Topical transport of hydrophilic compounds using water-in-oil nanoemulsions

Pharmacodynamic Studies of Pravastatin Sodium Nanoemulsion Loaded Transdermal Patch for Treatment of Hyperlipidemia

Pravastatin sodium (PVS) is a hypolipidemic drug with poor oral bioavailability due to the first-pass effect. Therefore, this study aims to formulate and evaluate transdermal patches containing PVS-loaded nanoemulsions (PVS-NEs) to increase PVS's hypolipidemic and hepatoprotective activities. PVS-NEs were prepared using the aqueous titration method, where oleic acid was chosen as an oil phase, and span 80 and tween 80 were used as surfactant and cosurfactant respectively. Droplet size (DS), polydispersity index (PDI), zeta potential (ZP), clarity, and thermodynamic stability of NEs were all characterized. Also, PVS-NEs (NE2) with 50% oil phase, 40% SC mix 2:1, and 10% water were selected as an optimum formula based on the results of DS (251 ± 16), PDI (0.4 ± 0.16), and ZP (-70 ± 10.4) to be incorporated into a transdermal patch, and PVS-NE2 loaded transdermal patches (PVS-NE2-TDPs) were prepared by solvent evaporation method. F1 patch with HPMC E15 and PVP K30 in a ratio of 3:1 represented satisfactory patch properties with good drug-excipients compatibility. Thus, it was selected as an optimum patch formula. The optimized F1 patch was characterized for thickness, moisture content, weight variation, and drug-excipients incompatibility. Therefore, it was subjected to ex vivo skin permeation and finally pharmacodynamic studies. Ex vivo permeation studies of F1 revealed that the cumulative amount of PVS permeated across rat skin was 271.66 ± 19 µg/cm2 in 72 h, and the pharmacodynamic studies demonstrated that the F1 patch was more effective in treating hyperlipidemia than PVS-TDP (control patch) based on both blood analysis and histopathological examination. .

Recent Update on Nanoemulsion Impregnated Hydrogel: a Gleam into the Revolutionary Strategy for Diffusion-Controlled Delivery of Therapeutics

Since earlier times, dermatological remedies have been utilized to treat diseases associated with pain, irritation, and skin conditions. Compared to other routes of drug delivery, topical delivery of drugs offers several benefits. Scientists are investigating different alterations in dosage forms in addition to existing topical formulations such as ointments, gels, creams, lotions, and ointments to significantly improve the permeation of drugs and enhance the pharmacological efficacy of medications that are poorly absorbed via the skin. Conventional formulations have a plethora of problems viz. poor absorption, no target specificity, low spreadability, and inadequate bioavailability which leads the researchers toward developing novel formulations like nanoemulsions. The nanoemulsion can enhance the gradient in concentration and thermodynamic movement toward the epidermis and enhance the penetration of its constituents. However, due to its difficult application, nanoemulsion's lower viscosity limited its use in transdermal delivery. Thus, the development of nanoemulsion-based hydrogels has shown to be a successful strategy for removing obstacles from existing drug formulations. The simple application, expedient spreadability, non-stickiness, safety, and effectiveness of nanoemulsion-based hydrogel have led to substantial growth in their research in recent years. This review gives a brief idea about the prevalence of skin diseases, skin as an obstacle for drug delivery, and recent research insights to combat these obstacles. The work highlights the mechanism of drug release via nanoemulsion, hydrogels, and nanoemulsion-based hydrogels with reference to recent research on hydrophobic and hydrophilic drugs.

Development of Miconazole-Loaded Microemulsions for Enhanced Topical Delivery and Non-Destructive Analysis by Near-Infrared Spectroscopy

The antifungal drug miconazole nitrate has a low solubility in water, leading to reduced therapeutic efficacy. To address this limitation, miconazole-loaded microemulsions were developed and assessed for topical skin delivery, prepared through spontaneous emulsification with oleic acid and water. The surfactant phase included a mixture of polyoxyethylene sorbitan monooleate (PSM) and various cosurfactants (ethanol, 2-(2-ethoxyethoxy) ethanol, or 2-propanol). The optimal miconazole-loaded microemulsion containing PSM and ethanol at a ratio of 1:1 showed a mean cumulative drug permeation of 87.6 ± 5.8 μg/cm² across pig skin. The formulation exhibited higher cumulative permeation, permeation flux, and drug deposition than conventional cream and significantly increased the in vitro inhibition of Candida albicans compared with cream (p < 0.05). Over the course of a 3-month study conducted at a temperature of 30 ± 2 °C, the microemulsion exhibited favorable physicochemical stability. This outcome signifies its potential suitability as a carrier for effectively administering miconazole through topical administration. Additionally, a non-destructive technique employing near-infrared spectroscopy coupled with a partial least-squares regression (PLSR) model was developed to quantitatively analyze microemulsions containing miconazole nitrate. This approach eliminates the need for sample preparation. The optimal PLSR model was derived by utilizing orthogonal signal correction pretreated data with one latent factor. This model exhibited a remarkable R² value of 0.9919 and a root mean square error of calibration of 0.0488. Consequently, this methodology holds potential for effectively monitoring the quantity of miconazole nitrate in various formulations, including both conventional and innovative ones.

Nanoemulsions of terpene by-products from cannabidiol production have promising insecticidal effect on Callosobruchus maculatus

Nanoemulsions of a terpene-rich by-product (TP) from commercial cannabidiol (CBD) production were successfully formulated and characterized. An enriched terpene distillate (DTP) was also obtained from steam distillation of TP and used for making nanoemulsions. The effects of formulation conditions including the hydrophilic lipophilic balance (HLB) value of the surfactant, TP and surfactant content, and sonication time on the properties of the emulsions were analyzed. The optimal formulation conditions were determined as surfactant HLB value of 13, TP content of 5 wt% in water, surfactant content of 2 times of TP, and sonication time of 1.5 min. A scaled-up production of the optimal nanoemulsion was also achieved using a microfluidizer and the effect of pressure and number of passes on emulsion properties was determined. The stability of the nanoemulsions was evaluated and the DTP nanoemulsion was determined to be the most stable. The nanoemulsions with desirable properties were then selected and evaluated for their insecticidal activity against the legume pest, Callosobruchus maculatus, with nanoemulsion of neem oil made under the same conditions as a control. Both TP and DTP nanoemulsions were found to exhibit excellent insecticidal activity, and the latter had the highest efficacy against the Callosobruchus maculatus.

Photodynamic inactivation of Staphylococcus aureus by ecological antibacterial solutions associating LED (ʎ 450 ± 10 nm) with curcumin and olive leaf extracts

Antimicrobial resistance is a problem in contemporary society, with Staphylococcus aureus standing out as a threat due to its ability to colonize, its pathogenicity, and its expression of several virulence factors. In this context, antimicrobial photodynamic inactivation (aPDI) emerges as an alternative to conventional microbicidal or microbiostatic systems, enabling numerous and successive applications without developing side effects and microbial resistance. In this context, an aPDI system against cultures of S. aureus based on a water-in-oil (W/O) emulsion incorporating curcumin as the photosensitizer (PS), with and without olive leaf extract (OLE), was developed and the antibacterial efficacy evaluated under LED activation (ʎ450 ± 10 nm) by depositing an energy density of 14 J/cm². The produced emulsified systems showed no significant differences in the droplet size and morphology, remaining stable along the tested period of 30 days. The bacterial reduction achieved after the first aPDI application for the emulsions added with curcumin and curcumin combined with the OLE was 5 log10 CFU.mL^-1 and 6 log10 CFU.mL^-1, respectively, revealing a significant difference between the two groups (p < 0.0001). After the second aPDI application, an increased microbial reduction (7 log10 CFU.mL^-1) was observed for both studied groups even with a low significant difference (p < 0.05). The PS loading through an emulsified system for aPDI obtained a bactericidal action against S. aureus, increased by applying two aPDI, showing a significant synergy between photodynamic inactivation, OLE delivery and antibacterial activity. In addition, the developed solutions were produced using natural products by an ecologically correct process.

Exploration of and insights into advanced topical nanocarrier systems for the treatment of psoriasis

Psoriasis is a chronic inflammatory skin disease with an underlying autoimmune pathogenesis that has brought great distress to patients. Current treatment options include topical therapy, systemic therapy, and phototherapy. By disrupting the stratum corneum, nanocarriers have unique advantages in allowing drug carriers to be tailored to achieve targeted drug delivery, improve efficacy, and minimize adverse effects. Furthermore, despite their limited success in market translatability, nanocarriers have been extensively studied for psoriasis, owing to their excellent preclinical results. As topical formulations are the first line of treatment, utilize the safest route, and facilitate a targeted approach, this study, we specifically describes the management of psoriasis using topical agents in conjunction with novel drug delivery systems. The characteristics, advantages, weaknesses, and mechanisms of individual nanocarriers, when applied as topical anti-psoriatic agents, were reviewed to distinguish each nanocarrier.

Beneath the Skin: A Review of Current Trends and Future Prospects of Transdermal Drug Delivery Systems

The ideal drug delivery system has a bioavailability comparable to parenteral dosage forms but is as convenient and easy to use for the patient as oral solid dosage forms. In recent years, there has been increased interest in transdermal drug delivery (TDD) as a non-invasive delivery approach that is generally regarded as being easy to administer to more vulnerable age groups, such as paediatric and geriatric patients, while avoiding certain bioavailability concerns that arise from oral drug delivery due to poor absorbability and metabolism concerns. However, despite its many merits, TDD remains restricted to a select few drugs. The physiology of the skin poses a barrier against the feasible delivery of many drugs, limiting its applicability to only those drugs that possess physicochemical properties allowing them to be successfully delivered transdermally. Several techniques have been developed to enhance the transdermal permeability of drugs. Both chemical (e.g., thermal and mechanical) and passive (vesicle, nanoparticle, nanoemulsion, solid dispersion, and nanocrystal) techniques have been investigated to enhance the permeability of drug substances across the skin. Furthermore, hybrid approaches combining chemical penetration enhancement technologies with physical technologies are being intensively researched to improve the skin permeation of drug substances. This review aims to summarize recent trends in TDD approaches and discuss the merits and drawbacks of the various chemical, physical, and hybrid approaches currently being investigated for improving drug permeability across the skin.

Exploring structure/property relationships to health and environmental hazards of polymeric polyisocyanate prepolymer substances-2. Dermal sensitization potential in the mouse local lymph node assay

The sensitization potencies of twenty custom-designed monomer-depleted polymeric polyisocyanate prepolymer substances and their associated toluene diisocyanate (TDI), methylene diphenyl diisocyanate (MDI), hexamethylene diisocyanate (HDI), and isophorone diisocyanate (IPDI) monomer precursors were investigated by means of the mouse Local Lymph Node Assay (LLNA). These polymeric prepolymers were designed to represent the structural features and physical-chemical properties exhibited by a broad range of commercial polymeric polyisocyanate prepolymers that are produced from the reaction of aromatic and aliphatic diisocyanate monomers with aliphatic polyether and polyester polyols. The normalization of LLNA responses to the applied (15-45-135 mM) concentrations showed that the skin sensitization potency of polymeric polyisocyanate prepolymers is at least 300 times less than that of the diisocyanate monomers from which they are derived. The sensitization potency of the prepolymers was shown to be mainly governed by their hydrophobicity (as expressed by the calculated octanol-water partition coefficient, log K_ow) and surfactant properties. Neither hydrophilic (log K_ow <0) nor very hydrophobic (log K_ow >25) prepolymers stimulated lymphocyte proliferation beyond that of the dosing vehicle control. The findings of this investigation challenge the generally held assumption that all isocyanate (-N=C=O) bearing substances are potential skin (and respiratory) sensitizers. Further, these findings can guide the future development of isocyanate chemistries and associated polyurethane applications toward reduced exposure and health hazard potentials.

Microemulsions and Nanoemulsions in Skin Drug Delivery

Microemulsions and nanoemulsions are lipid-based pharmaceutical systems with a high potential to increase the permeation of drugs through the skin. Although being isotropic dispersions of two nonmiscible liquids (oil and water), significant differences are encountered between microemulsions and nanoemulsions. Microemulsions are thermodynamically stable o/w emulsions of mean droplet size approximately 100–400 nm, whereas nanoemulsions are thermodynamically unstable o/w emulsions of mean droplet size approximately 1 to 100 nm. Their inner oil phase allows the solubilization of lipophilic drugs, achieving high encapsulation rates, which are instrumental for drug delivery. In this review, the importance of these systems, the key differences regarding their composition and production processes are discussed. While most of the micro/nanoemulsions on the market are held by the cosmetic industry to enhance the activity of drugs used in skincare products, the development of novel pharmaceutical formulations designed for the topical, dermal and transdermal administration of therapeutic drugs is being considered. The delivery of poorly water-soluble molecules through the skin has shown some advantages over the oral route, since drugs escape from first-pass metabolism; particularly for the treatment of cutaneous diseases, topical delivery should be the preferential route in order to reduce the number of drugs used and potential side-effects, while directing the drugs to the site of action. Thus, nanoemulsions and microemulsions represent versatile options for the delivery of drugs through lipophilic barriers, and many synthetic and natural compounds have been formulated using these delivery systems, aiming to improve stability, delivery and bioactivity. Detailed information is provided concerning the most relevant recent scientific publications reporting the potential of these delivery systems to increase the skin permeability of drugs with anti-inflammatory, sun-protection, anticarcinogenic and/or wound-healing activities. The main marketed skincare products using emulsion-based systems are also presented and discussed.

In Vitro Skin Delivery of Griseofulvin by Layer-by-Layer Nanocoated Emulsions Stabilized by Whey Protein and Polysaccharides

Griseofulvin is a poorly water-soluble drug administered orally to treat topical fungal infections of the skin and hair. However, oral administration leads to poor and unpredictable drug pharmacokinetics. Additionally, griseofulvin is unstable in the presence of light. A layer-by-layer (LbL) nanocoating approach was employed to curb these shortcomings by stabilizing emulsions, lyophilized emulsions, and reconstituted emulsions with a layer each of whey protein, and either hyaluronic acid, amylopectin, or alginic acid, which captured the drug. The coating materials are biological, environmentally benign, and plentiful. Photostability studies indicated that the LbL particles afforded 6 h of protection of the topical application. In vitro absorption studies showed that griseofulvin concentrated preferentially in the stratum corneum, with virtually no transdermal delivery. Therefore, LbL-nanocoated emulsions, lyophilized particles, and reconstituted lyophilized emulsions can produce a viable topical delivery system to treat superficial fungal infections.

Anti-rheumatic activity of topical nanoemulsion containing bee venom in rats

PURPOSE

Bee Venom (BV) has been used to treat rheumatoid arthritis (RA) for many centuries. However, its clinical use is limited by pain and fear of bee stings/injection. Nanoemulsions (NEs) are nanocarriers that are able to help their content(s) penetrate through the skin. They also act as drug reservoirs on the skin to provide an efficient, sustained-release vehicle.

METHODS

In this paper, we present the development of a stable water-in-oil NE to help passing BV through the animal skin when used topically.

RESULTS

Particle size of NE was 12.7 to 29.8 nm for NEs containing 0 to 150 µg/ml BV. Also, its anti-inflammatory effects were evaluated in rat models of type II collagen-induced arthritis. Topical administration of NEs containing 18.75 or 9.37 μg/ml BV were able to significantly (p<0.05) reduce inflammation in the rat paws compared to the blank and control groups.

CONCLUSION

Our findings demonstrated the efficacy of NEs containing BV to reduce inflammation caused by RA animal model.

Transdermal Delivery of Therapeutic Compounds With Nanotechnological Approaches in Psoriasis

Psoriasis is a chronic, immune-mediated skin disorder involving hyperproliferation of the keratinocytes in the epidermis. As complex as its pathophysiology, the optimal treatment for psoriasis remains unsatisfactorily addressed. Though systemic administration of biological agents has made an impressive stride in moderate-to-severe psoriasis, a considerable portion of psoriatic conditions were left unresolved, mainly due to adverse effects from systemic drug administration or insufficient drug delivery across a highly packed stratum corneum via topical therapies. Along with the advances in nanotechnologies, the incorporation of nanomaterials as topical drug carriers opens an obvious prospect for the development of antipsoriatic topicals. Hence, this review aims to distinguish the benefits and weaknesses of individual nanostructures when applied as topical antipsoriatics in preclinical psoriatic models. In view of specific features of each nanostructure, we propose that a proper combination of distinctive nanomaterials according to the physicochemical properties of loaded drugs and clinical features of psoriatic patients is becoming a promising option that potentially drives the translation of nanomaterials from bench to bedside with improved transdermal drug delivery and consequently therapeutic effects.

Mapping hair follicle-targeted delivery by particle systems: What has science accomplished so far?

The importance of the hair follicle in the process of cutaneous drug penetration has been established since this skin appendage was recognized as an entry point for topically applied substances. A comprehensive review on the hair follicle as a target per se is here provided, exploring the current knowledge on both targeted regions and delivery systems that take advantage of this permeation route. The follicular penetration is a complex process, whose effectiveness and efficiency strongly depends on a diversity of different factors including follicular density and size, activity status of hair follicles and physicochemical properties of the topically applied substances. Nanocarriers represent a heterogeneous assembly of molecules organized into particles and they have revolutionized drug delivery in several areas of medicine, pharmacology and cosmetics. As they possess an inherent ability to use the follicular route, they are reviewed here having in perspective the hair follicle zones that they are able to reach as reported. In this way, a follicular road map for the different delivery systems was compiled to assist as a guiding tool for those that have interest in the development and/or application of such delivery systems for hair and skin treatment or care.

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.

Slippery nanoemulsion-infused porous surfaces (SNIPS): anti-fouling coatings that can host and sustain the release of water-soluble agents

We report the design of 'slippery' nanoemulsion-infused porous surfaces (SNIPS). These materials are strongly anti-fouling to a broad range of substances, including microorganisms. Infusion with water-in-oil nanoemulsions also endows these slippery coatings with the ability to host and control or sustain the release of water-soluble agents, including polymers, peptides, and nucleic acids, opening the door to new applications of liquid-infused materials.

Current Advances of Nanocarrier Technology-Based Active Cosmetic Ingredients for Beauty Applications

Nanocarrier technology has been effectively applied to the development of drug delivery systems to overcome the limitations of traditional preparation. Its application has been extended to various pharmaceutical fields from injection preparation to oral preparation and external preparation, and now it has appeared in the field of cosmetics for beauty applications. The widespread influence of nanocarrier in the cosmetics industry is due to the fact that nanocarrier can effectively promote the percutaneous penetration and significantly increase skin retention of active components in functional cosmetics. Meanwhile, nanocarrier can effectively improve the water dispersion of insoluble active cosmetic ingredients, enhance the stability of efficacy components and achieve the codelivery of diverse cosmetics active ingredients. In this review, we summarized the current progress of nanocarrier technology in the functional cosmetics, including the types and the routes of dermal/transdermal drug delivery nanocarriers used in the functional cosmetics, the mechanism of nanocarriers promoting the percutaneous penetration of active cosmetic ingredients, the application and efficacy evaluation of different active cosmetic ingredients in nanocarriers and discussing the potential risks to human. This will provide a useful reference for the further development of nanocarriers in the field of functional cosmetics.

Water-in-Oil Nano-Emulsions Prepared by Spontaneous Emulsification: New Insights on the Formulation Process

Nano-emulsions consist of stable suspensions of nano-scaled droplets that have huge loading capacities and are formulated with safe compounds. For these reasons, a large number of studies have described the potential uses of nano-emulsions, focusing on various aspects such as formulation processes, loading capabilities, and surface modifications. These studies typically concern direct nano-emulsions (i.e., oil-in-water), whereas studies on reverse nano-emulsions (i.e., water-in-oil) remain anecdotal. However, reverse nano-emulsion technology is very promising (e.g., as an alternative to liposome technology) for the development of drug delivery systems that encapsulate hydrophilic compounds within double droplets. The spontaneous emulsification process has the added advantages of optimization of the energetic yield, potential for industrial scale-up, improved loading capabilities, and preservation of fragile compounds targeted for encapsulation. In this study, we propose a detailed investigation of the processes and formulation parameters involved in the spontaneous nano-emulsification that produces water-in-oil nano-emulsions. The following details were addressed: (i) the order of mixing of the different compounds (method A and method B), (ii) mixing rates, (iii) amount of surfactants, (iv) type and mixture of surfactants, (v) amount of dispersed phase, and (vi) influence of the nature of the oil. The results emphasized the effects of the formulation parameters (e.g., the volume fraction of the dispersed phase, nature or concentration of surfactant, or nature of the oil) on the nature and properties of the nano-emulsions formed.

Exploiting drug delivery systems for oral route in the peptic ulcer disease treatment

Peptic ulcer disease (PUD) is a common condition that is induced by acid and pepsin causing lesions in the mucosa of the duodenum and stomach. The pathogenesis of PUD is a many-sided scenario, which involves an imbalance between protective factors, such as prostaglandins, blood flow, and cell renewal, and aggressive ones, like alcohol abuse, smoking, Helicobacter pylori colonisation, and the use of non-steroidal anti-inflammatory drugs. The standard oral treatment is well established; however, several problems can decrease the success of this therapy, such as drug degradation in the gastric environment, low oral bioavailability, and lack of vectorisation to the target site. In this way, the use of strategies to improve the effectiveness of these conventional drugs becomes interesting. Currently, the use of drug delivery systems is being explored as an option to improve the drug therapy limitations, such as antimicrobial resistance, low bioavailability, molecule degradation in an acid environment, and low concentration of the drug at the site of action. This article provides a review of oral drug delivery systems looking for improving the treatment of PUD.

Effect of Salt on the Formation and Stability of Water-in-Oil Pickering Nanoemulsions Stabilized by Diblock Copolymer Nanoparticles

Sterically stabilized diblock copolymer nanoparticles are prepared in n-dodecane using polymerization-induced self-assembly. Precursor Pickering macroemulsions are then prepared by the addition of water followed by high-shear homogenization. In the absence of any salt, high-pressure microfluidization of such precursor emulsions leads to the formation of relatively large aqueous droplets with DLS measurements indicating a mean diameter of more than 600 nm. However, systemically increasing the salt concentration produces significantly finer droplets after microfluidization, until a limiting diameter of around 250 nm is obtained at 0.11 M NaCl. The mean size of these aqueous droplets can also be tuned by systematically varying the nanoparticle concentration, applied pressure, and the number of passes through the microfluidizer. The mean number of nanoparticles adsorbed onto each aqueous droplet and their packing efficiency are calculated. SAXS studies conducted on a Pickering nanoemulsion prepared using 0.11 M NaCl confirms that the aqueous droplets are coated with a loosely packed monolayer of nanoparticles. The effect of varying the NaCl concentration within the droplets on their initial rate of Ostwald ripening is investigated using DLS. Finally, the long-term stability of these water-in-oil Pickering nanoemulsions is assessed using analytical centrifugation. The rate of droplet ripening can be substantially reduced by using 0.11 M NaCl instead of pure water. However, increasing the salt concentration up to 0.43 M provided no further improvement in the long-term stability of such nanoemulsions.

Development of an Oil-in-Water Self-Emulsifying Microemulsion for Cutaneous Delivery of Rose Bengal: Investigation of Anti-Melanoma Properties

The topical delivery route is proposed as an alternative or adjunctive approach to melanoma treatment, since the target site for melanoma treatment-the epidermal basal layer-is potentially accessible by this route. Microemulsion systems are effective delivery vehicles for enhanced, targeted skin delivery. This work investigated the effect of Rose Bengal (RB) and RB-loaded self-emulsifying microemulsions (SEMEs) on growth inhibition of human melanoma and normal skin cell monolayers, the safety of the excipients incorporated in SEMEs on human cell lines, and the in-vitro human skin penetration of RB delivered in SEMEs and control solution. Cellular toxicity was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and the growth inhibitory mechanism of RB was investigated by flow cytometry using PI staining. Unloaded SEMEs caused reduced cellular toxicity compared to the surfactant excipient, Labrasol^®. RB-loaded SEMEs increased cell growth inhibition compared to the RB aqueous solution. Flow cytometry revealed apoptotic cells after treatment with RB-loaded SEMEs, indicating that apoptosis may be one of the mechanisms of cell death. Preliminary results of multiphoton microscopy with fluorescence lifetime imaging (MPM-FLIM) analysis showed deeper penetration with greater skin concentrations of RB delivered from SEMEs compared to the RB aqueous solution. This study highlights the enhanced skin penetration and antimelanoma effects of RB loaded in a SEME system.

Metformin loaded cholesterol-lysine conjugate nanoparticles: A novel approach for protecting HDFs against UVB-induced senescence

Cellular senescence is one of the hallmarks of aging. Since senescence of dermal fibroblasts has been reported in vivo, reduction of the deleterious effects of these cells, has been considered an important intervention to counteract skin aging. Promising anti-aging effect of metformin has been reported. However, permeation of metformin due to its high hydrophilicity through skin epidermal barriers is limited. In this study, solid lipid nanoparticles (SLNs) of metformin were designed with the newly synthesized cholesterol-lysine conjugate as lipid for topical delivery of metformin. Characterization of SLNs strongly confirmed the effect of cholesterol-lysine conjugate on increasing entrapment of metformin. The designed SLNs with particle size of 283 nm and spherical morphology represented controlled drug release up to 18 days. Fluorescent tracking of SLNs on mice skin samples showed an increase in epidermal penetration. SLNs containing metformin showed anti-senescence effects on UVB-induced senescence of human dermal fibroblasts, this effect was confirmed by senescence-associated β-galactosidase staining, RT q-PCR and cell cycle analyses. Furthermore, our drug-free SLNs showed anti-senescence effects, suggesting that they can be a suitable carrier for phytochemicals with anti-aging effect or other hydrophilic compounds which have constraints permeating skin.

Two-Step Optimization to Develop a Transdermal Film Loaded With Dapoxetine Nanoparticles: A Promising Technique to Improve Drug Skin Permeation

Dapoxetine (DPX) is an orally administered drug for the treatment of premature ejaculation (PE). One of the challenges of administering DPX orally as a tablet is its poor bioavailability (ie, 42%) due to extensive first-pass metabolism. Thus, it is vital to develop a new formulation and mode of delivery to achieve the unmet needs of PE treatment. In this study, an optimized DPX polymeric nanoparticle (PNP) was developed and subsequently loaded into a transdermal film. The Box–Behnken design was utilized to optimize 3 formulation factors affecting the particle size and entrapment efficiency (EE) of chitosan (CS)-alginate (ALG) PNPs. A 3-level factorial design was used to study the effect of 2 variables affecting DPX cumulative percent released and percent elongation from transdermal films loaded with DPX-PNPs. Permeation parameters were calculated following ex vivo permeation study through rat skin. Transport of the PNPs across the skin layers was investigated using a fluorescence laser microscope. Results revealed that an optimized PNPs formulation was developed with a particle size 415.94 nm and EE 37.31%. Dapoxetine was successfully entrapped in the polymeric matrix. Chitosan and ALG interacted electrostatically with the studied cross-linking agents to form a polyelectrolyte complex. The ex vivo study illustrated a sustained release profile of DPX with enhanced skin permeation from the film loaded PNPs. Moreover, the PNPs was able to penetrate deeper into skin layers. Therefore, DPX transdermal film developed in this work could be considered as a successful drug delivery with better patient compliance for the treatment of PE.

Nano-emulgel: Emerging as a Smarter Topical Lipidic Emulsion-based Nanocarrier for Skin Healthcare Applications

BACKGROUND

In recent decades, enormous efforts for different drug discovery processes have led to a number of drug molecules available today to overcome different challenges of the health care system. Unfortunately, more than half of these drugs are listed in either BCS (biopharmaceutical classification system) class II/ IV or both are eliminated from the development pipeline due to their limited clinical use. A nanotechnological approach bears much hope and lipoidal fabrication is found to be suitable for the delivery of such drugs. Nanoemulsion based gel i.e. nanoemulgel out of different nanolipoidal formulations has been found to be a suitable approach to successful drug delivery through topical routes. In past few years many herbal and synthetic active pharmaceutical ingredients (APIs) has been patented as nano sized emulsified gel for various therapeutic activities.

METHODS

Nanoemulgel is basically an emulsion-based topical gel formulation, where nanosized emulsion globules can be prepared with the help of high energy or low energy methods and further converted into nanoemulgel by adding a suitable gelling agent. Nanoemulgel fabrication enlists various kinds of polymeric materials, surfactants and fatty substances of natural, synthetic and semi-synthetic nature with a globule size range from 5 to 500 nm.

RESULTS

Nanoemulgel can be applicable to various acute and chronic diseases through topical routes.

CONCLUSION

Nanoemulgel preparations of many recently approved drugs are being used successfully in different areas of health care and have re-defined the significance of topical route of delivery as compared to other routes. However, along with various improvements in the current state of the delivery system, the safety factor needs to be taken into account by toxicological studies of the materials used in such formulations.

Development of Water-in-Oil Emulsions as Delivery Vehicles and Testing with a Natural Antimicrobial Extract

Water-in-oil (W/O) emulsions have high potential for several industrial areas as delivery systems of hydrophilic compounds. In general, they are less studied than oil-in-water (O/W) systems, namely in what concerns the so-called fluid systems, partly due to problems of instability. In this context, this work aimed to produce stable W/O emulsions from a natural oil, sweet almond oil, to be further tested as vehicles of natural hydrophilic extracts, here exemplified with an aqueous cinnamon extract. Firstly, a base W/O emulsion using a high-water content (40/60, v/v) was developed by testing different mixtures of emulsifiers, namely Tween 80 combined with Span 80 or Span 85 at different contents. Among the tested systems, the one using a 54/46 (v/v) Span 80/Tween 80 mixture, and subjected to 12 high-pressure homogenizer (HPH) cycles, revealed to be stable up to 6 months, being chosen for the subsequent functionalization tests with cinnamon extract (1.25-5%; w/v; water-basis). The presence of cinnamon extract leaded to changes in the microstructure as well as in the stability. The antimicrobial and antioxidant analysis were evidenced, and a sustained behavior compatible with an extract distribution within the two phases, oil and water, in particular for the higher extract concentration, was observed.

Strategic photosafety screening system consisting of in chemico photoreactivity and in vitro skin exposure for quinolone derivatives

The main objective of this study was to verify the applicable domain of a proposed photosafety screening system, consisting of a reactive oxygen species (ROS) assay and in vitro skin permeation test, for dermally-applied chemicals. Quinolones (QNLs) were selected as test compounds, including enoxacin, flumequine, moxifloxacin, nalidixic acid, orbifloxacin, and oxolinic acid. The ROS assay and in vitro skin permeation test were employed to evaluate photoreactivity and skin deposition of QNLs, respectively. All QNLs exhibited significant ROS generation on exposure to simulated sunlight; in particular, enoxacin was indicative of potent photoreactivity compared with the other 5 QNLs. Steady-state concentration values of flumequine and nalidixic acid were calculated to be 5.0 and 8.2 μg/mL, respectively, and higher than those of the other QNLs. Based on the photoreactivity and skin exposure of QNLs, the phototoxic risk was ranked, and the predicted phototoxic risk by the proposed system was mostly in agreement with observed in vivo phototoxicity, suggesting the applicability of the proposed strategy to photosafety assessment of QNLs. The proposed screening would be efficacious to predict phototoxic risk of dermally-applied chemicals.

Development and Assessment of Lipidic Nanoemulsions Containing Sodium Hyaluronate and Indomethacin

The present work attempts to develop and optimize the formula of a lipidic nanoemulsion (NE) containing sodium hyaluronate (HNa) and indomethacin (Ind) as HNa-Ind for enhanced transdermal antiarthritic activity. NEs were prepared by the spontaneous emulsification method and characterized by Fourier-transform infrared (FTIR) spectroscopy. The composition of the optimal formulation was statistically optimized using Box-Behnken experimental design method with three independent factors and was characterized for particle size, polydispersity index, and percent transmittance. The selected formula was tested for its in vitro antioxidant activity and in vivo anti-inflammatory activity. The optimized HNa-Ind NE formula was characterized and displayed a particle size of 12.87 ± 0.032 nm, polydispersity index of 0.606 ± 0.082, and 99.4 ± 0.1 percentage of transmittance. FTIR showed no interaction between HNa and Ind as a physical mixture. In addition, the optimized HNa-Ind NE was able to preserve the antioxidant ability of the two drugs, as evidenced through a 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition assay used to assess free radical scavenging ability. The cell viability was increased while the free radical scavenging activity was decreased (94.28% inhibition at higher concentrations compared with vitamin C as a reference with an inhibition of 100%). Moreover, the pharmacological anti-inflammatory potential of the optimized HNa-Ind NE formulation was assessed using an in vivo model. Compared with reference drugs (ibuprofen gel 5%), the remarkable activity of the optimized formulation was established using xylene-induced ear edema in mice model, in which the inflamed region reduced by 92.5% upon treatment. The optimized HNa-Ind NE formulation showed considerably higher skin permeation and drug deposition capability compared with the HNa-Ind solution. HNa-Ind NE was demonstrated to be a successful carrier with enhanced antioxidant and anti-inflammatory potential while showing better skin penetration, thus being a promising vehicle for transdermal drug delivery.

Nanoemulsion: A Review on Mechanisms for the Transdermal Delivery of Hydrophobic and Hydrophilic Drugs

Nanoemulsions (NEs) are colloidal dispersions of two immiscible liquids, oil and water, in which one is dispersed in the other with the aid of a surfactant/co-surfactant mixture, either forming oil-in-water (o/w) or water-in-oil (w/o) nanodroplets systems, with droplets 20–200 nm in size. NEs are easy to prepare and upscale, and they show high variability in their components. They have proven to be very viable, non-invasive, and cost-effective nanocarriers for the enhanced transdermal delivery of a wide range of active compounds that tend to metabolize heavily or suffer from undesirable side effects when taken orally. In addition, the anti-microbial and anti-viral properties of NE components, leading to preservative-free formulations, make NE a very attractive approach for transdermal drug delivery. This review focuses on how NEs mechanistically deliver both lipophilic and hydrophilic drugs through skin layers to reach the blood stream, exerting the desired therapeutic effect. It highlights the mechanisms and strategies executed to effectively deliver drugs, both with o/w and w/o NE types, through the transdermal way. However, the mechanisms reported in the literature are highly diverse, to the extent that a definite mechanism is not conclusive.

A Simple Non-Invasive Approach toward Efficient Transdermal Drug Delivery Based on Biodegradable Particulate System

Transdermal administration via skin appendages enables both localized and systemic drug delivery, as well as minimizes incidental toxicity. However, the design of an appropriate effective method for clinical use remains challenging. Here, we introduce calcium carbonate-based carriers for the transdermal transportation of bioactive substances. The proposed system presents easily manufacturable biodegradable particles with a large surface area enabling a high payload ability. Topical application of submicron porous CaCO₃ particles in rats followed by the therapeutic ultrasound treatment results in their deep penetration through the skin along with plentiful filling of the hair follicles. Exploiting the loading capacity of the porous particles, we demonstrate efficient transportation of a fluorescent marker along the entire depth of the hair follicle down the bulb region. In vivo monitoring of the carrier degradation reveals the active dissolution/recrystallization of CaCO₃ particles, resulting in their total resorption within 12 days. The proposed particulate system serves as an intrafollicular depot for drug storage and prolonged in situ release over this period. The urinary excretion profile proves the systemic absorption of the fluorescent marker. Hence, the elaborated transdermal delivery system looks promising for medical applications. The drug delivery to different target regions of the hair follicle may contribute to regenerative medicine, immunomodulation, and treatment of various skin disorders. In the meantime, the systemic uptake of the transported drug opens an avenue for prospective delivery routes beyond the scope of dermatology.

Interplay between bulk self-assembly, interfacial and foaming properties in a catanionic surfactant mixture of varying composition

The self-aggregation, surface properties and foamability of the catanionic surfactant mixture cetyltrimethylammonium bromide (CTAB)/sodium octyl sulfonate (SOSo) have been investigated to obtain insight on the relation between bulk nanostructures, surfactant packing, and foam stability and aging. Light microscopy, SANS, cryo-TEM, DLS, surface tension, rheometry and direct photography were used to characterize mixtures with varying CTAB molar fraction, x_CTAB. In the bulk, self-assembly is richer in the excess CTAB region than in the excess SOSo one. Starting from neat CTAB micelles and on addition of anionic surfactant, there is a change from small ellipsoidal micelles (1 < x_CTAB ≤ 0.80) to large rodlike micelles (0.65 ≤ x_CTAB ≤ 0.55) and then to vesicles (0 < x_CTAB ≤ 0.50), with coexistence regions in between; SOSo-rich mixtures are thus dominated by vesicles. High size polydispersity for the micelles and vesicles is an intrinsic feature of this system. Foam stability is concomitantly impacted by x_CTAB. SOSo is a small mobile molecule and so it disrupts foam stability, irrespective of the presence of vesicles. Foams are thus only stable in the CTAB-rich regions, and SANS shows that the shape of micelles and vesicles is unchanged inside the foam. Foam drainage is thereby mostly controlled by the presence of the elongated micelles through the solution viscosity, whereas coarsening is influenced by dense surfactant packing at the gas-liquid interfaces.

Nanoemulsion: Concepts, development and applications in drug delivery

Nanoemulsions are biphasic dispersion of two immiscible liquids: either water in oil (W/O) or oil in water (O/W) droplets stabilized by an amphiphilic surfactant. These come across as ultrafine dispersions whose differential drug loading; viscoelastic as well as visual properties can cater to a wide range of functionalities including drug delivery. However there is still relatively narrow insight regarding development, manufacturing, fabrication and manipulation of nanoemulsions which primarily stems from the fact that conventional aspects of emulsion formation and stabilization only partially apply to nanoemulsions. This general deficiency sets up the premise for current review. We attempt to explore varying intricacies, excipients, manufacturing techniques and their underlying principles, production conditions, structural dynamics, prevalent destabilization mechanisms, and drug delivery applications of nanoemulsions to spike interest of those contemplating a foray in this field.

Topical and cutaneous delivery using nanosystems

The goal of topical and cutaneous delivery is to deliver therapeutic and other substances to a desired target site in the skin at appropriate doses to achieve a safe and efficacious outcome. Normally, however, when the stratum corneum is intact and the skin barrier is uncompromised, this is limited to molecules that are relatively lipophilic, small and uncharged, thereby excluding many potentially useful therapeutic peptides, proteins, vaccines, gene fragments or drug-carrying particles. In this review we will describe how nanosystems are being increasingly exploited for topical and cutaneous delivery, particularly for these previously difficult substances. This is also being driven by the development of novel technologies, which include minimally invasive delivery systems and more precise fabrication techniques. While there is a vast array of nanosystems under development and many undergoing advanced clinical trials, relatively few have achieved full translation to clinical practice. This slow uptake may be due, in part, to the need for a rigorous demonstration of safety in these new nanotechnologies. Some of the safety aspects associated with nanosystems will be considered in this review.

Enhancing the in vivo transdermal delivery of gold nanoparticles using poly(ethylene glycol) and its oleylamine conjugate

In this study, we investigated the effect of (ethylene glycol) (PEG) and PEG-oleylamine (OAm) functionalization on the skin permeation property of gold nanoparticles (GNS) in vivo. Chemisorption of polymers onto GNS was verified by a red shift in the ultraviolet-visible spectrum as well as by a change in the nanoparticle surface charge. The physicochemical properties of pristine and functionalized nanoparticles were analyzed by ultraviolet-visible spectroscopy, zeta potential analyzer, and transmission electron microscopy. Transmission electron microscopy revealed that the interparticle distance between nanoparticles increased after GNS functionalization. Comparing the skin permeation profile of pristine and functionalized GNS, the follicular deposition of GNS increased twofold after PEG-OAm functionalization. Moreover, PEG- and PEG-OAm-functionalized nanoparticles were able to overcome the skin barrier and deposit in the deeper subcutaneous adipose tissue. These findings demonstrate the potential of PEG- and PEG-OAm-functionalized GNS in serving a multitude of applications in transdermal pharmaceuticals.

Nanoemulsions: formation, properties and applications

Nanoemulsions are kinetically stable liquid-in-liquid dispersions with droplet sizes on the order of 100 nm. Their small size leads to useful properties such as high surface area per unit volume, robust stability, optically transparent appearance, and tunable rheology. Nanoemulsions are finding application in diverse areas such as drug delivery, food, cosmetics, pharmaceuticals, and material synthesis. Additionally, they serve as model systems to understand nanoscale colloidal dispersions. High and low energy methods are used to prepare nanoemulsions, including high pressure homogenization, ultrasonication, phase inversion temperature and emulsion inversion point, as well as recently developed approaches such as bubble bursting method. In this review article, we summarize the major methods to prepare nanoemulsions, theories to predict droplet size, physical conditions and chemical additives which affect droplet stability, and recent applications.

Enhancement of photodynamic inactivation against Pseudomonas aeruginosa by a nano-carrier approach

As pathogens steadily develop resistance to widely used antibiotics, new methodologies for their efficient inactivation must be developed. Photodynamic therapy is an upcoming technique that provides an alternative option for treating pathogenic infections. The efficiency of photodynamic therapy has been limited by the use of aqueous mediums for dispersing photosensitising agents. Toluidine Blue O (TBO) was chosen for this study as a cationic photosensitiser to inhibit Gram-negative bacterium Pseudomonas aeruginosa. Enhanced delivery of the photosensitiser was ensured by utilising an essential oil-based microemulsion. The efficiency of photodynamic therapy was further improved by the use of a chemical penetration enhancer to improve permeability of the bacterial outer membrane. TBO accumulation patterns in neonate pig skin were studied using confocal laser scanning microscopy. The physicochemical properties of the TBO loaded microemulsion, including UV-vis absorbance, size distribution and zeta potential, were analysed to understand the enhanced antimicrobial activity. Confocal laser scanning microscopy confirmed the formation of a TBO reservoir in the skin by the TBO-loaded microemulsions. TBO (5 μg/mL) in the vehicles significantly inhibited the growth of P. aeruginosa. All these efforts resulted in inhibition obtained at a drug concentration and light intensity much lower than what is reported by the works of previous investigators.

Physicochemical, in vitro and in vivo evaluation of flurbiprofen microemulsion

Flurbiprofen, a potent nonsteroidal anti-inflammatory drug, is widely used for relief of pain in patients suffering from rheumatic diseases, migraine, sore throat and primary dysmenorrheal. However, this drug has many gastrointestinal side effects produced by its oral administration, such as gastric bleeding and peptic ulcer. These effects were responsible for non-compliance among patients, which ultimately results in treatment failure. The physicochemical properties of flurbiprofen, make it a suitable candidate for transdermal drug delivery, which can overcome the drawbacks of oral administration. In this sense, microemulsions have been proved to increase the cutaneous absorption of lipophilic drugs when compared to conventional drug delivery systems. The purpose of this study was to formulate and characterize gel based microemulsions, for topical delivery of flurbiprofen. Different gel bases, containing microemulsion and hydro-alcoholic solution of flurbiprofen, were developed and compared. In vitro study showed that gels containing microemulsion had a higher permeation rate than those containing hydro-alcoholic solutions. Additionally, formulation of Carbopol-I (microemulsion) showed higher percent of inhibition of inflammation than others bases. Further, skin irritation study demonstrated that Carbopol-I was none irritating. Flurbiprofen microemulsion incorporated on Carbopol-I showed physicochemical, in vitro and in vivo characteristics suitable for the development of alternative transdermal delivery formulation.

Herbal mouthwash containing extracts of Baccharis dracunculifolia as agent for the control of biofilm: clinical evaluation in humans

Baccharis dracunculifolia DC (Asteraceae), popularly known as “alecrim-do-campo,” is largely distributed in South America, is shown to exhibit protective actions against gastric ulcers, has anti-inflammatory properties, and is hepatoprotective. Several essential oils obtained from Baccharis species possess biological activities, such as antimicrobial and antivirus activities. This randomized controlled trial evaluated the efficacy of B. dracunculifolia in the reduction of dental biofilm, comparing this natural product with other mouthwashes already known in the dental market. In measuring the time after use of mouthwash (t = 1), there was no difference between products (P = 0.602); that is, subjects in the study had a similar PI after the first use. After one week (t = 2), there was no difference between the four products evaluated (P = 0.674), so, all research individuals completed the study with a similar reduction in dental biofilm between themselves but it was different from initial state (Friedman test). It is possible to conclude that B. dracunculifolia had the same efficiency of the materials used to oral hygiene in reduction of dental plaque and, consequently, prevention of dental caries. Thus, we can consider B. dracunculifolia as a good candidate for new material to be implemented in dental care.

Efficient immuno-modulation of TH1/TH2 biomarkers in 2,4-dinitrofluorobenzene-induced atopic dermatitis: nanocarrier-mediated transcutaneous co-delivery of anti-inflammatory and antioxidant drugs

The present study was conducted with the aim to investigate the immuno-modulatory and histological stabilization effects of nanocarrier-based transcutaneous co-delivery of hydrocortisone (HC) and hydroxytyrosol (HT). In this investigation, the clinical and pharmacological efficacies of nanoparticle (NP)-based formulation to alleviate 2,4-dinitrofluorobenzene (DNFB)-induced atopic dermatitis (AD) was explored by using an NC/Nga mouse model. Ex vivo visual examination of AD induction in experimental mice indicated remarkable control of NP-based formulations in reducing pathological severity of AD-like skin lesions. Therapeutic effectiveness of NP-based formulations was also evaluated by comparing skin thickness of AD-induced NP-treated mice (456±27 µm) with that of atopic mice (916±37 µm). Analysis of the immuno-spectrum of AD also revealed the dominance of NP-based formulations in restraining immunoglobulin-E (IgE), histamine, prostaglandin-E2 (PGE2), vascular endothelial growth factor-α (VEGF-α), and T-helper cells (TH1/TH2) producing cytokines in serum and skin biopsies of tested mice. These anti-AD data were further supported by histological findings that revealed alleviated pathological features, including collagen fiber deposition, fibroblasts infiltration, and fragmentation of elastic fibers in experimental mice. Thus, NP-mediated transcutaneous co-delivery of HC and HT can be considered as a promising therapy for managing immunological and histological spectra associated with AD.

Downregulation of immunological mediators in 2,4-dinitrofluorobenzene-induced atopic dermatitis-like skin lesions by hydrocortisone-loaded chitosan nanoparticles

Background

Atopic dermatitis is a chronic, noncontiguous, and exudative disorder accompanied by perivascular infiltration of immune mediators, including T-helper (Type 1 helper/Type 2 helper) cells, mast cells, and immunoglobulin E. The current study explores the immunomodulatory and histological effects of nanoparticle (NP)-based transcutaneous delivery of hydrocortisone (HC).

Methods

In this study, HC, the least potent topical glucocorticoid, was administered transcutaneously as chitosan NPs. The pharmacological and immunological effects of the NP-based HC delivery on the alleviation of 2,4-dinitrofluorobenzene-induced atopic dermatitis (AD)-like skin lesions were evaluated using the NC/Nga mouse model.

Results

In vivo Dino-Lite^® microscopic assessment revealed that the NP-based formulation displayed a remarkable ability to reduce the severity of the pathological features of AD (dermatitis index, 3.0). The AD suppressive activity of the NP-based topical formulation was expected owing to the interruption of a series of immunopathological events, including the production of immunoglobulin E, release of histamine, and expression of prostaglandin-E₂ and vascular endothelial growth factor-α in the sera and skin of the tested animals. Analysis of the cytokine expression in AD-like skin lesions further revealed that the NP-based formulation inhibited the pathological expression of interleukin (IL)-4, IL-5, IL-6, IL-13, IL-12p70, interferon-γ, and tumor necrosis factor-α in serum and skin homogenates of NC/Nga mice. Further, our histological findings indicated that the NP-based formulation inhibited fibroblast infiltration and fragmentation of elastic fibers, further supporting the clinical importance of these formulations in maintaining the integrity of elastic connective tissues.

Conclusion

The current investigation suggests that NP-mediated transcutaneous delivery of HC could be considered an effective therapeutic approach to manage dermatitis.

Microemulsion system for topical delivery of thai mango seed kernel extract: development, physicochemical characterisation and ex vivo skin permeation studies

A microemulsion system containing Thai mango seed kernel extract (MSKE, cultivar “Fahlun”) was developed and characterised for the purpose of topical skin delivery. The MSKE-loaded microemulsions were prepared by using the spontaneous emulsification method. Isopropyl myristate (IPM) was selected as the oil phase. A polyoxyethylene sorbitan monooleate and sorbitan monododecanoate (1:1, w/w) system was used as the surfactant phase; an aqueous mixture of different cosurfactants (absolute ethanol, 96.3% v/v ethanol, 1-propanol, 2-propanol or 1,2-propanediol) at a weight ratio of 1:1 was used as the aqueous phase. Among the cosurfactants studied, the 1-propanol aqueous mixture had the largest microemulsion region (48.93%) in the pseudo-ternary phase diagram. Microemulsions containing 1% MSKE demonstrated good physicochemical stability during a six-month study period at 25 ± 2 °C/60% ± 5% RH. The ex vivo skin permeation study demonstrated that the microemulsions exhibited a potent skin enhancement effect allowing MSKE to penetrate skin layers up to 60-fold higher compared with the control. Neither skin irritation nor skin corrosion was observed in ex vivo studies. The present study revealed that IPM-based microemulsion systems may be promising carriers to enhance skin penetration and delivering MSKE for topical treatment.