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.

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.

A paper-based analytical device coupled with electrochemical detection for the determination of dexamethasone and prednisolone in adulterated traditional medicines.

The adulteration of herbal medicines by dexamethasone or prednisolone is regarded as a serious problem in many communities. Herein, a novel platform for the separation and quantification of both target steroids in herbal medicines based on electrochemical paper-based analytical devices (ePADs) has been created. The ePAD was composed of Whatman SG81 chromatography paper, 3D-printed devices and a commercial screen-printed electrode. Whatman SG81 silica-coated paper was used for the separation of dexamethasone and prednisolone based on the difference in their partition coefficients during the flow of the mobile phase. The optimal mobile phase was composed of 60% ethyl acetate in cyclohexane and required 7 min for separation. The separated steroids on the paper were then quantified by electrochemical detection using differential pulse voltammetry, in which the 3D-printed devices facilitated the measurement. Analytical detection ranges of 10-500 µg mL-1 were obtained for both dexamethasone and prednisolone (r2 = 0.988 and 0.994, respectively). The limits of detection for dexamethasone and prednisolone were 3.59 and 11.98 µg mL-1, respectively, whereas the limits of quantification were 6.00 and 20.02 µg mL-1, respectively. The amounts of both target steroids derived from real herbal medicine samples determined by the proposed method were comparable to those obtained with assays using standard high-performance liquid chromatography. In addition, a simple evaporation step can be used to increase the concentration of the samples before analysis. These ePADs are simple, low-cost, rapid, and very promising for on-site quantitative detection.

Purity and stability of the membrane-limited glucocorticoid receptor agonist dexamethasone-BSA.

Cellular effects of glucocorticoids can be separated into classical transcriptional regulation via activation of the canonical nuclear glucocorticoid receptor and rapid actions mediated by activation of one or more putative membrane-associated glucocorticoid receptors that regulate both transcriptional and non-transcriptional signaling. Dexamethasone-bovine serum albumin (Dex-BSA) is one of several membrane-limited steroid receptor agonists. Dex-BSA and other steroid conjugates such as corticosterone-, estradiol- and testosterone-BSA have been used to study rapid steroid effects initiated by putative membrane receptors. The purity and stability of the steroid-BSA conjugate is crucial, therefore, since any steroid that is not bound to or that dissociates from the BSA conjugate could penetrate into the intracellular compartment and confound the experiment. We used fluorine NMR to determine if free Dex could be detected in a commercially available Dex-BSA dissolved in H2O. Non-covalently bound Dex was detected in the Dex-BSA solution, but the level of free Dex remained constant over time and with increasing temperature, indicating that the free Dex was not a result of instability of the Dex-BSA conjugate. The free Dex was lost when the Dex-BSA was denatured and subjected to dialysis, which suggested that it was trapped in the Dex-BSA three-dimensional structure and not covalently bound to the BSA. The purified, renatured Dex-BSA retained its rapid activity, which confirmed that the observed effects of Dex-BSA are not caused by non-covalently-bound Dex. Therefore, the Dex contaminant found in the Dex-BSA solution is likely to be tightly, but non-covalently, bound to BSA, and the Dex-BSA activity remains membrane-limited. Our findings indicate that Dex-BSA remains a suitable membrane-restricted glucocorticoid receptor agonist, but suggest that denaturing purification is a useful control for the study of membrane-initiated steroid-BSA actions.

Screening for Corticosteroid Adulterants in Korean Herbal Medicines.

The objective of this study was to determine the presence of corticosteroids in illegal herbal medicines using ultra-high-performance liquid chromatography-tandem mass spectrometry. We collected 212 herbal medicine samples that were advertised as being effective for treatment of joint pain and bone aches. Samples were from the Korean commercial market during a span of four years (2010-2013), and the method was validated. The limits of quantification ranged from 0.47 to 15.0 ng/mL, and recoveries ranged from 80.6% to 119.5%. The intra- and interday precision ranged from 0.18% to 8.82% and from 0.09% to 8.96%, respectively. Among the samples, three samples (1.4%) were identified as adulterants. Dexamethasone was the only compound detected in the adulterated products. As the corticosteroid-adulteration of herbal medicines may become a major problem and lead to side effects, the continued development of screening procedures for herbal medicines is critical.

Corticosteroid adulteration in proprietary Chinese medicines: a recurring problem.

OBJECTIVES: To investigate adulteration of proprietary Chinese medicines with corticosteroids in Hong Kong. DESIGN: Case series with cross-sectional analysis. SETTING: A tertiary clinical toxicology laboratory in Hong Kong. PATIENTS: All patients using proprietary Chinese medicines adulterated with corticosteroids and referred to the authors' centre from 1 January 2008 to 31 December 2012. MAIN OUTCOME MEASURES: Patients' demographic data, clinical presentation, medical history, drug history, laboratory investigations, and analytical findings of the proprietary Chinese medicines were analysed. RESULTS: The records of 61 patients who consumed corticosteroid-adulterated proprietary Chinese medicines were reviewed. The most common corticosteroid implicated was dexamethasone. Co-adulterants such as non-steroidal anti-inflammatory drugs and histamine H1-receptor antagonists were detected in the proprietary Chinese medicine specimens. Among the patients, seven (11.5%) required intensive care, two (3.3%) died within 30 days of presentation, and 38 (62.3%) had one or more complications that were potentially attributable to exogenous corticosteroids. Of 22 (36.1%) patients who had provocative adrenal function testing performed, 17 (77.3% of those tested) had adrenal insufficiency. CONCLUSION: The present case series is the largest series of patients taking proprietary Chinese medicines adulterated with corticosteroids. Patients taking these illicit products are at risk of severe adverse effects, including potentially fatal complications. Adrenal insufficiency was very common in this series of patients. Assessment of adrenal function in these patients, however, has been inadequate and routine rather than discretionary testing of adrenal function is indicated in this group of patients. The continuing emergence of proprietary Chinese medicines adulterated with western medication indicates a persistent threat to public health.

Development and characterization of a ricinoleic acid poloxamer gel system for transdermal eyelid delivery.

OBJECTIVE: This study deals with the preparation and evaluation of a pluronic lecithin organogel (PLO gel) containing ricinoleic acid for the transdermal eyelid delivery of dexamethasone and tobramycin. METHODS: Five different PLO gel formulations (F1, F2, F3, F4 and F5) containing tobramycin (0.3%) and dexamethasone (0.1%) were prepared and compared to a conventional PLO gel (light mineral oil PLO gel, F6) with respect to physical appearance and viscosity. The optimized ricinoleic acid PLO gel formulation (F2) was further characterized for pH, gelation temperature, morphology and drug content. Ex vivo permeability of dexamethasone and bactericidal activity of tobramycin from formulation F2 was tested, and values were compared to the marketed Tobradex® eye ointment. RESULTS: No apparent changes in the physical appearance and consistency were observed when ricinoleic acid was used as the oil phase. The pH of the optimized ricinoleic acid PLO gel (formulation F2) was found to be 6.54 with a gelation temperature of 31 °C. The drug content of tobramycin and dexamethasone were found to be 102.8% and 100.14%, respectively. The penetration profile of dexamethasone from formulation F2 was found to be much higher than the marketed Tobradex® eye ointment. F2 showed a better antimicrobial activity and higher zones of inhibition when compared to the marketed Tobradex® eye ointment. CONCLUSION: The findings of this investigation indicate that the ricinoleic acid PLO gel has the potential for use as a transdermal eyelid delivery system.

Confirmación de dexametasona y diclofenaco por LC-MS-MS como adulterantes en un producto herbolario / Dexamethasone and diclofenac by LC-MS-MS as herbal product adulterants

Objetivo. Confirmar la presencia de dexametasona y diclofenaco como adulterantes de un producto comercializado como de origen natural. Material y métodos. Para la identificación y confirmación de la presencia de los fármacos se utilizó un método de análisis instrumental por cromatografía de líquidos de alta presión acoplado a espectrometría de masas en tándem. Resultados. En el análisis de 11 frascos de Reumofan Plus obtenidos de pacientes y médicos de la localidad se confirmó la presencia de dexametasona y diclofenaco. La metodología utilizada permitió separar los esteroisómeros dexametasona y betametasona, las abundancias relativas de iones productos 237.2 y 279.2 m/z permiten diferenciar espectralmente un compuesto de otro. Conclusiones. Se confirmó la presencia de dexametasona y diclofenaco en muestras de un producto comercializado como "100% natural" obtenidas de diferentes pacientes o médicos en el periodo enero a diciembre de 2011.

Objective. To confirm the presence of dexamethasone and diclofenac as adulterants of an herbal product. Materials and methods. For identificaction and confirmation of drugs a method of instrumental analysis by liquid chromatography coupled with high pressure tandem mass spectrometry was used. Results. The presence of dexamethasone and diclofenac was confirmed in samples of 11 bottles of Reumofan Plus obtained from patients and/or physicians. The methodology used, allowed separation of stereoisomers dexamethasone and betamethasone, the relative abundances of product ions 237.2 and 279.2 m / z spectrally differentiate the compounds. Conclusions. The presence of dexamethasone and diclofenac was confirmed in samples of a product marketed as "100% natural" obtained from patients and / or physicians in a period from January to December, 2011.

Comparison of salivary cortisol as measured by different immunoassays and tandem mass spectrometry.

Assessing the amount of bioavailable cortisol in saliva with immunoassays and thus sampling an endocrine marker of hypothalamus-pituitary-adrenal axis activity is of major interest in both research and clinical practice. However, absolute cortisol concentrations obtained with different immunoassays (IAs) are barely comparable precluding direct comparison between studies or individuals whenever cortisol analyses were not based on the same IA. The present technical report aims to solve this problem by evaluating the validity of, as well as agreement between the most commonly used immunoassays in psychoneuroendocrinological research (i.e., IBL, DRG, Salimetrics, DSL, and DELFIA) and a reference method (LC-MS/MS) in a sample of 195 saliva specimen covering the whole range of cortisol concentrations in adults. A structural equation modelling framework is applied to decompose systematic assay variance and estimate cortisol reference values, which are adjusted for measurement error and interference of salivary cortisone. Our findings reveal nonlinear relations between IAs and LC-MS/MS, which are discussed in terms of IA cross-reactivity with saliva matrix components. Finally guidelines for converting cortisol concentrations being obtained by these immunoassays into comparable reference values are proposed by providing conversion functions, a conversion table, and an online conversion tool.

[Dexamethasone and diclofenac by LC-MS-MS as herbal product adulterants]. / Confirmación de dexametasona y diclofenaco por LC-MS-MS como adulterantes en un producto herbolario.

OBJECTIVE: To confirm the presence of dexamethasone and diclofenac as adulterants of an herbal product. MATERIALS AND METHODS: For identificaction and confirmation of drugs a method of instrumental analysis by liquid chromatography coupled with high pressure tandem mass spectrometry was used. RESULTS: The presence of dexamethasone and diclofenac was confirmed in samples of 11 bottles of Reumofan Plus obtained from patients and/or physicians. The methodology used, allowed separation of stereoisomers dexamethasone and betamethasone, the relative abundances of product ions 237.2 and 279.2 m / z spectrally differentiate the compounds. CONCLUSIONS: The presence of dexamethasone and diclofenac was confirmed in samples of a product marketed as "100% natural" obtained from patients and / or physicians in a period from January to December, 2011.

Effect of Ficus hispida L. on normal and dexamethasone suppressed wound healing

Ethanolic extract of roots of Ficus hispida was investigated in normal and dexamethasone depressed healing conditions, using incision, excision and dead space wound models in albino rats. The root extract of Ficus hispida has shown the maximum breaking strength compared to control group. The rate of epithelialization and wound contraction in excision model was better as compared to control groups. There was significant increase in granulation tissue weight and hydroxyproline content in dead space model compared to control group. The antihealing effect of dexamethasone was also reverted by the administration of ethanolic extract of Ficus hispida in all the wound models .The results indicated that the root extract of Ficus hispida has a significant wound healing activity and also promotes healing in dexamethasone depressed healing conditions.

O extrato etanólico de raízes de Ficus hispida foi ensaiado em ratos albinos normais e em condições de cicatrização deprimida por dexametasona, utilizando modelos de ferida por incisão, excisão e de espaço morto. O extrato da raiz de Ficus hispida mostrou a força máxima de tensão comparativamente ao grupo controle. A velocidade de epitelização e de contração da ferida no modelo de excisão foi melhor do que a dos grupos controles. Houve aumento significativo no peso do tecido de granulação e no conteúdo de hidroxiprolina no modelo de espaço morto comparativamente ao grupo controle. O efeito anticicatrizante da dexametasona foi, também, revertido pela administração do extrato etanólico de Ficus hispida em todos os modelos de feridas. Os resultados indicaram que o extrato de Ficus hispida tem atividade cicatrizante em feridas e, também, promove a cicatrização em condições de depressão de cicatrização pela dexametasona.

Hydrogel containing dexamethasone-loaded nanocapsules for cutaneous administration: preparation, characterization, and in vitro drug release study.

CONTEXT: Our group previously reported the development of dexamethasone-loaded polymeric nanocapsules as an alternative for topical dermatological treatments. OBJECTIVE: Our study aimed to prepare and characterize a hydrogel containing this system to improve the effectiveness of the glucocorticoid for cutaneous disorders. METHODS: For the antiproliferative activity assay, a dexamethasone solution and D-NC were tested on Allium cepa root meristem model. D-NC were prepared by the interfacial deposition of preformed polymer. Hydrogels were prepared using Carbopol Ultrez 10 NF, as polymer, and characterized according to the following characteristics: pH, drug content, spreadability, viscosity, and in vitro drug release. RESULTS AND DISCUSSION: Nanocapsules showed mean particle size and zeta potential of 201 +/- 6 and -5.73 +/- 0.42 nm, respectively. They demonstrated a lower mitotic index (4.62%) compared to free dexamethasone (8.60%). Semisolid formulations presented acidic pH values and adequate drug content (between 5.4% and 6.1% and 100% and 105%, respectively). The presence of nanocapsules in hydrogels led to a decrease in their spreadability factor. Intact nanoparticles were demonstrated by TEM as well as by dynamic light scattering (mean particle size < 300 nm). In vitro studies showed a controlled dexamethasone release from hydrogels containing the drug associated to the nanocapsules following the Higuchi's squared root model (k = 20.21 +/- 2.96 mg/cm(2)/h(1/2)) compared to the hydrogels containing the free drug (k = 26.65 +/- 2.09 mg/cm(2)/h(1/2)). CONCLUSION: Taking all these results together, the hydrogel containing D-NC represent a promising approach to treat antiproliferative-related dermatological disorders.

Development and validation of a fast and sensitive bioanalytical method for the quantitative determination of glucocorticoids--quantitative measurement of dexamethasone in rabbit ocular matrices by liquid chromatography tandem mass spectrometry.

A sensitive, selective, accurate and robust LC-MS/MS method was developed and validated for the quantitative determination of glucocorticoids in rabbit ocular tissues. Samples were processed by a simple liquid-liquid extraction procedure. Chromatographic separation was performed on Phenomenex reversed phase C18 gemini column (50mmx4.6mm i.d.,) with an isocratic mobile phase composed of 30% of acetonitrile in water containing 0.1% of formic acid, at a flow rate 0.2mL/min. Dexamethasone (DEX), prednisolone (PD) and hydrocortisone (HD) were detected with proton adducts at m/z 393.20-->355.30, 361.30-->147.20 and 363.20-->121.0 in multiple reaction monitoring (MRM) positive mode respectively. Finally, 50microL of 0.1% novel DEX mixed micellar formulation was topically administered to a rabbit eye and concentrations were measured. The method was validated over a linear concentration range of 2.7-617.6ng/mL. Lower limit of quantitation (LLOQ) of DEX and PD was measured in the concentration range of 2.7 and 11.0ng/mL respectively. The resulting method demonstrated intra and inter-day precision within 13.3% and 11.1% and accuracy within 19.3% and 12.5% for DEX and PD, respectively. Both analytes were found to be stable throughout freeze-thaw cycles and during bench top and postoperative stability studies (r(2)>0.999). DEX concentrations in various ocular tissue samples i.e., aqueous humor, cornea, iris ciliary body, sclera and retina choroid were found to be 344.0, 1050.07, 529.6, 103.9 and 48.5ng/mg protein respectively. Absorption of DEX after topical administration from a novel aqueous mixed micellar formulation achieved therapeutic concentration levels in posterior segment of the rabbit eye.

Compatibility and stability of dexamethasone sodium phosphate and ketamine hydrochloride subcutaneous infusions in polypropylene syringes.

The stability of ketamine hydrochloride injection and dexamethasone sodium phosphate injection, when mixed and stored in polypropylene syringes, was studied. Formulations containing ketamine hydrochloride (50 mg or 600 mg) and dexamethasone sodium phosphate (1 mg) in 0.9% sodium chloride injection (to 14 ml) were prepared and stored at 4 degrees C, 23 degrees C, and 37 degrees C, under normal fluorescent light conditions, for 192 hours. The concentrations of the drugs were determined at 0, 2, 4, 8, 24, 48, 96, and 192 hours using a validated high-pressure liquid chromatography method. The pH, color, and visible particles of each solution were also assessed at each time point. All formulations tested maintained more than 98% of the initial concentrations of both drugs, and no degradation products were detected. The solutions remained clear and colorless and the pH varied within 0.05 units throughout 192 hours. The results indicate that, at the concentrations studied, combinations of ketamine hydrochloride and dexamethasone sodium phosphate in 0.9% sodium chloride injection were physically and chemically stable for at least 192 hours (8 days) when stored in polypropylene syringes.

[Dexamethasone in a non-registered ointment from the Far East]. / Dexamethason in een niet-geregistreerde crème uit het Verre Oosten.

The Oriental cream Piyan Ping 999 has been used in the Netherlands as an unlicensed product. Chemical analysis revealed the presence of dexamethasone and dexamethasone-21-acetate in pharmacologically relevant concentrations. It was prescribed for 2 children; the 3-year-old girl had meanwhile developed bruises and small, poorly healing wounds.