when calculated through considering reversible metabolism. The present model-based interconversion pharmacokinetics of 4655K-09 in mice could be further extended to other species to support its development as anti-hyperlipidemic agent.

Quantitative LC-MS determination of liposomal encapsulated prednisolone phosphate and non-encapsulated prednisolone concentrations in murine whole blood and liver tissue

The underlying pharmacokinetic profile of liposomal drug delivery systems is not yet fully known. This is primarily due to a lack of suitable quantitative bioanalytical methodology to simultaneously determine separate liposomal-encapsulated and non-encapsulated drug tissue concentrations in complex biological samples. Here, an LC-MS method was developed which enables the simultaneous quantification of separate liposomal-encapsulated prednisolone phosphate and non-encapsulated prednisolone concentrations in whole blood and liver tissue. Liquid chromatography, negative electrospray ionization and Orbitrap-MS analysis allowed highly accurate and sensitive detection of prednisolone phosphate (PP) and prednisolone (P) in complex matrix. Using dexamethasone phosphate and dexamethasone as internal standards, the quantitative LC-MS method was optimized and validated for high selectivity, sensitivity and quantitative accuracy of PP and P from liposomes. The lower limits of quantitation were 0.99μmol/L blood and 0.53nmol/g liver for PP, and 229nmol/L blood and 0.514nmol/g liver for P. Quantitative accuracies of 84-118% were observed. The intra-run precision was ≤11%. Application of this new LC-MS method will yield the first liposomal pharmacokinetic profile showing accurate encapsulated and non-encapsulated drug tissue concentrations separately. This is also the first quantitative LC-MS method for the simultaneous quantification of the prodrug PP and its parent drug P in whole blood and liver tissue samples.

Pharmacokinetics of total and unbound prednisone and prednisolone in stable kidney transplant recipients with diabetes mellitus

BACKGROUND

The corticosteroid prednisone is an important component of posttransplantation immunosuppressive therapy. Pharmacokinetic parameters of prednisone or its pharmacologically active metabolite, prednisolone, are not well characterized in transplant recipients. The objective of this study was to compare the pharmacokinetics of total and unbound prednisone and prednisolone in diabetic and nondiabetic stable kidney transplant recipients and to evaluate the factors influencing plasma protein binding of prednisolone.

METHODS

Prednisone and prednisolone concentration-time profiles were obtained in 20 diabetic and 18 nondiabetic stable kidney transplant recipients receiving an oral dose of 5-10 mg prednisone per day. In addition to drug and metabolite exposures, factors influencing prednisolone protein binding were evaluated using a nonlinear mixed-effects modeling approach. This model takes into account the binding of prednisolone and cortisol to corticosteroid-binding globulin (CBG) in a saturable fashion and binding of prednisolone to albumin in a nonsaturable fashion. Finally, we have investigated the influence of several covariates including diabetes, glucose concentration, hemoglobin A1c, creatinine clearance, body mass index, gender, age, and time after transplantation on the affinity constant (K) between corticosteroids and their binding proteins.

RESULTS

In patients with diabetes, the values of dose-normalized area under the concentration-time curves were 27% and 23% higher for total and unbound prednisolone, respectively. Moreover, the ratio of total prednisolone to prednisone concentrations (active/inactive forms) was higher in diabetic subjects (P < 0.001). Modeling protein binding results revealed that the affinity constant of corticosteroid-binding globulin-prednisolone (KCBG,PL) was related to the patient's gender and diabetes status.

CONCLUSIONS

Higher prednisolone exposure could potentially lead to the increased risk of corticosteroid-related complications in diabetic kidney transplant recipients.

Detection and characterization of prednisolone metabolites in human urine by LC-MS/MS

Glucocorticosteroids are prohibited in sports when used by systemic administrations (e.g. oral), whereas they are allowed using other administration ways. Strategies to discriminate between administrations routes have to be developed by doping control laboratories. For this reason, the metabolism of prednisolone (PRED) was studied using liquid chromatography coupled to tandem mass spectrometry. A single oral (10 mg) dose of PRED was administered to two healthy male volunteers. Urine samples were collected up to 6 days after administration. Samples were hydrolyzed with β-glucuronidase and subjected to liquid-liquid extraction with ethyl acetate in alkaline conditions. The extracts were analyzed by liquid chromatography coupled to tandem mass spectrometry. Precursor ion scan methods (m/z 77, 91, 105, 121, 147 and 171) in positive ionization and neutral loss scan methods (76 and 94 Da) in negative ionization modes were applied for the open detection of PRED metabolites. Using these methods, PRED parent compound plus 20 metabolites were detected. PRED and 11 metabolites were characterized by comparison with standards of the compounds (PRED, prednisone, 20β-dihydro-PRED and 20α-dihydro-PRED, 20β-dihydro-prednisone and 20α-dihydro-prednisone, 6β-hydroxy-PRED and 6α-hydroxy-PRED, 20β isomers and 20α isomers of 6β,11β,17α,20,21-pentahydroxypregnan-1,4-diene-3-one, 6α,11β,17α,20β,21-pentahydroxypregnan-1,4-diene-3-one and Δ(6) -PRED). Using mass spectrometric data, feasible structures were proposed for seven of the remaining nine detected metabolites, including several 6-hydroxy-metabolites. Eleven of the characterized metabolites have not been previously described. Maximum excretion rates for PRED metabolites were achieved in first 24 h; however, most of the metabolites were still detectable in the last collected samples (day 6).

Plasma, blood and liver tissue sample preparation methods for the separate quantification of liposomal-encapsulated prednisolone phosphate and non-encapsulated prednisolone

Besides the development of sample preparation methods for the determination of separate liposomal-encapsulated prednisolone phosphate and non-encapsulated prednisolone concentrations in murine plasma and blood, this article also presents the first description of an accurate sample preparation method for the determination of such separate concentrations in the murine liver. The quantitative differentiation is based on the immediate hydrolysis of prednisolone phosphate (PP) into prednisolone (P) after its release from the liposomes in vivo: PP represents the encapsulated drug, while P represents the non-encapsulated drug. The use of 10 ml methanol/g tissue during homogenization of liver tissue ensures complete liposome rupture, prevention of the dephosphorylation of PP released during homogenization, sufficient clean supernatants, excellent extraction of P and sufficient extraction of PP and excellent accuracies and precision complying with the internal guidelines for pre-clinical studies (80-120% and maximal 20%, respectively). Similarly, the matching sample preparation methods for plasma and blood involve protein precipitation with four equivalents of methanol also ensuring accuracies and precision complying with the internal guidelines for pre-clinical studies. Application of these sample preparation methods is going to generate the first pharmacokinetic (PK) profile of a liposomal preparation, in which the encapsulated and non-encapsulated drug concentrations in a tissue are measured separately. Such separated concentration profiles can gain important insights into the PKs of liposomal PP and probably also with regard to liposomal formulations in general, like the quantification of the in vivo drug release from the liposomes.

Acute and acute severe (fulminant) autoimmune hepatitis

Autoimmune hepatitis frequently has an abrupt onset of symptoms, and it can present with acute liver failure. The abrupt presentation can indicate spontaneous exacerbation of a pre-existent chronic disease, newly created disease, a superimposed infectious or toxic injury, or new disease after viral infection, drug therapy, or liver transplantation. Deficiencies in the classical phenotype may include a low serum immunoglobulin G level and low or absent titers of the conventional autoantibodies. The original revised diagnostic scoring system of the International Autoimmune Hepatitis Group can guide the diagnostic evaluation, but low scores do not preclude the diagnosis. Liver tissue examination is valuable to exclude viral-related or drug-induced liver injury and support the diagnosis by demonstrating centrilobular necrosis (usually with interface hepatitis), lymphoplasmacytic infiltration, hepatocyte rosettes, and fibrosis. Conventional therapy with prednisone and azathioprine induces clinical and laboratory improvement in 68-75 % of patients with acute presentations, and high dose prednisone or prednisolone (preferred drug) is effective in 20-100 % of patients with acute severe (fulminant) presentations. Failure to improve or worsening of any clinical or laboratory feature within 2 weeks of treatment or worsening of a mathematical model of end-stage liver disease within 7 days justifies liver transplantation in acute liver failure. Liver transplantation for acute severe (fulminant) autoimmune hepatitis is as successful as liver transplantation for autoimmune hepatitis with a chronic presentation and other types of acute liver failure (patient survival >1 year, 80-94 %). Liver transplantation should not be delayed or superseded by protracted corticosteroid therapy or the empiric institution of nonstandard medications.

Drug choices in autoimmune hepatitis: part A--Steroids

Prednisone and prednisolone are the mainstays of treatment for autoimmune hepatitis. Prednisone is converted in the liver to the active metabolite, prednisolone. The principal therapeutic action of prednisolone is to suppress cytokine gene expression and to inhibit the differentiation and proliferation of activated lymphocytes. It also has anti-inflammatory effects that include decreased production of adhesion molecules, increased apoptosis of lymphocytes and decreased hepatic collagen deposition. Advanced liver disease does not sufficiently suppress hepatic conversion of prednisone to warrant the preferential use of prednisolone. Budesonide combined with azathioprine has been more effective and safer than the conventional prednisone-based regimen when given for 6 months to treatment-naive patients. It is emerging as a frontline treatment, especially for noncirrhotic patients with uncomplicated disease.

Interventions for bullous pemphigoid

BACKGROUND

Bullous pemphigoid (BP) is the most common autoimmune blistering disease in the West. Oral steroids are the standard treatment.This is an update of the review published in 2005.

OBJECTIVES

To assess treatments for bullous pemphigoid.

SEARCH STRATEGY

In August 2010 we updated our searches of the Cochrane Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials (Clinical Trials), MEDLINE, EMBASE, and the Ongoing Trials registers.

SELECTION CRITERIA

Randomised controlled trials of treatments for participants with immunofluorescence-confirmed bullous pemphigoid.

DATA COLLECTION AND ANALYSIS

At least two authors evaluated the studies for the inclusion criteria, and extracted data independently.

MAIN RESULTS

We included 10 randomised controlled trials (with a total of 1049 participants) of moderate to high risk of bias. All studies involved different comparisons, none had a placebo group. In 1 trial plasma exchange plus prednisone gave significantly better disease control at 1 month (0.3 mg/kg: RR 18.78, 95% CI 1.20 to 293.70) than prednisone alone (1.0 mg/kg: RR 1.79, 95% CI 1.11 to 2.90), while another trial showed no difference in disease control at 6 months.No differences in disease control were seen for different doses or formulations of prednisolone (one trial each), for azathioprine plus prednisone compared with prednisone alone (one trial), for prednisolone plus azathioprine compared with prednisolone plus plasma exchange (one trial), for prednisolone plus mycophenolate mofetil or plus azathioprine (one trial), for tetracycline plus nicotinamide compared with prednisolone (one trial). Chinese traditional medicine plus prednisone was not effective in one trial.There were no significant differences in healing in a comparison of a standard regimen of topical steroids (clobetasol) with a milder regimen (RR 1.00, 95% 0.97 to 1.03) in one trial. In another trial, clobetasol showed significantly more disease control than oral prednisolone in people with extensive and moderate disease (RR 1.09, 95% CI 1.02 to 1.17), with significantly reduced mortality and adverse events (RR 1.06, 95% CI 1.00 to 1.12).

AUTHORS' CONCLUSIONS

Very potent topical steroids are effective and safe treatments for BP, but their use in extensive disease may be limited by side-effects and practical factors. Milder regimens (using lower doses of steroids) are safe and effective in moderate BP. Starting doses of prednisolone greater than 0.75 mg/kg/day do not give additional benefit, lower doses may be adequate to control disease and reduce the incidence and severity of adverse reactions. The effectiveness of adding plasma exchange, azathioprine or mycophenolate mofetil to corticosteroids, and combination treatment with tetracycline and nicotinamide needs further investigation.

Duration of suppression of adrenal steroids after glucocorticoid administration

Hydrocortisone has long been the treatment of choice for congenital adrenal hyperplasia (CAH). However, treatment with this medication remains problematic. Patients with 21-hydroxylase deficiency CAH have significant diurnal variation in the secretion of 17-hydroxyprogesterone (17OHP). When considering treatment strategies, this variation must be considered along with the pharmacokinetic and pharmacodynamic properties of exogenous glucocorticoids. Orally administered hydrocortisone is highly bioavailable, but it has a short time to maximum concentration (T_max) and half life (T_1/2). While prednisone has a somewhat longer T_max and T_1/2, they remain relatively short. There have been several studies of the pharmacodynamics of hydrocortisone. We present data indicating that the maximum effect of hydrocortisone in CAH patients is seen 3 hours after a morning dose. After an evening dose, suppression of adrenal hormones continues until approximately 0500 the next day. In both situations, however, there is a large degree of intersubject variability. These data are consistent with earlier published studies. Use of alternate specimen types, possibly in conjunction with delayed release hydrocortisone preparations under development, may allow the practitioner to design a medication regimen that provides improved control of androgen secretion. Whatever dosing strategy is used, clinical judgment is required to ensure the best outcome.

Randomized clinical trial comparing oral prednisone (50 mg) with placebo before laparoscopic cholecystectomy

BACKGROUND

Intravenous administration of dexamethasone 90 min before laparoscopic cholecystectomy improves surgical outcome but may be impractical. The objective of this study was to assess the clinical efficacy of oral self-administration of prednisone 2 h before ambulatory laparoscopic cholecystectomy.

METHODS

In a double-blind placebo-controlled study, 200 patients were randomized to oral administration of prednisone (50 mg) or placebo 2 h before laparoscopic cholecystectomy. Patients received a similar standardized anaesthetic, surgical, and analgesic treatment. The primary outcome was pain 24 h after surgery and secondary outcomes were fatigue and malaise 24 h after surgery. Outcome parameters were registered before operation, on the day of operation, and the following two days. Analgesic and antiemetic requirements were registered, and nausea and vomiting were assessed twice within the first 24 h. Side-effects and 30-day follow-up for morbidity were registered.

RESULTS

Data from 184 patients were available for statistical analysis. There were no significant differences in side-effects or complications between the surgical groups (P > 0.05). No significant intergroup differences in 24-h pain, fatigue or malaise scores or any other variables were found (P > 0.05).

CONCLUSION

There is no important clinical gain of preoperative oral steroid administration compared with placebo in patients undergoing laparoscopic cholecystectomy.

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.

Androstadienetrione, a boldenone-like component, detected in cattle faeces with GC-MSnand LC-MSn

Boldenone (1,4-androstadiene-17-ol-3-one, Bol) has been the subject of a heated debate because of ongoing confusion about its endogenous or exogenous origin when detected in one of its forms in faecal or urine samples from cattle. An expert report was recently written on the presence and metabolism of Bol in various animal species. Androstadienedione (ADD) is a direct precursor of 17beta-boldenone (betaBol). It is a 3,17-dione; ssBol is a 17-ol-3-one. Not much is published on 1,4-androstadiene-3,17-diol, which is a 3,17-diol (ADL). If animals were exposed for a longer period to one of these analytes, a metabolic pathway would be initiated to eliminate these compounds. Similar to recent testosterone metabolism studies in the aquatic invertebrate Neomysis integer, ADD, ssBol and ADL could also be eliminated as hydroxymetabolites after exposure. The presence of 11-keto-steroids or 11-hydroxy-metabolites in faecal samples can interfere with a confirmation method by gas chromatography-negative chemical ionization mass spectrometry (GC-NCI-MS), after oxidation of corticosteroids with a double bond in the A-ring (e.g. prednisolone or its metabolite prednisone). The presence of androstadienetrione (ADT) in faecal samples of cattle has never been reported. The origin of its presence can be explained through different pathways, which are presented in this paper.

Interventions for bullous pemphigoid

BACKGROUND

Bullous pemphigoid is the most common autoimmune bullous disease in the West. Oral steroids are considered the standard treatment.

OBJECTIVES

To assess the effects of treatments for bullous pemphigoid.

SEARCH STRATEGY

We searched the Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE to March 2003 and bibliographies from identified studies.

SELECTION CRITERIA

Randomised controlled trials of treatments for patients with immunofluorescence confirmed bullous pemphigoid.

DATA COLLECTION AND ANALYSIS

Two reviewers evaluated the studies in terms of the inclusion criteria, five extracted data independently; disagreements were resolved by discussion. Statistical pooling of the data was inappropriate because of heterogeneity of treatments.

MAIN RESULTS

We found seven randomised controlled trials with a total of 634 patients. All studies involved different comparisons, none included a placebo group. Different doses, different formulations of corticosteroids and the addition of azathioprine failed to show significant differences in measures of disease control. However, patients who took azathioprine were able to almost halve the amount of prednisone required for disease control. Plasma exchange plus prednisone achieved significantly better disease control than prednisone alone; this favourable effect was not apparent in another study. The latter study also compared plasma exchange or azathioprine plus prednisone, but failed to show significant differences for disease control or mortality, although total adverse events at six months almost reached statistical significance in favour of plasma exchange plus prednisone. Comparing tetracycline plus nicotinamide with prednisolone, no significant difference for disease response was shown. A very potent topical corticosteroid was compared to oral prednisone in patients with moderate and extensive disease. In patients with extensive disease, the topical steroid group showed significantly better survival and disease control, and less severe complications, while no significant differences for these outcomes were seen in patients with moderate disease. Most of the reported deaths were in patients taking high doses of oral corticosteroids.

AUTHORS' CONCLUSIONS

Very potent topical steroids are effective and safe treatments for bullous pemphigoid; their use in extensive disease may be limited by side effects and practical factors. Starting doses of prednisolone greater than 0.75 mg/kg/day do not seem to give additional benefit, lower doses may be adequate for disease control; this could reduce the incidence and severity of adverse reactions. The effectiveness of the addition of plasma exchange or azathioprine to corticosteroids has not been established. Combination treatment with tetracycline and nicotinamide may be useful; this needs further validation.

Pharmacokinetics and pharmacodynamics of systemically administered glucocorticoids

Glucocorticoids have pleiotropic effects that are used to treat diverse diseases such as asthma, rheumatoid arthritis, systemic lupus erythematosus and acute kidney transplant rejection. The most commonly used systemic glucocorticoids are hydrocortisone, prednisolone, methylprednisolone and dexamethasone. These glucocorticoids have good oral bioavailability and are eliminated mainly by hepatic metabolism and renal excretion of the metabolites. Plasma concentrations follow a biexponential pattern. Two-compartment models are used after intravenous administration, but one-compartment models are sufficient after oral administration.The effects of glucocorticoids are mediated by genomic and possibly nongenomic mechanisms. Genomic mechanisms include activation of the cytosolic glucocorticoid receptor that leads to activation or repression of protein synthesis, including cytokines, chemokines, inflammatory enzymes and adhesion molecules. Thus, inflammation and immune response mechanisms may be modified. Nongenomic mechanisms might play an additional role in glucocorticoid pulse therapy. Clinical efficacy depends on glucocorticoid pharmacokinetics and pharmacodynamics. Pharmacokinetic parameters such as the elimination half-life, and pharmacodynamic parameters such as the concentration producing the half-maximal effect, determine the duration and intensity of glucocorticoid effects. The special contribution of either of these can be distinguished with pharmacokinetic/pharmacodynamic analysis. We performed simulations with a pharmacokinetic/pharmacodynamic model using T helper cell counts and endogenous cortisol as biomarkers for the effects of methylprednisolone. These simulations suggest that the clinical efficacy of low-dose glucocorticoid regimens might be increased with twice-daily glucocorticoid administration.

Corticosteroids, pregnancy, and HELLP syndrome: a review

Corticosteroids are potent antiinflammatory and immunosuppressive drugs, which are used in the treatment of a wide range of medical disorders. During pregnancy, several corticosteroids are administered for maternal as well as fetal reasons. Prednisone and prednisolone show limited transplacental passage and are thus used for treatment of maternal disease. Dexamethasone and betamethasone, drugs that can easily cross the placenta, are more suitable for fetal indications. During the last decade, administration of corticosteroids was introduced in the treatment of hemolysis, elevated liver enzymes, and low platelets (HELLP syndrome), a severe form of preeclampsia unique to human pregnancy. Several randomized, controlled trials as well as other prospective and retrospective studies have been performed to investigate this beneficial effect of corticosteroids on biochemical measures and clinical signs. This review discusses the characteristics of corticosteroids in humans and details the use of corticosteroids during pregnancy. A review of literature on the effect of corticosteroids on HELLP syndrome is given and possible mechanisms of action are discussed.

Lack of a Fluoxetine Effect on Prednisolone Disposition and Cortisol Suppression

STUDY OBJECTIVE

To evaluate the potential effect of fluoxetine, a cytochrome P450 isoenzyme inhibitor, on prednisolone disposition and cortisol suppression.

DESIGN

Sequential, two-phase, crossover, open-label pharmacokinetic study.

SETTING

General clinical research center.

SUBJECTS

Fourteen healthy volunteers.

INTERVENTION

A single intravenous dose of prednisolone 40 mg before and after 14 days of treatment with fluoxetine 20 mg/day for 5 days followed by 60 mg/day for 9 days to achieve steady-state concentrations.

MEASUREMENTS AND MAIN RESULTS

Pharmacokinetic parameters of the prednisolone and resulting pharmacodynamic effects on the time course of plasma cortisol suppression before and after fluoxetine administration were evaluated. No significant differences were observed for the mean +/- SD area under the prednisolone concentration-time curve (3739 +/- 992 vs 3498 +/- 797 microg x hr/L, respectively), clearance (8.58 +/- 2.62 vs 8.92 +/- 2.05 L/hr, respectively), volume of distribution (39.5 +/- 12.4 vs 38.2 +/- 9.9 L, respectively), elimination half-life (3.32 +/- 0.83 vs 3.05 +/- 0.80 hrs, respectively), or duration of plasma cortisol suppression (23.5 +/- 3.1 vs 22.0 +/- 4.2 hrs, respectively).

CONCLUSION

Fluoxetine administration did not significantly affect prednisolone disposition or prolong cortisol suppression. This finding suggests that coadministration of these agents is unlikely to result in clinically important pharmacokinetic or pharmacodynamic drug interactions. Prednisolone may be a useful alternative for patients who require both glucocorticoid and fluoxetine therapy.

Demographics, assessment and management of pain in the elderly

The prevalence of pain increases with each decade of life. Pain in the elderly is distinctly different from pain experienced by younger individuals. Cancer is a leading cause of pain; however, other conditions that cause pain such as facet joint arthritis (causing low back pain), polymyalgia rheumatica, Paget's disease, neuropathies, peripheral vascular disease and coronary disease most commonly occur in patients over the age of 50 years. Poorly controlled pain in the elderly leads to cognitive failure, depression and mood disturbance and reduces activities of daily living. Barriers to pain management include a sense of fatalism, denial, the desire to be 'the good patient', geographical barriers and financial limitations. Aging causes physiological changes that alter the pharmacokinetics and pharmacodynamics of analgesics, narrowing their therapeutic index and increasing the risk of toxicity and drug-drug interactions. CNS changes lead to an increased risk of delirium. Assessment among the verbal but cognitively impaired elderly is satisfactorily accomplished with the help of unidimensional and multidimensional pain scales. A comprehensive physical examination and pain history is essential, as well as a review of cognitive function and activities of daily living. The goal of pain management among the elderly is improvement in pain and optimisation of activities of daily living, not complete eradication of pain nor the lowest possible drug dosages. Most successful management strategies combine pharmacological and nonpharmacological (home remedies, massage, topical agents, heat and cold packs and informal cognitive strategies) therapies. A basic principle of the pharmacological approach in the elderly is to start analgesics at low dosages and titrate slowly. The WHO's three-step guideline to pain management should guide prescribing. Opioid choices necessitate an understanding of pharmacology to ensure safe administration in end-organ failure and avoidance of drug interactions. Adjuvant analgesics are used to reduce opioid adverse effects or improve poorly controlled pain. Adjuvant analgesics (NSAIDs, tricyclic antidepressants and antiepileptic drugs) are initiated prior to opioids for nociceptive and neuropathic pain. Preferred adjuvants for nociceptive pain are short-acting paracetamol (acetaminophen), NSAIDs, cyclo-oxygenase-2 inhibitors and corticosteroids (short-term). Preferred drugs for neuropathic pain include desipramine, nortriptyline, gabapentin and valproic acid. Drugs to avoid are pentazocine, pethidine (meperidine), dextropropoxyphene and opioids that are both an agonist and antagonist, ketorolac, indomethacin, piroxicam, mefenamic acid, amitriptyline and doxepin. The type of pain, and renal and hepatic function, alter the preferred adjuvant and opioid choices. Selection of the appropriate analgesics is also influenced by versatility, polypharmacy, severity and type of pain, drug availability, associated symptoms and cost.

Population pharmacokinetics of prednisolone in children with acute lymphoblastic leukemia

PURPOSE

To evaluate the plasma protein binding and pharmacokinetics of prednisolone during therapeutic use in children with acute lymphoblastic leukemia (ALL) using the population approach.

METHODS

A two-compartment pharmacokinetic model was used to describe data from 23 children with ALL (aged 2-15 years). Prednisolone (60 mg/m(2) per day in three divided doses) was administered both orally and intravenously, and samples were obtained on several days during the initial 5 weeks of remission induction therapy. Unbound plasma concentrations ( n=288) were determined by HPLC and ultrafiltration. Nonlinear mixed-effects modeling (WinNonMix version 2.0.1) was used to estimate the pharmacokinetic parameters, to identify significant covariates, and to estimate the protein binding parameters.

RESULTS

Prednisolone showed complete oral bioavailability. The median unbound clearance (32 l/h per m(2)) was lower, and the half-life (3.6 h) longer than previously reported in childhood ALL. Body weight was a significant covariate for the central and peripheral volumes of distribution resulting in interindividual variabilities of 50% and 42%. Including body surface area as a covariate for clearance decreased the interindividual variability to 14%. The estimated areas under the unbound plasma concentration-time curves showed less than twofold variation among patients, and a residual variability of 20% indicated that the pharmacokinetic parameters remained stable during induction therapy. The estimated protein binding parameters were comparable to, but slightly lower than, previously published values and independent of the albumin concentration.

CONCLUSIONS

The study showed complete oral bioavailability, a lower unbound clearance and a longer half-life for prednisolone than previously reported in childhood ALL. Plasma protein binding was independent of the albumin concentration. Due to the small inter- and intraindividual variations in the pharmacokinetic parameters, body surface area-based dosing is sufficient to obtain similar systemic exposure among patients.

Effect of rofecoxib on prednisolone and prednisone pharmacokinetics in healthy subjects

Patients receiving nonsteroidal anti-inflammatory drug therapy may also require administration of corticosteroids, particularly patients with rheumatoid arthritis. To investigate the effect of rofecoxib on the single-dose pharmacokinetics of oral prednisone and intravenous prednisolone, the authors conducted a randomized, double-blind, placebo-controlled crossover study in 12 healthy subjects. Oral rofecoxib (250.0 mg/day for 14 days) failed to influence prednisone or prednisolone pharmacokinetics after intravenous prednisolone or oral prednisone administration. The geometric mean ratio (GMR) (90% confidence interval) of prednisolone AUC infinity (rofecoxib/placebo) following intravenous and oral corticosteroid was 0.97 (0.94, 1.01) and 0.99 (0.91, 1.08), respectively. Similarly, the prednisone AUC infinity GMRs (rofecoxib/placebo) after intravenous and oral corticosteroid were 1.03 (0.95, 1.11) and 1.08 (0.92, 1.28), respectively. The absence of an effect of rofecoxib on the pharmacokinetics of oral prednisone or intravenous prednisolone indicates that no adjustment in dose of this corticosteroid is necessary when administered concurrently with rofecoxib.

Interventions for bullous pemphigoid

BACKGROUND

Bullous pemphigoid is the most common autoimmune bullous disease in the West. Oral steroids are considered the standard treatment.

OBJECTIVES

To assess the effects of treatments for bullous pemphigoid.

SEARCH STRATEGY

We searched the Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE to March 2003 and bibliographies from identified studies.

SELECTION CRITERIA

Randomised controlled trials of treatments for patients with immunofluorescence confirmed bullous pemphigoid.

DATA COLLECTION AND ANALYSIS

Two reviewers evaluated the studies in terms of the inclusion criteria, five extracted data independently; disagreements were resolved by discussion. Statistical pooling of the data was inappropriate because of heterogeneity of treatments.

MAIN RESULTS

We found seven randomised controlled trials with a total of 634 patients. All studies involved different comparisons, none included a placebo group. Different doses, different formulations of corticosteroids and the addition of azathioprine failed to show significant differences in measures of disease control. However, patients who took azathioprine were able to almost halve the amount of prednisone required for disease control. Plasma exchange plus prednisone achieved significantly better disease control than prednisone alone; this favourable effect was not apparent in another study. The latter study also compared plasma exchange or azathioprine plus prednisone, but failed to show significant differences for disease control or mortality, although total adverse events at six months almost reached statistical significance in favour of plasma exchange plus prednisone. Comparing tetracycline plus nicotinamide with prednisolone, no significant difference for disease response was shown. A very potent topical corticosteroid was compared to oral prednisone in patients with moderate and extensive disease. In patients with extensive disease, the topical steroid group showed significantly better survival and disease control, and less severe complications, while no significant differences for these outcomes were seen in patients with moderate disease. Most of the reported deaths were in patients taking high doses of oral corticosteroids.

REVIEWER'S CONCLUSIONS

Very potent topical steroids are effective and safe treatments for bullous pemphigoid; their use in extensive disease may be limited by side effects and practical factors. Starting doses of prednisolone greater than 0.75 mg/kg/day do not seem to give additional benefit, lower doses may be adequate for disease control; this could reduce the incidence and severity of adverse reactions. The effectiveness of the addition of plasma exchange or azathioprine to corticosteroids has not been established. Combination treatment with tetracycline and nicotinamide may be useful; this needs further validation.

Pharmacokinetic and pharmacoimmunodynamic interactions between prednisolone and sirolimus in adrenalectomized rats

Prednisolone (Pred) and sirolimus (SIR) are immunosuppressive compounds acting through different mechanisms with moderate synergism found in vitro. Both drugs are metabolized partly by CYP3A enzymes. After i.v. administration of placebo, Pred (5 mg/kg), SIR (1 mg/kg), or Pred with SIR (5 and 1 mg/kg doses) to adrenalectomized male rats, Pred plasma and SIR whole blood concentrations were followed for 48 hr along with circulating T-helper and T-cytotoxic cell counts. Ex vivo whole blood lymphocyte proliferation marked host responsiveness. An extended indirect PK/PD model was used to describe responses to these drugs, alone or combined. An interactive two-stage population analysis showed no modification in drug PK. Mean Pred plasma clearance was 0.655 L/hr (interrat++ variability: 11%) and significantly increased with weight. Mean SIR whole blood volume of distribution and clearance were 5.6 L (62%) and 0.28 L/hr (32%), and animal scaling showed weight-power proportionality. In vitro metabolism studies showed no significant inhibition of Pred or prednisone CYP3A metabolism by SIR (50 microM), but this pathway accounted for less than 5% of Pred metabolism. Pred decreased numbers of T-helper lymphocytes with a mean IC50 of 37.8 nM (21%) alone or 12.3 nM (130%) with SIR. Results for T-cytotoxic lymphocytes were similar. SIR increased lymphocyte numbers with a mean IC50 of 52.2 nM (24%) for T-helper and 28.8 nM (51%) for T-cytotoxic cells. Taking into account drug effects on lymphocyte trafficking, Pred directly inhibited ex vivo lymphocyte proliferation with a mean IC50 of 1.08 nM (38%). SIR, after a transduction step, inhibited proliferation with a mean IC50 of 1.00 nM (26%). Responses measured after drug coadministration were reasonably quantitated by addition of single drug effects. Since, at pharmacologic concentrations in rats, Pred and SIR did not interact in their PK but synergistically or additively interact in their dynamics, their joint therapeutic use is promising. The adrenalectomized rat may be a suitable animal model to characterize drug effects on lymphocyte trafficking and reactivity.

Prediction of human intestinal absorption of drug compounds from molecular structure

The absorption of a drug compound through the human intestinal cell lining is an important property for potential drug candidates. Measuring this property, however, can be costly and time-consuming. The use of quantitative structure-property relationships (QSPRs) to estimate percent human intestinal absorption (%HIA) is an attractive alternative to experimental measurements. A data set of 86 drug and drug-like compounds with measured values of %HIA taken from the literature was used to develop and test a QSPR mode. The compounds were encoded with calculated molecular structure descriptors. A nonlinear computational neural network model was developed by using the genetic algorithm with a neural network fitness evaluator. The calculated %HIA (cHIA) model performs wells, with root-mean-square (rms) errors of 9.4%HIA units for the training set, 19.7%HIA units for the cross-validation (CV) set, and 16.0%HIA units for the external prediction set.