Microemulsion formulation design and evaluation for hydrophobic compound: Catechin topical application

Development and Characterization of New Miconazole-Based Microemulsions for Buccal Delivery by Implementing a Full Factorial Design Modeling

This research aimed to develop miconazole-based microemulsions using oleic acid as a natural lipophilic phase and a stabilizer mixture comprising Tween 20 and PEG 400 to solubilize miconazole as an antifungal agent known for its activity in oral candidiasis and to improve its bioavailability. The formulation and preparation process was combined with a mathematical approach using a 23-full factorial plan. Fluid and gel-like microemulsions were obtained and analyzed considering pH, conductivity, and refractive index, followed by extensive analyses focused on droplet size, zeta potential, rheological behavior, and goniometry. In vitro release tests were performed to assess their biopharmaceutical characteristics. Independent variables coded X1-Oleic acid (%, w/w), X2-Tween 20 (%, w/w), and X3-PEG 400 (%, w/w) were analyzed in relationship with three main outputs like mean droplet size, work of adhesion, and diffusion coefficient by combining statistical tools with response surface methodology. The microemulsion containing miconazole base-2%, oleic acid-5%, Tween 20-40%, PEG 400-20%, and water-33% exhibited a mean droplet size of 119.6 nm, a work of adhesion of 71.98 mN/m, a diffusion coefficient of 2.11·10-5 cm2/s, and together with remarked attributes of two gel-like systems formulated with higher oil concentrations, modeled the final optimization step of microemulsions as potential systems for buccal delivery.

Topical Microemulsions: Skin Irritation Potential and Anti-Inflammatory Effects of Herbal Substances

Microemulsions (MEs) have gained prominence as effective drug delivery systems owing to their optical transparency, low viscosity, and thermodynamic stability. MEs, when stabilized with surfactants and/or co-surfactants, exhibit enhanced drug solubilization, prolonged shelf life, and simple preparation methods. This review examines the various types of MEs, explores different preparation techniques, and investigates characterization approaches. Plant extracts and bioactive compounds are well established for their utilization as active ingredients in the pharmaceutical and cosmetic industries. Being derived from natural sources, they serve as preferable alternatives to synthetic chemicals. Furthermore, they have demonstrated a wide range of therapeutic effects, including anti-inflammatory, antimicrobial, and antioxidant activities. However, the topical application of plant extracts and bioactive compounds has certain limitations, such as low skin absorption and stability. To overcome these challenges, the utilization of MEs enables enhanced skin absorption, thereby making them a valuable mode of administration. However, considering the significant surfactant content in MEs, this review evaluates the potential skin irritation caused by MEs containing herbal substances. Additionally, the review explores the topical application of MEs specifically for herbal substances, with an emphasis on their anti-inflammatory properties.

Improvement in Skin Penetration Capacity of Linalool by Using Microemulsion as a Delivery Carrier: Formulation Optimization and In Vitro Evaluation

Linalool is an aromatic oil with analgesic, anti-inflammatory and anti-UVB-induced skin damage effects. The aim of this study was to develop a linalool-loaded microemulsion formulation for topical application. In order to quickly obtain an optimal drug-loaded formulation, statistical tools of the response surface methodology and a mixed experimental design with four independent variables of oil (X₁), mixed surfactant (X₂), cosurfactant (X₃) and water (X₄) were used to design a series of model formulations in order to analyze the effect of the composition on the characteristics and permeation capacity of linalool-loaded microemulsion formulations and to obtain an appropriate drug-loaded formulation. The results showed that the droplet size, viscosity and penetration capacity of linalool-loaded formulations were significantly affected by formulation component proportions. The skin deposition amount of the drug and flux of such formulations expressively increased about 6.1-fold and 6.5-fold, respectively, when compared to the control group (5% linalool dissolved in ethanol). After 3 months of storage, the physicochemical characteristics and drug level did not show a significant change. The linalool formulation-treated rat skin showed non-significant irritation compared to skin treatments in the distilled-water-treated group. The results showed that specific microemulsion applications might be considered as potential drug delivery carriers for essential oil topical application.

Synthesis and Characterization of 𝒌-Carrageenan/PVA Nanocomposite Hydrogels in Combination with MgZnO Nanoparticles to Evaluate the Catechin Release

In the current study, nanocomposites were prepared by combining k-carrageenan, polyvinyl alcohol (PVA), and doped nanoparticles (Magnesium oxide) MgO, (Magnesium Zinc oxide) MgZnO 1%, MgZnO 3%, and MgZnO 5%. The nanoparticles were synthesized by a sol-gel method and mixed with a mixture of k-carrageenan/PVA (Ca/PVA) in various ratios. The structure of the composites was analyzed using thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The Ca/PVA mixture was then mixed with nanoparticles and loaded with active ingredient, catechin. Scanning electron microscope (SEM) and texture analysis were performed to analyze the nanocomposites. Entrapment efficiency (EE%) and drug release studies confirmed that k-carrageenan/PVA/MgZnO 5% had the highest EE% at 81.58% and a drug release of 75.21% ± 0.94. The EE% of k-carrageenan/PVA/MgO was 55.21% and its drug release was 45%. This indicates that ZnO plays an effective role in the structure and performance of Ca/PVA composites. The SEM images of MgO composites show smoother surfaces compared to MgZnO composites. This may be one of the reasons for the increased EE% and drug release of MgZnO composites. The addition of ZnO to the composite structure can lead to the appearance of pores on the surface of the composite, increasing entrapment and drug release.

Nanoencapsulation of Tea Catechins for Enhancing Skin Absorption and Therapeutic Efficacy

Tea catechins are a group of flavonoids that show many bioactivities. Catechins have been extensively reported as a potential treatment for skin disorders, including skin cancers, acne, photoaging, cutaneous wounds, scars, alopecia, psoriasis, atopic dermatitis, and microbial infection. In particular, there has been an increasing interest in the discovery of cosmetic applications using catechins as the active ingredient because of their antioxidant and anti-aging activities. However, active molecules with limited lipophilicity have difficulty penetrating the skin barrier, resulting in low bioavailability. Nevertheless, topical application is a convenient method for delivering catechins into the skin. Nanomedicine offers an opportunity to improve the delivery efficiency of tea catechins and related compounds. The advantages of catechin-loaded nanocarriers for topical application include high catechin loading efficiency, sustained or prolonged release, increased catechin stability, improved bioavailability, and enhanced accumulation or targeting to the nidus. Further, various types of nanoparticles, including liposomes, niosomes, micelles, lipid-based nanoparticles, polymeric nanoparticles, liquid crystalline nanoparticles, and nanocrystals, have been employed for topical catechin delivery. These nanoparticles can improve catechin permeation via close skin contact, increased skin hydration, skin structure disorganization, and follicular uptake. In this review, we describe the catechin skin delivery approaches based on nanomedicine for treating skin disorders. We also provide an in-depth description of how nanoparticles effectively improve the skin absorption of tea catechins and related compounds, such as caffeine. Furthermore, we summarize the possible future applications and the limitations of nanocarriers for topical delivery at the end of this review article.

Chronic Inflammation in Non-Healing Skin Wounds and Promising Natural Bioactive Compounds Treatment

Chronic inflammation is one of the hallmarks of chronic wounds and is tightly coupled to immune regulation. The dysregulation of the immune system leads to continuing inflammation and impaired wound healing and, subsequently, to chronic skin wounds. In this review, we discuss the role of the immune system, the involvement of inflammatory mediators and reactive oxygen species, the complication of bacterial infections in chronic wound healing, and the still-underexplored potential of natural bioactive compounds in wound treatment. We focus on natural compounds with antioxidant, anti-inflammatory, and antibacterial activities and their mechanisms of action, as well as on recent wound treatments and therapeutic advancements capitalizing on nanotechnology or new biomaterial platforms.

Insights from a Box-Behnken Optimization Study of Microemulsions with Salicylic Acid for Acne Therapy

The present study brings to attention a method to develop salicylic acid-based oil in water (O/W) microemulsions using a tensioactive system based on Tween 80, lecithin, and propylene glycol (PG), enriched with a vegetable oat oil phase and hyaluronic acid. The systems were physically characterized and the Quality by design approach was applied to optimize the attributes of microemulsions using Box-Behnken modeling, combined with response surface methodology. For this purpose, a 33 fractional factorial design was selected. The effect of independent variables namely X1: Tween 80/PG (%), X2: Lecithin (%), X3: Oil phase (%) was analyzed considering their impact upon the internal structure and evaluated parameters chosen as dependent factors: viscosity, mean droplet size, and work of adhesion. A high viscosity, a low droplet size, an adequate wettability-with a reduced mechanical work-and clarity were considered as desirable for the optimal systems. It was found that the optimal microemulsion which complied with the established conditions was based on: Tween 80/PG 40%, lecithin 0.3%, oat oil 2%, salicylic acid 0.5%, hyaluronic acid 1%, and water 56.2%. The response surface methodology was considered an appropriate tool to explain the impact of formulation factors on the physical properties of microemulsions, offering a complex pattern in the assessment of stability and quality attributes for the optimized formulation.

Polyphenols as Antioxidants for Extending Food Shelf-Life and in the Prevention of Health Diseases: Encapsulation and Interfacial Phenomena

Toxicity caused by the exposure to human-made chemicals and environmental conditions has become a major health concern because they may significantly increase the formation of reactive oxygen species (ROS), negatively affecting the endogenous antioxidant defense. Living systems have evolved complex antioxidant mechanisms to protect cells from oxidative conditions. Although oxidative stress contributes to various pathologies, the intake of molecules such as polyphenols, obtained from natural sources, may limit their effects because of their antioxidant and antimicrobial properties against lipid peroxidation and against a broad range of foodborne pathogens. Ingestion of polyphenol-rich foods, such as fruits and vegetables, help to reduce the harmful effects of ROS, but the use of supramolecular and nanomaterials as delivery systems has emerged as an efficient method to improve their pharmacological and therapeutic effects. Suitable exogenous polyphenolic antioxidants should be readily absorbed and delivered to sites where pathological oxidative damage may take place, for instance, intracellular locations. Many potential antioxidants have a poor bioavailability, but they can be encapsulated to improve their ideal solubility and permeability profile. Development of effective antioxidant strategies requires the creation of new nanoscale drug delivery systems to significantly reduce oxidative stress. In this review we provide an overview of the oxidative stress process, highlight some properties of ROS, and discuss the role of natural polyphenols as bioactives in controlling the overproduction of ROS and bacterial and fungal growth, paying special attention to their encapsulation in suitable delivery systems and to their location in colloidal systems where interfaces play a crucial role.

Enhancement of the Topical Bioavailability and Skin Whitening Effect of Genistein by Using Microemulsions as Drug Delivery Carriers

Genistein, the most abundant isoflavone of the soy-derived phytoestrogen compounds, is a potent antioxidant and inhibitor of tyrosine kinase, which can inhibit UVB-induced skin carcinogenesis in hairless mice and UVB-induced erythema on human skin. In current study, genistein-loaded microemulsions were developed by using the various compositions of oil, surfactants, and co-surfactants and used as a drug delivery carrier to improve the solubility, peremability, skin whitening, and bioavailbility of genistein. The mean droplet size and polydispersity index of all formulations was less than 100 nm and 0.26 and demonstrated the formation of microemulsions. Similarly, various studies, such as permeation, drug skin deposition, pharmacokinetics, skin whitening test, skin irritation, and stability, were also conducted. The permeability of genistein was significantly affected by the composition of microemulsion formulation, particular surfactnat, and cosurfactant. In-vitro permeation study revealed that both permeation rate and deposition amount in skin were significantly increased from 0.27 μg/cm²·h up to 20.00 μg/cm²·h and 4.90 up to 53.52 μg/cm², respectively. In in-vivo whitening test, the change in luminosity index (ΔL*), tended to decrease after topical application of genistein-loaded microemulsion. The bioavailability was increased 10-fold by topical administration of drug-loaded microemulsion. Conclusively, the prepared microemulsion has been enhanced the bioavailability of genistein and could be used for clinical purposes.

Microemulsified Gel Formulations for Topical Delivery of Clotrimazole: Structural and In Vitro Evaluation

Microemulsified gels (μEGs) with fascinating functions have become indispensable as topical drug delivery systems due to their structural flexibility, high stability, and facile manufacturing process. Topical administration is an attractive alternative to traditional methods because of advantages such as noninvasive administration, bypassing first-pass metabolism, and improving patient compliance. In this article, we report on the new formulations of microemulsion-based gels suitable for topical pharmaceutical applications using biocompatible and ecological ingredients. For this, two biocompatible μE formulations comprising clove oil/Brij-35/water/ethanol (formulation A) and clove oil/Brij-35/water/1-propanol (formulation B) were developed to encapsulate and improve the load of an antimycotic drug, Clotrimazole (CTZ), and further gelatinized to control the release of CTZ through skin barriers. By delimiting the pseudo-ternary phase diagram, optimum μE formulations with clove oil (∼15%) and Brij-35 (∼30%) were developed, keeping constant surfactant/co-surfactant ratio (1:1), to upheld 2.0 wt % CTZ. The as-developed formulations were further converted into smart gels by adding 2.0 wt % carboxymethyl cellulose (CMC) as a cross-linker to adhere to the controlled release of CTZ through complex skin barriers. Electron micrographs show a fine, monodispersed collection of CTZ-μE nanodroplets (∼60 nm), which did not coalesce even after gelation, forming spherical CTZ-μEG (∼90 nm). However, the maturity of CTZ nanodroplets observed by dynamic light scattering suggests the affinity of CTZ for the nonpolar microenvironment, which was further supported by the peak-to-peak correlation of Fourier transform infrared (FTIR) analysis and fluorescence measurement. In addition, HPLC analysis showed that the in vitro permeation release of CTZ-μEG from rabbit skin in the ethanolic phosphate buffer (pH = 7.4) was significantly increased by >98% within 6.0 h. This indicates the sustained release of CTZ in μEBG and the improvement in transdermal therapeutic efficacy of CTZ over its traditional topical formulations.

Lipid-based emulsion drug delivery systems - a comprehensive review

Lipid-based emulsion system - a subcategory of emulsion technology, has emerged as an enticing option to improve the solubility of the steadily rising water-insoluble candidates. Along with enhancing solubility, additional advantages such as improvement in permeability, protection against pre-systemic metabolism, ease of manufacturing, and easy to scale-up have made lipid-based emulsion technology very popular among academicians and manufacturers. The present article provides a comprehensive review regarding various critical properties of lipid-based emulsion systems, such as microemulsion, nanoemulsion, SMEDDS (self microemulsifying drug delivery system), and SNEDDS (self nanoemulsifying drug delivery system). The present article also explains in detail the similarities and differences between them, the stabilization mechanism, methods of preparation, excipients used to prepare them, and evaluation techniques. Subtle differences between nearly related terminologies such as microemulsion and nanoemulsion, SMEDDS, and SNEDDS are also explained in detail to clarify the basic differences. The present article also gives in-depth information regarding the chemical structure of various lipidic excipients, various possible chemical modifications to modify their inherent properties, and their regulatory status for rational selection.

Improved skin permeability and whitening effect of catechin-loaded transfersomes through topical delivery

The aim of the study was to prepare catechin-loaded transfersomes to enhance drug permeability through topical administration for the skin protection against ultraviolet radiation induced photo-damage. The results showed that the catechin-loaded transfersomes were monodispersed with polydispersity index (PDI) < 0.2, <200 nm in particle size and with high encapsulation efficiency (E.E.%) greater than 85%. The in vitro skin permeation test indicated that the catechin-loaded transfersomes enhanced the skin permeability by 85% compared to the catechin aqueous solution. Similarly, the in-vivo skin whitening study demonstrated that F5 transfersome formulation was effective in tyrosinase inhibition and had good biocompatibility to the guinea pig skin. Finally, the stability study showed that both physicochemical properties and E.E.% of the F5 transferosome formulation were fairly stable after 3 months storage. Therefore, topical administration of catechin-loaded transfersomes could be considered as a potential strategy for the treatment of UV-induced oxidative damage to the skin.

Herbal Drugs and Natural Products in the light of Nanotechnology and Nanomedicine for Developing Drug Formulations

Natural products and medicinal plants have played a vital role in providing healthcare and ensuring well-being for many civilizations since antiquity. It is estimated that around 50% of drugs in the market have a natural product origin especially medicinal plants and herbal drugs, animals, fungi, and marine organisms. Some of these biologically active constituents of extracts have low absorption and distribution which, as a result, lead to loss of bioavailability and efficacy and might hamper their applications in the clinic. To overcome these impediments for the formulation of herbal drugs, food supplements, and essential oils, several nanomedical approaches such as liposomes, microemulsions, polymeric nanoparticles, solid lipid nanoparticles (SLNs), liquid crystal systems (LC), and precursor systems for liquid crystals (PSLCs) have been proposed. Nanoparticles have been used to modify and ameliorate the pharmacokinetic and pharmacodynamic properties of different drugs, thus incorporating biotechnological systems may be useful to enhance the bioavailability and bioactivity of herbal drug formulations. Consequently, essential for any natural compounds is the extent of its absorption after being ingested and its ability to be distributed in various tissues or organs of the body. The present review article aims to give an overview of the recent advancements in developing herbal drug formulations based on nanoparticle technologies.

Preparation and Evaluation of Azelaic Acid Topical Microemulsion Formulation: In Vitro and In Vivo Study

The aim of this study was to design oil in water (O/W) microemulsion formulations for the topical administration of azelaic acid. The permeability of azelaic acid through rat skin and the anti-inflammatory activities of the formulations were conducted to examine the efficacy of the designed formulations. Skin irritation and stability tests were also performed. The permeability of azelaic acid was significantly increased by using O/W microemulsions as carriers. The edema index of ear swelling percentage was significantly recovered by the 5% drug-loaded formulation and a 20% commercial product, demonstrating that the experimental formulation possessed comparable effect with the commercial product on the improvement of inflammation. The experimental formulation did not cause significant skin irritation compared to the negative control group. Moreover, the drug-loaded formulation also showed thermodynamic stability and chemical stability after storage for 30 days. In conclusion, the O/W microemulsion was a potential drug delivery carrier for azelaic acid topical application.

Development of a Solid Formulation Containing a Microemulsion of a Novel Artemisia Extract with Nematocidal Activity for Oral Administration

Background: Intestinal nematode infections are usually treated with benzimidazole drugs, but the emergence of resistance to these drugs has led to an increasing demand of new anthelmintic strategies. A new microemulsion formulation (ME) consisting of an Artemisia absinthium extract with proven nematocidal efficacy was previously developed. The aim of our study is to implement a D-optimal mixture design methodology to increase the amount of a silica material (loaded with this ME) in a tablet formulation, considering its tensile strength and disintegration time. Methods: 16 experiments or combinations of the 6 tablet components (loaded silica, microcrystalline cellulose, polyvinylpyrrolidone, croscarmellose, Syloid^® 244 FP and magnesium stearate) were assessed. Tensile strength and disintegration time models were developed, and an optimization process was carried out. Results: Tensile strength was improved by increasing the polyvinylpyrrolidone content, while croscarmellose decreased the disintegration time. The optimized powder mixture contains 49.7% w/w of the loaded silica material. A compression force of 12 kN was applied to the powder mixture to form tablets with a tensile strength of 2.0 MPa and a disintegration time of 3.8 min. Conclusions: Our results show that D-optimal mixture designs provide a promising approach to formulate liquid-loaded silica materials.

In Vitro Skin Permeation and Antifungal Activity of Naftifine Microemulsions

Objectives

Microemulsions are fluid, isotropic, colloidal systems that have been widely studied as drug delivery systems. The percutaneous transport of active agents can be enhanced by their microemulsion formulation when compared to conventional formulations. The purpose of this study was to evaluate naftifine-loaded microemulsions with the objective of improving the skin permeation of the drug.

Materials and Methods

Microemulsions comprising oleic acid (oil phase), Kolliphor EL or Kolliphor RH40 (surfactant), Transcutol (co-surfactant), and water were prepared and physicochemical characterization was performed. In vitro skin permeation of naftifine from microemulsions was investigated and compared with that of its conventional commercial formulation. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy was used to evaluate the interaction between the microemulsions and the stratum corneum lipids. Candida albicans American Type Culture Collection (ATCC) 10231 and Candida parapsilosis were used to evaluate the antifungal susceptibility of the naftifine-loaded microemulsions.

Results

The microemulsion formulation containing Kolliphor RH40 as co-surfactant increased naftifine permeation through pig skin significantly when compared with the commercial topical formulation (p<0.05). ATR-FTIR spectroscopy showed that microemulsions increased the fluidity of the stratum corneum lipid bilayers. Drug-loaded microemulsions possessed superior antifungal activity against Candida albicans ATCC 10231 and Candida parapsilosis.

Conclusion

This study demonstrated that microemulsions could be suggested as an alternative topical carrier with potential for enhanced skin delivery of naftifine.

In vitro and in vivo studies of micro-depots using tailored microemulsion for sustained local anaesthesia

In clinical practice, lidocaine is used as local anesthetic for the management of post-operative pain. The commercial formulation including gels, injections and ointments showed short duration of action (1 to 2 h). In this paper, the efforts have being made to develop tailored lidocaine-microemulsion (o/w), which on penetration in the skin layer cause micro-depots formation due to destabilization of the microemulsion system. To identify the microemulsion region, pseudo ternary diagrams were constructed using Capmul MCM as oil, Pluronic F68 as tri-block surfactant, polyethylene glycol 200 as co-surfactant at 1:4 and 1:6 ratios (S:Co-S). The selected 5%w/v lidocaine loaded microemulsion [Ld-ME-2(1:4)] was stable in thermodynamic test and during shelf life period (3 months). In ex vivo permeability study, the lidocaine release from Ld-ME-2(1:4) microemulsion was sustained in comparison to the marketed lidocaine ointment. The skin irritation study confirmed the safety of lidocaine loaded microemulsion. Tail flick test showed improved and sustain local anaesthetic effect in comparison to the market ointment. The improved efficacy of microemulsion system, was due to high penetration in the skin layer due to local precipitation of lidocaine from microemulsion. The findings suggest that the tailored microemulsion could be a potential strategy to prolong the local anaesthesia.

Pharmaceutical Topical Delivery of Poorly Soluble Polyphenols: Potential Role in Prevention and Treatment of Melanoma

Melanoma is regarded as the fifth and sixth most common cancer in men and women, respectively, and it is estimated that one person dies from melanoma every hour in the USA. Unfortunately, the treatment of melanoma is difficult because of its aggressive metastasis and resistance to treatment. The treatment of melanoma continues to be a challenging issue due to the limitations of available treatments such as a low response rate, severe adverse reactions, and significant toxicity. Natural polyphenols have attracted considerable attention from the scientific community due to their chemopreventive and chemotherapeutic efficacy. It has been suggested that poorly soluble polyphenols such as curcumin, resveratrol, quercetin, coumarin, and epigallocatechin-3-gallate may have significant benefits in the treatment of melanoma due to their antioxidant, anti-inflammatory, antiproliferative, and chemoprotective efficacies. The major obstacles for the use of polyphenolic compounds are low stability and poor bioavailability. Numerous nanoformulations, including solid lipid nanoparticles, polymeric nanoparticles, micelles, and liposomes, have been formulated to enhance the bioavailability and stability, as well as the therapeutic efficacy of polyphenols. This review will provide an overview of poorly soluble polyphenols that have been reported to have antimetastatic efficacy in melanomas.

Using Microemulsion as Carrier for Drug Transdermal Delivery: The Effect of Surfactants and Cosurfactants

BACKGROUND

The purpose of this study was to evaluate the effect of types of surfactants and cosurfactants on physicochemical properties and permeability of sumatriptan-loaded microemulsions through rat skin.

METHODS

Different types of surfactants and cosurfactants were used to prepare drug-loaded microemulsions. The physicochemical characters and permeability parameters of these formulations were measured.

RESULTS

The experimental microemulsions with varying components had small droplet size ranging from 24.6 nm to 2568.8 nm, low viscosity ranging from 7.49 to 43.34 cps and significant permeation enhancement ratio ranging from 23.0 to 98.6 when compared to the control group.

CONCLUSION

The composition and proportion of surfactants and cosurfactants were key factors for the physiochemical properties of drug-loaded microemulsions. The cumulative transdermal amount of the microemulsion containing mixture surfactant of Laureth-3/Laureth-23 was higher than that of the microemulsion with a mixture of Tween 80/Span 20. In the selected cosurfactant, diethylene glycol monoethyl ether (DEGMEE) showed highest permeation enhancement. Thermodynamic stability tests revealed that the experimental microemulsion was a stable enough formulation to be considered as a suitable carrier for sumatriptan.

Amphotericin B-Loaded Emulgel: Effect of Chemical Enhancers on the Release Profile and Antileishmanial Activity In Vitro

Cutaneous leishmaniasis is a neglected parasitic disease. Treatment is preferably performed with pentavalent antimony associated or not with amphotericin B (AmB). This study aimed to develop an emulgel with different chemical enhancers of cutaneous release. Initially, AmB emulsions were obtained with the chemical promoters, oleic acid and geraniol and without promoter, then for the evaluation of the formulations, a preliminary stability study was carried out where the formulations were submitted to centrifugation, before and after the freeze-thaw cycle and analyzed appearance, color, pH, spreadability, viscosity, conductivity, droplet size, assay, in vitro release study, in vitro antileishmania activity in Leishmania major promastigotes, and macrophage toxicity in the MTT test. The emulsions were yellowish, with no signs of instability after the centrifugation test. The pH range corresponded to that of the skin, which is 4.6 to 5.8, before and after the freeze-thaw cycle, the formulations had good spreadability and did not present significant viscosity differences before and after the freeze-thaw cycle, presenting a non-Newtonian characteristic. AmB content was within the kinetic model of zero order release, the formulation of 3% AmB and 5% oleic acid (formulation 1) was chosen to proceed with the antileishmania activity test and showed potential activity against the in vitro parasite with significant reduction of cytotoxicity on murine macrophages, indicating that the formulation is promising for the treatment of cutaneous leishmaniasis.

Recent advances in topical delivery of flavonoids: A review

Flavonoids are one of the vital classes of bioactive chemicals, abundantly found in plants. These are natural polyphenolic compounds derived from plant metabolites. Their lipophilic nature and poor solubility lead to variable and limited oral bioavailability. The substantial pharmacological properties of flavonoids include antioxidant, anti-inflammatory, antiproliferative, photoprotective, depigmentation, anti-aging which are very promising in the treatment of several skin disorders. Thus, various topical delivery systems of flavonoids have been extensively studied. Mostly, colloidal carriers of flavonoids were reported which are very efficient for topical route with good encapsulation potential, reduced toxicity, and overcome the limitations of conventional dosage forms. This review focuses on various formulations aspects, in vitro characterization and in vivo studies of different classes of flavonoids administered by topical route. Although flavonoids offer tremendous potential in healing the skin conditions categorically, its clinical translation needs in depth safety and efficacy data, meeting established regulatory standards.

Technological development of microemulsions with perspectives for pain treatment: a patent review

INTRODUCTION

Microemulsions are thermodynamically stable translucent systems widely used for systemic delivery of drugs. The present study is the first to analyze the biotechnological potential of microemulsion systems for therapeutic purposes, through transdermal route, for pain treatment.

AREAS COVERED

Patents were searched in the World Intellectual Property Organization (WIPO), European Patent Office (Espacenet), United States Patent and Trademark Office (USPTO) and National Institute of Intellectual Property (INPI). The inclusion criteria were published patents containing the keywords; 'microemulsion' and 'transdermal' in their title or abstract. 208 patents were found. However, only those patents which mentioned in their abstract or in their description the use of microemulsion system (object of invention) for pain treatment were selected. Were excluded duplicate patents and those that did not report pharmacological use of MEs specifically for pain treatment. Thus, sixteen patents were selected and described in the present study.

EXPERT OPINION

Patents were found that focused specifically on the development process of microemulsion systems, the inclusion of essential oils in microemulsions, which place microemulsions as delivery systems for NSAIDs and other substances, as well as microemulsions for transdermal administration. These studies reinforce the therapeutic applicability of MEs in the treatment of acute and chronic pain.

Astaxanthin-alpha tocopherol nanoemulsion formulation by emulsification methods: Investigation on anticancer, wound healing, and antibacterial effects

Emulsion-based delivery systems have been fabricated and developed to increase the bioavailability of astaxanthin and alpha-tocopherol as active compounds for various biomedical applications. Astaxanthin-alpha tocopherol nanoemulsion (ATNE) is well known for its potential 6.-6.30 effect. The current study investigated ATNE by spontaneous (SENE) and ultrasonication emulsification (USNE) methods to optimally fabricate oil/water nanoemulsion characterized for biomedical applications. The two methods were compared by using a response surface method of 3-level Box-Behnken design (BBD) with significant factors. Transmission electron microscopy (TEM) confirmed spherical-shaped nanoemulsion from SENE and USNE methods and dynamic light scattering (DLS) proved the good stability of the fabricated nanoemulsion. Cytotoxicity studies on three different cancer cells confirmed that the nanoemulsion at higher concentrations was more toxic than one at lower concentrations by accompanying a significant decrease in the cellular viability after 24 and 48 h of exposure. The wound-healing potential using scratch assay evidenced faster healing effect of the nanoemulsion. Both minimal inhibitory concentration (MIC) and minimum bactericidal concentrations (MBC) methods confirmed significant antibacterial activity to disrupt the integrity of the bacterial cell membrane. The current results suggested that ATNE act as effectively targeted drug delivery vehicles in the future for cancer treatment applications due to its significant results of anticancer, wound healing, and antimicrobial effects.