Dapsone in dermatology and beyond

Dapsone Use in Dermatology

Dapsone, initially synthesized for textile dyeing, gained recognition in the 1930s for its antibacterial properties, leading to its utilization in dermatology for leprosy and dermatitis herpetiformis. Despite US Food and Drug Administration (FDA) approval for these conditions, dapsone's off-label uses have expanded, making it a valuable option in various dermatologic conditions. This review seeks to highlight the common uses of dapsone in its FDA indications and off-label indications. Diseases in which dapsone is considered first-line therapy or adjunctive therapy are reviewed, with highlights from the resources included. An overview of dapsone's pharmacokinetics, pharmacodynamics, indications, dosages, and safety profile are also reviewed. Dapsone's versatility and safety profile make it a cost-effective treatment option in dermatology, particularly for patients with limited access to specialized medications. Ongoing clinical trials are also described exploring dapsone's efficacy in novel dermatologic uses. Dapsone has been a valuable adjunctive therapy across various dermatologic conditions for years and evidence for its use continues to expand.

Dapsone as a Current Option for the Treatment of Autoimmune Bullous Diseases with Autoimmunity to Non-Enzymes: A Retrospective Study from a Single Central European Referral Center

Background and Objectives: Dapsone (DP) is employed in the management of various skin conditions, including autoimmune bullous diseases to non-enzymes (n-eAIBDs). This study aimed to assess the advantages and safety profile of DP treatment in n-eAIBDs patients. The evaluation focused on clinical remission, reduction in glucocorticosteroid (GCS) usage, and adverse incidents during a 12-month observation in a dermatology department at a Central European university. Materials and Methods: Our retrospective study included forty-one patients who met the inclusion criteria, comprising nineteen with pemphigus vulgaris, nine with pemphigus foliaceus, four with bullous pemphigoid, and nine with mucous membrane pemphigoid, including one patient with Brunsting-Perry pemphigoid. Patients received 25-50 mg/day of DP along with oral GCSs for a year, with a subsequent dose reduction where feasible. Results: The mean decreases in prednisone-equivalent dosages across all groups after 2, 6, and 12 months of DP treatment were 45.66%, 65.77%, and 63.03%, respectively. Throughout the 12-month observation period, 21.62% of patients experienced a relapse, while the remaining patients attained either complete or partial remission with minimal therapy. Adverse incidents were observed in 29.27% of patients; these were mild or moderate, and no severe negative effects were observed. Conclusions: DP is an effective and affordable choice to support the treatment of n-eAIBDs, but it may not be sufficient for long-term management in certain patients with severe n-eAIBDs.

Dual approaches in pharmacogenetics: Developing PCR-SSP and RT-PCR methods for HLA-B*13:01 screening to prevent dapsone and Co-trimoxazole SCARs

Dapsone and co-trimoxazole are potent antibiotics for treating various infections and inflammations. However, several studies reported the strongly association between severe cutaneous adverse drug reactions (SCARs) to both drugs and the HLA-B*13:01 allele. Rapid and reliable screening for the HLA-B*13:01 allele can mitigate the risk of dapsone-induced SCARs. We developed two methods, multiplex sequence-specific primer PCR (PCR-SSP) and real-time PCR (RT-PCR), tailored for different clinical settings. These methods were optimized to minimize false positives among the Thai population. Clinical validation demonstrated excellent reproducibility, with both methods showing 100 % concordance in repeated tests. PCR-SSP achieved a limit of detection as low as 100 pg of genomic DNA, while RT-PCR reached 1 pg. Overall statistical accuracy was 100.00 % (95 % CI: 98.18 %-100.00 %). Screening for drug-related HLA alleles is crucial for reducing mortality from severe cutaneous adverse drug reactions, especially dapsone hypersensitivity syndrome (DHS) and dapsone-induced hypersensitivity reactions (DIHRs). Our screening approach for dapsone can also be extended to co-trimoxazole, representing a significant advancement in personalized medicine and preemptive pharmacogenetic testing for tailored patient care and safety, albeit further validation in diverse ethnic populations is warranted to ensure universal applicability.

Evaluating the protective effect of dapsone on experimental osteoarthritis models induced by MIA in male rats

OBJECTIVES

Osteoarthritis, a degenerative condition that results in significant morbidity, is typically managed with treatments aimed at symptom relief rather than addressing the underlying degeneration. Dapsone, recognized for its anti-inflammatory, antioxidant, antiexcitotoxic, and antiapoptotic properties, has demonstrated promising effects in various neurodegenerative diseases. This study explores the potential of dapsone to mitigate articular destruction, inflammation, and pain in rat models of osteoarthritis.

METHODS

Osteoarthritis was induced in rats by injecting MIA into the right knee joint. Dapsone was then administered intraperitoneally at 5, 10, or 20 mg/kg every 2 days for 2 weeks. Behavioural tests were done on days 0, 7, and 14. On day 14, the articular cartilage was histologically analysed using H&E staining. Serum levels of NF-kB, IL-1β, and TNF-α were evaluated by ELISA.

RESULTS

Dapsone effectively reduces pain, inflammation, and articular cartilage damage in osteoarthritis. Specifically, it improves mechanical allodynia and thermal hyperalgesia, reduces inflammatory markers (TNF-α, IL-1β, and NF-κB), and protects against cartilage destruction and chondrocyte loss, with the most significant effects at 20 mg/kg.

CONCLUSIONS

Dapsone effectively prevents pain, inflammation, and cartilage damage in osteoarthritis rats, suggesting its potential as a therapeutic option for managing osteoarthritis.

Isobolographic Analysis of the Cytoprotective Effect of Dapsone and Cannabidiol Alone or Combination upon Oxygen-Glucose Deprivation/Reoxygenation Model in SH-SY5Y Cells

Oxidative stress and apoptosis cell death are critical secondary damage mechanisms that lead to losing neighboring healthy tissue after cerebral ischemia. This study aims to characterize the type of interaction between dapsone (DDS) and cannabidiol (CBD) and its cytoprotective effect in an in vitro model of oxygen and glucose deprivation for 6 h followed by 24 h of reoxygenation (OGD/R), using the SH-SY5Y cell line. For the combined concentrations, an isobolographic study was designed to determine the optimal concentration-response combinations. Cell viability was evaluated by measuring the lactate dehydrogenase (LDH) release and 3-[4, 5-dimethyl-2-thiazolyl]-2, 5-diphenyl-2H-tetrazolium bromide (MTT) assays. Also, the reactive oxygen species (ROS) and reduced glutathione (GSH) levels were analyzed as oxidative stress markers. Finally, caspase-3 activity was evaluated as a marker cell death by apoptosis. The results showed a decrease in cell viability, an increase in oxidant stress, and the activity of caspase-3 by the effect of OGD/R. Meanwhile, both DDS and CBD demonstrated antioxidant, antiapoptotic, and cytoprotective effects in a concentration-response manner. The isobolographic study indicated that the concentration of 2.5 µM of DDS plus 0.05 µM of CBD presented a synergistic effect so that in treatment, cell death due to OGD/R decreased. The findings indicate that DDS-CBD combined treatment may be a helpful therapy in cerebral ischemia with reperfusion.

Experimental and Theoretical Insights into the Intermolecular Interactions in Saturated Systems of Dapsone in Conventional and Deep Eutectic Solvents

Solubility is not only a crucial physicochemical property for laboratory practice but also provides valuable insight into the mechanism of saturated system organization, as a measure of the interplay between various intermolecular interactions. The importance of these data cannot be overstated, particularly when dealing with active pharmaceutical ingredients (APIs), such as dapsone. It is a commonly used anti-inflammatory and antimicrobial agent. However, its low solubility hampers its efficient applications. In this project, deep eutectic solvents (DESs) were used as solubilizing agents for dapsone as an alternative to traditional solvents. DESs were composed of choline chloride and one of six polyols. Additionally, water-DES mixtures were studied as a type of ternary solvents. The solubility of dapsone in these systems was determined spectrophotometrically. This study also analyzed the intermolecular interactions, not only in the studied eutectic systems, but also in a wide range of systems found in the literature, determined using the COSMO-RS framework. The intermolecular interactions were quantified as affinity values, which correspond to the Gibbs free energy of pair formation of dapsone molecules with constituents of regular solvents and choline chloride-based deep eutectic solvents. The patterns of solute-solute, solute-solvent, and solvent-solvent interactions that affect solubility were recognized using Orange data mining software (version 3.36.2). Finally, the computed affinity values were used to provide useful descriptors for machine learning purposes. The impact of intermolecular interactions on dapsone solubility in neat solvents, binary organic solvent mixtures, and deep eutectic solvents was analyzed and highlighted, underscoring the crucial role of dapsone self-association and providing valuable insights into complex solubility phenomena. Also the importance of solvent-solvent diversity was highlighted as a factor determining dapsone solubility. The Non-Linear Support Vector Regression (NuSVR) model, in conjunction with unique molecular descriptors, revealed exceptional predictive accuracy. Overall, this study underscores the potency of computed molecular characteristics and machine learning models in unraveling complex molecular interactions, thereby advancing our understanding of solubility phenomena within the scientific community.

Non-biologic immunosuppressive drugs for inflammatory and autoimmune skin diseases

Non-biologic immunosuppressive drugs, such as azathioprine, dapsone or methotrexate are fundamental treatment options for a wide range of autoimmune and chronic inflammatory skin diseases. Some of these drugs were initially used for malignancies (e.g., azathioprine or methotrexate) or infectious diseases (e.g., hydroxychloroquine or dapsone) but are nowadays mostly used for their immunosuppressive/immunomodulating action. Although dermatologists have years of clinical experience with these drugs, some of the mechanisms of action are not fully understood and are the subject of research. Although these drugs are commonly used, lack of experience or knowledge regarding their safety profiles and management leads to skepticism among physicians. Here, we summarize the mechanism of action and detailed management of adverse effects of the most commonly used immunosuppressive drugs for skin diseases. Furthermore, we discuss the management of these drugs during pregnancy and breastfeeding, as well as their interaction and handling during vaccination.

Nicht-Biologika-Immunsuppressiva bei entzündlichen und autoimmunen Hautkrankheiten: Non-biologic immunosuppressive drugs for inflammatory and autoimmune skin diseases

Nicht‐Biologika‐Immunsuppressiva wie Azathioprin, Dapson oder Methotrexat sind grundlegende Behandlungsmöglichkeiten für ein breites Spektrum von Autoimmunerkrankungen und chronisch‐entzündlichen Hauterkrankungen. Einige dieser Medikamente wurden ursprünglich bei malignen Erkrankungen (zum Beispiel Azathioprin oder Methotrexat) oder Infektionskrankheiten (zum Beispiel Hydroxychloroquin oder Dapson) eingesetzt, werden aber heute hauptsächlich wegen ihrer immunsuppressiven/immunmodulierenden Wirkung verwendet. Obwohl Dermatologen über jahrelange klinische Erfahrung mit diesen Arzneimitteln verfügen, sind einige der Wirkmechanismen noch nicht vollständig geklärt und noch Gegenstand der Forschung. Obwohl diese Medikamente häufig eingesetzt werden, führen mangelnde Erfahrung oder fehlendes Wissen über ihre Sicherheitsprofile und ihr Management zu einer skeptischen Haltung bei den Ärzten. Hier fassen wir den Wirkmechanismus und das detaillierte Management der Nebenwirkungen der am häufigsten verwendeten immunsuppressiven Medikamente für Hautkrankheiten zusammen. Darüber hinaus diskutieren wir den Umgang mit diesen Medikamenten während der Schwangerschaft und Stillzeit sowie ihre Wechselwirkung und Handhabung im Zusammenhang mit Impfungen.

The Pathophysiology and Treatment of Pyoderma Gangrenosum-Current Options and New Perspectives

Pyoderma gangrenosum (PG) is an uncommon inflammatory dermatological disorder characterized by painful ulcers that quickly spread peripherally. The pathophysiology of PG is not fully understood; however, it is most commonly considered a disease in the spectrum of neutrophilic dermatoses. The treatment of PG remains challenging due to the lack of generally accepted therapeutic guidelines. Existing therapeutic methods focus on limiting inflammation through the use of immunosuppressive and immunomodulatory therapies. Recently, several reports have indicated the successful use of biologic drugs and small molecules administered for coexisting diseases, resulting in ulcer healing. In this review, we summarize the discoveries regarding the pathophysiology of PG and present treatment options to raise awareness and improve the management of this rare entity.

Niosome as a promising tool for increasing the effectiveness of anti-inflammatory compounds

Niosomes are drug delivery systems with widespread applications in pharmaceutical research and the cosmetic industry. Niosomes are vesicles of one or more bilayers made of non-ionic surfactants, cholesterol, and charge inducers. Because of their bilayer characteristics, similar to liposomes, niosomes can be loaded with lipophilic and hydrophilic cargos. Therefore, they are more stable and cheaper in preparation than liposomes. They can be classified into four categories according to their sizes and structures, namely small unilamellar vesicles (SUVs), large unilamellar vesicles (LUVs,), multilamellar vesicles (MLVs), and multivesicular vesicles (MVVs). There are many methods for niosome preparation, such as thin-film hydration, solvent injection, and heating method. The current study focuses on the preparation methods and pharmacological effects of niosomes loaded with natural and chemical anti-inflammatory compounds in kinds of literature during the past decade. We found that most research was carried out to load anti-inflammatory agents like non-steroidal anti-inflammatory drugs (NSAIDs) into niosome vesicles. The studies revealed that niosomes could improve anti-inflammatory agents' physicochemical properties, including solubility, cellular uptake, stability, encapsulation, drug release and liberation, efficiency, and oral bioavailability or topical absorption. See also the graphical abstract(Fig. 1).

Systematic identification and repurposing of FDA-approved drugs as antibacterial agents against Streptococcus pyogenes: In silico and in vitro studies

Streptococcus pyogenes (Group A Streptococcus - GAS) is a human pathogen causing wide range of infections and toxin-mediated diseases in human beings of all age groups with fatality of 10-30 %. The limited success of antibiotics and the non-availability of vaccines makes GAS a global burden. The multi-subunit RNA polymerase (RNAP) is a validated bacterial therapeutic target as it is involved in transcription and can arrest growth. Of the five subunits of this enzyme complex, the β-subunit (RpoC) has attracted specific attention as a drug target, particularly in the switch region. Here we attempt to repurpose non-antimicrobial drugs to act as RpoC inhibitors against S. pyogenes. In this study, 1826 FDA approved drugs have been identified through high-throughput virtual screening. Free Energy Perturbation (FEP) based binding free energy calculations have been performed at the final step of the virtual screening funnel to ensure high accuracy in silico results. Three compounds identified have been tested for susceptibility of S. pyogenes MTCC 442 strain and two antibiotic-resistant clinical isolates of S. pyogenes using microdilution assay. Among the three, two drugs Amlodipine Besylate (Amd) and Ranitidine hydrochloride (Rnt) have shown inhibition against all the tested strains and its mechanism of interaction with RpoC has been studied. The docked complexes were analyzed to understand the binding mode of the drugs to the target. Classical Molecular Dynamics studies for RpoC-Rnt complex and the two stable conformations of RpoC-Amd complex was carried out. Root Mean Square Deviation (RMSD), Root Mean Square Fluctuation (RMSF), Radius of Gyration (RoG) and Solvent Accessible Surface Area (SASA) of the complexes were plotted and studied. The thermodynamic parameters of protein-drug were experimentally determined using Isothermal Titration Calorimetry (ITC). Infrared spectroscopic studies and Fluorescence quenching studies provided insights into the secondary structural changes in RpoC on binding to the drugs.

Evaluation of dapsone and its synthetic derivative DDS‑13 in cancer in vitro

The present study highlighted the repositioning of the drug dapsone (DDS) for cancer therapy. Due to its mechanism of action, DDS has a dual effect as an antibiotic and as an anti-inflammatory/immunomodulator; however, at high doses, it has important adverse effects. The derivative DDS-13 [N,N'-(sulfonyl bis (4,1-phenylene)) dioctanamide] was synthesized through an N-acylation reaction to compare it with DDS. Its cytotoxic effects in cancer cells (DU145 and HeLa) and non-cancer cells (HDFa) were observed at concentrations ranging 0.01-100 µM and its physicochemical/pharmacokinetic properties were analyzed using the SwissADME tool. The objectives of the present study were to evaluate the anticancer activity of both DDS and DDS-13 and to identify the physicochemical and pharmacokinetic properties of DDS-13. The results showed that DDS-13 presented a cytotoxic effect in the DU145 cell line (IC50=19.06 µM), while DDS showed a cytotoxic effect on both the DU145 (IC50=11.11 µM) and HeLa (IC50=13.07 µM) cell lines. DDS-13 appears to be a good cytotoxic candidate for the treatment of prostate cancer, while DDS appears to be a good candidate for both cervical and prostate cancer. Neither candidate showed a cytotoxic effect in non-cancerous cells. The different pharmacokinetic properties of DDS-13 make it a new candidate for evaluation in preclinical models for the treatment of cancer.

The Potential Effect of Dapsone on the Inflammatory Reactions in COVID-19: Staggering View

Severe SARS-CoV-2 infection is linked with an overstated immune response with the succeeding release of pro-inflammatory cytokines and progression of the cytokine storm. In addition, severe SARS-CoV-2 infection is associated with the development of oxidative stress and coagulopathy. Dapsone (DPS) is a bacteriostatic antibiotic that has a potent anti-inflammatory effect. Thus, this mini-review aimed to elucidate the potential role of DPS in mitigating inflammatory disorders in COVID-19 patients. DPS inhibits neutrophil myeloperoxidase, inflammation, and neutrophil chemotaxis. Therefore, DPS could be effective against neutrophilia-induced complications in COVID-19. In addition, DPS could be effective in mitigating inflammatory and oxidative stress disorders by suppressing the expression of inflammatory signaling pathways and the generation of reactive oxygen species (ROS) correspondingly. In conclusion, DPS might be effective in the management of COVID-19 through the attenuation of inflammatory disorders. Therefore, preclinical and clinical studies are reasonable in this regard.

Reductive coupling of nitro compounds with boronic acid derivatives: an overview

The purpose of this review is to summarize the current literature on reductive C-N coupling of nitro compounds and boronic acids, with special emphasis on the mechanistic features of the reactions. The metal-catalyzed reactions are discussed first. This is followed by electro-synthesis and organophosphorus-catalyzed reactions. Finally, the available examples of catalyst-free reactions will be covered at the end of this review.

The OSR9 Regimen: A New Augmentation Strategy for Osteosarcoma Treatment Using Nine Older Drugs from General Medicine to Inhibit Growth Drive

As things stand in 2023, metastatic osteosarcoma commonly results in death. There has been little treatment progress in recent decades. To redress the poor prognosis of metastatic osteosarcoma, the present regimen, OSR9, uses nine already marketed drugs as adjuncts to current treatments. The nine drugs in OSR9 are: (1) the antinausea drug aprepitant, (2) the analgesic drug celecoxib, (3) the anti-malaria drug chloroquine, (4) the antibiotic dapsone, (5) the alcoholism treatment drug disulfiram, (6) the antifungal drug itraconazole, (7) the diabetes treatment drug linagliptin, (8) the hypertension drug propranolol, and (9) the psychiatric drug quetiapine. Although none are traditionally used to treat cancer, all nine have attributes that have been shown to inhibit growth-promoting physiological systems active in osteosarcoma. In their general medicinal uses, all nine drugs in OSR9 have low side-effect risks. The current paper reviews the collected data supporting the role of OSR9.

Case Report: Insulin hypersensitivity in youth with type 1 diabetes

Objective

Immediate type I, type III, and delayed type IV hypersensitivity reactions to insulin are rare, but potentially serious complications of exogenous insulin administration required for the treatment of type 1 diabetes (T1D).

Methods

We present four cases of insulin hypersensitivity reactions occurring in youth with T1D and a literature review of this topic.

Results

Insulin hypersensitivity reactions included types I, III, and IV with presentations ranging from localized urticaria, erythematous nodules, and eczematous plaques to anaphylaxis with respiratory distress. Reactions occurred in youth with newly diagnosed T1D and in those with long-standing T1D who were using both injection and insulin pump therapy. Multidisciplinary care involving pediatric endocrinology and allergy/immunology utilizing trials of many adjunct therapies yielded minimal improvement. Despite the use of various treatments, including antihistamines, topical therapies, immunosuppressant medications, desensitization trials, and intravenous immune globulin, cutaneous reactions, elevated hemoglobin A1c levels, and negative effects on quality of life remain persistent challenges. One patient became one of the youngest pancreas transplant recipients in the world at age 12 years due to uncontrollable symptoms and intolerable adverse effects of attempted therapies.

Conclusion

Although rare, insulin hypersensitivity reactions negatively affect glycemic control and quality of life. These cases demonstrate the varying severity and presentation of insulin hypersensitivity reactions along with the limited success of various treatment approaches. Given the life-sustaining nature of insulin therapy, further studies are needed to better understand the underlying pathophysiology of insulin hypersensitivity and to develop targeted treatment approaches.

Intermolecular Interactions as a Measure of Dapsone Solubility in Neat Solvents and Binary Solvent Mixtures

Dapsone is an effective antibacterial drug used to treat a variety of conditions. However, the aqueous solubility of this drug is limited, as is its permeability. This study expands the available solubility data pool for dapsone by measuring its solubility in several pure organic solvents: N-methyl-2-pyrrolidone (CAS: 872-50-4), dimethyl sulfoxide (CAS: 67-68-5), 4-formylmorpholine (CAS: 4394-85-8), tetraethylene pentamine (CAS: 112-57-2), and diethylene glycol bis(3-aminopropyl) ether (CAS: 4246-51-9). Furthermore, the study proposes the use of intermolecular interactions as molecular descriptors to predict the solubility of dapsone in neat solvents and binary mixtures using machine learning models. An ensemble of regressors was used, including support vector machines, random forests, gradient boosting, and neural networks. Affinities of dapsone to solvent molecules were calculated using COSMO-RS and used as input for model training. Due to the polymorphic nature of dapsone, fusion data are not available, which prohibits the direct use of COSMO-RS for solubility calculations. Therefore, a consonance solvent approach was tested, which allows an indirect estimation of the fusion properties. Unfortunately, the resulting accuracy is unsatisfactory. In contrast, the developed regressors showed high predictive potential. This work documents that intermolecular interactions characterized by solute-solvent contacts can be considered valuable molecular descriptors for solubility modeling and that the wealth of encoded information is sufficient for solubility predictions for new systems, including those for which experimental measurements of thermodynamic properties are unavailable.

Comparison of the Efficacy of Longer versus Shorter Pulsed High Dose Dapsone Combination Therapy in the Treatment of Chronic Lyme Disease/Post Treatment Lyme Disease Syndrome with Bartonellosis and Associated Coinfections

Twenty-five patients with relapsing and remitting Borreliosis, Babesiosis, and bartonellosis despite extended anti-infective therapy were prescribed double-dose dapsone combination therapy (DDDCT), followed by one or several courses of High Dose Dapsone Combination Therapy (HDDCT). A retrospective chart review of these 25 patients undergoing DDDCT therapy and HDDCT demonstrated that 100% improved their tick-borne symptoms, and patients completing 6-7 day pulses of HDDCT had superior levels of improvement versus 4-day pulses if Bartonella was present. At the completion of treatment, 7/23 (30.5%) who completed 8 weeks of DDDCT followed by a 5-7 day pulse of HDDCT remained in remission for 3-9 months, and 3/23 patients (13%) who recently finished treatment were 1 ½ months in full remission. In conclusion, DDDCT followed by 6-7 day pulses of HDDCT could represent a novel, effective anti-infective strategy in chronic Lyme disease/Post Treatment Lyme Disease Syndrome (PTLDS) and associated co-infections, including Bartonella, especially in individuals who have failed standard antibiotic protocols.

The Impact of Patient Age and Corticosteroids in Patients With Sulfonamide Hepatotoxicity

INTRODUCTION

Sulfonamides are widely used to treat and prevent various bacterial and opportunistic infections. The aim of this study was to describe the clinical presentation and outcomes of a large cohort of patients with sulfonamide hepatotoxicity.

METHODS

Between 2004 and 2020, 105 patients with hepatotoxicity attributed to trimethoprim/sulfamethoxazole (TMP-SMZ) (n = 93) or other sulfonamides (n = 12) were enrolled. Available liver biopsies were reviewed by a single hepatopathologist.

RESULTS

Among the 93 TMP-SMZ cases, 52% were female, 7.5% younger than 20 years, and the median time to drug-induced liver injury (DILI) onset was 22 days (range: 3-157). Younger patients were significantly more likely to have rash, fever, eosinophilia, and a hepatocellular injury pattern at onset that persisted at the peak of liver injury compared with older patients ( P < 0.05). The 18 (19%) TMP-SMZ patients treated with corticosteroids had more severe liver injury and a higher mortality but a trend toward more rapid normalization of their laboratory abnormalities compared with untreated patients. During follow-up, 6.2% of the TMP-SMZ patients died or underwent liver transplantation. Chronic DILI developed in 20% and was associated with cholestatic injury at onset and higher peak total bilirubin levels.

DISCUSSION

Sulfonamide hepatotoxicity is characterized by a short drug latency with frequent hypersensitivity features at onset. Subject age is an important determinant of the laboratory profile at presentation, and patients with cholestasis and higher total bilirubin levels were at increased risk of developing chronic DILI. Corticosteroids may benefit a subgroup of patients with severe injury, but further studies are needed.

Insight into novel anti-mucormycosis therapies: investigation of new anti-mucormycosis laser-induced photodynamic therapy based on a sulphone bis-compound loaded silica nanoemulsion

For drug delivery applications, silica nanoemulsion encapsulated with organic compounds are becoming increasingly more desirable. Therefore, the emphasis of this research was on the synthesis of a new potent antifungal drug-like candidate (1,1'-((sulfonylbis(4,1-phenylene)bis(5-methyl-1H-1,2,3-triazole-1,4-diyl))bis(3-(dimethylamino)prop-2-en-1-one), SBDMP), the chemical structure of which was confirmed on the basis of its spectral and microanalytical data. Then, silica nanoemulsion loaded with SBDMP was prepared using Pluronic F-68 as a potent surfactant. The particle shape, hydrodynamic size, and zeta potential of the produced silica nanoemulsion (with and without drug loading) were assessed. The antitumoral activity of the synthesized molecules showed the superiority of SBDMP and silica nanoemulsion with and without SBDMP loading against Rhizopus microsporous and Syncephalastrum racemosum. Subsequently, the laser-induced photodynamic inactivation (LIPDI) of Mucorales strains was determined using the tested samples. The optical properties of the samples were investigated using UV-vis optical absorption and the photoluminescence. The photosensitivity of the selected samples appeared to enhance the eradication of the tested pathogenic strains when exposed to a red (640 nm) laser light. The optical property results verified that the SBDMP-loaded silica nanoemulsion has a high depth of penetration into biological tissues due to a two-absorption photon (TAP) mechanism. Interestingly, the photosensitizing of the nanoemulsion loaded with a newly synthesized drug-like candidate, SBDMP, opens up a new route to apply new organic compounds as photosensitizers under laser-induced photodynamic therapy (LIPDT).

Dapsone-Loaded Mixed Micellar Gel for Treatment OF Acne Vulgaris

Mixed polymeric micelles are potential nanocarriers for topical drug delivery. Dapsone (DAP) is an antibacterial used as anti-acne agent, but challenged by low water solubility and poor skin permeability. In the present study, DAP-loaded mixed micellar gel was developed comprising Pluronics F-68 and F-127. Micelles were prepared by solvent evaporation method and particle size, ex vivo permeation, drug loading, and entrapment efficiency were determined. Central Composite Design was used to optimize formulation. Independent variables were concentration of Pluronics at three levels while micelle size and drug loading capacities were dependent variables. Droplet size ranged from 400 to 500 nm. Transmission electron microscopy revealed spherical morphology of micelles. Optimized micelles were incorporated into gel base using HPMC K100M, Sodium CMC, and Carbopol 980 as gelling agents. Gels were evaluated for pH, drug content, spreadability, rheology, syneresis, ex vivo permeation, and subacute dermal toxicity. Compared with solubility of free DAP (0.24+0.056 µg/ml), solubility in mixed micelles was 18.42±3.4 µg/ml in water at room temperature. Order of spreadability of gels was Na CMC < HPMC < Carbopol 980. Carbopol gels displayed thixotropy with index of 3.17. Syneresis for all gels from day 0 to day 30 was found to be in range of 4.2 to 15.6% w/w. Subacute dermal toxicity studies showed no signs of erythema and edema on rat skin until 21 days. These results suggest that mixed micelles can significantly increase solubility and permeability and sustain release of DAP and are suitable carriers for topical DAP delivery in anti-acne therapies.

Characterization of the anticonvulsant effect of dapsone on metabolic activity assessed by [18F]FDG -PET after kainic acid-induced status epilepticus in rats

BACKGROUND

Development of effective drugs for epilepsy are needed, as nearly 30 % of epileptic patients, are resistant to current treatments. This study is aimed to characterize the anticonvulsant effect of dapsone (DDS), in the kainic acid (KA)-induced Status Epilepticus (SE) by recording the brain metabolic activity with an [¹⁸F]FDG-PET analysis.

METHODS

Wistar rats received KA (10 mg/kg, i.p., single dose) to produce sustained seizures. [¹⁸F]FDG-PET and electroencephalographic (EEG) studies were then performed. DDS or vehicle were administered 30 min before KA. [¹⁸F]FDG uptake and EEG were evaluated at baseline, 2 and 25 h after KA injection. Likewise, caspase-8, 3 hippocampal activities and Fluoro-Jade B neuronal degeneration and Hematoxylin-eosin staining were measured 25 h after KA.

RESULTS

PET data evaluated at 2 h showed hyper-uptake of [¹⁸F]FDG in the control group, which was decreased by DDS. At 25 h, hypo-uptake was observed in the control group and higher values due to DDS effect. EEG spectral power was increased 2 h after KA administration in the control group during the generalized tonic-clonic seizures, which was reversed by DDS, correlated with [¹⁸F]FDG-PET uptake changes. The values of caspases-8 activity decreased 48 and 43 % vs control group in the groups treated with DDS (12.5 y 25 mg/kg respectively), likewise; caspase-3 activity diminished by 57 and 53 %. Fewer degenerated neurons were observed due to DDS treatments.

CONCLUSIONS

This study pinpoints the anticonvulsant therapeutic potential of DDS. Given its safety and effectiveness, DDS may be a viable alternative for patients with drug-resistant epilepsy.

Evolution of pediatric pharmaceutical forms for treatment of Hansen's disease (leprosy)

INTRODUCTION

Leprosy is a neglected, infectious, granulomatous and chronic disease caused by the pathological agent Mycobacterium leprae. The course of the disease is more aggressive in patients under 15 years of age, but the current treatment offered worldwide consists of solid forms, by the combination of antibiotics such as rifampicin, clofazimine and dapsone. This represents results in lack of adherence in pediatric patients and drug therapy failure, although numerous formulations and technologies have already been developed.

AREA COVERED

This study aims to analyze the technological evolution of the pharmaceutical treatment of leprosy, aimed at children. A review of patents around the world was conducted to look for technical and clinical aspects of formulations and devices.

EXPERT OPINION

Innovative formulations for pediatric patients were classified according to the routes of administration as oral, inhalable, injectable and transdermal. The formulations were organized as alternatives for pediatric therapy, taking into account the physicochemical aspects of drugs and the physiological aspects of pediatric patients. Among the difficulties for the patented formulations to reach the market, of special note is the low stability of the physicochemical characteristics of the drugs. Optimization of formulations would favor the pediatric treatment of leprosy, aiming at therapeutic success.

Antagonizing FcαR1 (CD89) as treatment in IgA-mediated chronic inflammation and autoimmunity

Introduction

Immunoglobulin A (IgA) is mostly considered as a non-inflammatory regulator at mucosal areas. However, previous work of our group showed that IgA can also be involved in disease pathology, because it provides a potent stimulus to activate neutrophils after crosslinking of surface CD89 (FcaRI), resulting in chronic inflammation and tissue damage. IgA (auto)antibodies and neutrophils are key players in various diseases, including blistering skin diseases and rheumatoid arthritis. Therefore, we generated an array of anti-CD89 monoclonal antibodies (mAbs) for therapeutic targeting of CD89. The biological activity of newly developed anti-human CD89 mAbs and their potential therapeutic capacity were investigated.

Methods

Human neutrophils were isolated from heparinized healthy donor blood. The ability of anti-CD89 mAbs to bind human neutrophils was investigated by flow cytometry. Furthermore, the capacity of these anti-CD89 mAbs to inhibit IgA-mediated phagocytosis, neutrophil extracellular trap (NET) release and migration was studied. To this end, neutrophils were pre-incubated with/without anti-CD89 mAbs after which they were stimulated with IgA-coated beads. The amount of phagocytosed beads, NET release and migrated neutrophils were subsequently analysed. In parallel, chemoattractant leukotriene B4 and lactoferrin (as a measure for degranulation) release were determined. Finally, the therapeutic potential of our prototypic anti-CD89 mAb clone 10E7 was in vivo tested in anti-mouse collagen XVII human IgA-treated transgenic CD89 mice, a preclinical model for autoimmune linear IgA bullous disease (LABD).

Results

Our results show that all generated anti-CD89 mAbs bound surface CD89 on neutrophils. Although these anti-CD89 mAbs bind to different epitopes on EC1 of CD89, they all have the capacity to inhibit IgA-mediated phagocytosis, neutrophil extracellular trap (NET) release and neutrophil migration. Moreover, IgA mediated leukotriene B4 and lactoferrin release are decreased in supernatant from anti-CD89 mAbs-treated neutrophils. Finally, anti-CD89 mAb clone 10E7, that was selected based on its selective binding profile on tissue micro arrays, reduced anti-mouse collagen XVII hIgA-induced neutrophil influx in an in vivo linear IgA bullous disease (LABD) mice model.

Conclusion

This study clearly indicates that our newly developed anti-CD89 mAbs inhibited IgA-induced neutrophil activation and reduced anti-autoantigen IgA-induced neutrophil influx in vivo, supporting further clinical development for the treatment of LABD.

Dapsone Lowers Neutrophil to Lymphocyte Ratio and Mortality in COVID-19 Patients Admitted to the ICU

Some physicians use dapsone as part of the standard treatment of severe COVID-19 patients entering the ICU, though some do not. To obtain an indication of whether dapsone is helping or not, we undertook a retrospective chart review of 29 consecutive ICU COVID-19 patients receiving dapsone and 30 not receiving dapsone. As we previously reported, of those given dapsone, 9/29 (30%) died, while of those not given dapsone, 18/30 (60%) died. We looked back on that data set to determine if there might be basic laboratory findings in these patients that might give an indication of a mechanism by which dapsone was acting. We found that the neutrophil-to-lymphocyte ratio decreased in 48% of those given dapsone and in 30% of those not given dapsone. We concluded that dapsone might be lowering that ratio. We then reviewed collected data on neutrophil related inflammation pathways on which dapsone might act as presented here. As this was not a controlled study, many variables prevent drawing any conclusions from this work; a formal, randomized controlled study of dapsone in severe COVID-19 is warranted.

Dapsone-induced methemoglobinemia and hemolysis in a woman without G6PD deficiency presenting with idiopathic urticaria

BACKGROUND

The appearance of bite cells associated with methemoglobinemia can be caused by oxidizing drugs such as dapsone in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency or high drug serum levels. Bite cells are often pathognomonic for oxidant injury in patients with G6PD deficiency and suggest active hemolysis.

CASE PRESENTATION

We report a case of a woman with no prior history of G6PD deficiency who presented with anemia, methemoglobinemia and bite cells on peripheral blood smear after dapsone therapy for new onset idiopathic urticaria. Laboratory tests for G6PD, blood count and liver function were within normal limits prior to initiation of therapy. During the patient's hospital course, moderate methemoglobinemia and anemia were identified despite mildly increased serum G6PD level. These pathologies were reversed upon stopping dapsone therapy.

CONCLUSION

This case highlights the potential for therapeutic levels of dapsone to induce side effects in patients without G6PD deficiency and highlights the importance of routine blood monitoring for anemia and hemolysis during the course of drug therapy.

A comprehensive insight into the anti-inflammatory properties of dapsone

The 4,4'-diaminodiphenyl sulfone (DDS), also known as dapsone, is traditionally used as a potent anti-bacterial agent in clinical management of leprosy. For decades, dapsone has been among the first-line medications used in multidrug treatment of leprosy recommended by the World Health Organization (WHO). Shortly after dapsone's discovery as an antibiotic in 1937, the dual function of dapsone (anti-microbial and anti-inflammatory) was elucidated. Dapsone exerts its anti-bacterial effects by inhibiting dihydrofolic acid synthesis, leading to inhibition of bacterial growth, while its anti-inflammatory properties are triggered by inhibiting reactive oxygen species (ROS) production, reducing the effect of eosinophil peroxidase on mast cells and downregulating neutrophil-mediated inflammatory responses. Among the leading mechanisms associated with its anti-microbial/anti-protozoal effects, dapsone clearly has multiple antioxidant, anti-inflammatory, and anti-apoptotic functions. In this regard, it has been described in treating a wide variety of inflammatory and infectious skin conditions. Previous reports have explored different molecular targets for dapsone and provided insight into the anti-inflammatory mechanism of dapsone. This article reviews several basic, experimental, and clinical approaches on anti-inflammatory effect of dapsone.

An insight on topically applied formulations for management of various skin disorders

Various types of skin disorders across each age group and in each part of geographical world are very dreadful. Despite not being fatal each time they are always of social and mental concern for suffering individuals, causing complications in millions of patients every day and require comparatively longer duration of treatment. Off late, various topical/transdermal formulations have been widely explored for the treatment of various skin ailments. The efficiency of topical therapy depends on various physiochemical properties of drugs like particle size, particle size distribution, partition coefficient, viscosity of dosage form, skin permeability, skin condition and the site of application. Therefore, in plenty of examples, long-acting topical formulations have shown to be markedly excellent in comparison to conventional dosage forms. The major advantages of topical formulations accrue from their demonstrated ability: (i) Reduced serious side effects that may occur due to undesirably higher systemic absorption of drug. (ii) Enhancement of drug accumulation at the desired site. (iii) Easy incorporation of enormous range of hydrophilic and hydrophobic drugs and (iv) Reduced risk of dose dumping and comparatively easy termination of drug release. The prospective applications of topically applied formulations and the deposition of pharmaceuticals into the skin are examined.

Highly water-soluble dapsone nanocrystals: Towards innovative preparations for an undermined drug

Dapsone (DAP)is a dual-function drug substance; however, its limited water solubility may impair its bioavailability. Drug nanocrystals are an alternative to overcome this limitation. Herein, a DAP nanosuspension was prepared using adesign space approach aiming to investigate the influence of raw material properties and process parameters on the critical quality attributes of the drugnanocrystals. Optimized nanocrystals with 206.3 ± 6.7 nm using povacoat™ as stabilizer were made. The nanoparticles were characterized by dynamic light scattering, laser diffraction, scanning electron microscopy, differential scanning calorimetry, X-ray powder diffraction, and saturation solubility. Compared to the raw material, the nanocrystals were 250-times smaller. Meanwhile, its crystalline state remained basically unchanged even after milling and drying. The nanosuspension successfully maintained its physical stability inlong-termandaccelerated stability studiesover, 4 and 3 months. Furthermore, toxicity studiesshowed low a toxicity at a20 mg/kg. As expected for nanocrystals, the size reduction improvedsaturation solubility3.78 times in water. An attempt to scale up from lab to pilot scale resulted nanocrystals of potential commercial quality. In conclusion, the present study describes the development of dapsone nanocrystals for treating infectious and inflammatory diseases. The nanocrystal formuation can be scaled up for commercial use.

Hypoxia in A Patient with Anti-p200 Pemphigoid under Combined Dapsone and Pantoprazole Treatment

A 70-year-old male patient was admitted to our dermatology outpatient clinic with newly developed personality changes and signs of hypoxemia. His anti-p200 Pemphigoid was treated with Dapsone for a few weeks. Due to generalized tonic-clonic seizure with a subsequent Glasgow Coma Scale of 5 points and a peripheral oxygen saturation not exceeding 88% under conditions of high-flow nasal cannula, he was intubated by the emergency team and transferred to the intensive care unit. Comprehensive tests were performed, but Dapsone-induced methemoglobinemia remained the exclusive explanation for the observed scenario, although arterial MetHb analysis showed a peak value of only 6%. The patient recovered shortly after repeated infusions of Methylene blue and Ascorbate, and cessation of Dapsone. We provide an overview of the pathophysiology, diagnostic procedures, and possible explanations for this case of Dapsone-induced methaemoglobinaemia. In conclusion, our case report provides evidence that even mild chronic methemglobinemia can induce severe clinical symptoms.

Dapsone-Associated Anemia in Heart Transplant Recipients with Normal Glucose-6-Phosphate Dehydrogenase Activity

Dapsone is considered an alternative for pneumocystis jirovecii pneumonia (PJP) prophylaxis in sulfa-allergic or -intolerant transplant patients with normal glucose-6-phosphate dehydrogenase (G6PD) activity. Despite normal G6PD activity, anemia can still occur while on dapsone therapy. We retrospectively reviewed heart transplant patients transplanted at our center between January 2016 and June 2018 and identified those taking dapsone prophylaxis. There were 252 heart transplant recipients at our center between January 2016 and June 2018. 36 patients received dapsone prophylaxis. All had normal G6PD activity assessed prior to dapsone initiation. 8 (22%) patients developed significant anemia attributed to dapsone: 2 were hospitalized for anemia, 1 of whom required blood transfusion. These patients had a median reduction in hemoglobin of 2.1 g/dL from baseline prior to dapsone initiation. Overt evidence of hemolysis was present in six patients. Once dapsone was discontinued, Hgb increased by at least 2 g/dL in a median of 30 days. Anemia from dapsone may occur in a significant proportion of patients despite normal G6PD activity and resulting in significant morbidity. Careful monitoring of transplant recipients on dapsone prophylaxis is warranted, as well as consideration of alternative agents.

Dapsone for Refractory Gastrointestinal Symptoms in Children With Immunoglobulin A Vasculitis

Immunoglobulin A vasculitis (IgAV) is a systemic small-vessel vasculitis. Although corticosteroids (CS) are the primary treatment for gastrointestinal manifestations associated with IgAV, some patients develop refractory or recurrent symptoms such as vomiting and abdominal pain despite CS treatment. Dapsone, a synthetic sulfone antimicrobial, has been used to treat cutaneous purpura in IgAV, but few authors have reported its use for refractory gastrointestinal symptoms. In this retrospective observational study, we describe results in 7 children with IgAV who were treated with dapsone for abdominal pain resistant to CS. Dapsone rapidly relieved abdominal pain in all 7 patients, who then were tapered off CS without relapse. Side effects of mild methemoglobinemia and hemolysis appeared to be manageable with planned monitoring and dose adjustment; a single patient who discontinued dapsone had fatigue and hypoxia associated with methemoglobinemia. No side effects were life-threatening. Dapsone may be considered as a therapeutic option for gastrointestinal symptoms refractory to CS in children with IgAV.

Behcet's disease: Diagnosed as isolated recurrent oral aphthae; a case report

Background

Case report

Discussion

Conclusion

•Background: A case of Behcet syndrome presenting initially with isolated oral aphthous.

•

Case Report: A 32-year-old male with recurrent oral aphthous. A complete resolution of the lesions with no reproduction.

•

Conclusion: A case of Behcet's syndrome affected the oral mucosa and later caused uveitis and the genitalia aphthae.

•

Keywords: Oral aphthae, Behcet's Disease, Dapsone treatment .

Dapsone reduced cuprizone-induced demyelination via targeting Nrf2 and IKB in C57BL/6 mice

Objectives

Multiple Sclerosis (MS) is an inflammatory disorder wherein the myelin of nerve cells in the central nervous system is damaged. In the current study, we assessed the effect of Dapsone (DAP) on the improvement of behavioral dysfunction and preservation of myelin in the cuprizone (CPZ) induced demyelination model via targeting Nrf2 and IKB.

Materials and Methods

MS was induced in C57BL/6 mice through diet supplementation of CPZ (0.2%) for 6 weeks, and DAP (12.5 mg/kg/day; IP) was administered for the last 2 weeks of treatment. Pole test and rotarod performance test, LFB and H&E staining, and Immunohistochemistry (IHC) staining of p-Nrf2 and p-IKB were performed. Furthermore, superoxide dismutase (SOD) and nitrite were measured.

Results

DAP treatment prevented body loss induced by CPZ (P<0.001). Pole test showed that CPZ increased latency time to fall (P<0.0001) but the latency to reach the floor in the DAP-CPZ group was significantly shorter (P<0.0001). Rotarod performance test showed the effect of CPZ in reducing fall time in the CPZ group (P<0.0014); however, DAP significantly increased fall time (P=0.0012). In LFB staining, DAP reduced demyelination induced by CPZ. CPZ significantly decreased p-Nrf2 and elevated p-IKB levels compared with the control group (P<0.0001), but in DAP-treated groups markedly modified these changes (P<0.0001). CPZ increased the brain nitrite levels and reduced SOD activity, but in DAP-treated considerably reversed CPZ-induced changes.

Conclusion

These data support the suggestion that the beneficial properties of DAP on the CPZ-induced demyelination are mediated by targeting Nrf2 and NF-kB pathways.

Pyoderma Gangrenosum: An Updated Literature Review on Established and Emerging Pharmacological Treatments

Pyoderma gangrenosum is a rare inflammatory skin disease classified within the group of neutrophilic dermatoses and clinically characterized by painful, rapidly evolving cutaneous ulcers with undermined, irregular, erythematous-violaceous edges. Pyoderma gangrenosum pathogenesis is complex and involves a profound dysregulation of components of both innate and adaptive immunity in genetically predisposed individuals, with the follicular unit increasingly recognized as the putative initial target. T helper 17/T helper 1-skewed inflammation and exaggerated inflammasome activation lead to a dysregulated neutrophil-dominant milieu with high levels of tumor necrosis factor-α, interleukin (IL)-1β, IL-1α, IL-8, IL-12, IL-15, IL-17, IL-23, and IL-36. Low-evidence studies and a lack of validated diagnostic and response criteria have hindered the discovery and validation of new effective treatments for pyoderma gangrenosum. We review established and emerging treatments for pyoderma gangrenosum. A therapeutic algorithm based on available evidence is also provided. For emerging treatments, we review target molecules and their role in the pathogenesis of pyoderma gangrenosum.

MDACT: A New Principle of Adjunctive Cancer Treatment Using Combinations of Multiple Repurposed Drugs, with an Example Regimen

In part one of this two-part paper, we present eight principles that we believe must be considered for more effective treatment of the currently incurable cancers. These are addressed by multidrug adjunctive cancer treatment (MDACT), which uses multiple repurposed non-oncology drugs, not primarily to kill malignant cells, but rather to reduce the malignant cells' growth drives. Previous multidrug regimens have used MDACT principles, e.g., the CUSP9v3 glioblastoma treatment. MDACT is an amalgam of (1) the principle that to be effective in stopping a chain of events leading to an undesired outcome, one must break more than one link; (2) the principle of Palmer et al. of achieving fractional cancer cell killing via multiple drugs with independent mechanisms of action; (3) the principle of shaping versus decisive operations, both being required for successful cancer treatment; (4) an idea adapted from Chow et al., of using multiple cytotoxic medicines at low doses; (5) the idea behind CUSP9v3, using many non-oncology CNS-penetrant drugs from general medical practice, repurposed to block tumor survival paths; (6) the concept from chess that every move creates weaknesses and strengths; (7) the principle of mass-by adding force to a given effort, the chances of achieving the goal increase; and (8) the principle of blocking parallel signaling pathways. Part two gives an example MDACT regimen, gMDACT, which uses six repurposed drugs-celecoxib, dapsone, disulfiram, itraconazole, pyrimethamine, and telmisartan-to interfere with growth-driving elements common to cholangiocarcinoma, colon adenocarcinoma, glioblastoma, and non-small-cell lung cancer. gMDACT is another example of-not a replacement for-previous multidrug regimens already in clinical use, such as CUSP9v3. MDACT regimens are designed as adjuvants to be used with cytotoxic drugs.

Bilateral exudative retinal detachments and associated choroidal detachments in a patient on dapsone: a case report

BACKGROUND

Dapsone is a synthetic sulfonamide used to treat numerous dermatologic conditions. Ocular side effects have been rarely reported and include retinal necrosis, optic atrophy, and macular infarction. We report the first known case of bilateral choroidal effusions and exudative retinal detachments associated with dapsone use.

CASE PRESENTATION

A 57-year-old male with a past medical history of testicular seminoma presented with bilateral blurry vision for 2 months. His exam revealed bilateral choroidal effusions with bilateral exudative retinal detachments without evidence of intraocular tumor. The patient had recently been prescribed dapsone for urticarial vasculitis. The patient was instructed to discontinue dapsone and follow-up closely. Interval follow-up of 8 months demonstrated almost complete resolution of the choroidal effusions and retinal detachments with residual pigment epithelium changes after cessation of dapsone. The patient recovered his pre-detachment visual function.

CONCLUSIONS

Patients on dapsone who present with new visual complaints should undergo a thorough ophthalmic evaluation given the multiple mechanisms by which dapsone can affect the eye.

Implementation of genetic screening test to reduce the incidence of dapsone hypersensitivity syndrome among patients with leprosy in Papua, Indonesia: a study protocol

INTRODUCTION

The mainstay of leprosy treatment is multidrug treatment (MDT), which contains rifampicin, dapsone and clofazimine. The occurrence of dapsone hypersensitivity syndrome (DHS), a sudden, potentially fatal and traumatic adverse reaction due to dapsone, may affect treatment adherence and may result in fatality if untreated. Before MDT administration, screening for HLA-B*13:01 in patients with leprosy can potentially reduce DHS risk. The study aims to assess the effectiveness of using a screening test for HLA-B*13:01 in reducing the incidence of DHS and to evaluate the feasibility of using the quantitative PCR-based screening tool as DHS predictors before dapsone administration using individual patient testing in a referral centralised-lab model.

METHODS AND ANALYSIS

A total of 310 newly diagnosed patients with leprosy will be recruited from health centres in two highly endemic districts in Indonesia. Dried blood will be taken on filter paper as the specimen receptacle to collect DNA from the patients and transported at room temperature to the leprosy referral laboratory before MDT administration. Checking for HLA-B*13:01 from human DNA is performed using the Nala PGx 1301 V.1 kit. The results will be shared with the leprosy health workers on the site via phone call and courier. Patients with a positive test result will be treated with MDT without dapsone, and patients with a negative result will be treated with complete MDT. Physical examination (weight, height, skin, muscle and nerve function examination), complete blood tests (including renal function test) will be carried out at baseline. Follow-up will be performed at the fourth and eighth weeks to observe any development of adverse drug reactions.

ETHICS AND DISSEMINATION

The ethical approval for the study was issued by the Ethical Committee of the National Institute of Health Research and Development, Ministry of Health, Indonesia. Written informed consent will be sought from all participants.

Gut Dysbiosis in Ocular Mucous Membrane Pemphigoid

Mucous Membrane Pemphigoid is an orphan multi-system autoimmune scarring disease involving mucosal sites, including the ocular surface (OcMMP) and gut. Loss of tolerance to epithelial basement membrane proteins and generation of autoreactive T cell and/or autoantibodies are central to the disease process. The gut microbiome plays a critical role in the development of the immune system. Alteration in the gut microbiome (gut dysbiosis) affects the generation of autoreactive T cells and B cell autoantibody repertoire in several autoimmune conditions. This study examines the relationship between gut microbiome diversity and ocular inflammation in patients with OcMMP by comparing OcMMP gut microbiome profiles with healthy controls. DNA was extracted from faecal samples (49 OcMMP patients, 40 healthy controls), amplified for the V4 region of the 16S rRNA gene and sequenced using Illumina Miseq platform. Sequencing reads were processed using the bioinformatics pipeline available in the mothur v.1.44.1 software. After adjusting for participant factors in the multivariable model (age, gender, BMI, diet, proton pump inhibitor use), OcMMP cohort was found to be associated with lower number of operational taxonomic units (OTUs) and Shannon Diversity Index when compared to healthy controls. Within the OcMMP cohort, the number of OTUs were found to be significantly correlated with both the bulbar conjunctival inflammation score (p=0.03) and the current use of systemic immunotherapy (p=0.02). The linear discriminant analysis effect size scores indicated that Streptococcus and Lachnoclostridium were enriched in OcMMP patients whilst Oxalobacter, Clostridia uncultured genus-level group (UCG) 014, Christensenellaceae R-7 group and butyrate-producing bacteria such as Ruminococcus, Lachnospiraceae, Coprococcus, Roseburia, Oscillospiraceae UCG 003, 005, NK4A214 group were enriched in healthy controls (Log10 LDA score < 2, FDR-adjusted p <0.05). In conclusion, OcMMP patients have gut dysbiosis correlating with bulbar conjunctival inflammation and the use of systemic immunotherapies. This provides a framework for future longitudinal deep phenotyping studies on the role of the gut microbiome in the pathogenesis of OcMMP.

Anti-FcαRI Monoclonal Antibodies Resolve IgA Autoantibody-Mediated Disease

Immunoglobulin A (IgA) is generally considered as a non-inflammatory regulator of mucosal immunity, and its importance in diversifying the gut microbiota is increasingly appreciated. IgA autoantibodies have been found in several autoimmune or chronic inflammatory diseases, but their role in pathophysiology is ill-understood. IgA can interact with the Fc receptor FcαRI on immune cells. We now established a novel IgA autoimmune blistering model, which closely resembles the human disease linear IgA bullous disease (LABD) by using genetically modified mice that produce human IgA and express human FcαRI. Intravital microscopy demonstrated that presence of IgA anti-collagen XVII, - the auto-antigen in LABD-, resulted in neutrophil activation and extravasation from blood vessels into skin tissue. Continued exposure to anti-collagen XVII IgA led to massive neutrophil accumulation, severe tissue damage and blister formation. Importantly, treatment with anti-FcαRI monoclonal antibodies not only prevented disease, but was also able to resolve existing inflammation and tissue damage. Collectively, our data reveal a novel role of neutrophil FcαRI in IgA autoantibody-mediated disease and identify FcαRI as promising new therapeutic target to resolve chronic inflammation and tissue damage.

Update on Toxic Neuropathies

Purpose of Review

Toxic neuropathies are an important preventable and treatable form of peripheral neuropathy. While many forms of toxic neuropathies have been recognized for decades, an updated review is provided to increase vigilant in this area of neurology. A literature review was conducted to gather recent information about toxic neuropathies, which included the causes, clinical findings, and treatment options in these conditions.

Recent Findings

Toxic neuropathies continue to cause significant morbidity throughout the world and the causative agents, particularly with regards to medications, do not appear to be diminishing. A wide variety of causes of toxic neuropathies exist, which include alcohol, industrial chemicals, biotoxins, and medications. Unfortunately, no breakthrough treatments have been developed and prevention and symptom management remain the standard of care.

Summary

A detailed medication, occupational and hobby exposure history is critical to identifying toxic neuropathies. Increased research is warranted to identify mechanisms of neurotoxic susceptibility and potential common pathomechanistic pathways for treatment across diverse toxic neuropathies.

Dapsone Azo-Linked with Two Mesalazine Moieties Is a "Me-Better" Alternative to Sulfasalazine

Dapsone (DpS) is an antimicrobial and antiprotozoal agent, especially used to treat leprosy. The drug shares a similar mode of action with sulfonamides. Additionally, it possesses anti-inflammatory activity, useful for treating autoimmune diseases. Here, we developed a “me-better” alternative to sulfasalazine (SSZ), a colon-specific prodrug of mesalazine (5-ASA) used as an anti-inflammatory bowel diseases drug; DpS azo-linked with two molecules of 5-ASA (AS-DpS-AS) was designed and synthesized, and its colon specificity and anti-colitic activity were evaluated. AS-DpS-AS was converted to DpS and the two molecules of 5-ASA (up to approximately 87% conversion) within 24 h after incubation in the cecal contents. Compared to SSZ, AS-DpS-AS showed greater efficiency in colonic drug delivery following oral gavage. Simultaneously, AS-DpS-AS substantially limited the systemic absorption of DpS. In a dinitrobenzene sulfonic acid-induced rat colitis model, oral AS-DpS-AS elicited better efficacy against rat colitis than oral SSZ. Moreover, intracolonic treatment with DpS and/or 5-ASA clearly showed that combined treatment with DpS and 5-ASA was more effective against rat colitis than the single treatment with either DpS or 5-ASA. These results suggest that AS-DpS-AS may be a “me-better” drug of SSZ with higher therapeutic efficacy, owing to the combined anti-colitic effects of 5-ASA and DpS.

Dapsone as a Detrimental Cause of Necrotizing Fasciitis With Severe Resistant Neutropenia: A Case Report

Dapsone, which is used for treating dermatological conditions, can lead to neutropenia. Especially, resistant neutropenia makes patients vulnerable to invasive infections, indicating a medical emergency. Febrile neutropenia secondary to dapsone intake should be treated promptly before the development of sepsis, which may lead to shock and death. In addition, necrotizing fasciitis is a severe and potentially fatal soft-tissue infection that rarely develops in healthy individuals with skin lesions. In this report, we present a case of a patient with no comorbidities who presented with necrotizing fasciitis and neutropenia with a history of dapsone intake.

The anti-inflammatory effect of dapsone on ovalbumin-induced allergic rhinitis in balb/c mice

AIMS

Allergic rhinitis (AR), a major chronic inflammatory disease of the respiratory system, is a public health issue because of its substantial negative impact on quality of life and work efficiency alongside its high prevalence and costs. Dapsone is a sulfone chemical with reported anti-inflammatory and antibacterial properties. Accordingly, we investigated the anti-inflammatory impact of dapsone on ovalbumin-induced allergic rhinitis in balb/c mice.

MAIN METHODS

Intraperitoneal ovalbumin and hydroxide aluminum injection followed by intranasal ovalbumin administration sensitized female Balb/c mice. Mice received intraperitoneal dapsone either acute (5, 10, 20 mg/kg) 30 min before the last ovalbumin challenge, or chronic (20 mg/kg) on days 21 to 35.

KEY FINDINGS

Both acute and chronic intraperitoneal usage of dapsone showed a considerable decrease in the nasal scratching behavior, the number of sneezing, serum IL-4 and IgE levels of ovalbumin-induced AR in balb/c mice, but there was a significant increase in serum IFNγ level. Histopathological analysis demonstrated a significant reduction of eosinophil numbers, following dapsone injection. Goblet cell hyperplasia and respiratory epithelial-thickness decreased significantly in the acute and chronic 20 mg/kg dapsone groups compared to the ovalbumin-induced controls.

SIGNIFICANCE

This study shows that there is an association between acute and chronic dapsone treatment and some anti-allergic effects through an inflammation cascade.

Topical dapsone in the treatment of acne: a systematic review

BACKGROUND

Acne is one of the most common dermatological disorders. Initial therapies for acne include topical retinoids, benzoyl peroxide, and topical clindamycin. However, patients who fail initial therapies may benefit from alternative topicals, including dapsone gel.

OBJECTIVE

To analyze the current literature studying the efficacy of topical dapsone in the treatment of acne.

METHODS

PubMed, Embase, and Cochrane Library were systematically searched for clinical trials examining the efficacy of topical dapsone in the treatment of acne.

RESULTS

Fourteen studies were included in the analysis. Dapsone monotherapy showed a treatment success rate of 40.1-69.4% for dapsone gel 5% and 29.8-47.0% for dapsone gel 7.5% when used for 12-16 weeks. In all studies, inflammatory lesions decreased by a larger percentage than noninflammatory or total lesions. Dapsone gel was also studied in combination with various other acne treatments, including doxycycline, oral isotretinoin, benzoyl peroxide, and topical retinoids. While mild treatment-related adverse effects, most commonly consisting of skin irritation, occurred in 2.0-75.0% of participants, no major treatment-related adverse effects were reported.

LIMITATIONS

Limitations of the study include variable treatment regimens making it difficult to compare results across studies. Additionally, adverse effects and skin irritation were reported differently, and potential selection biases exist in the randomized trials.

CONCLUSION

Dapsone gel offers a safe and promising alternative therapy for patients with difficult to treat acne or those who experience adverse effects to first-line therapies.

Dapsone in Hidradenitis Suppurativa: A Systematic Review

INTRODUCTION

Hidradenitis suppurativa (HS) is a chronic, inflammatory, recurrent disease, usually presenting after puberty with inflammatory lesions that mainly affect the apocrine gland-bearing areas of the body, most commonly the axillary, inguinal and anogenital regions. The treatment of HS is associated with certain challenges due to intrinsic resistance to various treatments and the presence of comorbidities and complications. The antibiotic dapsone is an established treatment for HS, but the current evidence base is limited. The aim of this review is to systematically review the literature on the efficacy of dapsone in the treatment of HS.

METHODS

The Cochrane, PubMed and CINAHL databases were searched for relevant articles to be included in the systematic review.

RESULTS

A total of seven studies, with a cumulative patient population of 135 patients, were included. Of these 135 patients, 62.2% demonstrated various degrees of improvement following treatment. However, as only three of the seven studies used dapsone monotherapy it is difficult to assess the effectiveness of dapsone because the benefits observed may be due to concurrently administered treatment.

CONCLUSION

Overall, the quality of evidence supporting the use of dapsone is weak. However, it is a well established treatment recommended in current, various national guidelines. There is a crucial need for well-designed randomized controlled trials to support its usage.

Deep Eutectic Solvents for Improving the Solubilization and Delivery of Dapsone

Owing to a growing awareness toward environmental impact, the use of safer and eco-friendly solvents like deep eutectic solvents (DESs), has recently undergone important growth in the pharmaceutical field, with regard to their application as non-aqueous liquid administration vehicles, since they do not carry the same risks of toxicity and handling as traditional organic solvents. Major attention has been given to the development of advantageous transdermal drug delivery systems, because of their ease of use and better acceptability. Here, we report the use of two different DESs, based on choline chloride, used as hydrogen bond acceptor (HBA), and ascorbic acid or propylene glycol, used as hydrogen bond donors (HBDs), able to enhance the solubility and the topical delivery of dapsone, representing a class IV drug. The interactions between the DESs’ components and the drug were studied by performing DSC, FT-IR, and NMR analysis of the eutectic systems and the pure drug, confirming the establishment of H-bonds between the drug and the DESs’ components. Diffusion and permeability studies, carried out in a Franz cell, showed an increase in permeability, highlighting the great potential of DESs as dissolution and permeation enhancers in the development of novel and more effective drug delivery systems in topical administration.