Review of the unique properties of budesonide

Aerosol technology to mimic dry powder inhalation in vitro using pulmonary cell models

Inhaled therapy confers key advantages for the treatment of topical pulmonary diseases and offers potential for systemic delivery of medicines. Dry powder inhalers (DPIs) are generally the preferred devices for pulmonary delivery due to improved stability and satisfactory patient compliance. However, the mechanisms governing drug powder dissolution and availability in the lung and poorly understood. Here, we report a new in vitro system to study epithelial absorption of inhaled dry powders in lung barrier models of the upper and lower airway. The system is based on a CULTEX® RFS (Radial Flow System) cell exposure module joined to a Vilnius aerosol generator and allows the coupling of drug dissolution and permeability assessments. The cellular models recapitulate the barrier morphology and function of healthy and diseased pulmonary epithelium and incorporate the mucosal barrier to enable the investigation of drug powder dissolution in biorelevant conditions. With this system, we found differences in permeability across the airway tree and pinpointed the impact of diseased barriers in paracellular drug transport. Furthermore, we identified a different rank order of permeability for compounds tested in solution or powder form. These results highlight the value of this in vitro drug aerosolization setup for use in research and development of inhaled medicines.

Application of aerosol therapy in respiratory diseases in children: A Saudi expert consensus

The Saudi Pediatric Pulmonology Association (SPPA) is a subsidiary of the Saudi Thoracic Society (STS), which consists of a group of Saudi experts with well-respected academic and clinical backgrounds in the fields of asthma and other respiratory diseases. The SPPA Expert Panel realized the need to draw up a clear, simple to understand, and easy to use guidance regarding the application of different aerosol therapies in respiratory diseases in children, due to the high prevalence and high economic burden of these diseases in Saudi Arabia. This statement was developed based on the available literature, new evidence, and experts' practice to come up with such consensuses about the usage of different aerosol therapies for the management of respiratory diseases in children (asthma and nonasthma) in different patient settings, including outpatient, emergency room, intensive care unit, and inpatient settings. For this purpose, SPPA has initiated and formed a national committee which consists of experts from concerned specialties (pediatric pulmonology, pediatric emergency, clinical pharmacology, pediatric respiratory therapy, as well as pediatric and neonatal intensive care). These committee members are from different healthcare sectors in Saudi Arabia (Ministry of Health, Ministry of Defence, Ministry of Education, and private healthcare sector). In addition to that, this committee is representing different regions in Saudi Arabia (Eastern, Central, and Western region). The subject was divided into several topics which were then assigned to at least two experts. The authors searched the literature according to their own strategies without central literature review. To achieve consensus, draft reports and recommendations were reviewed and voted on by the whole panel.

Surfactant and budesonide for respiratory distress syndrome: an observational study

BACKGROUND

In preterm infants on moderately high ventilator support, the addition of budesonide to surfactant lowered bronchopulmonary dysplasia (BPD) rates by 20% without increased morbidity or mortality. The aim of this cohort comparison was to determine the safety and efficacy of the combination in infants with milder respiratory distress syndrome (RDS).

METHODS

In August 2016 we began administering budesonide (0.25 mg/kg) mixed with surfactant (Survanta 4 mL/kg) to all infants ≤ 1250 g who failed CPAP and required intubation. Infants were compared to a historical cohort (2013-2016) who received surfactant alone.

RESULTS

BPD or death did not change between the historical surfactant cohort (71%, n = 294) and the budesonide cohort (69%, n = 173). Budesonide was associated with a decrease in the need for continued mechanical ventilation, severe BPD type II or death (19-12%), grade III BPD or death (31-21%), and the median gestational age at discharge was 1 week earlier. Histologic chorioamnionitis was associated with decreased budesonide effects. Secondary morbidities (NEC, IVH, ROP, Sepsis) were similar.

CONCLUSION

Overall BPD rates remained unchanged with the addition of budesonide. Budesonide was associated with decreased severity of BPD, decreased mechanical ventilation use, earlier discharge, and similar short-term outcomes.

Effects of budesonide and surfactant in preterm fetal sheep

Mechanical ventilation causes lung injury and systemic inflammatory responses in preterm sheep and is associated with bronchopulmonary dysplasia (BPD) in preterm infants. Budesonide added to surfactant decreased BPD by 20% in infants. We wanted to determine the effects of budesonide and surfactant on injury from high tidal volume (V_T) ventilation in preterm lambs. Ewes at 125 ± 1 days gestational age had fetal surgery to expose fetal head and chest with placental circulation intact. Lambs were randomized to 1) mechanical ventilation with escalating V_T to target 15 ml/kg by 15 min or 2) continuous positive airway pressure (CPAP) of 5 cmH₂O. After the 15-min intervention, lambs were given surfactant 100 mg/kg with saline, budesonide 0.25 mg/kg, or budesonide 1 mg/kg. The fetuses were returned to the uterus for 24 h and then delivered and ventilated for 30 min to assess lung function. Budesonide levels were low in lung and plasma. CPAP groups had improved oxygenation, ventilation, and decreased injury markers compared with fetal V_T lambs. Budesonide improved ventilation in CPAP lambs. Budesonide decreased lung weights and lung liquid and increased lung compliance and surfactant protein mRNA. Budesonide decreased proinflammatory and acute-phase responses in lung. Airway thickness increased in animals not receiving budesonide. Systemically, budesonide decreased monocyte chemoattractant protein-1 mRNA and preserved glycogen in liver. Results with 0.25 and 1 mg/kg budesonide were similar. We concluded that budesonide with surfactant matured the preterm lung and decreased the liver responses but did not improve lung function after high V_T injury in fetal sheep.

Influence of respiratory tract disease and mode of inhalation on detectability of budesonide in equine urine and plasma

OBJECTIVE To evaluate the influence of respiratory tract disease (ie, recurrent airway obstruction [RAO]) and mode of inhalation on detectability of inhaled budesonide in equine plasma and urine samples. ANIMALS 16 horses (8 healthy control horses and 8 horses affected by RAO, as determined by results of clinical examination, blood gas analysis, bronchoscopy, and cytologic examination of bronchoalveolar lavage fluid). PROCEDURES 4 horses of each group inhaled budesonide (3 μg/kg) twice daily for 10 days while at rest, and the remaining 4 horses of each group inhaled budesonide during lunging exercise. Plasma and urine samples were obtained 4 to 96 hours after inhalation and evaluated for budesonide and, in urine samples, the metabolites 6β-hydroxybudesonide and 16α-hydroxyprednisolone. RESULTS Detected concentrations of budesonide were significantly higher at all time points for RAO-affected horses, compared with concentrations for the control horses. All samples of RAO-affected horses contained budesonide concentrations above the limit of detection at 96 hours after inhalation, whereas this was found for only 2 control horses. Detected concentrations of budesonide were higher, but not significantly so, at all time points in horses that inhaled budesonide during exercise, compared with concentrations for inhalation at rest. CONCLUSIONS AND CLINICAL RELEVANCE Results of this study indicated that the time interval between inhalation of a glucocorticoid and participation in sporting events should be increased when inhalation treatment is administered during exercise to horses affected by respiratory tract disease.

Clinical equivalence of budesonide dry powder inhaler and pressurized metered dose inhaler

INTRODUCTION

A delivery device is the most important factor that determines the local/systemic bioavailability of inhaled corticosteroids. Dry powder inhalers (DPIs) and pressurized metered dose inhalers (pMDIs) are the most commonly used delivery devices for localized drug delivery to the airways.

OBJECTIVE

This study was to compare the clinical equivalence of budesonide delivered by the Pulmicort Turbuhaler (DPI) and the Aeronide inhaler (pMDI).

MATERIALS AND METHODS

The two inhalers were compared for their pharmaceutical equivalence and clinical equivalence. The in vitro test included the uniformity of the delivered dose and determination of the aerodynamic particle size of budesonide. The in vivo test was carried out in 36 patients with mild to moderate asthma. This was a randomized, single-blinded study conducted for a period of 3 months. This included assessment of the spirometric parameters [forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), peak expiratory flow rate (PEFR), forced expiratory flow 25-75% (FEF25-75)], the severity of asthma symptoms, adverse events, frequency of short-acting inhaled bronchodilator usage and measurement of urinary cortisol levels.

RESULTS

The aerodynamic particle size was slightly different between the two inhalers (2.3 ± 0.2 µm for Pulmicort Turbuhaler and 2.2 ± 0.2 µm for Aeronide inhaler). Both inhalers passed the uniformity of delivered dose (95.4% and 97.4%) specified in the British Pharmacopoeia. There was no statistically significant difference observed between the two inhalers in terms of the spirometric parameters, symptom-free days, frequency of bronchodilator usage and the level of urinary cortisol.

CONCLUSION

In addition to pharmaceutical equivalence, no clinical difference observed between the two budesonide inhalers.

Nuclear receptors and their selective pharmacologic modulators

Nuclear receptors are ligand-activated transcription factors and include the receptors for steroid hormones, lipophilic vitamins, sterols, and bile acids. These receptors serve as targets for development of myriad drugs that target a range of disorders. Classically defined ligands that bind to the ligand-binding domain of nuclear receptors, whether they are endogenous or synthetic, either activate receptor activity (agonists) or block activation (antagonists) and due to the ability to alter activity of the receptors are often termed receptor "modulators." The complex pharmacology of nuclear receptors has provided a class of ligands distinct from these simple modulators where ligands display agonist/partial agonist/antagonist function in a tissue or gene selective manner. This class of ligands is defined as selective modulators. Here, we review the development and pharmacology of a range of selective nuclear receptor modulators.

Characterization of ZK 245186, a novel, selective glucocorticoid receptor agonist for the topical treatment of inflammatory skin diseases

BACKGROUND AND PURPOSE

Glucocorticoids are highly effective in the therapy of inflammatory diseases. Their value, however, is limited by side effects. The discovery of the molecular mechanisms of the glucocorticoid receptor and the recognition that activation and repression of gene expression could be addressed separately opened the possibility of achieving improved safety profiles by the identification of ligands that predominantly induce repression. Here we report on ZK 245186, a novel, non-steroidal, low-molecular-weight, glucocorticoid receptor-selective agonist for the topical treatment of inflammatory dermatoses.

EXPERIMENTAL APPROACH

Pharmacological properties of ZK 245186 and reference compounds were studied in terms of their potential anti-inflammatory and side effects in functional bioassays in vitro and in rodent models in vivo.

KEY RESULTS

Anti-inflammatory activity of ZK 245186 was demonstrated in in vitro assays for inhibition of cytokine secretion and T cell proliferation. In vivo, using irritant contact dermatitis and T cell-mediated contact allergy models in mice and rats, ZK 245186 showed anti-inflammatory efficacy after topical application similar to the classical glucocorticoids, mometasone furoate and methylprednisolone aceponate. ZK 245186, however, exhibits a better safety profile with regard to growth inhibition and induction of skin atrophy after long-term topical application, thymocyte apoptosis, hyperglycaemia and hepatic tyrosine aminotransferase activity.

CONCLUSIONS AND IMPLICATIONS

ZK 245186 is a potent anti-inflammatory compound with a lower potential for side effects, compared with classical glucocorticoids. It represents a promising drug candidate and is currently in clinical trials.

Safety of inhaled budesonide: clinical manifestations of systemic corticosteroid-related adverse effects

Inhaled corticosteroid (ICS) therapy is central to the long-term management of asthma and is extensively used in the management of chronic obstructive pulmonary disease (COPD). While administration via inhalation limits systemic exposure compared with oral or injected corticosteroids and, therefore, the risk of systemic corticosteroid-related adverse effects, concerns over the long-term safety of ICS persist. The assessment of the long-term effects of ICS therapy requires considerable research effort over years or even decades. Surrogate markers/predictors for clinical endpoints such as adrenal crisis, reduced final height and fractures have been identified for use in relatively short-term studies. However, the predictive value of such markers remains questionable.Inhaled budesonide has been available since the early 1980s and there is a considerable evidence base investigating the safety of this agent. To assess the long-term safety of inhaled budesonide therapy in terms of the actual incidence of the clinical endpoints adrenal crisis/insufficiency, reduced final height, fractures and pregnancy complications, we undertook a review of the scientific literature. The external databases BIOSIS, Cochrane Central Register of Controlled Trials, Current Contents, EMBASE, International Pharmaceutical Abstracts and MEDLINE were searched, in addition to AstraZeneca's internal product literature database Planet, up to 29 February 2008. Only original articles of epidemiological studies, national surveys, clinical trials and case reports concerning inhaled budesonide were included.Eight surveys of adrenal crisis were found. The only survey with specified criteria for diagnosis involved 2912 paediatricians and endocrinologists and revealed 33 patients with adrenal crisis associated with ICS therapy; only one patient used budesonide (in co-treatment with fluticasone propionate). In addition, 14 case reports of adrenal crisis in budesonide-treated patients were found. In only two of these, budesonide was used at recommended doses and in the absence of interacting medication.Three retrospective studies and one prospective study assessing final height were found. None of them showed any reduced final height in patients receiving inhaled budesonide during childhood or adolescence.Seventeen epidemiological studies investigating the risk of fractures were found. When adjusting for confounding factors, they did not provide any unequivocal data for an increased fracture risk with budesonide. Four prospective placebo-controlled clinical trials of 2-6 years duration with inhaled budesonide in patients with asthma or COPD were found. None of the studies identified any association between inhaled budesonide and increased risk for fractures.Four studies using data from the Swedish birth and health registries showed there was no increased risk for congenital malformations, cardiovascular defects, decreased gestational age, birth weight or birth length among infants born to women using inhaled budesonide during pregnancy compared with the general population. This was confirmed by five observational studies in Australia, Canada, Hungary, Japan and the US. Similarly, one randomized clinical trial comparing pregnancy outcomes among asthma patients receiving inhaled budesonide or placebo did not demonstrate any difference in outcome of pregnancy.In summary, based on 25 years of experience with different doses and in different populations, inhaled budesonide therapy only in very rare cases appears to be associated with an increased risk of adrenal crisis, reduction in final height, increases in the number of fractures or complications during pregnancy.

Effect of COPD treatments on MRP1-mediated transport in bronchial epithelial cells

Background

Smoking is the principle risk factor for development of chronic obstructive pulmonary disease (COPD). Multidrug resistance-associated protein 1 (MRP1) is known to protect against toxic compounds and oxidative stress, and might play a role in protection against smoke-induced disease progression. We questioned whether MRP1-mediated transport is influenced by pulmonary drugs that are commonly prescribed in COPD.

Methods

The immortalized human bronchial epithelial cell line 16HBE14o⁻ was used to analyze direct in vitro effects of budesonide, formoterol, ipratropium bromide and N-acetylcysteine (NAC) on MRP1-mediated transport. Carboxyfluorescein (CF) was used as a model MRP1 substrate and was measured with functional flow cytometry.

Results

Formoterol had a minor effect, whereas budesonide concentration-dependently decreased CF transport by MRP1. Remarkably, addition of formoterol to the highest concentration of budesonide increased CF transport. Ipratropium bromide inhibited CF transport at low concentrations and tended to increase CF transport at higher levels. NAC increased CF transport by MRP1 in a concentration-dependent manner.

Conclusions

Our data suggest that, besides their positive effects on respiratory symptoms, budesonide, formoterol, ipratropium bromide, and NAC modulate MRP1 activity in bronchial epithelial cells. Further studies are required to assess whether stimulation of MRP1 activity is beneficial for long-term treatment of COPD.

Preparation of Budesonide-Poly (Ethylene Oxide) Solid Dispersions Using Supercritical Fluid Technology

The purpose of this study was to investigate the possibility of preparing solid dispersions of the poorly soluble budesonide by supercritical fluid (SCF) technique, using poly (ethylene oxide) (PEO) as a hydrophilic carrier. The budesonide-PEO solid dispersions were prepared, using supercritical carbon dioxide (SC CO(2)) as the processing medium, and characterized by scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), solubility test and dissolution test in order to understand the influence of the SCF process on the physical status of the drug. The endothermic peak of budesonide in the SCF-treated mixtures was significantly reduced, indicating that budesonide was in amorphous form inside the carrier system. This was further confirmed by SEM and PXRD studies. The enhanced dissolution rates of budesonide were observed from SCF-treated budesonide-PEO mixtures. The amorphous characteristic of the budesonide, the better mixing of drug and PEO powders in the presence of SC CO(2), together with the improved wettability of the drug in PEO, produced a remarkable enhancement of the in vitro drug dissolution rate. Thus, budesonide-PEO solid dispersions with enhanced dissolution rate can be prepared using organic solvent-free SCF process.

The oral, once-daily phosphodiesterase 4 inhibitor roflumilast lacks relevant pharmacokinetic interactions with inhaled budesonide

This open-label, randomized, 3-period crossover study evaluated the pharmacokinetic interaction potential of roflumilast and budesonide following repeated coadministration to healthy male subjects (N = 12). Treatments consisted of oral roflumilast 500 mug, once daily, orally inhaled budesonide 800 mug, twice daily, and concomitant administration of both treatments for 7 days each. Roflumilast and roflumilast N-oxide in plasma and budesonide serum levels were measured by specific assays. Geometric mean test/reference ratios of steady-state pharmacokinetic parameters were evaluated by analysis of variance. Safety and tolerability were monitored. Pharmacokinetic parameters of roflumilast, roflumilast N-oxide, and budesonide after coadministration of roflumilast and budesonide were similar to those after mono-treatment. Compared with budesonide and roflumilast mono-treatments, slightly lower maximum serum/plasma concentration (C(max)) and area under the curve (AUC) values of roflumilast N-oxide and budesonide (ranging from -8% to -16%) were observed with combined treatment. All test/reference ratios were within predefined equivalence acceptance ranges for roflumilast AUC (0.80, 1.25) and C(max) (0.70, 1.43) and for roflumilast N-oxide and budesonide AUC and C(max) (all 0.67, 1.50). Coadministration of roflumilast and budesonide did not alter the steady-state disposition of each other and did not affect safety and tolerability of either drug.

Selective glucocorticoid receptor agonists (SEGRAs): novel ligands with an improved therapeutic index

Glucocorticoids are among the most successful therapies in the treatment of chronic inflammatory and autoimmune diseases. Their efficacy seems to be caused by the interference of the ligand-activated glucocorticoid receptor with many pro-inflammatory pathways via different mechanisms. The ubiquitous expression of the glucocorticoid receptor is a prerequisite for efficacy. Their main drawback, however, is due to their potential to induce adverse effects, in particular upon high dosage and prolonged usage. For the purpose reducing systemic side effects, topical glucocorticoids that act locally have been developed. Nevertheless, undesirable cutaneous effects such as skin atrophy persist from the use of topical glucocorticoids. Therefore a high medical need exists for drugs as effective as glucocorticoids but with a reduced side effect profile. Glucocorticoids function by binding to and activating the glucocorticoid receptor which positively or negatively regulates the expression of specific genes. Several experiments suggest that negative regulation of gene expression by the glucocorticoid receptor accounts for its anti-inflammatory action. This occurs through direct or indirect binding of the receptor to pro-inflammatory transcription factors that are already bound to their regulatory sites. The positive action of the receptor occurs through homodimer binding of the ligand receptor complex to discrete nucleotide sequences and this contributes to some of the adverse effects of the hormone. Glucocorticoid receptor ligands that promote the negative regulatory action of the receptor with reduced positive regulatory function should therefore show an improved therapeutic index. A complete separation of the positive from the negative regulatory activities of the receptor has so far not been possible because of the interdependent nature of the two regulatory processes. Nevertheless, recent understanding of the molecular mechanisms of the GR has triggered several drug discovery programs and these have led to the identification of dissociated GR-ligands. Such selective GR agonists (SEGRAs) are likely to enter clinical testing soon.

Chitosan-based controlled porosity osmotic pump for colon-specific delivery system: Screening of formulation variables and in vitro investigation

A microbially triggered colon-targeted osmotic pump (MTCT-OP) has been studied. The gelable property at acid condition and colon-specific biodegradation of chitosan were used to: (1) produce the osmotic pressure, (2) form the drug suspension and (3) form the in situ delivery pores for colon-specific drug release, respectively. The scanning electron microscopy (SEM) study and the calculation of membrane permeability were applied to elucidate the mechanism of MTCT-OP. The effects of different formulation variables, including the level of pH-regulating excipient (citric acid) and the amount of chitosan in the core, the weight gain of semipermeable membrane and enteric-coating membrane, and the level of pore former (chitosan) in the semipermeable membrane, have been studied. Results of SEM showed that the in situ delivery pores could be formed in predetermined time after coming into contact with dissolution medium, and the number of pore was dependent on the initial level of pore former in the membrane. The amount of budesonide release was directly proportional to the initial level of pore former, but inversely related to the weight of semipermeable membrane. The effects of variations in the level of citric acid and chitosan in the core formulation on drug release were studied. The different levels of enteric-coating membrane could prevent cellulose acetate membrane (containing chitosan as pore former) from forming pore or rupture before contact with simulated colonic fluid, but had no effect on the drug release. Budesonide release from the developed formulation was inversely proportional to the osmotic pressure of the release medium, confirming that osmotic pumping was the major mechanism of drug release. These results showed that MTCT-OP based on osmotic technology and microbially triggered mechanism had a high potential for colon-specific drug delivery.

The systemic safety of inhaled corticosteroid therapy: a focus on ciclesonide

OBJECTIVE

To review the potential systemic activity of ciclesonide and its active metabolite, desisobutyryl-ciclesonide, by evaluation of the effects on hypothalamic-pituitary-adrenal (HPA) axis function.

DATA SOURCES

EMBASE and MEDLINE searches using the keyword ciclesonide, without date restrictions, were conducted to identify published articles that related to clinical trials that included ciclesonide.

STUDY SELECTION

The primary articles that reported systemic safety data for ciclesonide were reviewed.

RESULTS

Ciclesonide (320-1,280 microg/d) demonstrated no detectable, clinically relevant effect on HPA axis function as evaluated by basal cortisol excretion measurements and dynamic stimulation tests. Furthermore, ciclesonide had no effect on the normal diurnal rhythm of endogenous cortisol secretion while simultaneously improving pulmonary function and reducing bronchial hyperresponsiveness. These results suggest that ciclesonide has a low systemic activity that may be attributable to unique pharmacologic properties, including a high degree of serum protein binding, a low oral bioavailability, and rapid systemic elimination, that reduce the level of systemically available pharmacologically active drug.

CONCLUSIONS

Even at the higher doses used to treat more severe cases of asthma, ciclesonide was observed to have no effect on HPA axis function. These data, in conjunction with the observed clinical efficacy, suggest that ciclesonide may have an improved therapeutic margin compared with some other currently available inhaled corticosteroid treatments and, therefore, the potential to improve therapeutic outcomes.

Insight into the molecular mechanisms of glucocorticoid receptor action promotes identification of novel ligands with an improved therapeutic index

Glucocorticoids are highly effective in the therapy of inflammatory and autoimmune disorders. Their beneficial action is restricted because of their adverse effects upon prolonged usage. Topical glucocorticoids that act locally have been developed to significantly reduce systemic side effects. Nonetheless, undesirable cutaneous effects such as skin atrophy persist from the use of topical glucocorticoids. There is therefore a high medical need for drugs as effective as glucocorticoids but with a reduced side-effect profile. Glucocorticoids function by binding to and activating the glucocorticoid receptor that positively or negatively regulates the expression of specific genes. Several experiments suggest that the negative regulation of gene expression by the glucocorticoid receptor accounts for its anti-inflammatory action. This occurs through direct or indirect binding of the receptor to transcription factors such as activator protein-1, nuclear factor-kappaB or interferon regulatory factor-3 that are already bound to their regulatory sites. The positive action of the receptor occurs through homodimer binding of the receptor to discrete nucleotide sequences and this possibly contributes to some of the adverse effects of the hormone. Glucocorticoid receptor ligands that promote the negative regulatory action of the receptor with reduced positive regulatory function should therefore show improved therapeutic potential. A complete separation of the positive from the negative regulatory activities of the receptor has so far not been possible because of the interdependent nature of the two regulatory processes. Nevertheless, considerable improvement in the therapeutic action of glucocorticoid receptor ligands is being achieved through the use of key molecular targets for screening novel glucocorticoid receptor ligands.

Sulfonation in pharmacology and toxicology

Sulfonation has a major function in modulating the biological activities of a wide number of endogenous and foreign chemicals, including: drugs, toxic chemicals, hormones, and neurotransmitters. The activation as well as inactivation of many xenobiotics and endogenous compounds occurs via sulfonation. The process is catalyzed by members of the cytosolic sulfotransferase (SULT) superfamily consisting of at least ten functional genes in humans. The reaction in intact cells may be reversed by arylsulafatase present in the endoplasmic reticulum. Under physiological conditions, sulfonation is regulated, in part, by the supply of the co-substrate/donor molecule 3'-phosphadensoine-5-phosphosulfate (PAPS), and transport mechanisms by which sulfonated conjugates enter and leave cells. Variation in the response of individuals to certain drugs and toxic chemicals may be related to genetic polymorphisms documented to occur in each of the above pathways. Sulfonation has a major function in regulating the endocrine status of an individual by modulating the receptor activity of estrogens and androgens, steroid biosynthesis, and the metabolism of catecholamines and iodothyronines Sulfonation is a key reaction in the body's defense against injurious chemicals and may have a major function during early development since SULTs are highly expressed in the human fetus. As with many Phase I and Phase II reactions, sulfonation may also serve as the terminal step in activating certain dietary and environmental agents to very reactive toxic intermediates implicated in carcinogenesis.

Preclinical properties of budesonide: translation to the clinical setting

BACKGROUND

Since the introduction of inhaled corticosteroids (ICSs) nearly 30 years ago, the management of asthma has been transformed. It is now understood that asthma is primarily a disease of chronic inflammation, even in its milder forms, and that to delay treatment may lead to deterioration in lung function. International treatment guidelines for asthma recommend early intervention with a potent ICS, with the greatest benefit observed when treatment is started within 2 years of the onset of symptoms. Each of the currently available ICSs has distinct physical and pharmacokinetic properties and is delivered via different devices.

OBJECTIVE

This article brings together the findings and concepts presented in this supplement. It provides an overview of budesonide's predicted clinical efficacy and tolerability in patients with asthma based on its physical properties and pharmacokinetic and pharmacodynamic characteristics.

CONCLUSIONS

Budesonide's physical properties and pharmacokinetic and pharmacodynamic profiles help predict its clinical efficacy and tolerability when used as early intervention in asthma. Study results indicate that lung deposition of budesonide is increased by delivery via dry-powder inhaler, enhancing the drug's efficacy in patients with newly diagnosed mild persistent asthma. The preclinical, clinical, and safety data support budesonide's predicted performance in the clinical setting.