Suppression of toxicity of the mutant huntingtin protein by its interacting compound, desonide.

Identifying inhibitors of pathogenic proteins is the major strategy of targeted drug discoveries. This strategy meets challenges in targeting neurodegenerative disorders such as Huntington's disease (HD), which is mainly caused by the mutant huntingtin protein (mHTT), an "undruggable" pathogenic protein with unknown functions. We hypothesized that some of the chemical binders of mHTT may change its conformation and/or stability to suppress its downstream toxicity, functioning similarly to an "inhibitor" under a broader definition. We identified 21 potential mHTT selective binders through a small-molecule microarray­based screening. We further tested these compounds using secondary phenotypic screens for their effects on mHTT-induced toxicity and revealed four potential mHTT-binding compounds that may rescue HD-relevant phenotypes. Among them, a Food and Drug Administration­approved drug, desonide, was capable of suppressing mHTT toxicity in HD cellular and animal models by destabilizing mHTT through enhancing its polyubiquitination at the K6 site. Our study reveals the therapeutic potential of desonide for HD treatment and provides the proof of principle for a drug discovery pipeline: target-binder screens followed by phenotypic validation and mechanistic studies.

Nanoemulgel for Improved Topical Delivery of Desonide: Formulation Design and Characterization.

This research aimed to develop a novel drug delivery system to improve treatment of skin disorders. The system is comprised of a Carbopol 980-based nanoemulgel (NE-gel) containing a desonide (DES; 0.05%, w/w) nanoemulsion (NE), which has a small particle size, high encapsulation efficiency, good thermodynamic stability, good permeation ability, and high skin retention. DES-loaded NE (DES-NE) was prepared by high-pressure homogenization. The developed formulation was characterized by differential scanning calorimetry (DSC), X-ray diffraction, drug release, skin permeation, and drug retention. DES in vitro release and skin permeation studies with different formulations of artificial membrane and rat abdominal skin were performed with the Franz diffusion cell system. Confocal laser scanning microscopy (CLSM) was used to detect the localization and permeation pathways of drugs in the skin. Compared with commercially available gel (CA-gel) and NE, the NE-gel release process conformed to the Higuchi release model (R2 = 0.9813). NE-gel prolonged the drug release time and allowed for reduced administration dose and frequency. The unit cumulative permeation of NE and NE-gel through the skin for 12 h was 63.13 ± 2.78 and 42.53 ± 2.06 µg/cm2, respectively, values significantly higher (p < 0.01) than that of the CA-gel (30.65 ± 1.25 µg/cm2) and CA-cream (15.21 ± 0.97 µg/cm2). The DES-NE and DES NE-gel skin drug retention was significantly higher than commercially available formulations (p < 0.01). Hence, the prepared NE-gel is a potential vehicle for improved topical DES delivery for better treatment of skin disorders.

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

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

Observational Clinical Investigation Evaluating an Ophthalmic Solution Containing Xanthan Gum and Low Concentration Desonide Phosphate in Dry Eye Disease Treatment.

INTRODUCTION: Patients with dry eye disease (DED) complain of a multitude of symptoms that affect their visual function and quality of life (QoL). This clinical investigation assessed the performance, tolerance, and safety of a novel preservative-free ophthalmic solution containing xanthan gum 0.2% and desonide sodium phosphate 0.025%. METHODS: This was an observational, prospective, multicentric, and post-market clinical investigation to assess the effect of three times a day instillation of the study formulation in patients suffering from DED. The primary objective was to achieve a 50% reduction in conjunctival hyperemia index as assessed with the OCULUS Keratograph after 1 month of treatment compared to baseline values. The secondary objectives included patient-reported outcomes, clinical performance, and safety. RESULTS: Thirty patients were enrolled (21 women, 9 men) with a mean age of 61.10 ± 14.53 years. The instillation of the study formulation was associated with a significant reduction in redness scores after 1 month of treatment compared to baseline (mean - 0.51 ± 0.51; p ≤ 0.0001). Although the primary endpoint was not completely met, a 50% reduction in the conjunctival hyperemia index was achieved in 23% of the participants, and 77% showed a reduction of 26% of the same index. In addition, the ophthalmic solution significantly increased tear film break-up time, and a significant reduction of corneal and conjunctival staining with fluorescein was achieved. It also reduced DED symptoms and had a very good safety profile. CONCLUSIONS: the study formulation produced a significant improvement in the signs, symptoms, and QoL of patients with mild to moderate DED with a good safety profile after 1 month of treatment.

Desonide Nanoemulsion Gel for Transdermal Absorption Drug Delivery: Pharmacodynamic and Safety Evaluation.

BACKGROUND: When administered transdermally, desonide is ineffective due to its poor solubility. As a new transdermal delivery system, nanoemulsion gel has demonstrated significant advantages for drug delivery over conventional formulations. We have established desonide nanoemulsion gel (DES NE gel) for better transdermal absorption, but its efficacy and safety still need to be evaluated. This study aims to provide additional evidence demonstrating the improved pharmacodynamics and safety of transdermal delivery of Desonide via nanoemulsion gel. METHODS: Pharmacodynamics and safety of Desonide nanoemulsion gel were evaluated using Desonate ® as the reference formulation. To assess the difference in curative effect between DES NE gel and Desonate® and to ensure safety, atopic dermatitis (AD) models in KM mice were developed using 2,4-dinitrofluorobenzene (DNFB). The degree of ear swelling, ear mass difference, thymus, spleen index, and HE conventional pathology of mice were used as pharmacodynamic evaluation indexes, and the irritation was predicted by the New Zealand rabbit epidermal stimulation assay. RESULTS: Nanoemulsion gels may facilitate transdermal penetration of drugs by influencing the skin condition. Medium and high doses of DES NE gel significantly ameliorated the inflammation and swelling of the ear caused by dermatitis/eczema in mice. In addition, compared with DES gel, skin irritation extent did not increase. CONCLUSION: Nanoemulsion gel can be applied to improve the efficacy of drugs with low potency or poor solubility. DES NE gel provides a higher transdermal potential than other delivery systems. In this study, it was found that nanoemulsion gel is a promising percutaneous carrier of DES. DES NE-GEL has a significant curative effect on dermatitis/eczema in a mouse model and is expected to provide a new, efficient, and low toxic preparation for clinical treatment of dermatitis/eczema through the percutaneous system.

Development of a novel HPLC method for the determination of the impurities in desonide cream and characterization of its impurities by 2D LC-IT-TOF MS.

A novel HPLC method for the determination of the impurities in desonide cream was established and validated for the further improvement of the official monograph in USP. Desonide was well resolved from the photodegradation impurity, which overlapped with desonide in USP method. The method was validated in accordance to the regulatory guidelines recommended by the International Conference on Harmonisation and this validation included specificity, limit of detection, limit of quantification, linearity and accuracy. Four degradation impurities in desonide cream were characterized by a trap-free two-dimensional liquid chromatography coupled to high resolution ion trap/time-of-flight mass spectrometry (2D LC-IT-TOF MS) in positive mode of electrospray ionization. Through the multiple heart-cutting 2D LC approach and online demineralization technique, the problem of incompatibility between non-volatile salt mobile phase and mass spectrometry was solved completely, and the TIC chromatogram of LC-MS could be in conformity with the LC chromatogram of the official analytical method in the peak sequence of impurities. In the first dimension, the column was Phenomenex Kinetex C8 (4.6 mm × 150 mm, 2.6 µm) with a non-volatile salt mobile phase. In the second dimension, the column was Shimadzu Shim-pack GISS C18 (50 mm × 2.1 mm, 1.9 µm) with a volatile salt mobile phase. The structures of four degradation impurities in desonide cream were deduced based on the HPLC-MSn data. The established method in this study was simple and reliable for routine quality control of desonide cream.

Topical niacinamide 4% and desonide 0.05% for treatment of axillary hyperpigmentation: a randomized, double-blind, placebo-controlled study.

BACKGROUND: Axillary hyperpigmentation is a frequent cause of cosmetic consultations in dark-skinned women from tropical areas, including Latin America. Currently, there is no widely accepted treatment for the disorder, but it is usually treated with bleaching agents because it is considered a variant of inflammatory hyperpigmentation. The purpose of this study was to assess the efficacy of niacinamide 4% and desonide 0.05% emulsions compared with placebo in the treatment of axillary hyperpigmentation. METHODS: Twenty-four women aged 19-27 years with hyperpigmented axillae (phototype III-V) were randomly assigned to receive the study treatments in the axillary region. Improvement was assessed at baseline, then clinically and by colorimetry 9 weeks later. Quantitative evaluation including melanin, inflammatory infiltrates, NKI/Beteb, CD1a, CD68, and collagen type IV content was performed by histochemistry and immunohistochemistry, assisted by computerized morphometric analysis. RESULTS: Both niacinamide and desonide induced significant colorimetric improvement compared with placebo; however, desonide showed a better depigmenting effect than niacinamide. A good to excellent response was achieved in 24% of cases for niacinamide, 30% for desonide, and 6% for placebo. We observed a marked disruption of the basal membrane in axillary hyperpigmentation and an inflammatory infiltrate that improved after treatment. Decreased pigmentation in the desonide-treated axillae was associated with recovery of disruption at the basal membrane. CONCLUSION: Niacinamide and desonide showed depigmenting properties in women with axillary hyperpigmentation. These findings may be explained by their antimelanogenic and anti-inflammatory properties, respectively.