Concentrations Of Dexamethasone Research Articles

Prolonged exposure to the synthetic glucocorticoid dexamethasone induces brain damage via oxidative stress and apoptotic response in adult Daniorerio

Due to its extensive use as a painkiller, anti-inflammatory, and immune modulatory agent, as well as its effectiveness in treating severe COVID-19, dexamethasone, a synthetic glucocorticoid, has gained attention not only for its impact on public health but also for its environmental implications. Various studies have reported its presence in aquatic environments, including urban waters, surface samples, sediments, drinking water, and wastewater effluents. However, limited information is available regarding its toxic effects on nontarget aquatic organisms. Therefore, this study aimed to investigate the mechanism of toxicity underlying dexamethasone-induced brain damage in the bioindicator Danio rerio following long-term exposure. Adult zebrafish were treated with environmentally relevant concentrations of dexamethasone (20, 40, and 60 ng L-1) for 28 days. To elucidate the possible mechanisms involved in the toxicity of the pharmaceutical compound, we conducted a behavioral test battery (Novel Tank and Light and Dark tests), oxidative stress biomarkers, acetylcholinesterase enzyme activity quantification, histopathological analysis, and gene expression analysis using qRT-PCR (p53, bcl-2, bax, caspase-3, nrf1, and nrf2).The results revealed that the pharmaceutical compound could produce anxiety-like symptoms, increase the oxidative-induced stress response, decrease the activity of acetylcholinesterase enzyme, and cause histopathological alterations, including perineuronal vacuolization, granular and molecular layers deterioration, cell swallowing and intracellular spaces. The expression of genes involved in the apoptotic process (p53, bax, and casp-3) and antioxidant defense (nrf1 and nrf2) was upregulated in response to oxidative damage, while the expression of the anti-apoptotic gene bcl-2 was down-regulated indicating that the environmental presence of dexamethasone may pose a threat to wildlife and human health.

Endothelial Cell-Derived Exosomes Inhibit Osteoblast Apoptosis and Steroid-Induced Necrosis of Femoral Head Progression by Activating the PI3K/Akt/Bcl-2 Pathway

The aim of the study was to investigate the therapeutic potential of exosomes secreted by endothelial cells (EC-exos) on steroid-induced osteonecrosis of femoral head (SNFH). First, we successfully obtained EC-exos through differential centrifugation. Then, the effects of EC-exos on mouse embryo osteoblast precursor (MC3T3-E1) cells under high concentration of dexamethasone (Dex) were analysed in vitro, which included cell migration, viability, and apoptosis. In vivo, a SNFH rat model was successfully established and treated with EC-exos. Micro-computed tomography (micro-CT) and haematoxylin and eosin (H&E) were used to observe femoral trabeculae. Our in vitro results showed that EC-exos improved cell viability and migration of osteoblasts and reduced the apoptotic effect of high concentration of Dex on osteoblasts in vitro. Phosphoinositide 3-kinase (PI3K)/Akt/Bcl-2 signalling pathway was activated in MC3T3-E1 cells under the response to EC-exos. In vivo, increased bone volume per tissue volume (BV/TV) p=0.031, trabecular thickness (Tb.Th) p=0.020, and decreased separation (Tb.Sp) p=0.040 were observed in SNFH rats treated with EC-exos. H&E staining revealed fewer empty lacunae and pyknotic osteocytes in trabeculae. The expression of Bcl-2 and Akt in EC-exos group was significantly increased in trabeculae tissue. Overall, our finding indicated that EC-exos could attenuate SNFH by inhibiting osteoblast apoptosis via the PI3K/Akt/Bcl-2 pathway.

α2-macroglobulin alleviates glucocorticoid-induced avascular necrosis of the femoral head in mice by promoting proliferation, migration and angiogenesis of vascular endothelial cells

To explore the mechanism underlying the protective effect of α2-macroglobulin (A2M) against glucocorticoid-induced femoral head necrosis. In a human umbilical vein endothelial cell (HUVEC) model with injuries induced by gradient concentrations of dexamethasone (DEX; 10-8-10-5 mol/L), the protective effects of A2M at 0.05 and 0.1 mg/mL were assessed by examining the changes in cell viability, migration, and capacity of angiogenesis using CCK-8 assay, Transwell and scratch healing assays and angiogenesis assay. The expressions of CD31 and VEGF-A proteins in the treated cells were detected using Western blotting. In BALB/c mouse models of avascular necrosis of the femoral head induced by intramuscular injections of methylprednisolone, the effects of intervention with A2M on femoral trabecular structure, histopathological characteristics, and CD31 expression were examined with Micro-CT, HE staining and immunohistochemical staining. In cultured HUVECs, DEX treatment significantly reduced cell viability, migration and angiogenic ability in a concentration- and time-dependent manner (P<0.05), and these changes were obviously reversed by treatment with A2M in positive correlation with A2M concentration (P<0.05). DEX significantly reduced the expression of CD31 and VEGF-A proteins in HUVECs, while treatment with A2M restored CD31 and VEGF-A expressions in the cells (P<0.05). The mouse models of femoral head necrosis showed obvious trabecular damages in the femoral head, where a large number of empty lacunae and hypertrophic fat cells could be seen and CD31 expression was significantly decreased (P<0.05). A2M treatment of the mouse models significantly improved trabecular damages, maintained normal bone tissue structures, and increased CD31 expression in the femoral head (P<0.05). A2M promotes proliferation, migration, and angiogenesis of DEX-treated HUVECs and alleviates methylprednisolone-induced femoral head necrosis by improving microcirculation damages and maintaining microcirculation stability in the femoral head.

The response mechanism and dynamic succession of microbial community in activated sludge system under dexamethasone stress

The mass production and widespread use of dexamethasone (DEX) during the COVID-19 pandemic inevitably led to the increase of residue concentrations in wastewater treatment plants. In this study, the effects of DEX at different concentrations on the activated sludge system were investigated. The results indicated that organic matter removal and ammonia nitrogen oxidation were inhibited. The effluent COD and TN gradually increased with increasing DEX concentration. The extracellular polymeric substance was secreted as a protective barrier against DEX stress, ensuring the integrity of the cell membrane. According to assembly mechanism analysis, the relative importance of homogeneous selection in deterministic processes gradually increased under DEX stress, which acts as the main driving force to alter the distribution of abundance and rare taxa, causing the decrease of rare taxa and community diversity, thus forming more homogeneous and similar community structure. These negative consequences, coupled with the inhibition in autotrophic nitrifiers such as Nitrosomonas and Ellin6067, and the decrease in gene abundance of nitrification metabolism including AmoCAB and Hao, were directly responsible for the obvious deterioration of NH4+-N oxidation capacity. This study provided reliable experimental data about the effects of DEX on activated sludge systems, which is conducive to reducing the environmental risk of DEX and maintaining the stable operation of the activated sludge system.

Comprehensive ocular and systemic pharmacokinetics of dexamethasone after subconjunctival and intravenous injections in rabbits

Even though subconjunctival injections are used in clinics, their quantitative pharmacokinetics has not been studied systematically. For this purpose, we evaluated the ocular and plasma pharmacokinetics of subconjunctival dexamethasone in rabbits. Intravenous injection was also given to enable a better understanding of the systemic pharmacokinetics. Dexamethasone concentrations in plasma (after subconjunctival and intravenous injections) and four ocular tissues (iris-ciliary body, aqueous humour, neural retina and vitreous) were analysed using LC-MS/MS.Population pharmacokinetic modelling for plasma data from both injection routes were used, and for first time the constant rate of absorption of dexamethasone from the subconjunctival space into plasma was estimated (ka,plasma = 0.043 min−1, i.e. absorption half-life of 17.3 min). Non-compartmental analysis was used for the ocular data analysis and resulting in ocular drug exposure of iris-ciliary body (AUC0-∞= 41984 min·ng/g) > neural retina (AUC0-∞= 25511 min·ng/g) > vitreous (AUC0-∞= 7319 min·ng/mL) > aqueous humour (AUC0-∞= 6146 min·ng/mL). The absolute bioavailability values after subconjunctival injection, reported for the first time, were 0.74 % in aqueous humour (comparable to topical dexamethasone suspensions), and 0.30 % in vitreous humour (estimated to be higher than in topical administration).These novel and comprehensive pharmacokinetic data provide valuable information on the potential for exploiting this route in ocular drug development for treating both, anterior and posterior segment ocular diseases. Moreover, the new generated dexamethasone-parameters are a step-forward in building predictive pharmacokinetic models to support the design of new subconjunctival dexamethasone formulations, which may sustain drug effect for longer period of time.

Circulating cell-free mitochondrial DNA levels and glucocorticoid sensitivity in a cohort of male veterans with and without combat-related PTSD

Circulating cell-free mitochondrial DNA (ccf-mtDNA) is a biomarker of cellular injury or cellular stress and is a potential novel biomarker of psychological stress and of various brain, somatic, and psychiatric disorders. No studies have yet analyzed ccf-mtDNA levels in post-traumatic stress disorder (PTSD), despite evidence of mitochondrial dysfunction in this condition. In the current study, we compared plasma ccf-mtDNA levels in combat trauma-exposed male veterans with PTSD (n = 111) with those who did not develop PTSD (n = 121) and also investigated the relationship between ccf mt-DNA levels and glucocorticoid sensitivity. In unadjusted analyses, ccf-mtDNA levels did not differ significantly between the PTSD and non-PTSD groups (t = 1.312, p = 0.191, Cohen’s d = 0.172). In a sensitivity analysis excluding participants with diabetes and those using antidepressant medication and controlling for age, the PTSD group had lower ccf-mtDNA levels than did the non-PTSD group (F(1, 179) = 5.971, p = 0.016, partial η2 = 0.033). Across the entire sample, ccf-mtDNA levels were negatively correlated with post-dexamethasone adrenocorticotropic hormone (ACTH) decline (r = −0.171, p = 0.020) and cortisol decline (r = −0.149, p = 0.034) (viz., greater ACTH and cortisol suppression was associated with lower ccf-mtDNA levels) both with and without controlling for age, antidepressant status and diabetes status. Ccf-mtDNA levels were also significantly positively associated with IC50-DEX (the concentration of dexamethasone at which 50% of lysozyme activity is inhibited), a measure of lymphocyte glucocorticoid sensitivity, after controlling for age, antidepressant status, and diabetes status (β = 0.142, p = 0.038), suggesting that increased lymphocyte glucocorticoid sensitivity is associated with lower ccf-mtDNA levels. Although no overall group differences were found in unadjusted analyses, excluding subjects with diabetes and those taking antidepressants, which may affect ccf-mtDNA levels, as well as controlling for age, revealed decreased ccf-mtDNA levels in PTSD. In both adjusted and unadjusted analyses, low ccf-mtDNA levels were associated with relatively increased glucocorticoid sensitivity, often reported in PTSD, suggesting a link between mitochondrial and glucocorticoid-related abnormalities in PTSD.

A physiologically based toxicokinetic model of P-glycoprotein transporter-mediated placenta perfusion of dexamethasone in the pregnant rat

The present dosage of Dexamethasone (DEX) administered to pregnant women may pose a risk of toxicity to their unborn offspring. We aimed to develop a maternal-fetal physiologically based toxicokinetic (PBTK) model for DEX in pregnant rats, with a specific focus on the role of the P-glycoprotein (P-gp) transporter in placenta perfusion, and finally facilitate the optimization of clinical DEX dosage. We conducted animal experiments to determine DEX concentrations in various rat tissues, and constructed the PBTK model using MATLAB software. Sensitivity analysis was performed to assess input parameters and the model stability, with fold error (FE) values serving as evaluation indices. Our results indicate the successful construction of the PBTK model, with the fitting key parameters such as the absorption rate constant (Ka), intrinsic hepatic clearance (CLh,int) and intrinsic P-gp clearance (CLint,P-gp). The median concentration of DEX in maternal plasma, fetal plasma, fetal lung, and fetal brain were determined, which allowed us to fit the tissue-to-plasma partition coefficients for the fetal lung (Kp,lung,f) and fetal brain (Kp,brain,f). After making adjustments, all calculated FE values were found to be less than 2, demonstrating the acceptability and accuracy of our model's predictions. Our model integrated external literature data and internal animal experimentation to comprehensively evaluate the maternal-fetal PK characteristics of DEX. These findings provide valuable support for the optimization of clinical DEX dosing.

Controlled release of dexamethasone from fibrin sealant for intratympanic administration in inner ear therapy

The aim of the present work was to show the sustainability of fibrin sealant in releasing dexamethasone and adjust the protocol for clinical application of the novel method in the treatment of Meniere's disease (MD) and sudden sensorineural hearing loss (SSHL). Gelation occurred shortly after mixing dexamethasone-containing fibrinogen with thrombin. Dexamethasone was constantly released for at least 16 d at a stable level after 7 d in protocol 1 (low-dose), while it was robustly released within 4 d and slowed afterward until 10 d in protocol 2 (high-dose). There were significant differences among the time points in Protocol 2 (p < 0.01, ANOVA), and the exponential model with the formula y = 15.299 * e−0.483 *t fits the association. The estimated concentration of dexamethasone released on 7 d in protocol 2 was slightly lower than that observed in protocol 1. The fibrin sealant is capable of constantly releasing dexamethasone with adjustable dynamics. Targeted and minimally invasive administration of the material can be achieved in the clinic by sequential injections of the fluids using a soft-tipped catheter.

A Dexamethasone-Loaded Polymeric Electrospun Construct as a Tubular Cardiovascular Implant.

Cardiovascular tissue engineering is providing many solutions to cardiovascular diseases. The complex disease demands necessitating tissue-engineered constructs with enhanced functionality. In this study, we are presenting the production of a dexamethasone (DEX)-loaded electrospun tubular polymeric poly(l-lactide) (PLA) or poly(d,l-lactide-co-glycolide) (PLGA) construct which contains iPSC-CMs (induced pluripotent stem cell cardiomyocytes), HUVSMCs (human umbilical vein smooth muscle cells), and HUVECs (human umbilical vein endothelial cells) embedded in fibrin gel. The electrospun tube diameter was calculated, as well as the DEX release for 50 days for 2 different DEX concentrations. Furthermore, we investigated the influence of the polymer composition and concentration on the function of the fibrin gels by imaging and quantification of CD31, alpha-smooth muscle actin (αSMA), collagen I (col I), sarcomeric alpha actinin (SAA), and Connexin 43 (Cx43). We evaluated the cytotoxicity and cell proliferation of HUVECs and HUVSMCs cultivated in PLA and PLGA polymeric sheets. The immunohistochemistry results showed efficient iPSC-CM marker expression, while the HUVEC toxicity was higher than the respective HUVSMC value. In total, our study emphasizes the combination of fibrin gel and electrospinning in a functionalized construct, which includes three cell types and provides useful insights of the DEX release and cytotoxicity in a tissue engineering perspective.

THU412 Role of Glucocorticoid On Bone Metabolism Through AKAP13

Abstract Disclosure: K. Igarashi: None. A. Ishida: None. H. Koide: None. K. Yokote: None. It is not completely clear to what extent glucocorticoids are involved in which stages and sites of bone differentiation, development, and maintenance. we investigated the mechanism of glucocorticoid regulation through the regulation of Rho activation using a regulatory system for the expression of the RhoA activator AKAP13. To examine the effect of glucocorticoids on preosteoblasts, immortalized bone marrow mesenchymal stem cells (imBMSCs) were sown in 6-well plates at a concentration of 2x105/well and treated with various concentrations (0-1000 nM) of dexamethasone (Dex) 24 hr later, and The expression of GILZ, osteoblast and adipocyte-associated markers were evaluated using qRT-PCR. AKAP13 expression vector and AKAP13 siRNA were used to examine the response to Dex. GILZ was induced in a Dex-dependent manner on both day1 and day4. In the differentiation phase, PPARG2 expression was not changed by Dex, but GILZ was induced in a similar Dex-dependent manner. In proliferating imBMSCs, Dex treatment tended to enhance PPARG2 expression in a dose-dependent manner by introducing AKAP13 expression vectors. On the other hand, AKAP13 gene expression was significantly down-regulated in imBMSCs treated with AKAP13 siRNA, and Alp2 mRNA was up-regulated in imBMSCs treated with Dex compared to those not treated with Dex. It has a nuclear receptor binding domain and is known to be involved in osteogenesis. On the other hand, AKAP13 expression was decreased by osteoblast differentiation in an in vitro system, suggesting that AKAP13 may influence the regulation of GC action between the proliferative and differentiation phases of BMSCs. Presentation: Thursday, June 15, 2023

OR11-03 A Novel Mutation In The Ligand-binding Domain Of The NR3C1 Gene Associated With Fluctuating Resistance To Glucocorticoids

Abstract Disclosure: M. Laulhé: None. E. Kuhn: None. J. Bouligand: None. L. Amazit: None. J. Perrot: None. P. Kamenicky: None. M. Lombes: None. J. Fagart: None. S. Viengchareun: None. L. Martinerie: None. Introduction: Constitutive glucocorticoid resistance is associated with mutations in the NR3C1 gene, encoding the Glucocorticoid Receptor (GR). We identified a novel heterozygous point mutation causing fluctuating resistance to glucocorticoid depending on ligand concentrations. Initially, the propositus, a 45-year-old man, was diagnosed with a right adrenal incidentaloma and an ACTH-independent biological hypercortisolism. Shortly after adrenal surgery, plasma cortisol increased again (612 nmol/L) associated with inadequate ACTH levels (122 pg/mL) without any evidence of pituitary adenoma or ectopic ACTH-secreting tumor, suggesting a glucocorticoid resistance syndrome. Methods: We sequenced NR3C1 gene and performed in vitro analysis to assess contribution of this variant to the patient’s phenotype and how it affects biological activity of GR. Results: Exon sequencing of the NR3C1 gene identified a novel missense variant located on exon 5 (NM_000176.3, c.1706 G&amp;gt;A) resulting in substitution of arginine to glutamine at amino acid 569 (GR R569Q) in the Ligand-Binding Domain (LBD) of GR. We characterized transcriptional activity of GR R569Q in HEK 293T cells transiently co-transfected with either GR WT or GR R569Q, together with a luciferase reporter gene construct placed under control of a promoter containing two glucocorticoid responsive elements. We observed a decreased transcriptional activity of GR R569Q (EC50 4.55 nM [3.8;5.3]) compared to GR WT (EC50 0.19 nM [0.15; 0.24]), in response to dexamethasone. Interestingly, GR R569Q exerted a dominant negative effect on GR WT, with a decrease in transcriptional activity of 80% when stimulated with 1 nM dexamethasone (2-way ANOVA test, P&amp;lt;0.0001), which was blunted when stimulated with a 100-fold higher concentration of dexamethasone. As the variant is located within the second nuclear localization signal, we studied nuclear translocation in response to 1 nM cortisol for 1 h. As expected, nuclear-cytoplasmic ratio was lower in patients’ fibroblasts (2.3 ± 0.14 vs 3.0 ± 0.98, ANOVA 2-Way, P &amp;lt; 0.0001) compared with control fibroblasts, as quantified by automated high-throughput microscopy. Three-dimensional modeling revealed that arginine substitution leads to loss of a hydrogen bond stabilizing the LBD structure. This may result in a lower ligand affinity that can be bypassed by high concentrations of agonist. We are currently testing receptor affinity and reversibility of phenotype after hydrogen bond restoration by directed mutagenesis (c.1705 C&amp;gt;A, p.Q569K). Conclusion: Overall, we identified a novel variant of the NR3C1 gene associated with fluctuating GR sensitivity depending on ligand concentration. This finding may provide new insights into mechanisms involved in GR sensitivity. Presentation: Friday, June 16, 2023

SAT328 Severe Exogenous Cushing Syndrome Caused By A Potent Steroid Concealed In Arthritis Supplement

Abstract Disclosure: S. Maraqa: None. L. Bushnaq: None. R. Singh, PhD: None. N. Genere: None. Cushing syndrome (CS) is a rare disorder caused by excessive systemic glucocorticoids and associated with increased mortality and worsening quality of life. CS most commonly occurs from exogenous glucocorticoid use, while Cushing disease causes most of endogenous cases. Here, we present a case of a 64-year-old woman with rapidly progressive CS due to an over-the-counter (OTC) arthritis supplement with unlisted dexamethasone. A 64-year-old woman with reported CS who was evaluated in our Endocrinology center after she moved to the United States. She was previously diagnosed with pituitary CS in Mexico following a 6 months history of rapid 50-pound weight gain, profound proximal muscle weakness requiring assistive device, and unprovoked vertebral fractures; laboratory evaluation found elevated 24-hour urinary cortisol 272 mcg/24h, 1mg dexamethasone suppression test total cortisol 5.6 mcg/dl (&amp;lt; 1.8), and adrenocorticotropic hormone (ACTH) 16 pg/mL. Pituitary MRI was unremarkable. Past medical history included primary hypothyroidism and hypertension. Physical exam was notable for blood pressure 160/108 mmHg, heart rate 96, BMI 33 kg/m², moon face, supraclavicular fat pads, central obesity, skin bruises, and proximal muscle weakness. Unexpectedly, re-evaluation showed undetectable serum ACTH and cortisol. A thorough review of medications identified no recent exposure to glucocorticoids. However, a synthetic glucocorticoid screen showed markedly elevated serum dexamethasone concentration. Follow-up discussion revealed that she had started an arthritis supplement “Artri-King” 6 months prior to these symptoms. We collaborated with Mayo Clinic Labs to evaluate dexamethasone contents in this drug; each tablet was found to contain 0.9 mg of dexamethasone, which was unreported in the ingredient list. This supplement was stopped, and the patient was started on physiologic hydrocortisone. Two months later, AM cortisol was 5.6 mcg/dL and ACTH 23 pg/ml. Eight months later, she continues to have adrenal insufficiency but has had a substantial clinical improvement.Exogenous CS is readily diagnosed in patients taking prescribed glucocorticoids; however, diagnosis can be more challenging in cases where the presence of glucocorticoids is concealed. The US Food and Drug Administration follows more limited regulatory guidelines for dietary supplements compared to prescribed drugs. A study by Tucker.et.al. reported that 20% of dietary supplements have unapproved ingredients.1 This is especially concerning, considering that over half of the US population admits to taking dietary supplements.2 On April 2022, the FDA published a public notice for “Artri-King”, declaring the presence of unlisted dexamethasone.3 Should such agents prove to be the culprit of CS, they must be tapered off gradually or in the presence of physiologic hydrocortisone to avoid the risk of adrenal crisis. Presentation: Saturday, June 17, 2023

FRI171 Can 11-Dehydrodexamethasone Improve The Salivary Dexamethasone Suppression Test?

Abstract Disclosure: D. Marshall: None. B.G. Issa: None. B.G. Keevil: None. Background: The 1 mg overnight dexamethasone suppression test (ONDST) is recommended as a first-line test for the investigation of Cushing Syndrome. Measurement of dexamethasone alongside cortisol in a 9am serum sample has been credited with improving diagnostic sensitivity of the test. Previous studies have also looked at the utility of salivary dexamethasone and have observed poor correlation with serum dexamethasone. Herein we introduce the concept of measuring 11-dehydrodexamethasone: a dexamethasone metabolite produced in the salivary duct through metabolism with 11β-hydroxysteroid dehydrogenase type 2 (11Β-HSD2). Methods: Paired 9am serum and saliva samples (n=44) were collected post ONDST. The saliva samples were analysed utilising a novel in-house LC-MS/MS assay which measured cortisol, cortisone, dexamethasone and 11-dehydrodexamethasone. Serum cortisol and dexamethasone had previously been analysed separately by LC-MS/MS. Results were compared and correlations were assessed using Pearson regression. Results: Serum and salivary dexamethasone exhibited poor correlation (R-squared = 0.16), supporting what has been observed previously. Salivary dexamethasone and 11-dehydrodexamethasone also showed poor correlation (R-squared = 0.19). Serum dexamethasone and salivary 11-dehydrodexamethasone yielded a positive correlation with an R-squared of 0.65. However, at higher concentrations the correlation appeared non-linear. Conclusion: Correlation of serum dexamethasone with 11-dehydrodexamethasone is a novel finding, which to the author’s knowledge, has not been previously established/investigated. It is hypothesized that the non-linear correlation might be due to saturation kinetics of the enzyme 11Β-HSD2 in the salivary duct, a similar relationship was observed when comparison of salivary cortisol and cortisone was assessed. The development of this LC-MS/MS assay for salivary measurement of 11-dehydrodexamethasone opens the possibility for a fully remote DST, whereby patients could administer the drug and take a 9am saliva sample. Further sample comparisons are required to develop a 11-dehydrodexamethasone cut-off which equates to a serum dexamethasone concentration of 3.3 nmol/L. Presentation: Friday, June 16, 2023

Sound conditioning strategy promoting paracellular permeability of the blood-labyrinth-barrier benefits inner ear drug delivery.

The therapeutic effects of pharmaceuticals depend on their drug concentrations in the cochlea. Efficient drug delivery from the systemic circulation into the inner ear is limited by the blood-labyrinth-barrier (BLB). This study investigated a novel noninvasive sound conditioning (SC) strategy (90 dB SPL, 8-16 kHz, 2 h sound exposure) to temporally enhance BLB permeability in a controllable way, contributing to maximizing the penetration of pharmaceuticals from blood circulation into the cochlea. Trafficking of Fluorescein Isothiocyanate conjugated dextran and bovine serum albumin (FITC-dextran and FITC-BSA) demonstrated that paracellular leakage of BLB sustained for 6 h after SC, providing a controllable time window for systemic administration. Cochlear concentrations of dexamethasone (DEX) and dexamethasone phosphate (DEX-P), respectively transported by transcellular and paracellular pathways, showed a higher content of the latter one after SC, further confirming the key role of paracellular pathway in the SC-induced hyperpermeability. Results of high-throughput RNA-sequencing identified a series of tight junction (TJ)-associated genes after SC. The expressions of TJ (ZO-1) were reduced and irregular rearrangements of the junction were observed by transmission electron microscopy after SC. We further determined the inhibiting role of Rab13 in the recruitment of ZO-1 and later in the regulation of cellular permeability. Meanwhile, no significant change in the quantifications of endothelial caveolae vesicles after SC indicated that cellular transcytosis accounted little for the temporary hyperpermeability after SC. Based on these results, SC enhances the BLB permeability within 6 h and allows systemically applied drugs which tend to be transported by paracellular pathway to readily enter the inner ear, contributing to guiding the clinical medications on hearing loss.

Statistical modeling and optimization of dexamethasone adsorption from aqueous solution by Fe3O4@NH2-MIL88B nanorods: Isotherm, Kinetics, and Thermodynamic

The presence of pharmaceutical compounds in the environment poses a significant threat to human and aquatic animal health. Dexamethasone (DEX), a synthetic steroid hormone with endocrine-disrupting effects, is one such compound that needs to be effectively removed before discharging into the environment. This research presents a novel approach utilizing magnetically recyclable Fe3O4@NH2-MIL88B NRs as an efficient adsorbent for the treatment of DEX from aqueous solutions. The synthesized adsorbent was characterized by X-ray diffraction (XRD), scanning microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), diffuse reflectance spectra (DRS), and Fourier transform infrared spectroscopy (FTIR). Response surface methodology based on central composite design (RSM-CCD) was employed to optimize DEX removal efficiency by determining the optimal conditions, including pH, adsorbent dose, time, and DEX concentration. Under the optimized conditions (pH: 5.53, adsorbent dose: 0.185 g/L, time: 16.068 min, and DEX concentration: 33.491 mg/L), Fe3O4@NH2-MIL88B NRs revealed remarkable DEX adsorption efficiency of 91 ± 1.34% and adsorption capacity of 180.01 mg/g. The Langmuir isotherm and pseudo-second-order kinetic model were found to fit well with the experimental data, indicating a monolayer and chemical adsorption process. Thermodynamic analysis revealed that the adsorption process was spontaneous and endothermic. The study also investigated the inhibitory effect of background ions on DEX removal by Fe3O4@NH2-MIL88B NRs. Magnesium exhibited superior competitive ability with dexamethasone to occupy the active sites of the adsorbent compared to other background ions. The reuse of the adsorbent over ten consecutive cycles resulted in a 39.46% decrease in removal efficiency. The Fe3O4@NH2-MIL88B NRs are surrounded by abundant amounts of functional groups and π-electrons bands that can play a key role in the adsorption and separation of DEX from aqueous environments. The promising results obtained under real conditions highlight the potential of Fe3O4@NH2-MIL88B NRs as a practical and efficient adsorbent for the removal of DEX and other similar corticosteroids from aqueous solutions.

Sensitive and rapid quantitation of dexamethasone in human plasma using liquid chromatography coupled with triple quadrupole mass spectrometer.

The aim of this paper was to develop, validate, and utilize a sensitive liquid chromatography-tandem mass spectrometry bioanalytical method for bioequivalence/clinical trial studies conducted in human plasma. To accomplish the target, a stable labeled internal standard, that is, dexamethasone D4 was used as an internal standard to track and compensate the parent compound during processing, and extraction from plasma. The method involves a rapid liquid-liquid phase extraction from plasma, followed by reverse phase chromatography, and mass spectrometry detection, with a total run time of 3.5 min. The method was developed and validated from 2 to 600 ng/ml for dexamethasone. The mean recovery for dexamethasone was found to be 81.0%. The validated method enabled the analysis of dexamethasone in samples from clinical pharmacokinetic studies. The peak concentration of dexamethasone ranged between 253 to 281 ng/ml and 319 to 343 ng/ml, respectively, in fasted and fed conditions. The terminal half-life values for dexamethasone ranged between 3.5 to 8.2 h and 3.0 to 7.5 h, respectively.

Wastewater surveillance of pharmaceuticals during the COVID-19 pandemic in Mexico City and the Mezquital Valley: A comprehensive environmental risk assessment

This study tracked five pharmaceutically active compounds (PhACs) in Mexico City's sewage, namely, famotidine, indomethacin, dexamethasone, azithromycin, and ivermectin, which were used to treat COVID-19. The monitoring campaign was carried out over 30 months (May 2020 to November 2022), covering the five COVID-19 waves in Mexico. In the Central Emitter, the main sewage outflow, famotidine displayed levels of 132.57 ± 28.16 ng L−1 (range from < LOQ to 189.1 ng L−1), followed by indomethacin (average 672.46 ± 116.4 ng L−1, range from 516.7 to 945.2 ng L−1), dexamethasone (average 610.4 ± 225.7 ng L−1, range from 233.4 to 1044.5 ng L−1), azithromycin (average 4436.2 ± 903.6 ng L−1, range from 2873.7 to 5819.6 ng L−1), and ivermectin (average 3413.3 ± 1244.6 ng L−1, range from 1219.8 to 4622.4 ng L−1). The concentrations of dexamethasone, azithromycin and ivermectin were higher in sewage from a temporary COVID-19 care unit, by a factor of 3.48, 3.52 and 2.55, respectively, compared with those found in municipal wastewater. In the effluent of the Atotonilco Wastewater Treatment Plant (AWWTP), which treats near 60 % of the Mexico City's sewage, famotidine was absent, while concentrations of indomethacin, dexamethasone, azithromycin and ivermectin were 78.2 %, 76.7 %, 74.4 %, and 88.1 % lower than those in the influent, respectively. The occurrence of PhACs in treated and untreated wastewater resulted in medium to high environmental risk since Mexico City's wastewater is reused for irrigation in the Mezquital Valley. There, PhACs were found in irrigation canals at lower levels than those observed in Mexico City throughout the monitoring. On the other hand, famotidine, indomethacin, and dexamethasone were not found in surface water resulting from the infiltration of wastewater through soil in Mezquital Valley, while azithromycin and ivermectin sporadically appeared in surface water samples collected through 2021. Using an optimized risk assessment based on a semi-probabilistic approach, the PhACs were prioritized as ivermectin > azithromycin > dexamethasone > famotidine > indomethacin.

Effect of Dexamethasone in Management of Postoperative Nausea, Vomiting and Pain After Tonsillectomy in Paediatric Patients

Introduction: The effectiveness of dexamethasone (DEX) in reducing complication rates following paediatric tonsillectomy is still up for debate. The incidence of postoperative nausea and vomiting (PONV) and the severity of pain following paediatric tonsillectomy were examined by comparing concentrations of DEX 0.15 and DEX 0.5 mg/kg, respectively. Aim of the study: The aim of the study is to assess the effect of Dexamethasone in management of postoperative nausea, vomiting and pain after tonsillectomy where the targeted patients are of 3 to 10 years children. Methods: This prospective cross sectional study was conducted in the Department of Paediatric Anaesthesiology and Surgical ICU in Bangladesh Shishu Hospital and Institute, Dhaka, Bangladesh during July 2019 to June 2022. This study included 123 children undergoing elective tonsillectomy. The Institutional Ethics Committee approved this study and informed parental written consent was obtained from the parents before collecting the patients’ information. Results: The prevalence of early PONV was lower in both DEX groups (DEX 0.15: 22%; DEX 0.5: 26%; placebo: 48%; P=0.001). On the second day after surgery, the DEX groups had a lower rate of severe pain (DEX 0.15: 20%; DEX 0.5: 5%; placebo: 47%; P&lt;0.001). The study was not conducted to assess a difference between the two dose groups of Dexamethasone. Conclusions: The frequency of early and late PONV and the level of pain on the second postoperative day were both reduced by an i.v injection of DEX during the induction of anesthesia. To reduce the incidence of PONV, it appeared that a dose of DEX 0.15 mg/kg was just as effective as a dose of DEX 0.5 mg/kg.

Short-term exposure to dexamethasone at environmentally relevant concentrations impairs embryonic development in Cyprinus carpio: Bioconcentration and alteration of oxidative stress-related gene expression patterns

In recent years and as a result of the Covid-19 pandemic, the consumption of dexamethasone (DXE) has increased. This favors that this corticosteroid is highly released in aquatic environments, generating deleterious effects in aquatic organisms. The information on the toxic effects of DXE in the environment is still limited. Thus, the objective of this work was to determine whether DXE at short-term exposure can cause alterations to embryonic development and alteration of oxidative stress-related gene expression patterns in Cyprinus carpio. For this purpose, common carp embryos (2 hpf) were exposed to realistic concentrations of DXE until 96 hpf. Alterations to embryonic development were evaluated at 12, 24, 48, 72 and 96 hpf. In addition, oxidative stress in carp embryos at 72 and 96 hpf was evaluated by cellular oxidation biomarkers (lipoperoxidation level, hydroperoxide and carbonyl protein content) and antioxidant enzymes activities (superoxide dismutase and catalase). Oxidative stress-related gene expression (sod, cat and gpx1) was also evaluated. Our results showed that DXE concentrations above 35 ng/L are capable of producing alterations to embryonic development in 50 % of the embryo population. Furthermore, DXE was able to induce alterations such as scoliosis, hypopigmentation, craniofacial malformations, pericardial edema and growth retardation, leading to the death of half of the population at 50 ng/L of DXE. Concerning oxidative stress, the results demonstrated that DXE induce oxidative damage on the embryos of C. carpio. In conclusion, DXE is capable of altering embryonic development and generating oxidative stress in common carp C. carpio.

81-LB: Novel Microsphere Technology Reducing Injection Site Reaction in the Development of Long-Acting GLP-1 RA Formulation

Microspheres are typically used for long-acting injectable formulation, but often the injection site reactions are reported as side effects. This can reduce patient compliance with medication despite the benefit of reducing the number of administrations. Side effects at the injection site are mostly derived from inflammatory reactions. Therefore, it is necessary to minimize inflammatory reactions for the successful development of long-acting diabetes treatments, including GLP-1 receptor agonists. The purpose of this study is to evaluate the injection site reaction in the placebo, semaglutide and tirzepatide microspheres manufactured using the conventional microsphere technology and to investigate the injection site reaction improvement in the placebo, semaglutide and tirzepatide microspheres manufactured using novel technology by adding anti-inflammatory agent, dexamethasone. Skin samples were collected from the injection site of SD rats on days 3 and 8 after the administration of microspheres with or without dexamethasone. The collected skin was stained with H&amp;E to determine infiltration of inflammatory cells, angiogenesis, and fibrosis and was graded. When microspheres manufactured using the conventional method were subcutaneously administered to rats, infiltration of inflammatory cells and fibrous tissue formation occurred on both days 3 and 8. Higher dexamethasone content in the microsphere showed a tendency for the lesser occurrence of inflammation and greater anti-inflammatory effect in the test group. Surprisingly, improvement in the injection site reaction for microspheres containing dexamethasone was observed even at systemic dexamethasone concentrations much lower than the therapeutic level. In conclusion, this novel microsphere containing a small amount of dexamethasone shows potential for the development of a long-acting GLP-1 microsphere injectable for diabetes treatment with reduced injection site reaction. Disclosure Y. Kim: None. E. Seol: None. Funding Ministry of Health &amp; Welfare, Republic of Korea (HI21C1732)