Development of a broad-spectrum one-step immunoassay for detection of glucocorticoids in milk using magnetosome-based immunomagnetic beads.

Immunomagnetic beads provide novel tools for high-throughput immunoassay techniques. In this study, protein G (PG) was immobilized onto bacterial magentic particles (BMPs) using an additional cysteine residue at the C-terminus. A broad-spectrum monoclonal antibody against glucocorticoids (GCs) was attached to BMPs through PG-Fc interaction, generating BMP-PG-mIgG immunomagentic beads. A sensitive one-step immunoassay was developed for GCs based on combination of BMP-PG-mIgG and dexamethasone-horseradish peroxidase tracer (DMS-HRP). The developed assay exhibited half inhibitory concentrations (IC50) for dexamethasone (DMS), betamethasone (BMS), prednisolone (PNS), hydrocortisone (HCS), beclomethasone (BCMS), cortisone (CS), 6-α-methylprednisone (6-α-MPNS), fludrocortisone acetate (HFCS) of 0.98, 1.49, 2.42, 9.29, 1.63, 6.13, 7.3, and 4.89 ng/mL, respectively. The method showed recoveries ranging rates from 86.5 % to 117 % with a coefficient of variation less than 12.3 % in milk sample, which showed a good correlation with LC-MS/MS. Thus, the proposed assay offers a rapid and broad-spectrum screening tool for simultaneous detection of GCs in milk.

The Utility of Salivary Cortisone in the Overnight Dexamethasone Suppression Test in Adrenal Incidentalomas.

CONTEXT: Guidelines recommend the assessment of cortisol secretion in patients with adrenal incidentalomas (AI) using the overnight dexamethasone suppression test (ONDST). This requires attendance at a health care facility and venepuncture. Alternatively, the ONDST can be done by measuring salivary cortisol and cortisone, which can be collected at home. OBJECTIVE: We aimed to assess the utility of these measurements in patients with AI. METHODS: A retrospective analysis of data from 173 patients with AI who underwent an ONDST and salivary cortisol/cortisone diurnal studies. Serum and salivary cortisol and salivary cortisone were collected at 09:00, late night, and at 09:00 the following morning after dexamethasone. Dexamethasone levels were measured in the postdexamethasone samples. Serum and salivary samples were analyzed with liquid chromatography-tandem mass spectrometry. RESULTS: We identified a strong correlation between salivary cortisone and serum cortisol after 1 mg of dexamethasone (r = 0.95). Stepwise multivariate regression showed that postdexamethasone salivary cortisone, baseline serum cortisol, salivary cortisone suppression (predexamethasone/postdexamethasone ratio), and sex were the only significant or near-significant independent variables. Performance of predictive indices using these 4 parameters (sensitivity = 88.5%, specificity = 91.2%; kappa 0.80) and postdexamethasone salivary cortisone alone (sensitivity = 85.3%, specificity = 91.7%; kappa 0.77) were comparable when used to predict an ONDST serum cortisol of ≤50 nmol/L. No correlation was observed with any of the other measured parameters. CONCLUSION: In AI patients, after dexamethasone, salivary cortisone correlates very strongly with serum cortisol in the ONDST and could therefore be used as an alternative sampling method which does not require venepuncture or attendance at hospital.

Physiological and transcriptional effects in the male western mosquitofish (Gambusia affinis) following exposure to dexamethasone.

Dexamethasone (DEX) is a synthetic glucocorticoid widely found in a variety of aquatic environments and has potential adverse effects on aquatic organisms. This study was to assess the toxic effects of exposure to different concentrations (0, 5 and 50 µg/L) of DEX for 60 days on adult male mosquitofish (Gambusia affinis). Morphological analyses of skeleton and anal fin, histological effects of testes and livers, and transcriptional expression levels of genes related to reproductive and immune system were determined. The results showed that exposure to DEX significantly increased 14L and 14D values of hemal spines, which suggested DEX could affect skeleton development and result in more masculine characteristics in male fish. In addition, the damage to testis and liver tissue was observed after DEX treatment. It also enhanced mRNA expression of Erß gene in the brain and Hsd11b1 gene in the testis. The findings of this study reveal physiological and transcriptional effects of DEX on male mosquitofish.

Presence and toxicity of drugs used to treat SARS-CoV-2 in Llobregat River, Catalonia, Spain.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a strain of coronavirus that causes COVID-19 (coronavirus disease 2019), the respiratory illness responsible for the on-going COVID-19 pandemic. In March 2020, it was declared global pandemic, causing millions of deaths. An evident tendency of global pharmaceutical consumption due to COVID-19 pandemic should be seen worldwide, and this increase might suppose an environmental threat. Pharmaceuticals administrated at home or in pharmacies are excreted by faeces and urine after consumption, and wastewater treatment plants (WWTPs) are not able to remove all pharmaceuticals residues that eventually will end up in the aquatic media (rivers and sea). For this reason, analytical techniques such as liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) have become prominent to identify and quantify pharmaceuticals residues in aquatic matrices. In view of the scarce data on the occurrence of pharmaceuticals used as COVID-19 treatment, the aim of the present study was to evaluate the presence of these class of pharmaceuticals in river water which were dexamethasone, prednisone, ciprofloxacin, levofloxacin, remdesivir, ritonavir, lopinavir, acetaminophen, hydroxychloroquine, chloroquine and cloperastine, their toxicity in the aquatic environment using D. magna and to perform an exhaustive risk assessment in seven points of the Llobregat river basin. Dexamethasone, cloperastine and acetaminophen were the pharmaceuticals with higher concentrations, showing mean levels between 313 and 859 ng L-1.

A long-wavelength mitochondria-targeted fluorescent probe for imaging of peroxynitrite during dexamethasone treatment.

Peroxynitrite (ONOO-), as a strong oxidizing reactive nitrogen substance (RNS), is generated endogenously by cells. Its visualization research is crucial to understand relevant disease processes. Herein, we reported a long-wavelength mitochondria-targeted fluorescence "turn on" probe TL. The probe TL could react with ONOO- by using 4-(Bromomethyl)benzeneboronic as a reactive site, which exhibited outstanding characteristics for detection of ONOO-, thus improving response time (about 50 s), sensitivity (DL, 10.1 nM), and emission wavelength (667 nm). Besides, TL displayed well mitochondria targeting and biological visualizing of exogenous and endogenous ONOO- in biological systems. Finally, TL was used to monitor high concentration of dexamethasone-induced an up-regulation of ONOO-. This indicated that TL has excellent potential to study the fluctuation of ONOO- in the physiological and pathological system.

Dexamethasone-doped nanoparticles improve mineralization, crystallinity and collagen structure of human dentin.

OBJECTIVES: Bioactive materials have been used for functionalization of adhesives to promote dentin remineralization. This study aims to evaluate bonding ability and both mechanical and chemical behavior of demineralized dentin infiltrated with polymeric nanoparticles doped with dexamethasone (Dex-NPs). METHODS: Dentin conditioned surfaces were infiltrated with NPs, Dex-NPs or Dex-Zn-NPs. Bonded interfaces were also created and stored for 24 h or 21d, and then submitted to microtensile bond strength testing. Dentin remineralization was analyzed by Nanohardness, Young's modulus and Raman analysis. RESULTS: At 21d of storage, dentin treated with undoped-NPs attained the lowest nanohardness and Young's modulus. Dex-NPs and Zn-Dex-NPs increased dentin nanohardness and Young's modulus after 21d Raman analysis showed high remineralization, crystallinity, crosslinking and better structure of collagen when functionalized Dex-NPs were present at the dentin interface. CONCLUSIONS: Infiltration of dentin with Dex-NPs promoted functional remineralization as proved by nanomechanical and morpho-chemical evaluation tests. Dexamethasone in dentin facilitated crystallographic maturity, crystallinity and improved maturity and secondary structure of dentin collagen. CLINICAL SIGNIFICANCE: Using dexamethasone-functionalized NPs before resin infiltration is a clear option to obtain dentin remineralization, as these NPs produce the reinforcement of the dentin structure, which will lead to the improvement of the longevity of resin restorations.

Dexamethasone and zinc loaded polymeric nanoparticles reinforce and remineralize coronal dentin. A morpho-histological and dynamic-biomechanical study.

OBJECTIVE: To investigate the effect of novel polymeric nanoparticles (NPs) doped with dexamethasone (Dex) on viscoelasticity, crystallinity and ultra-nanostructure of the formed hydroxyapatite after NPs dentin infiltration. METHODS: Undoped-NPs, Dex-doped NPs (Dex-NPs) and zinc-doped-Dex-NPs (Zn-Dex-NPs) were tested at dentin, after 24 h and 21 d. A control group without NPs was included. Coronal dentin surfaces were studied by nano-dynamic mechanical analysis measurements, atomic force microscopy, X-ray diffraction and transmission electron microscopy. Mean and standard deviation were analyzed by ANOVA and Student-Newman-Keuls multiple comparisons (p < 0.05). RESULTS: At 21 d of storage time, both groups doped with Dex exhibited the highest complex, storage and loss moduli among groups. Zn-Dex-NPs and Dex-NPs promoted the highest and lowest tan delta values, respectively. Dex-NPs contributed to increase the fibril diameters of dentin collagen over time. Dentin surfaces treated with Zn-Dex-NPs attained the lowest nano-roughness values, provoked the highest crystallinity, and produced the longest and shortest crystallite and grain size. These new crystals organized with randomly oriented lattices. Dex-NPs induced the highest microstrain. Crystalline and amorphous matter was present in the mineral precipitates of all groups, but Zn and Dex loaded NPs helped to increase crystallinity. SIGNIFICANCE: Dentin treated with Zn-Dex-NPs improved crystallographic and atomic order, providing structural stability, high mechanical performance and tissue maturation. Amorphous content was also present, so high hydroxyapatite solubility, bioactivity and remineralizing activity due to the high ion-rich environment took place in the infiltrated dentin.

Development and Validation of Facile RP-HPLC Method for Simultaneous Determination of Timolol Maleate, Moxifloxacin Hydrochloride, Diclofenac Sodium and Dexamethasone in Plasma, Aqueous Humor and Pharmaceutical Products.

The present study aimed to develop a validated RP-HPLC method for the simultaneous determination of timolol maleate (TM), moxifloxacin hydrochloride (MOXI), diclofenac sodium (DS) and dexamethasone (DEXA) in human plasma, bovine aqueous humor and pharmaceutical preparations. The chromatographic separation was studied using the C18 column. The chromatographic conditions, such as composition, pH, the flow rate of mobile phase, the temperature of column, wavelength of absorption and injection volume of the sample, were studied. The method was validated to confirm specificity, linearity and accuracy in accordance with an International Conference on Harmonization guidelines. The optimum conditions for separation included mobile phase 0.05 M monobasic phosphate buffer: acetonitrile (65:35 v/v), pH of buffer adjusted to 6.2 and the flow rate of 1 mL/minute. The optimum temperature of the column was found to be 35°C, absorption wavelength 265 nm and injection volume 50 µL. The baseline separation of all four drugs with good sensitivity, resolution, and a less than 15 min run time was achieved. The retention time of TM, MOXI, DS and DEXA were 4.3,5.7,9.9 and 13.5 minutes respectively. The limit of detection (LOD) values were 6.2, 4.8, 0.8 and 1.2 ng/mL for TM, MOXI, DS and DEXA, respectively, whereas their respective limit of quantification (LOQ) values was: were 42.6, 26.8, 5.6 and 6.2 ng/mL. The coefficient of variation for intra-day and inter-day were in the range of 0.32-1.57 and 1.29-3.07%, respectively. The method was found to be sensitive, precise and accurate in human plasma and bovine aqueous humor and can be applied for the quantification of these compounds in plasma, aqueous humor and pharmaceuticals.

Stability of dexamethasone sodium phosphate over a 28 day period when added to commercial veterinary wipe and pad products.

Background - Topical glucocorticoids commonly are used in the management of canine atopic dermatitis to control and prevent allergy flares. Compounding commercial veterinary wipe/pad products to include dexamethasone sodium phosphate (Dex SP) can simplify treatment protocols for owners. Dex SP has not been evaluated for stability when added to wipes/pads. Hypothesis/objective - To evaluate the stability of Dex SP when compounded in three commercial veterinary wipe/pad products containing chlorhexidine. Methods and materials - Dex SP (Dexium, Bimeda; Oakbrook Terrace, IL, USA) was added to TrizCHLOR 4 wipes (TCL; Dechra Veterinary Products; Overland Park, KS, USA), KetoHex wipes (KH; VetOne; Boise, ID, USA), and DOUXO Chlorhexidine Pads (DCP; Ceva Animal Health; Lenexa, KS, USA), creating a 0.04% Dex SP solution. The concentration of Dex SP was measured in µg/mL/wipe or pad in triplicate at Day (D)0, D14 and D28 using liquid chromatography with tandem mass spectrometry. The amount of Dex SP at baseline (D0) was compared to the amount recovered at D14 and D28. Results - The amount of Dex SP in TCL and KH was unchanged between D0, D14 and D28. The amount of Dex SP recovered from DCP on D0 (mean 89.40 µg/mL/pad), D14 (mean 65.58 µg/mL/pad) and D28 (mean 68.09 µg/mL/pad) revealed a significant decline from D0 to D14 (P = 0.004). Conclusions and clinical importance - These data provide evidence that Dex SP is stable for 28 days in TCL and KH, and not in DCP from D0 to D14 or D28 days.

Contexte - Les glucocorticoïdes topiques sont couramment utilisés dans la prise en charge de la dermatite atopique canine pour contrôler et prévenir les poussées allergiques. La composition de produits commerciaux de lingettes / tampons vétérinaires pour inclure du phosphate de dexaméthasone sodique (Dex SP) peut simplifier les protocoles de traitement pour les propriétaires. Dex SP n'a pas été évalué pour la stabilité lorsqu'il est ajouté aux lingettes/tampons. Hypothèse/objectif - Évaluer la stabilité de Dex SP lorsqu'il est mélangé dans trois produits commerciaux de lingettes/tampons vétérinaires contenant de la chlorhexidine. Matériels et méthodes - Dex SP (Dexium, Bimeda; Oakbrook Terrace, IL, États-Unis) a été ajouté aux lingettes TrizCHLOR 4 (TCL; Dechra Veterinary Products; Overland Park, KS, États-Unis), aux lingettes KetoHex (KH; VetOne; Boise, ID, États-Unis) et DOUXO Chlorhexidine Pads (DCP ; Ceva Animal Health ; Lenexa, KS, États-Unis), créant une solution de Dex SP à 0,04 %. La concentration de Dex SP a été mesurée en µg/mL/lingette ou tampon en triple exemplaire aux jours (J)0, J14 et J28 par chromatographie liquide avec spectrométrie de masse en tandem. La quantité de Dex SP à l'inclusion (J0) a été comparée à la quantité récupérée à J14 et J28. Résultats - La quantité de Dex SP dans le TCL et le KH était inchangée entre J0, J14 et J28. La quantité de Dex SP récupérée du DCP à J0 (moyenne 89,40 µg/mL/pad), J14 (moyenne 65,58 µg/mL/pad) et J28 (moyenne 68,09 µg/mL/pad) a révélé une baisse significative de J0 à J14 (P = 0,004). Conclusions et importance clinique - Ces données fournissent des preuves que Dex SP est stable pendant 28 jours en TCL et KH, et non en DCP de J0 à J14 ou J28 jours.

Introducción- los glucocorticoides tópicos se usan comúnmente en el tratamiento de la dermatitis atópica canina para controlar y prevenir los brotes de alergia. La combinación de productos comerciales de toallitas/apósitos veterinarios para incluir fosfato sódico de dexametasona (Dex SP) puede simplificar los protocolos de tratamiento para los propietarios. No se ha evaluado la estabilidad de Dex SP cuando se agrega a toallitas/apósitos. Hipótesis/objetivo- evaluar la estabilidad de Dex SP cuando se mezcla en tres productos comerciales de toallitas/apósitos veterinarios que contienen clorhexidina. Métodos y materiales- se agregó Dex SP (Dexium, Bimeda; Oakbrook Terrace, IL, EE. UU.) a las toallitas TrizCHLOR 4 (TCL; Dechra Veterinary Products; Overland Park, KS, EE. UU.), toallitas KetoHex (KH; VetOne; Boise, ID, EE. UU.) y los apósitos de clorhexidina DOUXO (DCP; Ceva Animal Health; Lenexa, KS, EE. UU.), creando una solución de Dex SP al 0,04 %. La concentración de Dex SP se midió en µg/mL/toallita o apósito por triplicado en el día (D)0, D14 y D28 usando cromatografía líquida con espectrometría de masas en tándem. La cantidad de Dex SP al inicio (D0) se comparó con la cantidad recuperada en D14 y D28. Resultados- la cantidad de Dex SP en TCL y KH no cambió entre D0, D14 y D28. La cantidad de Dex SP recuperada de DCP en D0 (media de 89,40 µg/ml/almohadilla), D14 (media de 65,58 µg/ml/almohadilla) y D28 (media de 68,09 µg/ml/almohadilla) reveló una disminución significativa de D0 a D14 (P = 0,004). Conclusiones e importancia clínica- estos datos proporcionan evidencia de que Dex SP es estable durante 28 días en TCL y KH, y no en DCP de D0 a D14 o D28 días.

Contexto - Os glicocorticoides tópicos são comumente usados no manejo da dermatite atópica canina para controlar e prevenir crises alérgicas. A inclusão de incluir fosfato sódico de dexametasona (Dex SP) na fórmula de produtos comerciais em lenços/toalhas veterinárias pode simplificar os protocolos de tratamento para os proprietários. Dex SP não foi avaliado quanto à estabilidade quando adicionado a lenços/toalhas. Hipótese/objetivo - Avaliar a estabilidade do Dex SP quando formulado em três lenços/almofadas veterinárias comerciais contendo clorexidina. Métodos e materiais - Dex SP (Dexium, Bimeda; Oakbrook Terrace, IL, EUA) foi adicionado aos lenços TrizCHLOR 4 (TCL; Dechra Veterinary Products; Overland Park, KS, EUA), lenços KetoHex (KH; VetOne; Boise, ID, EUA) e DOUXO Chlorhexidine Pads (DCP; Ceva Animal Health; Lenexa, KS, EUA), criando uma solução de Dex SP a 0,04%. A concentração de Dex SP foi medida em µg/mL/lenço ou almofada em triplicata no Dia (D)0, D14 e D28 utilizando cromatografia líquida com espectrometria de massa em tandem. A quantidade de Dex SP no dia zero (D0) foi comparada com a quantidade recuperada em D14 e D28. Resultados - A quantidade de Dex SP em TCL e KH permaneceu inalterada entre D0, D14 e D28. A quantidade de Dex SP mensurada no DCP em D0 (média de 89,40 µg/mL/lenço), D14 (média de 65,58 µg/mL/lenço) e D28 (média de 68,09 µg/mL/lenço) revelou uma redução significativa de D0 para D14 (P=0,004) Conclusões e importância clínica - Esses dados fornecem evidências de que Dex SP é estável por 28 dias em TCL e KH, e não em DCP de D0 a D14 ou D28 dias.

Screening for drugs potentially interfering with MCT8-mediated T3 transport in vitro identifies dexamethasone and some commonly used drugs as inhibitors of MCT8 activity.

BACKGROUND: Monocarboxylate transporter 8 (MCT8) is the first thyroid hormone transporter that has been linked to a human disease. Besides genetic alterations other factors might impair MCT8 activity. AIM: This study aimed at investigating whether some common drugs having a structural similarity with TH and/or whose treatment is associated with thyroid function test abnormalities, or which behave as antagonists of TH action can inhibit MCT8-mediated T3 transport. METHODS: [125I]T3 uptake and efflux were measured in COS-7 cells transiently transfected with hMCT8 before and after exposure to increasing concentrations of hydrocortisone, dexamethasone, prednisone, prednisolone, amiodarone, desethylamiodarone, dronedarone, buspirone, carbamazepine, valproic acid, and L-carnitine. The mode of inhibition was also determined. RESULTS: Dexamethasone significantly inhibited T3 uptake at 10 µM; hydrocortisone reduced T3 uptake only at high concentrations, i.e. at 500 and 1000 µM; prednisone and prednisolone were devoid of inhibitory potential. Amiodarone caused a reduction of T3 uptake by MCT8 only at the highest concentrations used (44% at 50 µM and 68% at 100 µM), and this effect was weaker than that produced by desethylamiodarone and dronedarone; buspirone resulted a potent inhibitor, reducing T3 uptake at 0.1-10 µM. L-Carnitine inhibited T3 uptake only at 500 mM and 1 M. Kinetic experiments revealed a noncompetitive mode of inhibition for all compounds. All drugs inhibiting T3 uptake did not affect T3 release. CONCLUSION: This study shows a novel effect of some common drugs, which is inhibition of T3 transport mediated by MCT8. Specifically, dexamethasone, buspirone, desethylamiodarone, and dronedarone behave as potent inhibitors of MCT8.

A comparative physicochemical and pharmacological evaluation of dexamethasone sodium phosphate and betamethasone sodium phosphate mucoadhesive gels for the treatment of oral submucous fibrosis in rats

Abstract The present study is aimed to formulate steroidal oral mucoadhesive gels of dexamethasone sodium phosphate and betamethasone sodium phosphate. Six gel formulations each of dexamethasone sodium phosphate and betamethasone sodium phosphate prepared using two different polymers carboxymethyl cellulose sodium and hydroxypropyl methylcellulose, in variable proportions. All the formulations subjected for assessment of various physicochemical parameters and mechanical properties. The formulations BSP5 and DSP5, both containing 1.25 % carboxymethyl cellulose sodium, 1.25 % hydroxypropyl methylcellulose, exhibiting mucoadhesive strength of 12.300 ± 0.004 and 12.600 ± 0.01, adhesiveness of 28.04 ± 00 and 30.02 ± 00, cohesiveness of 28.04 ± 00 and 30.02 ± 00, drug release of 86.869 ± 0.380 % and 88.473 ± 0.457 % respectively were considered as promising ones and were further subjected for stability studies and in vivo study in male albino rats. Formulation DSP5 upon oral application for 4 months in arecoline induced oral submucous fibrosis rats, showed more than 80 % reduction in fibrosis as compared with BSP5 which showed nearly 50 % reduction. These results were concluded on the basis of histopathological profile and weight gain among the experimental animals during in vivo study. Hence, DSP5 by minimizing the painful injuries and morbidities justifies being suitable noninvasive model for OSMF treatment.

Environmental obesogens (bisphenols, phthalates and parabens) and their impacts on adipogenic transcription factors in the absence of dexamethasone in 3T3-L1 cells.

Endocrine-disrupting chemicals (EDCs) are exogenous compounds that are capable of blocking or mimicking the action of bioidentical hormones. Obesogenic EDCs, commonly called obesogens, play an important role in adipogenesis. This study was carried out to determine the effects of select obesogens and their alternatives on adipogenesis in 3T3-L1 cells under dexamethasone (DEX)-free conditions. Preadipocytes were treated with a cocktail of 3-isobutyl-1-methylxanthine (IBMX) and insulin to which an obesogen (viz., bisphenol A (BPA) or its analogs BPS and BPF; dioctyl terephthalate; tris (2-ethylhexyl) trimellitate; or various parabens) had been added. A mixture containing IBMX, insulin, and DEX, which constitute the typical hormonal cocktail required for adipocyte differentiation, was used as the control against which the other groups were measured. The obesogens and the PBA analogs all had evident adipogenic effects under DEX-free conditions, as was determined by estimating the lipid accumulation levels in the cells using Oil Red O staining. Furthermore, the expression of adipogenic transcription factors (CCAAT/enhancer-binding protein-alpha, peroxisome proliferator-activated receptor-gamma, and adipocyte protein 2) was induced by 20 µM of BPA, BPS, or BPF at both the mRNA and protein levels, as determined through reverse transcription-polymerase chain reaction and western blot assays. Taken together, the results reveal that adipocyte differentiation can be induced by obesogens and their alternatives in the absence of DEX.

Accuracy of the dexamethasone suppression test for the prediction of autonomous cortisol secretion-related comorbidities in adrenal incidentalomas.

PURPOSE: The aim of this study was to evaluate the diagnostic accuracy of the 1 mg dexamethasone suppression test (DST) for the prediction of autonomous cortisol secretion (ACS)-related comorbidities in patients with adrenal incidentalomas (AIs). METHODS: This was a retrospective multicenter study. We recruited patients with AI/s ≥ 1 cm, excluding those who, during the study, were found during the extension study of an extra-adrenal cancer, with a known diagnosis of hereditary syndromes characterized by adrenal tumors, those presenting with overt hormonal excess syndromes, and those in whom the DST results were missing. RESULTS: A total of 823 patients met the inclusion criteria. Based on the 1.8, 3.0, and 5.0 µg/dl post-DST cortisol thresholds, the prevalence of ACS was 33.5%, 13.7%, and 5.6%, respectively. The prevalence of hypertension (OR = 1.8, 95% CI = 1.3-2.4), diabetes (OR = 1.6, 95% CI = 1.2-2.2), and dyslipidemia (OR = 1.4, 95% CI = 1.0-1.9) was higher with cortisol post-DST ≥ 1.8 µg/dl; the prevalence of hypertension (OR = 2.1, 95% CI = 1.4-3.3) and diabetes (OR = 1.7, 95% CI = 1.1-2.6) was higher with values ≥ 3.0 µg/dl; and the prevalence of hypertension (OR = 2.0, 95% CI = 1.0-3.7) was higher with levels ≥ 5.0 µg/dl. However, the diagnostic accuracy of the DST for the prediction of cardiometabolic comorbidities in patients with AIs was poor, with areas under the ROC curve < 0.61. CONCLUSIONS: The DST is a poor predictor of cardiometabolic comorbidities in patients with AIs regardless of the cortisol cut-off values applied. This finding suggests that the diagnosis of ACS should not be based solely on the results of the DST. Other clinical, metabolic, or imaging markers showing a better performance for the prediction of the development and progression of cardiometabolic comorbidities in AIs need to be identified.

Simultaneous quantification of dexamethasone and 6ß-hydroxydexamethasone in rabbit plasma, aqueous and vitreous humor, and retina by UHPLC-MS/MS.

Aim: To develop and validate a fit for purpose method for the simultaneous determination of dexamethasone and its major metabolite, 6ß-hydroxydexamethasone, in rabbit plasma and ocular matrices to measure the in vivo release and distribution profile of dexamethasone from intravitreal implants. Materials & methods: An UHPLC-MS/MS system was employed to perform the bioanalysis. The method was validated according to the US FDA Bioanalytical Method Validation Guidance for Industry. Results & conclusion: The method was found to be fit-for-purpose for the described biological matrices and had a LLOQ of 0.1 ng/ml.

Rapid and simultaneous determination of dexamethasone and dexamethasone sodium phosphate using HPLC-UV: Application in microneedle-assisted skin permeation and deposition studies.

Dexamethasone is a fluorinated derivative of the natural glucocorticoid, cortisone, with a very high systemic anti-inflammatory effect. In this study, a simple and rapid high performance liquid chromatography (HPLC) method was developed and validated to quantify dexamethasone and its prodrug dexamethasone sodium phosphate in skin permeation studies. The separation of both the compounds was achieved on a Vydac Denali C18 column(250 × 4.6 mm, 5 µm) with a mobile phase composed of 5 mM ammonium acetate buffer-acetonitrile-methanol (43:32:25, v/v) at a flow rate of 0.9 mL/min and UV detection at 240 nm. The standard curves were found to be linear in the range from 0.5 to 100 µg/mL for both the drugs and the method could successfully separate the drug peaks from interfering peaks of endogenous skin constituents. Accuracy values of both the drugs were within 98.60 to 108.60% (intra-day) and 98.70 to 107.20% (inter-day) and precision values were within 2% at the studied concentrations. The developed method was used to investigate the effect of microneedles on transdermal delivery of dexamethasone sodium phosphate. The hydrolysis of dexamethasone sodium phosphate to dexamethasone in the presence of rat skin homogenate and rat plasma was also evaluated to confirm the conversion that occurs during skin permeation and in the blood circulation. The skin permeation and deposition characteristics of microneedle-assisted diffusion were compared to those achieved by passive diffusion. The observed data demonstrated that transdermal permeation of dexamethasone is significantly enhanced with microneedle pretreatment of rat skin, showing a marked increase in flux and permeability coefficient, compared to passive diffusion. This simple isocratic HPLC method can, be effectively applied for the evaluation of skin permeation of topical/transdermal dexamethasone formulations.

LC-MS/MS method for simultaneous quantification of dexamethasone and tobramycin in rabbit ocular biofluids.

The complexity of Tobradex® ointment formulation (dexamethasone 0.1 wt% and tobramycin 0.3 wt%) and the high cost of pharmacokinetic (PK) studies in human aqueous humor may prevent generic drug companies from moving forward with a Tobradex®-equivalent product development. The in vitro drug release test would be an alternative approach for differentiating the generic formulations containing both dexamethasone (DEX) and tobramycin (TOB), and the results should be correlated with the in vivo ocular PK studies for further evaluation. To facilitate the in vivo ocular PK studies, a sensitive, rapid and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method that can simultaneously quantify both DEX and TOB in rabbit ocular matrices including tear, aqueous humor and cornea was established and validated. The lower limit of quantification (LLOQ) was 1.5 ng/ml for DEX and 3 ng/ml for TOB with good precision and accuracy. Both intra- and inter-batch precisions were within ±15%, and the accuracy for all QCs was within the range of 85-115%. This new method was successfully applied for a pilot pharmacokinetic analysis of DEX and TOB in rabbit tears after topical administration of Tobradex® ointment.

Determination of dexamethasone acetate in CETETH 20-based in liquid crystalline systems using HPLC.

Dexamethasone acetate (DEX), a potent anti-inflammatory, is used primarily in the treatment of inflammatory and autoimmune diseases. It was incorporated in CETETH 20 (polyoxyethylene 20 cetyl alcohol)-based liquid crystalline systems to enhance the purpose of the drug. Concomitant with the pharmaceutical technology performed, a HPLC method was developed and validated for the quantification of dexamethasone acetate in CETETH 20-based liquid crystalline systems for the evaluation of the drug in the new matrix. The method was performed using a C18 column with acetonitrile:methanol:water (35:35:30, v/v/v) as the mobile phase at a flow rate of 0.8 mL min-1 at 239 nm. The method was linear in the range of 1-25 µg mL-1 ; the limit of quantification and limit of detection were 0.05 and 0.16 µg mL-1 , respectively; the accuracy of the method was 99.92% (relative standard deviation < 1%), and it presented intra-day and inter-day precision with deviations less than 1%. In this context, the method was successfully used to determine the incorporation efficiency of DEX in CETETH 20-based liquid crystalline systems and can be easily used by pharmaceutical companies and laboratories around the world.

Latex microsphere immunochromatography for quantitative detection of dexamethasone in milk and pork.

Dexamethasone (DEX) is a synthetic long-acting glucocorticoid, which can increase the risk of hypertension and diabetes if it is abused or used improperly. In this study, lateral flow immunoassays (LFIA) based on black and blue latex microspheres (LMs), integrated with a strip reader, was developed for quantitative detection of DEX in milk and pork. The results could be achieved within 15 min. The visible limits of detection (vLODs) were 0.3 ng/mL and 0.7 µg/kg for milk and pork, respectively. The quantitative limits of detection (qLODs) were 0.047 ng/mL and 0.087 µg/kg, respectively. The recoveries ranged from 80.0% to 122.8%. 20 milk and 10 pork samples were analyzed to confirm the performance of the on-site application. The detection results were consistent with the data from LC-MS/MS, indicating the practical reliability of our established assay. The developed LMs-LFIA provides a promising technical support for rapid, sensitive, and on-site detection of DEX.

Semiquantitative immunochromatographic colorimetric biosensor for the detection of dexamethasone based on up-conversion fluorescent nanoparticles.

A low-cost bifunctional immunochromatographic colorimetric biosensor was developed that can be read visually or by using an optical density scanner. Five test lines (T lines) coated with different antigens were set on a nitrocellulose (NC) membrane to indicate the concentration of analyte. This method was applied for the detection of dexamethasone. The corresponding detection range was 0.1-9 ng mL-1, and the detection limit for dexamethasone in food supplements and cosmetic samples was 2.0 µg kg-1. For visual inspection of the colour the quantitative relative error range between the proposed method and liquid chromatography was -62 to -25%, with a detection time of only 10 min. More accurate assay results were obtained by using an optical density scanner with the relative error range of -31 to 20%. The results indicated that the proposed method has the potential of application for rapid and efficient screening of dexamethasone in cosmetics and food supplements. Graphical abstract.

LC-MS/MS analyses of bile and histological analyses of thymus as diagnostic tools to detect low dose dexamethasone illicit treatment in beef cattle at slaughterhouse.

Dexamethasone (DXM) is a synthetic adrenal corticosteroid with anti-inflammatory properties used for therapeutic purposes in a wide range of pathologies and of the most common corticosteroids used for anabolic purposes in beef cattle. It is proven that DXM induces histological changes, traceable as increasing fatty infiltration of the thymus associated with a concurrent decrease of the cortex-medulla ratio, so the histological examination of the thymus gland has been established as an indirect morphological biomarker. The aim of the present study is to compare thymus histology and DXM concentrations in biological fluids collected at slaughterhouse after 1 month of DXM treatment. Our findings demonstrate that a low dosage of DXM administered to 12 months-old-Chianina beef cattle induces severe thymic atrophy with concurrent reduction of the cortex/medulla ratio, demonstrable even when DXM residues are not found in serum and urine samples. It is worth to note that, at the slaughterhouse, DXM residues are detectable in bile samples, indicating the ability of this biological fluid to bio-concentrate the administered drug if compared to serum and urine. Therefore, bile could be candidates as new liquid matrix for the screening programs planned to contrast the illegal use of anabolic substances.