Analytical performance of poly(L-cysteine) modified pencil graphite electrode for Dapsone detection.

Nanocoating technology for by-product bagasse papers (BPs) utilizes hybrid polymers to create a superhydrophobic surface that enhances several properties of the BP material, which is highly promising for many applications, including active food packaging. Thus, this study aimed to prepare a functional nanocoating from polycaprolactone (PCL) grafted with dapsone (DAP) and silver nanoparticles (Ag NPs) for promoting the properties of hydrophilic BPs. The outcome of grafting DAP into PCL, as well as the interactions between the components after the coating process, were investigated by FT-IR and XRD analyses. Varied contents of the Ag NPs (i.e., 0.05%, 0.15%, and 0.30%) were used to fabricate a PCL-DAP-Ag nanocoating for treating the hydrophilic BPs using a dip-coating approach. The net-treated BPs (TBPs) were subjected to various analyses and tests, including morphological tests by XRD and SEM analyses, mechanical and barrier property evaluation, wettability assessment by the water contact angle (WCA), flammability resistance testing, and antibacterial activity measurements. The results revealed that most of the properties of the TBPs were further enhanced by the presence of Ag NPs, especially at 0.15%, compared to raw BP or unfilled TBP. The flammability resistance of TBP-0.30% Ag was achieved when the Ag NP content in the nanocoating reached 0.30%. Moreover, the treated BPs demonstrated superior antibacterial activity, which effectively killed microbes and inhibited their growth within an inhibitory zone ranging from 14 to 33 mm, depending on the microbe and sample type. In summary, PCL grafting is influential, and applying PCL-DAP-based Ag NPs as a nanocoating to hydrophilic BPs presents a highly promising strategy for antimicrobial food packaging applications.

Salbutamol (SAL) and dapsone (DPSN) derivatization reactions and analysis procedures were established and improved in this study. SAL was used as a derivatization agent for DPSN, and DPSN was a derivatization agent for SAL. The method of derivatization, the diazonium coupling of SAL and DPSN, was optimized. The optimum parameters were 12 mM hydrochloric acid and 2.4 mM sodium nitrite for diazotization and 24 mM potassium hydroxide for azo coupling. Surfactant-modified dispersive liquid‒liquid microextraction (SM-DLLME) was optimized using a new solvent mixture: an aqueous dye derivative sample mixture, 600 µL of butanol as the extracting solvent, 1.05 wt.% Triton X-100 as the dispersive solvent, and 42 mM potassium chloride. Compared to existing methods, the linearity, correlation coefficients, limits of detection, and molar absorptivities were improved when SM-DLLME followed by HPLC-UV was employed. The proposed technique can detect pharmacological, environmental, and medicinal trace concentrations of SAL and DPSN.

In this study, a simple and eco-friendly spectrophotometric method was developed for the determination of dapsone (DAP) in pharmaceutical formulations using an ion-pair cloud point extraction (IP-CPE) approach. The IP-CPE method is based on the coupling reaction of dapsone with salbutamol (SUB) in an alkaline medium, producing a stable orange DAP-SUB azo dye with a maximum absorption wavelength at 457 nm. This is followed by the formation of ion-pair associates between the negatively charged DAP-SUB dye and the cationic surfactant CTAB. Triton X-114 was then employed as a non-ionic surfactant to facilitate the cloud point extraction (CPE) procedure. The method exhibited a linear range of 0.25–6 mg/L, with limits of detection (LOD) and quantification (LOQ) of 0.0808 mg/L and 0.245 mg/L, respectively. Good sensitivity was achieved, with a distribution ratio (D) of 3.22 and a preconcentration factor (PF) of 20. Salbutamol was used as a green reagent according to the PBT (persistent, bioaccumulative, and toxic) criteria, and only a small volume of ethanol was required for desorption, significantly reducing solvent waste. The IP-CPE method was further validated using environmental assessment tools BAGI, CACI, and AGREES, all of which confirmed its compliance with green analytical chemistry principles. Overall, the proposed method provides a simple, low-cost, environmentally friendly, and accurate procedure for the preconcentration and determination of dapsone.

New insights from the integration of dapsone, flutamide, tea tree oil, and rose oil as a topical combined microemulsion for the management of Acne Vulgaris: Design, development, and in vitro/in vivo characterization

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.

The shipboard power system (SPS) composed of multiple zones including both AC-SPS and DC-SPS has become the development trend of all electric ships (AES). In order to cope with the sudden drop in voltage or frequency caused by pulsed power load (PPL) in SPS, this paper proposes a model-predictive-based power management. Firstly, for the important bidirectional power converters (BPC) in multi-zonal SPS, multi-functional controller based on modified droop characteristics with the defined mutual power assistance components, local power management components and mode transfer coefficients are established. Then, power management with predicted DC bus voltage and AC bus frequency values is developed to calculate the mode transfer coefficients and schedule the different operation modes of DC and AC zones. With the proposed power energy management, BPC can still maintain the operation of adjacent zones which lose the voltage/frequency support resources. Furthermore, the fast dynamic response of PPL can be well realized with the help of model predictive control and the unnecessary power transmission loss can be avoid due to the adaptive mode transfer coefficients. Finally, the results of controller hardware in the loop (HIL) tests verify the correctness and effectiveness of the proposed power energy management.

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.

Dapsone (DAP) is an anti-inflammatory and antimicrobial active pharmaceutical ingredient used to treat, e.g., AIDS-related diseases. However, low solubility is a feature hampering its efficient use. First, deep eutectic solvents (DES) were used as solubilizing agents for DAP as an alternative to traditional solvents. Second, intermolecular interactions in the systems were described and quantified. Finally, the solubility prediction model, previously created using the machine learning protocol, was extended and improved using new data obtained for eutectic systems. New DES were created by blending choline chloride (ChCl) with 6 selected polyols. The solubility of DAP in these solvents was measured spectrophotometrically. The impact of water dilution on the solubility curve was investigated. Experimental research was enriched with theoretical interpretations of intermolecular interactions, identifying the most probable pairs in the systems. Dapsone self-association and its ability to interact with components of the analyzed systems were considered. Thermodynamic characteristics of pairs were utilized as molecular descriptors in the machine learning process, predicting solubility in both traditional organic solvents and the newly designed DES. The newly formulated solvents demonstrated significantly higher efficiency compared to traditional organic solvents, and a small addition of water increased solubility, indicating its role as a co-solvent. The interpretation of the mechanism of DAP solubility highlighted the competitive nature of self-association and pair formation. Thermodynamic parameters characterizing affinity were instrumental in developing an efficient model for theoretical screening across diverse solvent classes. The study emphasized the necessity of retraining models when introducing new experimental data, as exemplified by enriching the model with data from DES. The research showcased the efficacy of developing new DES for enhancing solubility and creating environmentally and pharmaceutically viable systems, using DAP as an example. Molecular interactions proved valuable in understanding solubility mechanisms and formulating predictive models through machine learning processes.

Heavy metals exist in different water resources and can threaten human health, inducing several chronic illnesses such as cancer and renal diseases. Therefore, this work dealt with the fabrication of highly efficient nanomembranes based on silver nanoparticle (Ag NP)-doped hybrid polyvinyl chloride (PVC) by dapsone (DAP) using an in situ method. Fourier-transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD) analysis were used to confirm the hybridization of PVC as well as the crystalline structure of hybrid PVC nanocomposites. Three varying proportions of Ag NPs (i.e., 0.1, 0.2, and 0.3%) were used to fabricate hybrid PVC-DAP nanomembranes. The Brunauer-Emmet-Teller (BET) method was used to estimate membrane surface area, porosity and distribution of pore volume. The mechanical strength and antibacterial properties of the cased films notably improved when Ag NPs were added depending on the NP ratio inside the matrix. Results obtained from adsorption experiments of PVC-DAP nanomembranes at 35 °C revealed that the optimum nanomembrane was achieved at 0.2% NPs and its percentage of removal effectiveness ranged from 71 to 95% depending on the ion type. The surface morphology of the PVC-DAP-0.2 Ag NPs before and after the adsorption process of the metal ions was analyzed using SEM-EDX. Moreover, the impact of other parameters such as the initial concentrations, pH media, temperature, and contacting time, on the adsorption efficiency of PVC-DAP-0.2 Ag NPs was also investigated. Furthermore, kinetic and adsorption isotherm models were suggested to describe the adsorption efficiency of the PVC-DAP-0.2 Ag NP membrane, and the uptake mechanism of metal ion removal was studied. The obtained outcomes for these fabricated nanomembranes demonstrated that they could be potential candidates for water purification and other potential purposes including biomedical areas.

Several studies have demonstrated the feasibility of in situ co-crystallization in different pharmaceutical processes such as spray drying, hot melt extrusion, and fluidized bed granulation (FBG) to produce co-crystal-in-excipient formulations. However, no previous studies have examined such a one step in situ co-crystallization process for co-crystal formulations where the coformer is a polymer. In the current study, we explored the use of FBG to produce co-crystal granules of dapsone (DAP) and different molecular weight polyethylene glycols (PEGs). Solvent evaporation (SE) was proven to generate DAP-PEGs co-crystals at a particular weight ratio of 55:45 w/w between DAP and PEG, which was subsequently used in FBG, using microcrystalline cellulose and hydroxypropyl methyl cellulose as filler excipient and binder, respectively. FBG could generate co-crystals with higher purity than SE. Granules containing DAP-PEG 400 co-crystal could be prepared without any additional binder. DAP-PEG co-crystal granules produced by FBG demonstrated superior pharmaceutical properties, including flow properties and tableting properties, compared to DAP and DAP-PEG co-crystals prepared by SE. Overall, in situ co-crystallization via FBG can effectively produce API-polymer co-crystals and enhance the pharmaceutical properties.

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.

Selection of appropriate dapsone and poly(1-vinylpyrrolidone-co-vinyl acetate) ratios for the preparation of amorphous solid dispersions

Drug delivery systems (DDSs) that are derived from biocompatible carriers are attractive platforms for sustained release of drugs. In particular, sustained and controlled release of poorly soluble BCS (Biopharmaceutics Classification System) class IV drugs is important and this requires the development of new DDSs. In this work, we exploit two porous metal-organic frameworks (MOFs) MIL-100(Fe) and MIL-53(Fe) as carriers/DDSs for the release of two BCS class IV drugs hydrochlorothiazide (HCT) and dapsone (DAP). The chosen MOFs are known to possess good physicochemical stability and we realized high drug loading capacity that is attributed to the high porosity of the MOFs. The drug-encapsulated MOFs were characterized thoroughly and our results show ∼23.1% loading of HCT in MIL-100(Fe) and ∼27.6% loading of DAP in MIL-Fe(53), respectively. The release study of these drugs was carried out under simulated physiological conditions that shows sustained release of the drug molecules from the MOFs up to 72 h. Cell viability studies through MTT assays show insignificant cytotoxicity signalling biocompatibility of the proposed DDSs. Our investigations suggest MIL-100(Fe) and MIL-53(Fe) are potential DDSs for enhancing the performance of poorly soluble drugs HCT and DAP.

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

Voltage source converter (VSC) based DC segemenation system has great prospect applications because it can limit the short- circuit current level, prevent cascading failure, and improve the power supply reliability of the urban power grid. However, the capitalized cost and the volume are the main problems that hinder the development of the VSC-DC segmentation technology. To tackle these problems, this paper proposes a novel redundancy based VSC-DC segmentation design to decrease the total demanding capacity of the VSC converters, realizing the ecomonic and practical interconnection of different AC zones for urban power grid. Firstly, the topology of the redundancy based VSC-DC segmentation system is proposed in details. Secondly, the design principle of the proposed system is discussed. Moreover, an equal power loading rate based emergency control strategy is proposed to make full use of the proposed redundancy based VSC-DC segmentation system. Finally, a case of three zones interconnected by the proposed system is adopted to validate the correctness and the effectiveness of the proposed system.

Topical formulations composed of API-pure crystals have been increasingly studied, especially in regards to the impact of particle size in penetration efficiency. Less attention, however, has been devoted to the solid-state properties of drugs delivered to the skin. In this study, we address the effect of formulation composition on the crystal form existing in topical products. Dapsone (DAP) gel formulations were prepared by mixing an organic solution containing DAP with an aqueous solution containing polymers and preservatives. The organic solvent was chosen as ethoxydiglycol (DEGEE), polyethylene glycol (PEG), or 1-methyl-2-pirrolidone (MPR) to assess the impact of composition on DAP crystal form. Such solvent variations resulted in different particulate matter. In terms of crystalline nature, the presence of DEGEE in formulations induced the crystallization of DAP hydrate, while PEG cocrystal and a mixture of hydrate and MPR solvate crystallized from the same amounts of PEG and MPR, respectively. Microscopic analysis of the gels showed heterogeneous particles with different characteristics. The behavior of gels after application to the skin was also tested. Interestingly, the different formulations seemed to accumulate in different regions of the skin. This could be the result of the effect of vehicle composition/excipients on the characteristics of the skin, such as hydration. The site-specific accumulation, however, was more pronounced in crystal-loaded gels as opposed to blank formulations. These results indicate that future studies should consider the effect of formulation composition on the API crystal form landscape as part of the strategies used to successfully target drug delivery to the skin.

Objective(s):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.

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.

Abstract This study aimed to evaluate the efficacy of mesenchymal stem cells (MSC), alone or associated with dapsone (DAP), in treating dermonecrotic wounds caused by Loxosceles laeta venom. Twenty-five male rabbits were distributed into five groups. Negative control received ultrapure water (C-), whilst all other groups were injected with 20 μg of L. laeta venom. After 4 hours, each group received one of the following treatments: PBS (C+), DAP, MSC, and DAP+MSC. Animals were evaluated daily and photographic records made for analysis of wound area. Twelve days after, animals were euthanized and skin samples removed for histological analysis. We observed that DAP showed the best percentage of wound contraction at day 3. In the treatments using MSCs, a negative value of wound contraction was observed for the isolated MSCs, as well as a lower contraction value for the association of the MSC + DAP when compared to PBS, probably, by the increase in initial infammation after the application of stem cells, due to the fact that MSCs secrete a broad spectrum of bioactive molecules such as cytokines and growth factors that favor regeneration. Histologically, it was observed that animals of C+ showed extensive areas of necrosis, ulcers, neutrophilic infiltrate, and mineralization. Collagen deposition showed increase in MSC+DAP treatment, however vascularization remained unchanged. This is the first report using MSC and MSC+DAP as a treatment for cutaneous loxoscelism and more studies are needed to determine its use as an alternative therapy for dermonecrotic lesions caused by Loxosceles spider.