Limitations of high dose carrier based formulations.

PURPOSE: This study was performed to investigate how increasing the active pharmaceutical ingredient (API) content within a formulation affects the dispersion of particles and the aerosol performance efficiency of a carrier based dry powder inhalable (DPI) formulation, using a custom dry powder inhaler (DPI) development rig. METHODS: Five formulations with varying concentrations of API beclomethasone dipropionate (BDP) between 1% and 30% (w/w) were formulated as a multi-component carrier system containing coarse lactose and fine lactose with magnesium stearate. The morphology of the formulation and each component were investigated using scanning electron micrographs while the particle size was measured by laser diffraction. The aerosol performance, in terms of aerodynamic diameter, was assessed using the British pharmacopeia Apparatus E cascade impactor (Next generation impactor). Chemical analysis of the API was observed by high performance liquid chromatography (HPLC). RESULTS: Increasing the concentration of BDP in the blend resulted in increasing numbers and size of individual agglomerates and densely packed BDP multi-layers on the surface of the lactose carrier. BDP present within the multi-layer did not disperse as individual primary particles but as dense agglomerates, which led to a decrease in aerosol performance and increased percentage of BDP deposition within the Apparatus E induction port and pre-separator. CONCLUSION: As the BDP concentration in the blends increases, aerosol performance of the formulation decreases, in an inversely proportional manner. Concurrently, the percentage of API deposition in the induction port and pre-separator could also be linked to the amount of micronized particles (BDP and Micronized composite carrier) present in the formulation. The effect of such dose increase on the behaviour of aerosol dispersion was investigated to gain greater insight in the development and optimisation of higher dosed carrier-based formulations.

Molecular Integration of Incretin and Glucocorticoid Action Reverses Immunometabolic Dysfunction and Obesity.

Chronic inflammation has been proposed to contribute to the pathogenesis of diet-induced obesity. However, scarce therapeutic options are available to treat obesity and the associated immunometabolic complications. Glucocorticoids are routinely employed for the management of inflammatory diseases, but their pleiotropic nature leads to detrimental metabolic side effects. We developed a glucagon-like peptide-1 (GLP-1)-dexamethasone co-agonist in which GLP-1 selectively delivers dexamethasone to GLP-1 receptor-expressing cells. GLP-1-dexamethasone lowers body weight up to 25% in obese mice by targeting the hypothalamic control of feeding and by increasing energy expenditure. This strategy reverses hypothalamic and systemic inflammation while improving glucose tolerance and insulin sensitivity. The selective preference for GLP-1 receptor bypasses deleterious effects of dexamethasone on glucose handling, bone integrity, and hypothalamus-pituitary-adrenal axis activity. Thus, GLP-1-directed glucocorticoid pharmacology represents a safe and efficacious therapy option for diet-induced immunometabolic derangements and the resulting obesity.

Lipid/alginate nanoparticle-loaded in situ gelling system tailored for dexamethasone nasal delivery.

In this study, we suggest the development of nanoparticle loaded in situ gelling system suitable for corticosteroid nasal delivery. We propose lipid/alginate nanoparticles (size 252.3±2.4nm, polydispersity index 0.241, zeta-potential -31.7±1.0mV, dexamethasone (Dex) content 255±7µgml-1) dispersed in pectin solution (5mgml-1) that undergoes a sol-gel phase transition triggered by Ca2+ present in nasal mucosa. The viscoelasticity of gel obtained by mixing nanoparticle suspension in pectin continuous phase with simulated nasal fluid (1:1V/V) is characterised by a log-linear shear thinning viscosity behaviour. Observed viscosity corresponds to the range of viscosities of nasal mucus at physiological as well as under disease conditions. Nanoparticle-loaded gel was biocompatible with the selected epithelial cell model and, in comparison to dexamethasone solution, provided reduction in Dex release (t50% 2.1h and 0.6h, respectively) and moderated transepithelial permeation in vitro (Papp 7.88±0.15 and 9.73±0.57×10-6cms-1, respectively). In conclusion, this study showed the potential of the proposed system to provide local therapeutic effect upon administration of a lower corticosteroid dose and minimize the possibility for adverse effects as it can be easily sprayed as solution and delivered beyond nasal valve, ensure prolonged contact time with nasal mucosa upon gelation, and moderate corticosteroid release and permeation.

Evaluation of Biological Activity and Computer-Aided Design of New Soft Glucocorticoids.

Soft glucocorticoids are compounds that are biotransformed to inactive and non-toxic metabolites and have fewer side effects than traditional glucocorticoids. A new class of 17ß-carboxamide steroids has been recently introduced by our group. In this study, local anti-inflammatory activity of these derivatives was evaluated by use of the croton oil-induced ear edema test. Glucocorticoids with the highest maximal edema inhibition (MEI) were pointed out, and the systemic side effects of those with the lowest EC50 values were significantly lower in comparison to dexamethasone. A 3D-QSAR model was created and employed for the design of 27 compounds. By use of the sequential combination of ligand-based and structure-based virtual screening, three compounds were selected from the ChEMBL library and used as a starting point for the design of 15 derivatives. Molecular docking analysis of the designed derivatives with the highest predicted MEI and relative glucocorticoid receptor binding affinity (20, 22, 24-1, 25-1, 27, VS7, VS13, and VS14) confirmed the presence of interactions with the glucocorticoid receptor that are important for the activity.

In vitro and in vivo evaluation of a desonide gel-cream photostabilized with benzophenone-3.

CONTEXT: Our group previously reported the photoinstability of some desonide topical commercial formulations under direct exposure to UVA radiation. OBJECTIVE: This study aimed to prepare and characterize a gel-cream containing desonide, with greater photostability than the commercial gel-cream (C-GC). Benzophenone-3 (BP-3) was used as a photostabilizing agent. METHODS: The gel-cream developed (D-GC) containing BP-3 at 0.1% was prepared and characterized regarding its pH, drug content, spreadability, viscosity, in vitro drug release and in vitro permeation. The in vivo anti-inflammatory effect was assessed by ear edema measurement, croton oil-induced acute skin inflammation and myeloperoxidase assay. RESULTS AND DISCUSSION: D-GC presented characteristics compatible with topical application, appropriate drug content and good spreadability, and non-Newtonian behavior with pseudoplastic flow. D-GC showed a good photostability profile, presenting a desonide content of 95.70% after 48 h of exposure to UVA radiation, and stability under room conditions during 60 days. The amount of desonide released from D-GC and C-GC was 57.8 and 51.7 µg/cm2, respectively, measured using the vertical Franz cell. The in vitro skin permeation showed that desonide reached the site of action of the topical corticosteroids, from both formulations; however, the desonide amount retained in the dermis was lower with D-GC. The in vivo evaluation of topical anti-inflammatory activity indicated that D-GC presented the same biological effect as C-GC. CONCLUSION: D-GC represents a promising approach to treat dermatological disorders, since it presented satisfactory physicochemical characteristics, the same biological activity as C-GC and superior photostability, conferred by the addition of BP-3 at 0.1%.

Use of Nanotechnology in Diagnosis and Treatment of Hepatic Fibrosis: A Review.

Liver fibrosis is an important cause of morbidity and mortality worldwide and represent a difficult clinical challenge of global importance. The liver fibrosis progression needs to be controlled because persisted liver fibrosis can lead to liver cirrhosis or even hepatocellular carcinoma. Despite significant advances in the understanding of the liver fibrosis development, the therapeutic effect of drugs used in liver fibrosis treatment is not sufficient. Today, nanotechnology has been considered as a potential tool for developing novel drug delivery systems for the improved imaging and various diseases, including liver fibrosis. In this article, we discussed the use of nanotechnology for the treatment and imaging of liver fibrosis.

Bone Tissue Properties Measurement by Reference Point Indentation in Glucocorticoid-Induced Osteoporosis.

Glucocorticoids, widely used in inflammatory disorders, rapidly increase bone fragility and, therefore, fracture risk. However, common bone densitometry measurements are not sensitive enough to detect these changes. Moreover, densitometry only partially recognizes treatment-induced fracture reductions in osteoporosis. Here, we tested whether the reference point indentation technique could detect bone tissue property changes early after glucocorticoid treatment initiation. After initial laboratory and bone density measurements, patients were allocated into groups receiving calcium + vitamin D (Ca+D) supplements or anti-osteoporotic drugs (risedronate, denosumab, teriparatide). Reference point indentation was performed on the cortical bone layer of the tibia by a handheld device measuring bone material strength index (BMSi). Bone mineral density was measured by dual-energy X-ray absorptiometry (DXA). Although Ca+D-treated patients exhibited substantial and significant deterioration, risedronate-treated patients exhibited no significant change, and both denosumab- and teriparatide-treated participants exhibited significantly improved BMSi 7 weeks after initial treatment compared with baseline; these trends remained stable for 20 weeks. In contrast, no densitometry changes were observed during this study period. In conclusion, our study is the first to our knowledge to demonstrate that reference point indentation is sensitive enough to reflect changes in cortical bone indentation after treatment with osteoporosis therapies in patients newly exposed to glucocorticoids.

Preclinical evaluation of thermoreversible triamcinolone acetonide hydrogels for drug delivery to the inner ear.

Intratympanic glucocorticoid therapy aims to reduce the side effects associated with systemic long-time therapy of inner ear diseases or traumata after cochlear implantation. For that purpose, thermoreversible hydrogels being fluid at room temperature but solid at body temperature are known to be appropriate drug delivery systems. In this work, the two key parameters sol-gel transition time and temperature of Poloxamer 407 (POX 407) based hydrogels containing oto-compatible micronized triamcinolone acetonide (TAAc) were evaluated by rheological experiments varying the concentrations of the different compounds. A 20% POX 407 hydrogel in PBS containing 30% TAAc emerged as the most appropriate formulation. Oscillation-rotation-oscillation studies at two temperature levels were found to be an useful in-vitro test system for the hydrogel which revealed sufficient storage stability at 4 °C, injectability of the sol, solidification within 20s at body temperature and persistent stiffness indicating prolonged adhesion at the round window membrane. According to the in-vitro release studies using the Transwell™ system, absorption of the poor water soluble TAAc is partly due to the low amount of dissolved drug but predominantly due to micellar transport resulting in a cumulative release of 262.6±13.4 µg TAAc within one week followed by a sustained release of 193.1±8.3 µg TAAc within the next three weeks. Thus, the formation of POX 407 micelles is the basis not only for gel formation but also absorptivity of TAAc. All in all, fine tuned rheological experiments and absorption studies emerged as useful tools for preclinical evaluation of intratympanally administered hydrogels.

Steroid-decorated antibiotic microparticles for inhaled anti-infective therapy.

Despite advances in vaccination and antimicrobial therapy, community-acquired pneumonia (CAP) remains as a leading cause of morbidity and mortality worldwide. As the severity of CAP has been linked to the extent of inflammation in the body, adjunctive therapeutic measures aimed at modulating the immune response have therefore become increasingly attractive in recent years. In particular, for CAP patients with underlying medical conditions such as chronic obstructive pulmonary disease (COPD), a steroid-antibiotic combination will no doubt be a useful and timely therapeutic intervention. Unfortunately, no combined steroid-antibiotic dry powder formulation is available commercially or has been reported in the academic literature. The aim of this work was hence to develop a novel steroid-antibiotic dry powder inhaler formulation [ciprofloxacin hydrochloride (CIP) and beclomethasone dipropionate (BP)] for inhaled anti-infective therapy. The spray-dried powder was of respirable size (d50 of ∼2.3 µm), partially crystalline and had BP preferentially deposited on the particle surface. Favorably, when formulated as a binary mix, both CIP and BP showed much higher drug release and fine particle fractions (of the loaded dose) over their singly delivered counterparts, and had robust activity against the respiratory tract infection-causing bacteria Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus.

Dexamethasone-loaded hydroxyapatite enhances bone regeneration in rat calvarial defects.

A combination of bioceramics and osteogenic factors is potentially useful for bone regeneration applications. In the present study, hydroxyapatite particles (HA) were loaded with dexamethasone (Dex) and then characterized using SEM and drug release study. The bone regeneration ability of Dex-loaded HA (Dex/HA) was investigated in a rat critical size bone defect using digital mammography, multislice spiral-computed tomography (MSCT) imaging, and histological analysis. The HA and Dex/HA showed nano and micro-scale morphology with a nearly homogenous distribution of diameter. In addition, about 90 % of the drug was released from Dex/HA over a period of three days. After 8 weeks of implantation in rat calvarial defects, no sign of inflammation or complication was observed at the site of surgery. According to digital mammography and MSCT, Dex/HA showed the highest bone regeneration in rat bone defects compared to those received drug-free HA. Histological studies confirmed these data and showed osteointegration to the surrounding tissue. Taking all together, it was demonstrated that Dex/HA can be used as an appropriate synthetic graft for bone tissue engineering applications. These newly developed bioceramics can be used as new bone graft substitutes in orthopaedic surgery and is capable of enhancing bone regeneration.

VBP15: preclinical characterization of a novel anti-inflammatory delta 9,11 steroid.

Δ9,11 modifications of glucocorticoids (21-aminosteroids) have been developed as drugs for protection against cell damage (lipid peroxidation; lazaroids) and inhibition of neovascularization (anecortave). Part of the rationale for developing these compounds has been the loss of glucocorticoid receptor binding due to the Δ9,11 modification, thus avoiding many immunosuppressive activities and deleterious side effect profiles associated with binding to glucocorticoid and mineralocorticoid receptors. We recently demonstrated that anecortave acetate and its 21-hydroxy analog (VBP1) do, in fact, show glucocorticoid and mineralocorticoid receptor binding activities, with potent translocation of the glucocorticoid receptor to the cell nucleus. We concluded that Δ9,11 steroids showed novel anti-inflammatory properties, retaining NF-κB inhibition, but losing deleterious glucocorticoid side effect profiles. Evidence for this was developed in pre-clinical trials of chronic muscle inflammation. Here, we describe a drug development program aimed at optimizing the Δ9,11 chemistry. Twenty Δ9,11 derivatives were tested in in vitro screens for NF-κB inhibition and GR translocation to the nucleus, and low cell toxicity. VBP15 was selected as the lead compound due to potent NF-κB inhibition and GR translocation similar to prednisone and dexamethasone, lack of transactivation properties, and good bioavailability. Phamacokinetics were similar to traditional glucocorticoid drugs with terminal half-life of 0.35 h (mice), 0.58 h (rats), 5.42 h (dogs), and bioavailability of 74.5% (mice), and 53.2% (dogs). Metabolic stability showed ≥80% remaining at 1 h of VBP6 and VBP15 in human, dog, and monkey liver microsomes. Solubility, permeability and plasma protein binding were within acceptable limits. VBP15 moderately induced CYP3A4 across the three human hepatocyte donors (24-42%), similar to other steroids. VBP15 is currently under development for treatment of Duchenne muscular dystrophy.

A chemical biology screen identifies glucocorticoids that regulate c-maf expression by increasing its proteasomal degradation through up-regulation of ubiquitin.

The oncogene c-maf is frequently overexpressed in multiple myeloma cell lines and patient samples and contributes to increased cellular proliferation in part by inducing cyclin D2 expression. To identify regulators of c-maf, we developed a chemical screen in NIH3T3 cells stably overexpressing c-maf and the cyclin D2 promoter driving luciferase. From a screen of 2400 off-patent drugs and chemicals, we identified glucocorticoids as c-maf-dependent inhibitors of cyclin D2 transactivation. In multiple myeloma cell lines, glucocorticoids reduced levels of c-maf protein without influencing corresponding mRNA levels. Subsequent studies demonstrated that glucocorticoids increased ubiquitination-dependent degradation of c-maf and up-regulated ubiquitin C mRNA. Moreover, ectopic expression of ubiquitin C recapitulated the effects of glucocorticoids, demonstrating regulation of c-maf protein through the abundance of the ubiquitin substrate. Thus, using a chemical biology approach, we identified a novel mechanism of action of glucocorticoids and a novel mechanism by which levels of c-maf protein are regulated by the abundance of the ubiquitin substrate.

Discovery and optimization of novel, non-steroidal glucocorticoid receptor modulators.

A virtual screening approach comprising a 3-D similarity search based on known GR modulators was used to identify a novel series of non-steroidal glucocorticoid receptor (GR) antagonists. Optimization of the initial hit to provide potent compounds which exhibit good selectivity against other steroidal nuclear hormone receptors is described.

Distinct interaction of cortivazol with the ligand binding domain confers glucocorticoid receptor specificity: cortivazol is a specific ligand for the glucocorticoid receptor.

Ligand-receptor coupling is one of the important constituents of signal transduction and is essential for physiological transmission of actions of endogenous substances including steroid hormones. However, molecular mechanisms of the redundancy between glucocorticoid and mineralocorticoid actions remain unknown because of complicated cross-talk among, for example, these adrenal steroids, their cognate receptors, and target genes. Receptor-specific ligand that can distinctly modulate target gene expression should be developed to overcome this issue. In this report, we showed that a pyrazolosteroid cortivazol (CVZ) does not induce either nuclear translocation or transactivation function of the mineralocorticoid receptor (MR) but does both for the glucocorticoid receptor (GR). Moreover, deletion analysis of the C-terminal end of the GR has revealed that CVZ interacts with the distinct portion of the ligand binding domain (LBD) and differentially modulates the ligand-dependent interaction between transcription intermediary factor 2 and the LBD when compared with cortisol, dexamethasone, and aldosterone. Thus, it is indicated that CVZ may not be only a molecular probe for the analysis of the redundancy between the GR and MR in vivo but also a useful reagent to clarify structure-function relationship of the GR LBD.

Synthesis and structure elucidation of potential 6-oxygenated metabolites of (22R)-6alpha,9alpha-difluoro-11beta,21-dihydroxy-1 6alpha,17alpha-propyl methylenedioxypregn-4-ene-3,20-dione, and related glucocorticosteroids.

(22R)-6alpha,9alpha-Difluoro-11beta,21-dihydroxy-16 alpha,17alpha-propylmethylenedioxypregn-4-ene-3,20-dione (rofleponide) is a synthetic glucocorticosteroid with high affinity for the rat thymus glucocorticoid receptor and a very high biotransformation rate demonstrated through incubation with a human liver S9 subcellular fraction. Because oxidation in the 6-position is an important metabolic pathway of glucocorticosteroids, the potential 6beta-hydroxy and 6-oxo metabolites of rofleponide were synthesized to be used as reference compounds. Three alternative routes were used to reach the 6-hydroxy compound: (a) a one-step procedure involving allylic oxidation of rofleponide by selenium dioxide, (b) selenium dioxide oxidation of the corresponding 1,4-diene followed by selective 1,2-hydrogenation using Wilkinson's catalyst, and (c) autoxidation of a 3-methoxypregna-3,5-diene derivative. All three routes proceeded stereospecifically. Routes (a) and (c) gave approximately the same overall yield of the 6beta-hydroxy epimer, whereas the overall yield from route (b) was much lower, primarily because of incomplete 1,2-hydrogenation. The 6-oxo compound was prepared through Pfitzner/Moffat oxidation of the 6-hydroxy compound. The stereochemistry of the 6-hydroxy substituent is discussed on the basis of 1H-NMR spectroscopy and supplementary 2D NOESY experiments.

Compatibility of corticosteroids and antibiotics in combination.

PURPOSE: To study the compatibility of combinations of antibiotics and steroids commonly used in anterior segment surgery. SETTING: Research Laboratory, Helsinki University, Finland. METHODS: Aggregate production in vitro and in vivo was studied for three injectable antibiotics (cefotaxime sodium, tobramycin sulfate, and gentamicin) and four corticosteroids (triamcinolone acetonide, methylprednisolone sodium succinate, methylprednisolone acetate, and dexamethasone sodium phosphate) using conventional and dark-field microscopy. Aggregate formation on collagen shields and subconjunctival aggregate formation of tobramycin sulfate in combination with methylprednisolone acetate or dexamethasone sodium phosphate was also studied. RESULTS: Dexamethasone sodium phosphate (4 mg/mL) did not form aggregates with any of the three antibiotics tested. Cefotaxime sodium did not cause aggregates when 24 mg/mL of dexamethasone sodium phosphate was used both in vitro and in vivo or in association with collagen shields. CONCLUSIONS: To avoid undesired side effects, such as epithelial sloughing and corneal edema after collagen shield application, antibiotics and steroids must be carefully selected.