Pharmacological Basis of Differences in Dose Response, Dose Equivalence, and Duration of Action of Inhaled Corticosteroids

INTRODUCTION

Asthma treatment guidelines classify inhaled corticosteroid (ICS) regimens as low, medium, or high dose. However, efficacy and safety are not independently assessed accordingly. Moreover, differences in ICS duration of action are not considered when a dose regimen is selected. We investigated the efficacy and safety implications of these limitations for available ICS molecules.

METHODS

Published pharmacodynamic and pharmacokinetic parameters were used, alongside physiological and pharmacological principles, to estimate the efficacy and safety of available ICS molecules. Extent and duration of glucocorticoid receptor (GR) occupancy in the lung (efficacy) and cortisol suppression (systemic exposure and safety) were estimated.

RESULTS

Some ICS regimens (e.g., fluticasone furoate, fluticasone propionate, and ciclesonide) rank high for efficacy but low for systemic exposure, contrary to how ICS dose equivalence is currently viewed. Differences in dose-response relationships for efficacy and systemic exposure were unique for each ICS regimen and reflected in their therapeutic indices. Notably, even low doses of most ICSs can generate high GR occupancy (≥ 90%) across the entire dose interval at steady state, which may explain previously reported difficulties in obtaining dose responses within the clinical dose range and observations that most clinical benefit typically occurs at low doses. The estimated post dose duration of lung GR occupancy for ICS molecules was categorized as 4-6 h (short), 14-16 h (medium), 25-40 h (long), or > 80 h (ultra-long), suggesting potentially large differences in anti-inflammatory duration of action.

CONCLUSION

In a real-world clinical setting where there may be poor adherence to prescribed therapy, our findings suggest a significant therapeutic advantage for longer-acting ICS molecules in patients with asthma.

Clinical pharmacokinetics and pharmacodynamics of topical non-biological therapies for psoriasis patients

INTRODUCTION

Psoriasis is a chronic inflammatory cutaneous disease that causes patients psychosocial distress. Topical therapies are utilized for mild-to-moderate disease and for more severe disease in conjunction with systemic therapies. Topical corticosteroids are a cornerstone of treatment for psoriasis, but long-term use can cause stria and cutaneous atrophy and as well as systemic side effects such as topical steroid withdrawal. Non-steroidal topical therapies tend to be safer than topical corticosteroids for long-term use.

AREAS COVERED

We conducted a literature review on the pharmacokinetic (PK) and pharmacodynamic (PD) properties of topical therapies for psoriasis. We discuss how the PK and PD characteristics of these therapies inform clinicians on efficacy and toxicity when prescribing for patients.

EXPERT OPINION

Topical corticosteroids, used intermittently, are very safe and effective. Long-term, continuous use of topical corticosteroids can cause systemic side effects. Several generic and newly approved non-steroidal options are available, but no head-to-head studies compare the effectiveness of the generics (vitamin D analogs, tacrolimus, pimecrolimus) against the newer therapies (roflumilast, tapinarof). Patients often do not respond to topical therapies due to poor adherence to treatment regimens. For patients resistant to topical treatment, phototherapy or systemic therapy may be an option.

Minimal physiologically-based hybrid model of pharmacokinetics in pregnant women: Application to antenatal corticosteroids

Minimal physiologically-based pharmacokinetic (mPBPK) models are an alternative to full physiologically-based pharmacokinetic (PBPK) models as they offer reduced complexity while maintaining the physiological interpretation of key model components. Full PBPK models have been developed for pregnancy, but a mPBPK model eases the ability to perform a "top-down" meta-analysis melding all available pharmacokinetic (PK) data in the mother and fetus. Our hybrid mPBPK model consists of mPBPK models for the mother and fetus with connection by the placenta. This model was applied to describe the rich PK data of antenatal corticosteroid betamethasone (BET) jointly with the limited data for dexamethasone (DEX) in the mother and fetus. Physiologic model parameters were obtained from the literature while drug-dependent parameters were estimated by the simultaneous fitting of all available data for DEX and BET. Maternal clearances of DEX and BET confirmed the literature values, and the expected fetal-to-maternal plasma ratios ranged from 0.3 to 0.4 for both drugs. Simulations of maternal plasma concentrations for the dosing regimens of BET and DEX recommended by the World Health Organization based on our findings revealed up to 60% lower exposures than found in nonpregnant women and offers a means of devising alternative dosing regimens. Our hybrid mPBPK model and meta-analysis approach could facilitate assessment of other classes of drugs indicated for the treatment of pregnant women.

Corticosteroid-Antibiotic Interactions in Bacteria that Cause Corneal Infection

Purpose

Although a comprehensive knowledge of antibiotic/corticosteroid combinations is essential for the appropriate treatment of eye infections, the impact of their co-administration has not been well studied to date. A systematic pharmacodynamic/pharmacokinetic study to determine the effects of cotreatment with various antibiotics and corticosteroids was conducted.

Methods

Four bacterial strains, seven antibiotics, and four corticosteroids were used in the analyses. Drug interactions were evaluated by considering antibacterial effects with a checkerboard assay and intracellular concentrations in human corneal epithelial cells.

Results

The drug combinations that showed the most stable effects against Pseudomonas aeruginosa was levofloxacin-prednisolone. Stable combinations against the three types of Gram-positive bacteria were neomycin-prednisolone, ofloxacin-dexamethasone, ofloxacin-prednisolone, and polymyxin-dexamethasone. The cellular concentrations were changed for the gatifloxacin-fluorometholone, moxifloxacin-fluorometholone, tobramycin-dexamethasone, and tobramycin-prednisolone combinations.

Conclusions

Loteprednol and fluorometholone reduced the antibacterial effects of all of the tested antibiotics in this study. Dexamethasone and prednisolone showed various effects in this regard, depending on the co-administered antibiotic. Prior knowledge of specific antibiotic/corticosteroid interactions provides valuable information to clinical practitioners by combining data on the antibacterial and intracellular uptake effects of their co-administration.

Translational Relevance

When using antibiotics and corticosteroids, drug combinations can be selected by referring to the results of this study.

Polymer-free corticosteroid dimer implants for controlled and sustained drug delivery

Polymeric drug carriers are widely used for providing temporal and/or spatial control of drug delivery, with corticosteroids being one class of drugs that have benefitted from their use for the treatment of inflammatory-mediated conditions. However, these polymer-based systems often have limited drug-loading capacity, suboptimal release kinetics, and/or promote adverse inflammatory responses. This manuscript investigates and describes a strategy for achieving controlled delivery of corticosteroids, based on a discovery that low molecular weight corticosteroid dimers can be processed into drug delivery implant materials using a broad range of established fabrication methods, without the use of polymers or excipients. These implants undergo surface erosion, achieving tightly controlled and reproducible drug release kinetics in vitro. As an example, when used as ocular implants in rats, a dexamethasone dimer implant is shown to effectively inhibit inflammation induced by lipopolysaccharide. In a rabbit model, dexamethasone dimer intravitreal implants demonstrate predictable pharmacokinetics and significantly extend drug release duration and efficacy (>6 months) compared to a leading commercial polymeric dexamethasone-releasing implant.

Population pharmacokinetic modeling of intramuscular and oral dexamethasone and betamethasone in Indian women

Population analysis of pharmacokinetic data for five differing dosage forms and routes for dexamethasone and betamethasone in 48 healthy nonpregnant Indian women was performed that accounted for a partial and complex cross-over design. Single doses of 6 mg dexamethasone phosphate (DEX-P), betamethasone phosphate (BET-P), or 1:1 mixture of betamethasone phosphate and acetate (BET-PA) were administered orally (PO) or intramuscularly (IM). Plasma concentrations collected for two periods over 96 h were described with a two-compartment model with differing PO and IM first-order absorption inputs. Clearances and volumes were divided by the IM bioavailability [Formula: see text]. The homogeneous ages, body weights, and ethnicity of the women obviated covariate analysis. Parameter estimates were obtained by the Laplace estimation method implemented in NONMEM 7.4. Typical values for dexamethasone were clearance ([Formula: see text] of 9.29 L/h, steady-state volume ([Formula: see text] of 56.4 L, IM absorption constant [Formula: see text] of 0.460 1/h and oral absorption constant ([Formula: see text] of 0.936 1/h. Betamethasone parameters were CL/FIM of 5.95 L/h, [Formula: see text] of 72.4 L, [Formula: see text] of 0.971 1/h, and [Formula: see text] of 1.21 1/h. The PO to IM F values were close to 1.0 for both drugs. The terminal half-lives averaged about 7.5 h for DEX, 17 h for BET, and 78 h for BET from BET-PA with the latter reflecting very slow release of BET from the acetate ester. Overall, BET exhibited slower clearance, larger volume of distribution, faster absorption, and longer persistence than DEX. These data may be useful in considering exposures when substituting one form of corticosteroid for another.

The dexamethasone suppression test and DSM-III-R diagnoses in suicide attempters

Previous research on hypothalamic-pituitary adrenal (HPA) axis-activity in suicide attempter research has shown conflicting outcomes. The design of the present study was to test the influence of personality disorders and concominant axis I diagnoses on the dexamethasone suppression diagnostic test by use of multiple regression analyses. The sample consisted of 184 patients with a recent suicide attempt and 42 healthy controls. As expected, the lowest pre- and postdexamethasone cortisol levels were found in patients with personality disorders axis II, cluster B as compared to the other patients. The results remained significant when analysed for covariance with DSM-III-R axis I diagnoses, age or sex. Whether these low cortisol levels are due to previous experience of extreme stressful events or long-lasting burden, or whether they may be a consequence of biogenetic or psychological predisposal of interest, remains to be elucidated. Axis I comorbidity needs to be further examined.

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.

Oral dosing for antenatal corticosteroids in the Rhesus macaque

Antenatal corticosteroids (ACS) are standard of care for women at risk of preterm delivery, although choice of drug, dose or route have not been systematically evaluated. Further, ACS are infrequently used in low resource environments where most of the mortality from prematurity occurs. We report proof of principle experiments to test betamethasone-phosphate (Beta-P) or dexamethasone-phosphate (Dex-P) given orally in comparison to the clinical treatment with the intramuscular combination drug beta-phosphate plus beta-acetate in a Rhesus Macaque model. First, we performed pharmacokinetic studies in non-pregnant monkeys to compare blood levels of the steroids using oral dosing with Beta-P, Dex-P and an effective maternal intramuscular dose of the beta-acetate component of the clinical treatment. We then evaluated maternal and fetal blood steroid levels with limited fetal sampling under ultrasound guidance in pregnant macaques. We found that oral Beta is more slowly cleared from plasma than oral Dex. The blood levels of both drugs were lower in maternal plasma of pregnant than in non-pregnant macaques. Using the pharmacokinetic data, we treated groups of 6–8 pregnant monkeys with oral Beta-P, oral Dex-P, or the maternal intramuscular clinical treatment and saline controls and measured pressure-volume curves to assess corticosteroid effects on lung maturation at 5d. Oral Beta-P improved the pressure-volume curves similarly to the clinical treatment. Oral Dex-P gave more variable and nonsignificant responses. We then compared gene expression in the fetal lung, liver and hippocampus between oral Beta-P and the clinical treatment by RNA-sequencing. The transcriptomes were largely similar with small gene expression differences in the lung and liver, and no differences in the hippocampus between the groups. As proof of principle, ACS therapy can be effective using inexpensive and widely available oral drugs. Clinical dosing strategies must carefully consider the pharmacokinetics of oral Beta-P or Dex-P to minimize fetal exposure while achieving the desired treatment responses.

Cross-sectional CT Assessment of the Extent of Injectate Spread at CT Fluoroscopy-guided Cervical Epidural Interlaminar Steroid Injections

Background Previous studies analyzed contrast agent spread during cervical interlaminar epidural steroid injections (CILESIs) by using planar fluoroscopy and reported wide variance of the rate of spread to the ventral epidural space (VES). Cross-sectional CT allows for direct viewing of contrast agent in the VES, providing improved spread assessment and thereby informing needle placement decisions when targeting pain generators. Purpose To determine the extent of injectate spread at CT fluoroscopy-guided CILESI, with particular attention to the VES and bilateral neuroforamina, by using cross-sectional CT. Materials and Methods This study reviewed 83 consecutive CT fluoroscopy-guided CILESIs at which a postprocedural cervical spine CT was performed (June 2016 to December 2017). All procedures used the same injectate (2 mL corticosteroid, 3 mL contrast agent). Postprocedural CT scans were reviewed for the presence of contrast within the VES, dorsal epidural space, ipsilateral neuroforamen, and contralateral neuroforamen in every cervical interlaminar level. Descriptive data are presented as frequencies or means. McNemar tests or hierarchical logistic models were used to assess associations between covariates and contrast agent spread to particular locations. Results The study cohort included 73 individual patients (59% women; 43 of 73) (mean patient age, 57.6 years ± 11.5 [standard deviation]). Mean number of levels of cranial spread were 0.6 level for VES, 1.9 levels for contralateral neuroforamen, 2.1 levels for ipsilateral neuroforamen, and 3 levels for dorsal epidural space. No VES spread in any level was found with 35% (29 of 83) of injections. VES spread was more likely to occur in the level of needle placement (43%; 36 of 83) than in other interlaminar levels (19.5%; 97 of 498; P < .001). Spread was more likely to occur in the neuroforamen ipsilateral to the needle approach compared with contralateral (P < .001). Conclusion Cervical interlaminar epidural steroid injections have injectate spreads with a mean of less than one level cranially in the ventral epidural space (VES) and approximately two levels in the neuroforamen. VES spread occurs more frequently at the level of needle placement and within the ipsilateral neuroforamen. © RSNA, 2019.

A Narrative Review on Anti-Tumor Necrosis Factor α Therapies in Inflammatory Bowel Disease During Pregnancy: Immunoglobulin Placental Translocation and its Impact

INTRODUCTION

Inflammatory bowel disease activity is associated with adverse pregnancy outcomes. Anti-tumor necrosis factor α therapy is often required to treat flares and to maintain disease remission. However, there are concerns regarding treatment with these agents during pregnancy, as they actively cross the placental barrier.

MATERIAL AND METHODS

Studies regarding anti-tumor necrosis factor α therapy during pregnancy were identified from PubMed from 1958 to January 2018. The reference lists of the selected studies were reviewed to identify complementary publications.

RESULTS AND DISCUSSION

Anti-tumor necrosis factor α agents are efficient treatments for moderate-to-severe inflammatory bowel disease and may ensure remission during pregnancy. Although these drugs cross the placenta, they are considered safe for both the mother and the fetus. Furthermore, up-to-date guidelines support therapy continuation during pregnancy aiming for disease control. The same guidelines also consider stopping treatment during the third trimester to limit maternal-fetal drug transfer. However, data shows that this strategy does not completely prevent fetus exposure. In addition, stopping treatment incurs in risk of disease flare and threatens subsequent therapy response. Fetus drug exposure has not showed an association with adverse childhood development. However, as infant drug levels could be detected up to seven months after birth, postponement of live virus vaccination is recommended.

CONCLUSION

There should be no disagreement among the medical community as to the need to maintain therapy aiming for disease remission during gestation in inflammatory bowel disease. Anti-tumor necrosis factor α agents are safe for both the mother and the fetus.

Bioequivalence Study Methods with Pharmacokinetic Endpoints for Topical Ophthalmic Corticosteroid Suspensions and Effects of Subject Demographics

PURPOSE

To establish bioequivalence for topical ophthalmic corticosteroid suspensions, some of U.S. product-specific guidances (PSGs) for generic drug products recommend evaluation of aqueous humor (AH) pharmacokinetics (PK). However, the AH PK study is complex because the relationships among AH PK, subject demographics, ocular anatomy, physiology and the compounds' physicochemical characteristics are not well understood. The objective of this research is to provide an overview of the in vivo human AH studies submitted to the U.S. Food and Drug Administration (FDA) for ophthalmic corticosteroid suspensions and to investigate the impact of subject demographics on the human AH PK.

METHODS

We summarized demographic data, sampling time points, sample size per time point and PK parameters to investigate correlations in the studies submitted to the FDA.

RESULTS

In the evaluation of subject-specific covariates, the area under the concentration-time curves (AUC) and maximum concentrations (C_max) were significantly different among ethnicities and age groups. Gender was not primarily associated with differences in AH PK.

CONCLUSIONS

Our results suggest that the difference in ethnicity and age of the study population play an important role in the AH PK profiles of topical ophthalmic corticosteroid suspensions. Considering the subject-specific covariate effects in designing bioequivalence studies with AH PK endpoints could reduce bias from covariate imbalance and help identify true effects of formulation differences.

Injectable drug depot engineered to release multiple ophthalmic therapeutic agents with precise time profiles for postoperative treatment following ocular surgery

A multi-drug delivery platform is developed to address current shortcomings of post-operative ocular drug delivery. The sustained biodegradable drug release system is composed of biodegradable polymeric microparticles (MPs) incorporated into a bulk biodegradable hydrogel made from triblock copolymers with poly(ethylene glycol) (PEG) center blocks and hydrophobic biodegradable polyester blocks such as poly(lactide-co-glycolide) (PLGA), Poly(lactic acid) (PLA), or Poly(lactide-co-caprolactone) (PLCL) blocks. This system is engineered to flow as a liquid solution at room temperature for facile injection into the eye and then quickly gel as it warms to physiological body temperatures (approximately 37 °C). The hydrogel acts as an ocular depot that can release three different drug molecules at programmed rates and times to provide optimal release of each species. In this manuscript, the hydrogel is configured to release a broad-spectrum antibiotic, a potent corticosteroid, and an ocular hypotensive, three ophthalmic therapeutic agents that are essential for post-operative management after ocular surgery, each drug released at its own timescale. The delivery platform is designed to mimic current topical application of postoperative ocular formulations, releasing the antibiotic for up to a week, and the corticosteroid and the ocular hypotensive agents for at least a month. Hydrophobic blocks, such as PLCL, were utilized to prolong the release duration of the biomolecules. This system also enables customization by being able to vary the initial drug loading to linearly tune the drug dose released, while maintaining a constant drug release profile over time. This minimally invasive biodegradable multi-drug delivery system is capable of replacing a complex ocular treatment regimen with a simple injection. Such a depot system has the potential to increase patient medication compliance and reduce both the immediate and late term complications following ophthalmic surgery.

STATEMENT OF SIGNIFICANCE

After ocular surgery, patients routinely receive multiple medications including antibiotics, steroids and ocular hypotensives to ensure optimal surgical outcomes. The current standard of care for postoperative treatment after ocular surgery involves using eye drops daily, which has limited effectiveness mainly due to poor patient adherence. To improve patient experience and outcomes, this article presents the first thermoresponsive hydrogel able to release multiple drug molecules for the application of post-operative treatment following ocular surgery. By varying the parameters such as hydrogel type and polymer hydrophobicity, the drug release profile, duration and dosage can finely be tuned. The approach presented in this article can readily be applied to other applications by simply changing the drug loaded in the drug delivery system.

Scientific rationale for the possible inhaled corticosteroid intraclass difference in the risk of pneumonia in COPD

Inhaled corticosteroids (ICSs) treatment combined with long-acting β2-adrenoceptor agonists (LABAs) reduces the risk of exacerbations in COPD, but the use of ICSs is associated with increased incidence of pneumonia. There are indications that this association is stronger for fluticasone propionate than for budesonide. We have examined systematic reviews assessing the risk of pneumonia associated with fluticasone propionate and budesonide COPD therapy. Compared with placebo or LABAs, we found that fluticasone propionate was associated with 43%-78% increased risk of pneumonia, while only slightly increased risk or no risk was found for budesonide. We have evaluated conceivable mechanisms which may explain this difference and suggest that the higher pneumonia risk with fluticasone propionate treatment is caused by greater and more protracted immunosuppressive effects locally in the airways/lungs. These effects are due to the much slower dissolution of fluticasone propionate particles in airway luminal fluid, resulting in a slower uptake into the airway tissue and a much longer presence of fluticasone propionate in airway epithelial lining fluid.

Tacrolimus concentration/dose ratio as a therapeutic drug monitoring strategy: the influence of gender and comedication

BACKGROUND/AIM. A combination of tacrolimus and other drugs such as corticosteroids has been commonly used immunosuppressive regimens. On the other hand, there is a growing body of evidence that male and female may differ in their response to the equal drug treatment. The aim of the study was to estimated the use of tacrolimus concentration/dose (C/D) ratio for the assessment of the influence of gender differences and comedication on tacrolimus exposure in renal transplant recipients. METHODS. This prospective case series study included 54 patients, in which the unit of monitoring was outpatient examination (1,872) of the renal transplant patients. The patients were monitored in the period 2010-2014, starting one month after the transplantation. Tacrolimus trough concentrations (TTC) were measured by chemiluminescence microparticles immunoassay. RESULTS. TTC and the tacrolimus C/D ratio were significantly lower in the females comparing with the males. Contrary to the males, in the females a significant increase of the tacrolimus daily dose (TDD) per body weight and TTC, along with the corticosteroid dose increase, was not accompanied by any significant changes in the tacrolimus C/D ratio; in different corticosteroid doses faster elimination of tacrolimus was found with the exception of the doses > 0.25 mg/kg. In the patients treated with proton pump inhibitors, mainly with pantoprazole TDD per body weight and TTC were significantly higher, while the tacrolimus C/D ratio was significantly lower compared to the patients without this treatment. In the patients treated with calcium channel blockers, TDD per body weight was significantly lower (particularly with amlodipine). while the tacrolimus C/D ratio was higher compared to the patients who were not treated by them.

CONCLUSION

A lower tacrolimus exposure was detected in females in comparison to males. When gender differences were considered in the context of different corticosteroid doses, faster elimination of tacrolimus in the females was also seen, with the exception of the doses > 0.25 mg/kg. Tacrolimus exposure in the pantoprazole-treated patients was significantly less expressed, while in patients treated with CCB amplodipine the tacrolimus C/D ratio was significantly higher in comparison with the patients not treated with them.

Contrast Dispersion Pattern and Efficacy of Corticosteroid at the Glenohumeral Joint in Adhesive Capsulitis

BACKGROUND

Corticosteroid injection has a wide range of success in adhesive capsulitis but the reason for this has not yet been explained. We hypothesized that this difference might be due to the distribution of the corticosteroids injected into the joint cavity because particulate steroid deposits in the capsule and will not be moved over time by shoulder motion.

OBJECTIVES

The purpose of this study is to determine whether the therapeutic efficacy of particulate corticosteroid injection into the glenohumeral joint differs according to the dispersion pattern.

STUDY DESIGN

Prospective evaluation.

SETTING

Outpatient clinics at a tertiary university hospital.

METHODS

Seventy-two patients diagnosed as having adhesive capsulitis received a corticosteroid injection at the glenohumeral joint. The posterior capsule and the subscapular bursa were selected as dispersion sites and the dispersion of contrast dye was expressed as a ratio (%). Two weeks and 3 months after the injection clinical improvement ("not improved," "slightly improved," "much improved"), numeric rating scale (NRS), and passive range of motions (PROM) were evaluated. The dispersion of the contrast dye was compared according to the clinical improvements by an analysis of variance test. Pearson correlation test was done to find the relationship between PROM and the dispersion and between change of NRS and the dispersion.

RESULTS

The distribution in the subscapular area was 30.0% in the "much improved" group, 22.0% in the "slightly improved" group, and 37.1% in the "no improvement" group which was not significantly different (P = 0.179). Correlations between changes of NRS and the dye distribution were not statistically significant (P = 0.429 at 2 weeks and P = 0.629 at 3 months). The change of passive external rotation 3 months after the injection was significantly correlated with the dye distribution (P = 0.035).

LIMITATIONS

Because of diverse pathologic findings in adhesive capsulitis, further studies will be needed to address the effect of the dye distribution on the pain improvement according to pathologic findings revealed by magnetic resonance imaging (MRI).

CONCLUSION

External rotation of the shoulder in adhesive capsulitis has greater improvement as the corticosteroid solutions injected into the glenohumeral joint are increasingly dispersed to the subscapularis area. However, this does not affect the pain improvement after the injection.

[Utility of challenge test in immediate hypersensitivity to hydrocortisone sodium succinate]

Corticosteroid hypersensitivity is a complex phenomenon in which many factors interact, such as idiosyncrasy, intolerance or allergic reactions. The prevalence of immediate hypersensitivity reactions to corticosteroids is 0.2%-0.5%. Corticosteroids have major therapeutic implications; thus, when hypersensitivity is suspected, in-vitro and/or in-vivo testing can be performed to confirm diagnosis, being the drug challenge the gold standard. After definitive diagnosis, cross-reactivity among the different corticosteroid groups should be considered, to choose wisely if corticosteroid therapy is still required. In Coopman classification, steroids belonging to groups A, B and D2 have high cross-reactivity, however, more studies are needed to determine the degree of cross-reaction among these drugs. This paper presents the case of a woman, in who hypersensitivity to hydrocortisone succinate was confirmed by drug challenge test.

Dose Equivalency Evaluation of Major Corticosteroids: Pharmacokinetics and Cell Trafficking and Cortisol Dynamics

The integrity of current corticosteroid dose equivalency tables, as assessed by mechanistic models for cell trafficking and cortisol dynamics, was investigated in this study. Single, presumably equivalent, doses of intravenous hydrocortisone, methylprednisolone, dexamethasone, and oral prednisolone were given to 5 white men, according to total body weight, in a 5-way crossover, placebo-controlled study. Pharmacodynamic (PD) response-time profiles for T helper cells, T suppressor cells, neutrophils, and adrenal suppression were evaluated by extended indirect response models. For adrenal suppression, prednisolone appears to be less potent than methylprednisolone or dexamethasone. A good correlation was found between the estimated in vivo EC50 values and relative receptor affinity (equilibrium dissociation constants normalized to dexamethasone). Area under the effect curves of all PD responses was calculated using a linear-trapezoidal method. Although T helper cell trafficking and adrenal suppression achieved significant differences by repeated-measures ANOVA (p = 0.014 and 0.022), post hoc analysis using the Bonferroni method revealed no difference between treatments. Although limited by the use of single doses and a relatively small sample size, this study applies mechanistic models for several biomarkers showing that currently used dosing tables reflect reasonable dose equivalency relationships for four corticosteroids.

The therapeutic potential of intraocular depot steroid systems: developments aimed at prolonging duration of efficacy

BACKGROUND

Corticosteroids play a major role in the treatment of many diseases of the posterior ocular segment. Systemically or topically administered steroids usually do not attain therapeutic concentrations in the retina, as they must first cross the blood-retina barrier. Intravitreal application is a useful alternative means of achieving therapeutic concentrations in the posterior segment but must be repeated every few weeks, because drugs given in this way have a short half-life. Intraocular sustained-release implants have been now developed in order to prolong the effect of intravitreal drugs and to lessen the need for repeated application. Macular edema is a typical indication for intravitreal steroid treatment.

METHODS

Selective review of the literature.

RESULTS

Various intravitreal corticosteroid implants have been evaluated in prospective, randomized clinical trials in recent years, and some have been approved for clinical use. Implants are either longer-acting and non-resorbable (fluocinolone acetonide implants) or shorter-acting and resorbable (dexamethasone implants). Major adverse effects of intravitreal corticosteroids include the induction or worsening of cataracts and elevated intraocular pressure. The likelihood of a complication varies from implant to implant and depends on the duration of action of the particular one used.

CONCLUSION

Intravitreal corticosteroid implants are a new option in the treatment of diseases of the posterior ocular segment. Long-term results are not yet available. The optimal treatment for these diseases will need to be the focus of further clinical research.

Corticosteroid injection into the osteoarthritic knee: drug selection, dose, and injection frequency

OBJECTIVE

Although some disagreement exists amongst practitioners as to the efficacy of corticosteroid injection into the osteoarthritic knee, this procedure remains the most common reason to perform knee joint injection. There is disagreement too over the most efficacious corticosteroid for the procedure; the dose required at injection; the frequency, and total quantity of corticosteroid that can be injected into the knee. This paper examines the controversies surrounding the efficacy of corticosteroid injection into the osteoarthritic knee, and attempts to provide guidance as to appropriate corticosteroid selection, dose, and treatment interval.

METHOD

Searches were made of electronic databases, and appropriate papers were identified and hand-searched.

RESULTS AND CONCLUSION

Although numerous investigations have been conducted in an attempt to identify the optimal corticosteroid agent, and its optimal dosing regimen for the intra-articular treatment of osteoarthritis, a consensus has not been established. The current recommendations for dosing interval appear to have arisen as a consequence of a misinterpretation of previously published works. This paper recommends that practitioners refine and individually tailor their selection of agent and dosing regimen to patient needs and clinical response.

Evidence-based neonatal pharmacotherapy: postnatal corticosteroids

Corticosteroids are used in the neonatal intensive care unit primarily to treat two conditions: bronchopulmonary dysplasia (BPD) and hypotension (cardiovascular insufficiency). Historically, high-dose dexamethasone was used for BPD, but its use was later associated with adverse neurodevelopmental outcomes and decreased substantially. Data from randomized controlled trials regarding efficacy and safety of lower-dose dexamethasone therapy are insufficient to recommend its use. Hydrocortisone may be an alternative to dexamethasone, but again data are insufficient to support use. Hydrocortisone therapy is increasingly used to treat hypotension in critically ill newborns; however, the outcomes of this therapy must be evaluated in randomized trials.

Local and systemic safety of intranasal corticosteroids

The safety and efficacy of intranasal corticosteroids (INCs) are well established for the management of allergic rhinitis, rhinosinusitis, and nasal polyps. As seen in numerous studies, INCs demonstrate markedly reduced systemic bioavailability compared with oral and even inhaled corticosteroids and have shown an excellent safety profile over 3 decades of use. Nonetheless, concerns remain among some prescribers and patients that these agents may reach the systemic circulation in sufficient concentration to produce adverse effects (AEs). Available evidence does not support these concerns. A review of the published literature indicates that the side effect profiles of INCs consist primarily of a low incidence of mostly mild and often transient local AEs, such as nasal irritation and epistaxis.The second-generation INC agents currently in use (mometasone furoate nasal spray, fluticasone propionate, ciclesonide, and fluticasone furoate) have favorable pharmacokinetic characteristics that further minimize systemic bioavailability (< 1%) compared with older INCs and compared with oral agents, thereby limiting the risk for systemic adverse events.

Influence of drug solubility and lipophilicity on transscleral retinal delivery of six corticosteroids

The influence of drug properties including solubility, lipophilicity, tissue partition coefficients, and in vitro transscleral permeability on ex vivo and in vivo transscleral delivery from corticosteroid suspensions was determined. Solubility, tissue/buffer partition coefficients for bovine sclera and choroid-retinal pigment epithelium (CRPE), and in vitro bovine sclera and sclera-choroid-retinal pigment epithelium (SCRPE) transscleral transport were determined at pH 7.4 for triamcinolone, prednisolone, dexamethasone, fluocinolone acetonide, triamcinolone acetonide, and budesonide in solution. Ex vivo and in vivo transscleral delivery was assessed in Brown Norway rats after posterior subconjunctival injection of a 1 mg/ml suspension of each corticosteroid. Corticosteroid solubility and partition coefficients ranged from ∼ 17 to 300 μg/ml and 3.0 to 11.4 for sclera and from 7.1 to 35.8 for CRPE, respectively, with the more lipophilic molecules partitioning more into both tissues. Transport across sclera and SCRPE was in the range of 3.9 to 10.7% and 0.3 to 1.8%, respectively, with the transport declining with an increase in lipophilicity. Ex vivo and in vivo transscleral delivery indicated tissue distribution in the order CRPE ≥ sclera > retina > vitreous. Tissue partitioning showed a positive correlation with drug lipophilicity (R(2) = 0.66-0.96). Ex vivo and in vivo sclera, CRPE, retina, and vitreous tissue levels of all corticosteroids showed strong positive correlation with drug solubility (R(2) = 0.91-1.0) but not lipophilicity (R(2) = 0.24-0.41) or tissue partitioning (R(2) = 0.24-0.46) when delivered as suspensions. In vivo delivery was lower in all eye tissues assessed than ex vivo delivery, with the in vivo/ex vivo ratios being the lowest in the vitreous (0.085-0.212). Upon exposure to corticosteroid suspensions ex vivo or in vivo, transscleral intraocular tissue distribution was primarily driven by the drug solubility.

[Theophylline, a new look to an old drug]

OBJECTIVES

To emphasize the safety and efficacy of theophylline in chronic inflammatory respiratory diseases. To mention its immunomodulatory effects.

DATA SOURCES

PubMed search using the keywords: theophylline, histone deacetylase, antiinflammatory, asthma, chronic obstructive pulmonary disease (COPD), corticoresistance.

RESULTS

Theophylline is a methylxantine, that inhibits phosphodiesterase (PDE), induces histone deacetylase and antagonizes adenosine. Its main effect is to relax airway smooth muscle. The immunomodulatory effects of theophylline are obtained at low plasma concentrations (less than 10 mg/L). The combination of inhaled corticoesteroids and theophylline exerts a synergistic antiinflammatory effect that improves asthma control and reduces COPD exacerbations. Histones are a group of transcriptional cofactors involved in chromatin remodeling. Histone deacetylases (HDACs) suppress inflammatory gene expression. In patients with COPD and severe asthma there is a reduction in HDAC-2 secondary to the increased oxidative and nitrative stress. HDAC-2 is required by corticosteroids to switch off activated inflammatory genes, then its reduction favors corticosteroid resistance. Theophylline via HDAC-2 induction and PDE inhibition, suppresses inflammatory gene expression, and inhibits free oxygen radicals production.

CONCLUSIONS

Theophylline at low plasma concentrations exerts antiinflammatory effects, restoring corticosteroid sensitivity in COPD and severe asthma.

Pharmacogenomics in the treatment of inflammatory bowel disease

In recent years, the benefits of early aggressive treatment paradigms for inflammatory bowel disease have emerged. Symptomatic improvement is no longer considered adequate; instead, the aim of treatment has become mucosal healing and altered natural history. Nonetheless, we still fail to achieve these end points in a large number of our patients. There are many reasons why patients fail to respond or develop toxicity when exposed to drugs used for inflammatory bowel disease, but genetic variation is likely to account for a significant proportion of this. Some examples, notably thiopurine methyltransferase polymorphism in thiopurine treatment, are already established in clinical practice. We present a review of the expanding literature in this field, highlighting many interesting developments in pharmacogenomics applied to inflammatory bowel disease and, where possible, providing guidance on the translation of these developments into clinical practice.

Brain permeability of inhaled corticosteroids

The aim of this study was to evaluate if the permeability of inhaled corticosteroids entering the brain is reduced and if P-glycoprotein (P-gp) transporters are involved. Currently employed inhaled corticosteroids were given intravenously and intratracheally to rats at a dose of 100 μg kg−1. An ex-vivo receptor binding assay was used to monitor over 12 h the glucocorticoid receptor occupancy in the brain and a systemic reference organ (kidney). The involvement of P-gp in the brain permeability of triamcinolone acetonide was assessed in wild-type mice and mdr1a(-/-) knockout mice (mice lacking the gene for expressing P-gp). After both forms of administration, the average brain receptor occupancies were 20–56% of those of the reference organ, with the more lipophilic drugs showing a more pronounced receptor occupation. While the receptor occupancies in the liver of wild-type and mdr1a(-/-) mice were similar after administration of triamcinolone acetonide, brain receptor occupancies in mdr1a(-/-) mice were significantly greater (mdr1a(-/-): 47.6%, 40.2–55.0%, n = 2; wild-type: 11.5±33.0%, n = 3). Penetration into the brain for inhaled corticosteroids (especially those of lower lipophilicity) is reduced. Experiments in mdr1a(-/-) mice confirmed the involvement of P-gp transporters. Further studies are needed to assess whether potential drug interactions at the transporter level are of pharmacological significance.

Comparison of skin concentrations following topical versus oral corticosteroid treatment: reconsidering the treatment of common inflammatory dermatoses

BACKGROUND

Topical corticosteroids are often considered to have greater safety and poorer efficacy than oral corticosteroids in treating psoriasis and atopic dermatitis. There are limited data for assessing relative efficacy of topical and systemic corticosteroids, however. The concentration of corticosteroid in skin, adjusted for the relative potency of the active compound, may be a predictor of clinical efficacy and can be estimated for both topical and oral administration.

PURPOSE

To analyze the assumption that oral corticosteroid therapy should be more potent than topical therapy by comparing relative corticosteroid concentrations in the skin expected with topical versus systemic administration.

METHODS

The estimated skin concentration of prednisone following oral dosing was calculated based on data showing 70-100% bioavailability and an even tissue distribution. Data on the concentration of corticosteroids found in skin after topical application were obtained from the literature. The relative potencies of corticosteroid molecules were then used to compare skin concentrations of corticosteroid following topical versus oral treatment.

RESULTS

Data derived from the existing literature demonstrated that hydrocortisone 2.5% ointment, triamcinolone 0.1% ointment, and clobetasol 0.05% foam achieved effective skin concentrations greater than the effective concentration achieved by oral prednisone. Betamethasone 0.1% cream achieved effective concentrations in skin within the range created by oral prednisone.

LIMITATIONS

This analysis was limited by the paucity of data regarding cutaneous concentrations of corticosteroids after topical application, and by the differing experimental designs utilized in the available studies.

CONCLUSION

Most topical corticosteroids have the potential to achieve greater effective drug levels in the superficial layers of skin than those achieved with standard doses of oral prednisone. The apparently greater efficacy of oral corticosteroid therapy may be attributable, in part, to poor patient compliance with topical therapy. Systemic alterations in immune function following oral, but not topical, corticosteroid use may also play a role.

Sodium hyaluronate gels as a drug-release system for corticosteroids: release kinetics and antiproliferative potential for glaucoma surgery

PURPOSE

To evaluate the release kinetics, biocompatibility and antiproliferative potential of a concentrated hydrophilic steroid formulation from commercially available sodium hyaluronate gels as a potential adjunct in glaucoma surgery.

METHODS

Dexamethasone and sodium hyaluronate 1% (Healon) and sodium hyaluronate 2.3% (Healon 5) were mixed to yield sodium hyaluronate formulations containing dexamethasone in concentrations of 4-20 mg/ml (7.7-38 mm). Non-cumulative and cumulative release into balanced salt solution (BSS) or phosphate buffered saline (PBS) was measured spectrophotometrically over 2-6 days. For cytotoxicity assays, human tenon fibroblasts (HTFB) and human retinal pigment epithelium cells (ARPE19) were cultured in a serum-deficient medium to ensure a static milieu; 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazoliumbromide (MTT) assay and Live/Dead cell-mediated cytotoxicity assay were used to exclude cytotoxicity. Cellular proliferative activity was monitored by 5'-bromo-2'-deoxyuridine (BrdU)-incorporation into cellular DNA.

RESULTS

The release kinetics from sodium hyaluronate 1% and 2.3% were almost identical. Steady state was achieved after approximately 44 hrs in non-cumulative measurements. The release plotted as a function of the square root of time was consistent with a largely diffusion-controlled release system. No cytotoxicity could be observed. Dexamethasone-loaded sodium hyaluronate showed a significant antiproliferative effect on HTFB and ARPE19 cells.

CONCLUSION

Dexamethasone-loaded sodium hyaluronate shows extended release of steroid over almost 2 days in concentrations high enough to inhibit the proliferation of HTFB and RPE cells without evoking cytotoxic effects. Thus, this formulation may be an easy-to-prepare adjunct in glaucoma surgery or other procedures in which cellular growth inhibition is desired.

Molecular and clinical pharmacology of intranasal corticosteroids: clinical and therapeutic implications

Intranasal corticosteroids (INSs) are effective treatments for allergic rhinitis, rhinosinusitis, and nasal polyposis. In recent years, increased understanding of corticosteroid and glucocorticoid receptor pharmacology has enabled the development of molecules designed specifically to achieve potent, localized activity with minimal risk of systemic exposure. Pharmacologic potency studies using affinity and other assessments have produced similar rank orders of potency, with the most potent being mometasone furoate, fluticasone propionate, and its modification, fluticasone furoate. The furoate and propionate ester side chains render these agents highly lipophilic, which may facilitate their absorption through nasal mucosa and uptake across phospholipid cell membranes. These compounds demonstrate negligible systemic absorption. Systemic absorption rates are higher among the older corticosteroids (flunisolide, beclomethasone dipropionate, triamcinolone acetonide, and budesonide), which have bioavailabilities in the range of 34-49%. Studies, including 1-year studies with mometasone furoate, fluticasone propionate, and budesonide that evaluated potential systemic effects of INSs in children have generally found no adverse effects on hypothalamic-pituitary-adrenal axis function or growth. Clinical data suggest no significant differences in efficacy between the INSs. Theoretically, newer agents with lower systemic availability may be preferable, and may come closer to the pharmacokinetic/pharmacologic criteria for the ideal therapeutic choice.

Soft corticosteroids for local immunosuppression: exploring the possibility for the use of loteprednol etabonate for islet transplantation

Transplantation of pancreatic islets into subcutaneous, neovascularized devices is one of the possibilities explored as part of our search for a cure of diabetes. We have recently reported that syngeneic transplantation in a subcutaneous prevascularized device can restore euglycemia and sustain long-term function in rats and that explanted grafts showed preserved islets and intense vascular networks. Because all of the transplanted tissue is localized within the device, if such a bioartificial pancreas approach is used, localized immunosuppression might provide sufficient protection against rejection to achieve long-term function, while also avoiding the serious systemic side effects and the susceptibility for opportunistic infections that are commonly associated with systemic immunosuppressive therapies as only much smaller and localized doses are needed. Soft steroids are obvious candidates because soft drugs are specifically designed to produce targeted local activity, but no systemic side effects due to prompt metabolic (preferably extrahepatic, e.g., hydrolytic) inactivation. However, local concentrations that are effective for immunosuppression, but non-toxic to insulin-producing beta-cells have to be found, and nontrivial difficulties related to long-term local deliverability have to be addressed. Here, we report preliminary results obtained using in vitro studies with human islets used to establish a tentative therapeutic concentration range together with fully scaled three-dimensional finite element method (FEM)-based Comsol multiphysics computational models that were used to explore various possibilities to achieve and maintain these concentration levels within the device.

Multilayer PVA adsorption onto hydrophobic drug substrates to engineer drug-rich microparticles

Despite the availability of numerous crystal engineering techniques, generating drug-rich microparticles with a predetermined size, morphology and crystallinity still represents a significant challenge. A microparticle manufacturing method has recently been developed that attempts to 'shield' the physicochemical properties of micronised drugs by the application of a microfine polymer coating. The aims of this study were to investigate the nature of the drug-polymer interactions and determine the effects of this manufacturing strategy upon release of the drug from the microparticles. The adsorption of poly(vinyl alcohol) (PVA) on the micronised hydrophobic drug surface was found to reach equilibrium between 23 and 27 h. The Freundlich isotherm model was shown to give the most accurate fit to the experimental data and thus multilayer adsorption was assumed. The adsorptive capacity (1/n) was specific to the substrate and PVA grade. An increase in the PVA (%) hydrolysis value caused 1/n to increase from 0.76 to 1.05 using budesonide and from 0.31 to 0.79 when betamethasone valerate (BMV) was used. Increasing the molecular weight of the adsorbing polymer caused a reduction in the strength of PVA-adsorbate interaction when budesonide was used as the substrate (from 0.76 to 0.59), whereas a three-fold increase (from 0.31 to 0.86) was achieved when the BMV substrate was employed. A proportion of the adsorbed polymer was shown to remain associated with the substrate during the spray-drying process and the polymer coating resulted in a significantly higher (p<0.05, ANOVA) amount of drug release in 60 min (ca. 100%) compared to budesonide alone.

Transfer of the experimental methodology described in the FDA guidance for corticosteroid bioequivalence testing to pharmacodynamic effects caused by nicotinates

BACKGROUND

The measurement of the pharmacodynamic response allows the noninvasive quantification of cutaneous drug penetration.

AIMS

The objective of this study was to investigate whether the experimental methods described in the US Food and Drug Administration Guidance for Industry "Topical Dermatologic Corticosteroids: In vivo Bioequivalence" may be transferred to other response parameters such as skin redness and surface temperature.

METHODS

Drug penetration experiments with methyl nicotinate in two different lipophilic vehicles were performed according to the FDA guidance for corticosteroid bioequivalence testing measuring the cutaneous erythema and skin temperature response.

RESULTS

The guidance methodology was transferred to the response parameters redness and temperature. Bioequivalence testing was feasible with these response parameters.

CONCLUSIONS

An open one-compartment model could only be confirmed for skin redness data by a compartmental analysis of response vs. time profiles. The obtained temperature data can neither be described by an open one-compartment nor by a two-compartment model. A correlation between skin color and skin surface temperature could not be found.

Inhaled corticosteroids in children with asthma: pharmacologic determinants of safety and efficacy and other clinical considerations

The role of inhaled corticosteroids (ICS) in the treatment of childhood asthma has been well established. An ideal corticosteroid should demonstrate high pulmonary deposition and residency time, in addition to a low systemic bioavailability and rapid systemic clearance. The lung depositions of the ICS have been compared, with beclomethasone (beclometasone)-hydrofluoroalkane (HFA) and ciclesonide showing the highest lung deposition. Lung deposition is influenced by not only the inhalation device and type of propellant (HFA or chlorofluorocarbon), but also by whether the aerosol is a solution or suspension, and the particle size of the respirable fraction. Pulmonary residency time increases when budesonide and des-ciclesonide undergo reversible fatty acid esterification. The bioavailability of the drug depends on the oral bioavailable fraction and the amount absorbed directly from the pulmonary vasculature. The clearance rate of des-ciclesonide is very high (228 L/h), increasing its safety profile by utilizing extra-hepatic clearance mechanisms. Both des-ciclesonide and mometasone have a high protein binding fraction (98-99%). The volume of distribution (Vd) is proportional to the lipophilicity of the drug, with the Vd of fluticasone being 332L compared with 183L for budesonide. Increasing the Vd will also increase the elimination half-life of a drug. The pharmacodynamics of ICS depend on both the receptor binding affinity and the dose-response curve. Among the ICS, fluticasone and mometasone have the highest receptor binding affinity (1800 and 2200, respectively), followed by budesonide at 935 (relative to dexamethasone = 100). Compared with other nonsteroid asthma medications (long-acting beta-agonists, theophylline, and montelukast) ICS have proven superiority in improving lung function, symptom-free days, and inflammatory markers. One study suggests that early intervention with ICS reduces the loss in lung function (forced expiratory volume in 1 second) over 3 years. Whether airway remodeling is reduced or prevented in the long term is unknown. Potential adverse drug effects of ICS include adrenal and growth suppression. While in low-to-medium doses ICS have shown little suppression of the adrenal pituitary axis, in high doses the potential for significant adrenal suppression and adrenal crisis exists. Several longitudinal studies evaluating the effect of ICS on growth have shown a small decrement in growth velocity (approximate 1-2 cm) during the first year of treatment. However, when investigators followed children treated with budesonide for up to 10 years, no change in target adult height was noted. In conclusion, the development of optimal delivery devices for young children, as well as optimizing favorable pharmacokinetic properties of ICS should be priorities for future childhood asthma management.

Inhaled corticosteroids in obstructive airway disease

Inhaled corticosteroids play an important role in the management of obstructive airway disease, by suppressing airway inflammation that is central to the pathophysiology of these conditions. In asthma there is strong clinical evidence supporting the use of inhaled corticosteroids in mild, moderate, and severe persistent asthma to improve lung function, reduce exacerbations, and prevent death. In chronic obstructive pulmonary disease, inhaled corticosteroids improve symptoms, reduce frequency of exacerbations and hospitalizations, and should be considered in patients with moderate-to-severe airflow limitation who have persistent symptoms despite optimal bronchodilator therapy. Though the adverse effects of corticosteroids are less when given via inhalation than when given systemically, nevertheless, the adverse effects are important and need to be considered. Newer inhaled corticosteroids with better pharmacologic properties are being developed and will probably be available in the near future.

A systematic review of the safety of topical therapies for atopic dermatitis

BACKGROUND

The safety of topical therapies for atopic dermatitis (AD), a common and morbid disease, has recently been the focus of increased scrutiny, adding confusion as how best to manage these patients.

OBJECTIVES

The objective of these systematic reviews was to determine the safety of topical therapies for AD.

METHODS

Databases searched included: OVID Medline, Medline In-Process and Other Non-Indexed Citations, Embase, and the Cochrane Central Register of Controlled Trials. In addition to the articles identified by this search, investigators were also referred to a list of links (most recently updated 25 September 2005) to recent Food and Drug Administration (FDA) studies, reports and meetings regarding the topical calcineurin inhibitors for further potential references. Only fully published papers available in English and data obtained from FDA sites were included. Furthermore, the criteria for inclusion and exclusion for each systematic review were further evaluated at a meeting of all of the content and evidence-based medicine experts participating in this process and alteration of the inclusion criteria was done at that time when it was felt necessary to avoid inclusion of lower-quality data in the review. Qualitative review of the abstracted data was performed and reviewed at a meeting of all of the content and evidence-based medicine experts.

RESULTS

While systemic exposure to these topical agents does occur, physiological changes appear to be uncommon and systemic complications rare and have only been found with use of topical corticosteroids.

CONCLUSIONS

Based on the data that are available the overall safety of AD therapies appears to be good with the only documented systemic side-effects of therapy those occasionally seen with use of topical corticosteroids.

[Secondary osteoporosis: Inhaled corticosteroids induced osteoporosis in respiratory diseases]

Inhalation and oral steroids therapy has been used in the management of asthma, chronic obstructive pulmonary disease (COPD) and interstitial lung disease. This article described the effects of inhaled corticosteroids on bone. Inhaled corticosteroids are the standard of therapy in asthma and are commonly prescribed for chronic obstructive pulmonary disease. Accumulating evidence suggests that the effect of inhaled corticosteroids on bone is not small. Recent studies have shown that long-term use of inhaled corticosteroid at moderate or high doses is also associated with increased risk for the effects of inhaled corticosteroids on bone. Older age, inmobility and steroid treatment are major risk factors of osteoporosis. Treatment with bisphosphonate will be recommended in these patients, so earlier prevention for corticosteroids induced osteoporosis is necessary at administration of inhaled corticosteroids.

Corticosteroid treatment of severe community-acquired pneumonia

OBJECTIVE

To assess the evidence for adjunctive corticosteroids for severe community-acquired pneumonia (CAP).

DATA SOURCES

MEDLINE (1966-February 2007) and EMBASE (1980-February 2007) were searched to identify English- and French-language publications that evaluated the use of corticosteroids for CAP in adults. Major search terms included community-acquired pneumonia, intensive care unit, steroids, glucocorticoids, and adrenal cortex hormones.

STUDY SELECTION AND DATA EXTRACTION

Clinical studies that evaluated the use of corticosteroids for CAP in adults were included. Clinical and surrogate markers of pneumonia were evaluated.

DATA SYNTHESIS

Severe CAP is associated with an increase in pulmonary and circulatory cytokines such as interleukin-6 and tumor necrosis factor-alpha that may be associated with higher mortality. Corticosteroids suppress inflammatory reactions and prevent migration of inflammatory cells from the circulation to tissues by suppressing the synthesis of chemokines and cytokines. One observational comparative study and 2 randomized, controlled studies examined the effects of corticosteroid therapy at various doses on endpoints of pulmonary and systemic inflammation and clinical outcomes. One small observational pilot study revealed that methylprednisolone blunted some of the pulmonary and systemic markers of inflammation. One small, randomized, placebo-controlled study revealed that hydrocortisone had no significant effects on markers of pulmonary and systemic inflammation or clinical outcomes. Another small, randomized, placebo-controlled preliminary study with methodological limitations revealed improvements in oxygenation, organ dysfunction score, and markers of inflammation favoring hydrocortisone over placebo.

CONCLUSIONS

Given the lack of proven benefit on clinically meaningful endpoints and adverse events, corticosteroids cannot be recommended for adjunctive treatment of severe CAP.

Ultra-Sensitive Quantification of Corticosteroids in Plasma Samples Using Selective Solid-Phase Extraction and Reversed-Phase Capillary High-Performance Liquid Chromatography/Tandem Mass Spectrometry

Low-dose corticosteroids may provide a favorable benefit/risk ratio for many therapeutic applications. However, the extremely low plasma drug concentrations achieved, in conjunction with the insufficient sensitivity/ selectivity of current analytical methods, renders the evaluation of corticosteroid pharmacokinetics (PK) a significant challenge under such conditions. Furthermore, targeted therapeutic strategies involving administration by inhalation or intraocular injection could result in very low but sustained systemic corticosteroid concentrations, which must be quantified to determine potential side effects. Here we describe a robust method for the ultrasensitive quantification of corticosteroids in plasma samples. This was achieved by the combination of a selective solid-phase extraction (SPE) with a highly sensitive capillary LC (microLC)-MS/MS analysis. SPE washing and elution conditions were optimized so that target drugs are selectively extracted from plasma. By eliminating most undesirable compounds from the sample matrix, this selective SPE procedure enabled a high sample loading volume on the microLC column without compromising chromatographic performance and operational robustness and helped to achieve ultralow detection limits for the corticosteroids in plasma. The effect of microLC separation on the signal-to-noise ratio of corticosteroid peaks in plasma samples was investigated. It was found that with sufficient microLC separation, sensitivity was improved because of a decrease in matrix effects and the removal of endogenous interferences. Detection limits of four clinically important corticosteroids (budesonide, dexamethasone, triamcinolone acetonide, and dexamethasone acetate) ranged from 0.2 to 1 pg/mL in plasma, and linearity was good for all drugs in the range of 5-5000 pg/mL. Accuracy was 88-107% and the variation (CV%) was 2.3-11.1%. A limit of quantification (LOQ) of 5 pg/mL was validated for all four compounds. We applied this method to quantify the low levels of triamcinolone acetonide (TACA) in porcine plasma following suprachoroidal administration, which is necessary to estimate systemic drug exposure resulting from this novel clinical approach for treating inflammatory diseases of the eye. TACA in plasma could be quantified at low pg/mL levels for up to 90 days posttreatment. To our knowledge, this is the first practical analytical approach that can monitor plasma corticosteroids after intraocular administration, given the ultralow plasma concentrations achieved. In summary, this strategy enables PK analysis of corticosteroids in treatment regimens that result in extremely low systemic concentrations, and the approach can be extended for the sensitive quantification of other drugs.

In vitro activation of the corticosteroid ciclesonide in animal nasal mucosal homogenates

Ciclesonide, a new corticosteroid for allergic rhinitis, is administered as an inactive parent compound that is converted by esterases to the pharmacologically active metabolite, desisobutyryl-ciclesonide (des-CIC). This study investigated the in vitro activation of ciclesonide in nasal mucosa of multiple animal species. Nasal mucosal homogenates from rats, guinea-pigs, rabbits and dogs were incubated with ciclesonide 0.5 micromol/l (0.271 microg/ml) or 5 micromol/l (2.71 microg/ml) for up to 120 min. Concentrations of ciclesonide and des-CIC were measured by high-performance liquid chromatography with tandem mass spectrometry. Ciclesonide was metabolized to des-CIC in nasal mucosal homogenates of each species. The initial velocities of des-CIC formation ranged from 0.0038 to 0.0150 nmol/min/mg protein and 0.0319 to 0.0983 nmol/min/mg protein in nasal mucosal homogenates incubated with ciclesonide 0.5 micromol/l and 5 micromol/l, respectively. Furthermore, the initial velocities of ciclesonide metabolism ranged from 0.0032 to 0.0142 nmol/min/mg protein and 0.0445 to 0.1316 nmol/min/mg protein in nasal mucosal homogenates incubated with ciclesonide 0.5 micromol/l and 5 micromol/l, respectively. This study confirms that ciclesonide is converted to des-CIC in nasal mucosal homogenates without any marked differences among animal species.

Pharmacokinetic and pharmacodynamic properties of inhaled ciclesonide

Inhaled corticosteroids are recommended first-line therapy for persistent asthma of all severities; however, oropharyngeal and systemic adverse events can be a concern. Inhaled corticosteroids exert their therapeutic and adverse effects by interacting with glucocorticoid receptors within and outside the lungs, respectively. Ciclesonide is a novel inhaled corticosteroid that possesses a unique pharmacokinetic and pharmacodynamic profile. Ciclesonide is inactive itself and converted to its pharmacologically active metabolite, desisobutyryl-ciclesonide, in the target organ, the lungs. Pulmonary activation combined with low oral deposition may minimize oropharyngeal adverse events, and low oral bioavailability, rapid clearance, and high protein binding may reduce systemic exposure. In addition, high pulmonary deposition due to the highly respirable particles, combined with the potential for prolonged lung retention via lipid conjugation, provides for effective therapeutic action.

Population pharmacokinetic/pharmacodynamic modeling of systemic corticosteroid inhibition of whole blood lymphocytes: modeling interoccasion pharmacodynamic variability

PURPOSE

To develop a population pharmacokinetic/pharmacodynamic (PK/PD) model that characterizes the effects of major systemic corticosteroids on lymphocyte trafficking and responsiveness.

MATERIALS AND METHODS

Single, presumably equivalent, doses of intravenous hydrocortisone (HC), dexamethasone (DEX), methylprednisolone (MPL), and oral prednisolone (PNL) were administered to five healthy male subjects in a five--way crossover, placebo--controlled study. Measurements included plasma drug and cortisol concentrations, total lymphocyte counts, and whole blood lymphocyte proliferation (WBLP). Population data analysis was performed using a Monte Carlo-Parametric Expectation Maximization algorithm.

RESULTS

The final indirect, multi-component, mechanism-based model well captured the circadian rhythm exhibited in cortisol production and suppression, lymphocyte trafficking, and WBLP temporal profiles. In contrast to PK parameters, variability of drug concentrations producing 50% maximal immunosuppression (IC(50)) were larger between subjects (73-118%). The individual log-transformed reciprocal posterior Bayesian estimates of IC(50) for ex vivo WBLP were highly correlated with those determined in vitro for the four drugs (r ( 2 ) = 0.928).

CONCLUSIONS

The immunosuppressive dynamics of the four corticosteroids was well described by the population PK/PD model with the incorporation of inter-occasion variability for several model components. This study provides improvements in modeling systemic corticosteroid effects and demonstrates greater variability of system and dynamic parameters compared to pharmacokinetics.

Advances in single-entity inhaled corticosteroid therapy

The aim of inhaled corticosteroid (ICS) therapy is to achieve optimal drug targeting by producing pulmonary effects with a minimum of systemic side effects. To achieve a favorable safety and efficacy profile, an ICS should possess the necessary pharmacokinetic and pharmacodynamic characteristics. Ideally, an ICS would have high pulmonary deposition efficiency, high systemic clearance, negligible oral bioavailability, sustained pulmonary residence time, selective binding to the corticosteroid receptor, and high plasma protein binding. Recent developments in ICS therapy have used these concepts in producing more effective compounds resulting in drugs with a very high therapeutic index. Additional developments may consider exploring improvements in delivery devices and drug formulations to improve pulmonary residence time.

Corticosteroid design for the treatment of asthma: structural insights and the therapeutic potential of soft corticosteroids

Inhaled and intranasal corticosteroids (ICSs) still are the most effective treatment available for allergic airway diseases and are likely to remain the cornerstone of managing persistent asthma/allergic rhinitis in the foreseeable future. Even if the therapeutic index of this class increased significantly with the introduction of newer corticosteroids, and even if new therapeutic potentials are beginning to emerge with our increasing understanding of the mechanisms of asthma, chronic obstructive pulmonary disease, and rhinitis, corticosteroid development still remains a very important field for drug designers. After a brief review of issues related to the structure-activity relationships of glucocorticoids and the main determinants of their receptor-binding affinity at the glucocorticoid receptor, the main focus of the present article will be on the development of soft corticosteroids, as they are particularly well suited to separate local activity from systemic side effects, which still is an important issue for ICSs. Design consideration required in the search for safe and effective soft drugs on one hand, and safe and effective ICSs on the other hand, will be briefly discussed and illustrated with a number of cases, in particular, with that of loteprednol etabonate and etiprednol dicloacetate, soft corticosteroids that are being developed for a full spectrum of therapeutic applications including asthma and allergic rhinitis.