Nanoemulsion containing dapsone for topical administration: a study of in vitro release and epidermal permeation

Leprosy: Comprehensive insights into pathology, immunology, and cutting-edge treatment strategies, integrating nanoparticles and ethnomedicinal plants

Mycobacterium leprae is the causative agent responsible for the chronic disease known as leprosy. This condition is characterized by dermal involvement, often leading to peripheral nerve damage, sensory-motor loss, and related abnormalities. Both innate and acquired immunological responses play a role in the disease, and even in individuals with lepromatous leprosy, there can be a transient increase in T cell immunity during lepromatous reactions. Diagnosing of early-stage leprosy poses significant challenges. In this context, nanoparticles have emerged as a promising avenue for addressing various crucial issues related to leprosy. These include combatting drug resistance, mitigating adverse effects of conventional medications, and enhancing targeted drug delivery. This review serves as a comprehensive compilation, encompassing aspects of pathology, immunology, and adverse effects of multidrug delivery systems in the context of leprosy treatment. Furthermore, the review underscores the significance of ethnomedicinal plants, bioactive secondary metabolites, and nanotherapeutics in the management of leprosy. It emphasizes the potential to bridge the gap between existing literature and ongoing research efforts, with a profound scope for validating traditional claims, developing herbal medicines, and formulating nanoscale drug delivery systems that are safe, effective, and widely accepted.

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.

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.

Nanotechnology-based Drug Delivery Systems as Potential for Skin Application: A Review

Administration of substances through the skin represents a promising alternative, in relation to other drug administration routes, due to its large body surface area, in order to offer ideal and multiple sites for drug administration. In addition, the administration of drugs through the skin avoids the first-pass metabolism, allowing an increase in the bioavailability of drugs, as well as reducing their side effects. However, the stratum corneum (SC) comprises the main barrier of protection against external agents, mainly due to its structure, composition and physicochemical properties, becoming the main limitation for the administration of substances through the skin. In view of the above, pharmaceutical technology has allowed the development of multiple drug delivery systems (DDS), which include liquid crystals (LC), cubosomes, liposomes, polymeric nanoparticles (PNP), nanoemulsions (NE), as well as cyclodextrins (CD) and dendrimers (DND). It appears that the DDS circumvents the problems of drug absorption through the SC layer of the skin, ensuring the release of the drug, as well as optimizing the therapeutic effect locally. This review aims to highlight the DDS that include LC, cubosomes, lipid systems, PNP, as well as CD and DND, to optimize topical skin therapies.

Design and optimization of nano invasomal gel of Glibenclamide and Atenolol combination: in vitro and in vivo evaluation

Background

There are many circumstances where chronic disease is associated with other disorders, especially in diseases such as diabetes with noncommunicable disease risk factors, such as hypertension. The current therapies for treating such chronic comorbid diseases are limited and challenging due to the difficulties in overcoming the side effects from complex therapeutic treatment regimen. The present study is aimed to develop and optimize the combinational nano invasomal gel of Glibenclamide (GLB) and Atenolol (ATN) as a novel combination therapy for comorbid treatment of diabetic hypertensive patients. The developed formulations were characterized for various parameters, including in-vitro skin permeation, skin irritation, in-vivo antidiabetic, and antihypertensive activities.

Results

OCNIG showed that the % entrapment efficiency of GLB is 96.67 ± 0.65% and % entrapment efficiency of ATN is 93.76 ± 0.89%, flux of GLB (240.43 ± 1.76 μg/cm2/h), and flux of ATN (475.2 ± 1.54 μg/cm2/h) which was found to conform to the expected value. The results indicated desired release and permeation profiles. Optimized formulation showed significant pharmacokinetic properties, which shows improvement in bioavailability by 134.30% and 180.32% respectively for two drugs, when compared to marketed oral preparation. Pharmacodynamic studies showed improved and prolonged management of diabetes and hypertension in Wistar rats, compared to oral and drug-loaded nano invasomes formulations.

Conclusion

Overall, the results showed that nano invasomal gel was found to be a useful and promising transdermal delivery system for the treatment of concurrent diseases.

Drug Delivery Systems on Leprosy Therapy: Moving Towards Eradication?

Leprosy disease remains an important public health issue as it is still endemic in several countries. Mycobacterium leprae, the causative agent of leprosy, presents tropism for cells of the reticuloendothelial and peripheral nervous system. Current multidrug therapy consists of clofazimine, dapsone and rifampicin. Despite significant improvements in leprosy treatment, in most programs, successful completion of the therapy is still sub-optimal. Drug resistance has emerged in some countries. This review discusses the status of leprosy disease worldwide, providing information regarding infectious agents, clinical manifestations, diagnosis, actual treatment and future perspectives and strategies on targets for an efficient targeted delivery therapy.

Influence of Terpene Type on the Release from an O/W Nanoemulsion: Experimental and Theoretical Studies

The interaction between a drug molecule and its carrier’s components is an important factor which influences the drug release profile. For this purpose, molecular dynamics (MD) may be the in silico tool which can help to understand the mechanism of drug loading/release. The aim of this work is to explain the effect of interactions between different types of terpenes, namely perillyl alcohol, forskolin, ursolic acid, and the nanoemulsion droplet core, on the release by means of experimental and theoretical studies. The basic nanoemulsion was composed of caprylic/capric triglyceride as the oil phase, polysorbate 80 as the emulsifier, and water. The in vitro release tests from a terpene-loaded nanoemulsion were carried out to determine the release profiles. The behavior of terpenoids in the nanoemulsion was also theoretically investigated using the molecular dynamics method. The forskolin-loaded nanoemulsion showed the highest percentage of drug release (almost 80% w/w) in contrast to ursolic acid and perillyl alcohol-loaded nanoemulsions (about 53% w/w and 19% w/w, respectively). The results confirmed that the kinetic model of release was terpene-type dependent. The zero-order model was the best to describe the ursolic acid release profile, while the forskolin and the perillyl alcohol followed a first-order and Higuchi model, respectively. Molecular dynamics simulations, especially energetical analysis, confirmed that the driving force of terpenes diffusion from nanoemulsion interior was their interaction energy with a surfactant.

Biocompatible Nutmeg Oil-Loaded Nanoemulsion as Phyto-Repellent

Plant essential oils are widely used in perfumes and insect repellent products. However, due to the high volatility of the constituents in essential oils, their efficacy as a repellent product is less effective than that of synthetic compounds. Using a nanoemulsion as a carrier is one way to overcome this disadvantage of essential oils. Nutmeg oil-loaded nanoemulsion (NT) was prepared using a high speed homogenizer and sonicator with varying amounts of surfactant, glycerol, and distilled water. Using a phase diagram, different formulations were tested for their droplet size and insect repellent activity. The nanoemulsion containing 6.25% surfactant and 91.25% glycerol (NT 6) had the highest percentage of protection (87.81%) in terms of repellent activity among the formulations tested for the 8 h duration of the experiment. The droplet size of NT 6 was 217.4 nm, and its polydispersity index (PDI) was 0.248. The zeta potential value was -44.2 mV, and the viscosity was 2.49 Pa.s at pH 5.6. The in vitro release profile was 71.5%. When the cytotoxicity of NT 6 at 400 μg/mL was tested using the MTS assay, cell viability was 97.38%. Physical appearance and stability of the nanoemulsion improved with the addition of glycerol as a co-solvent. In summary, a nutmeg oil-loaded nanoemulsion was successfully formulated and its controlled release of the essential oil showed mosquito repellent activity, thus eliminating the disadvantages of essential oils.

Alternatives to Biological Skin in Permeation Studies: Current Trends and Possibilities

: The transdermal route of drugs has received increased attention in recent years due to numerous advantages over the oral and injectable routes, such as avoidance of the hepatic metabolism, protection of drugs from the gastrointestinal tract, sustained drug delivery, and good patient compliance. The assessment of ex vivo permeation during the pharmaceutical development process helps in understanding the product quality and performance of a transdermal delivery system. Generally, excised human skin relevant to the application site or animal skin is recommended for ex vivo permeation studies. However, the limited availability of the human skin and ethical issues surrounding the use of animal skin rendered these models less attractive in the permeation study. In the last three decades, enormous efforts have been put into developing artificial membranes and 3D cultured human skin models as surrogates to the human skin. This manuscript provides an insight on the European Medicines Agency (EMA) guidelines for permeation studies and the parameters affected when using Franz diffusion cells in the permeation study. The need and possibilities for skin alternatives, such as artificially cultured human skin models, parallel artificial membrane permeability assays (PAMPA), and artificial membranes for penetration and permeation studies, are comprehensively discussed.

Evaluation of Skin Permeation and Retention of Topical Dapsone in Murine Cutaneous Leishmaniasis Lesions

The oral administration of dapsone (DAP) for the treatment of cutaneous leishmaniasis (CL) is effective, although serious hematological side effects limit its use. In this study, we evaluated this drug for the topical treatment of CL. As efficacy depends on potency and skin penetration, we first determined its antileishmanial activity (IC50 = 100 μM) and selectivity index in vitro against Leishmania major-infected macrophages. In order to evaluate the skin penetration ex vivo, we compared an O/W cream containing DAP that had been micronized with a pluronic lecithin emulgel, in which the drug was solubilized with diethylene glycol monoethyl ether. For both formulations we obtained similar low flux values that increased when the stratum corneum and the epidermis were removed. In vivo efficacy studies performed on L. major-infected BALB/c mice revealed that treatment not only failed to cure the lesions but made their evolution and appearance worse. High plasma drug levels were detected and were concomitant with anemia and iron accumulation in the spleen. This side effect was correlated with a reduction of parasite burden in this organ. Our results evidenced that DAP in these formulations does not have an adequate safety index for use in the topical therapy of CL.

Kinetic Study of Controlled Asphaltene Inhibitor Release from Nanoemulsions

Asphaltene aggregation and subsequent precipitation in the nonpolar medium may have a profound effect on plugging wellbores and production equipment. Continuing our work on controlled release of asphaltene inhibitor (AI) by using nanoemulsions (NEs), this work provides new evidence about long-term asphaltene stability by using optical measurement and reveals the kinetic processes of inhibitor transport/release mechanisms. Multiple light scattering (Turbiscan) and dynamic light scattering have been used to study "in situ" the effectiveness and performance of the proposed controlled release in three cases of asphaltene aggregation/precipitation in the presence of: (i) strong organic acids (dodecyl benzene sulfonic acid, DBSA), (ii) NEs (blank NEs), and (iii) NEs loaded with DBSA (DBSA NEs). The results suggested that the new approach reduced the amount of AI by ∼20 times and achieved high asphaltene inhibition efficiency of ∼84% with a prolonged release time. A mechanistic understanding of the controlled release effect was proposed based on the effect of DBSA NEs on the asphaltene particle morphology variation, which was related to the hydrophilicity of DBSA and the strong intermolecular interactions among all DBSA NE components. The release mechanism of the AI from the NE was evaluated using eight release models and was found to follow the Korsmeyer-Peppas kinetic model.

Patient Awareness of Antimicrobial Resistance and Antibiotic Use in Acne Vulgaris

Background: Antibiotic resistance presents a threat to public health. In dermatology, antibiotics are used extensively for the treatment of acne, sometimes for extended periods. Thus, awareness of antibiotic resistance among dermatology patients is relevant in clinical practice. Methods: An online survey assessed antibiotic resistance awareness in adults with acne (n=809) and the parents of adolescents with acne (n=210).Results: More than 80 percent of subjects said that they were "somewhat familiar" or "very familiar" with antibiotic resistance. Overall, 86 percent of the survey respondents identified the correct definition of antibiotic resistance, with parents more likely than their children to choose the proper definition of resistance, as follows: "When antibiotics and/or antibacterials are used for a period of time, the infectious organism adapts to them and becomes immune, resulting in less effective treatment" (95% confidence interval). Among subjects who might have been prescribed antibiotic treatment for their acne, including individuals that reported antibiotic treatment and individuals that were not sure, 76.9 percent reported that they would be very or extremely likely to use effective antibiotic-free options if given the opportunity. More than 90 percent of people with acne and their parents agreed that healthcare providers should do more to educate patients about antibiotics and antibiotic resistance. Conclusions: This survey indicated that patients with acne and their parents think more should be done to educate the public about about the potential risks associated with antibiotic use and the availability of antibiotic-free treatment options. Discussions with patients about antibiotic therapies, antibiotic resistance, and alternative therapies represent areas of opportunity for healthcare providers in dermatology.

Biomimetic Solid Lipid Nanoparticles of Sophorolipids Designed for Antileprosy Drugs

The objective of the present work was to develop solid lipid nanoparticles (SLNs) as drug-encapsulating structures by the solvent injection method. In this report, for the first time the inherent potential of lactonic sophorolipid (glycolipid) was exploited to formulate SLNs. A range of different Pluronic copolymers were screened by dynamic and static light scattering with the aim of obtaining most stable SLNs. To comprehend the structure of the SLNs, techniques such as transmission electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, and X-ray diffraction were employed. A clear correlation between the type of Pluronic and size and stability of the SLNs could be drawn. The vector properties of the formed SLNs were assessed for both the encapsulated hydrophobic drugs-rifampicin and dapsone. To elucidate the transport mechanism of drug release, kinetic modeling was carried out on the drug release profiles. The promising results of sophorolipid-based SLNs have actually established a new arena beneath the significantly developed field of SLNs.

Activity of Dapsone versus Community and Hospital Pathogens from the CANWARD Study

BACKGROUND

Topical dapsone gel is a sulfone antibiotic approved for acne treatment. No microbiology studies were conducted during dapsone gel clinical trials and it is unclear whether 1) dapsone has antimicrobial activity that may be of clinical relevance in dermatology and 2) dapsone could affect the normal microbiome of facial skin where it is most commonly applied. This study assessed the in vitro activity of dapsone versus Gram-positive and Gram-negative bacterial pathogens obtained from patients with infections.

METHODS

CANWARD is a national, annual, and ongoing surveillance system to assess the patterns of antibiotic-resistant pathogens in Canada. In 2014, 15 tertiary care medical centers collected 3,511 isolates from blood, respiratory tract, urine, and wounds. Antimicrobial susceptibility was assessed using CLSI broth microdilution method.

RESULTS

Dapsone demonstrated relatively poor activity versus Gram-negative bacilli with most MIC50, MIC90 in the range of 512μg/mL and >512μg/mL, respectively. In contrast, dapsone demonstrated activity versus Gram-positive cocci, such as Staphylococcus (including methicillin-resistant S. aureus [MRSA], methicillin-sensitive S. aureus [MSSA]), Streptococcus, and Enterococcus-several strains of S. epidermidis had MICs of 32 and 64μg/mL; there were strains of E. faecalis with MICs of 8, 16, 32, and 64μg/mL; and several strains of S. agalactiae and S. pyogenes demonstrated dapsone MICs of 4, 8, 16, 32, and 64μg/mL.

CONCLUSION

Dapsone has demonstrated antimicrobial activity in vitro. Whether this activity is part of the mechanism of action of topical dapsone in acne remains unknown. There are limited cutaneous pharmacokinetic data with topical dapsone including skin concentrations achieved with topical dapsone therapy; however, topical dapsone as a 2% nanoemulsion has shown very high (1196-3837.34μg/cm(2)) local skin concentrations. At these high concentrations, topical dapsone would be expected to affect the skin flora of patients with acne (especially Gram-positive cocci, such as Staphylococcus and Streptococcus). These concentrations are multiple times higher (20x-1000x) than the dapsone MICs found for many MSSA, MRSA, S. epidermidis, S. agalactiae, and S. pyogenes, any of which may be present on the skin of acne patients. Whether this results in resistance to dapsone or more importantly results in resistance to chemically unrelated antimicrobials is currently unknown.