Biomedical applications of microemulsion through dermal and transdermal route

A, Nayak UY. Low-Frequency Sonophoresis: A Promising Strategy for Enhanced Transdermal Delivery

Sonophoresis is the most approachable mode of transdermal drug delivery system, wherein low-frequency sonophoresis penetrates the drug molecules into the skin. It is an alternative method for an oral system of drug delivery and hypodermal injections. The cavitation effect is thought to be the main mechanism used in sonophoresis. The cavitation process involves forming a gaseous bubble and its rupture, induced in the coupled medium. Other mechanisms used are thermal effects, convectional effects, and mechanical effects. It mainly applies to transporting hydrophilic drugs, macromolecules, gene delivery, and vaccine delivery. It is also used in carrier-mediated delivery in the form of micelles, liposomes, and dendrimers. Some synergistic effects of sonophoresis, along with some permeation enhancers, such as chemical enhancers, iontophoresis, electroporation, and microneedles, increased the effectiveness of drug penetration. Sonophoresis-mediated ocular drug delivery, nail drug delivery, gene delivery to the brain, sports medicine, and sonothrombolysis are also widely used. In conclusion, while sonophoresis offers promising applications in diverse fields, further research is essential to comprehensively elucidate the biophysical mechanisms governing ultrasound-tissue interactions. Addressing these gaps in understanding will enable the refinement and optimization of sonophoresis-based therapeutic strategies for enhanced clinical efficacy.

Key Transdermal Patch Using Cannabidiol-Loaded Nanocarriers with Better Pharmacokinetics in vivo

Purpose

Cannabidiol (CBD) is a promising therapeutic drug with low addictive potential and a favorable safety profile. However, CBD did face certain challenges, including poor solubility in water and low oral bioavailability. To harness the potential of CBD by combining it with a transdermal drug delivery system (TDDS). This innovative approach sought to develop a transdermal patch dosage form with micellar vesicular nanocarriers to enhance the bioavailability of CBD, leading to improved therapeutic outcomes.

Methods

A skin-penetrating micellar vesicular nanocarriers, prepared using nano emulsion method, cannabidiol loaded transdermal nanocarriers-12 (CTD-12) was presented with a small particle size, high encapsulation efficiency, and a drug-loaded ratio for CBD. The skin permeation ability used Strat-M™ membrane with a transdermal diffusion system to evaluate the CTD and patch of CTD-12 (PCTD-12) within 24 hrs. PCTD-12 was used in a preliminary pharmacokinetic study in rats to demonstrate the potential of the developed transdermal nanocarrier drug patch for future applications.

Results

In the transdermal application of CTD-12, the relative bioavailability of the formulation was 3.68 ± 0.17-fold greater than in the free CBD application. Moreover, PCTD-12 indicated 2.46 ± 0.18-fold higher relative bioavailability comparing with free CBD patch in the ex vivo evaluation. Most importantly, in the pharmacokinetics of PCTD-12, the relative bioavailability of PCTD-12 was 9.47 ± 0.88-fold higher than in the oral application.

Conclusion

CTD-12, a transdermal nanocarrier, represents a promising approach for CBD delivery, suggesting its potential as an effective transdermal dosage form.

Nanofiber-based Delivery of Luliconazole: Fabrication, Characterization, and Therapeutic Performance Assessment

This study introduces and assesses the potential of a Luliconazole-loaded nanofiber (LUL-NF) patch, fabricated through electrospinning, for enhancing topical drug delivery. The primary objectives involve evaluating the nanofiber structure, characterizing physical properties, determining drug loading and release kinetics, assessing antifungal efficacy, and establishing the long-term stability of the NF patch. LUL-NF patches were fabricated via electrospinning and observed by SEM at approximately 200 nm dimensions. The comprehensive analysis included physical properties (thickness, folding endurance, swelling ratio, weight, moisture content, and drug loading) and UV analysis for drug quantification. In vitro studies explored sustained drug release kinetics, while microbiological assays evaluated antifungal efficacy against Candida albicans and Aspergillus Niger. Stability studies confirmed long-term viability. Comparative analysis with the pure drug, placebo NF patch, LUL-NF patch, and Lulifod gel was conducted using agar diffusion, revealing enhanced performance of the LUL-NF patch. SEM analysis revealed well-defined LUL-NF patches (0.80 mm thickness) with exceptional folding endurance (> 200 folds) and a favorable swelling ratio (12.66 ± 0.73%). The patches exhibited low moisture uptake (3.4 ± 0.09%) and a moisture content of 11.78 ± 0.54%. Drug loading in 1 cm2 section was 1.904 ± 0.086 mg, showing uniform distribution and sustained release kinetics in vitro. The LUL-NF patch demonstrated potent antifungal activity. Stability studies affirmed long-term stability, and comparative analysis highlighted increased inhibition compared to a pure drug, LUL-NF patch, and a commercial gel. The electrospun LUL-NF patch enhances topical drug delivery, promising extended therapy through single-release, one-time application, and innovative drug delivery strategies, supported by thorough analysis.

QbD Based Formulation Development and Optimisation of Ozenoxacin Topical Nano-Emulgel and Efficacy Evaluation Using Impetigo Mice Model

To formulate and optimize Ozenoxacin nano-emulsion using Quality by Design (QbD) concept by means of Box-Behnken Design (BBD) and converting it to a gel to form Ozenoxacin nano-emulgel followed by physico-chemical, in-vitro, ex-vivo and in-vivo evaluation. This study demonstrates the application of QbD methodology for the development and optimization of an effective topical nanoemulgel formulation for the treatment of Impetigo focusing on the selection of appropriate excipients, optimization of formulation and process variables, and characterization of critical quality attributes. BBD was used to study the effect of "% of oil, % of Smix and homogenization speed" on critical quality attributes "globule size and % entrapment efficiency" for the optimisation of Ozenoxacin Nano-emulsion. Ozenoxacin loaded nano-emulgel was characterized for "description, identification, pH, specific gravity, amplitude sweep, viscosity, assay, organic impurities, antimicrobial effectiveness testing, in-vitro release testing, ex-vivo permeation testing, skin retention and in-vivo anti-bacterial activity". In-vitro release and ex-vivo permeation, skin retention and in-vivo anti-bacterial activity were found to be significantly (p < 0.01) higher for the nano-emulgel formulation compared to the innovator formulation (OZANEX™). Antimicrobial effectiveness testing was performed and found that even at 70% label claim of benzoic acid is effective to inhibit microbial growth in the drug product. The systematic application of QbD principles facilitated the successful development and optimization of a Ozenoxacin Nano-Emulsion. Optimised Ozenoxacin Nano-Emulgel can be considered as an effective alternative and found to be stable at least for 6 months at 40 °C / 75% RH and 30 °C / 75% RH.

Confined microemulsions: pore diameter induced change of the phase behavior

In the present work, the temperature-dependent phase behavior of a C10E4 based microemulsion is studied in different meso-macroporous glasses, as a function of their pore diameter. The phase behavior in these pores is investigated by small-angle X-ray scattering (SAXS). The crucial parameter we discuss based on the SAXS results is the domain size of the bicontinuous phase. Using a simplified model to fit the scattering data, we can observe the microemulsion inside the pores. These experiments reveal a temperature-dependent change in domain sizes of the bicontinuous microemulsion only for large pores.

Two-dimensional correlation infrared spectroscopy elucidated the volatilization process of the microemulsion composed of peppermint essential oil and composite herbal extract

Microemulsion is usually a transparent and isotropic liquid mixture composed of oil phase, water phase, surfactant and cosurfactant. The surfactant-framed nanoscale droplets in the microemulsion can penetrate into the skin surface to reduce its barrier function. This makes microemulsion an ideal preparation for the transdermal drug delivery. The permeability of microemulsion may be further enhanced when botanical essential oils that can dissolve the stratum corneum are used as the oil phase. However, the volatility of essential oils is possible to shorten the retention time of the microemulsion on the skin surface. Therefore, analytical methods are required to understand the volatilization process of the microemulsion composed of essential oils to develop the reasonable topical drug carrier system. In this research, Fourier transform infrared (FTIR) spectroscopy with an attenuated total reflection (ATR) accessory cooperated with two-dimensional correlation spectroscopy (2DCOS) to elucidate the volatilization processes of some microemulsions composed of peppermint essential oil. Principal component analysis (PCA) and moving-window two-dimensional correlation spectroscopy (MW2DCOS) revealed the multiple stages of the volatilization processes of the microemulsions. Synchronous 2D correlation infrared spectra indicated the compositional changes during each stage. It was found that the successive volatilizations of ethanol, water and menthone were the major events during the volatilization process of the microemulsion composed of peppermint essential oil. Ethanol can accelerate the volatilization of water, while the composite herbal extract seemed to not influence the volatilization of the other ingredients. After a 20-min-long volatilization process, the remaining microemulsion still contained considerable peppermint essential oil to affect the skin. The above results showed the feasibility of developing the microemulsion composed of peppermint essential oil for the transdermal drug delivery of composite herbal extract. This research also proved that the combination of ATR-FTIR spectroscopy and 2DCOS was valuable to study the volatilization process of the microemulsion.

Novel Microemulsion Containing Benzocaine and Fusidic Acid Simultaneously: Formulation, Characterization, and In Vitro Evaluation for Wound Healing

Modern drug carrier technologies, such as microemulsions with small droplet sizes and high surface areas, improve the ability of low water solubility active ingredients to permeate and localize. The goal of this study was to create microemulsion formulations for wound healing that contained both fusidic acid (FA), an antibacterial agent, and benzocaine (BNZ), a local anesthetic. Studies on characterization were carried out, including viscosity, droplet size, and zeta potential. The drug-loaded microemulsion had a stable structure with -3.014 ± 1.265 mV of zeta potential and 19.388 ± 0.480 nm of droplet size. In both in vitro release and ex vivo permeability studies, the microemulsion was compared with Fucidin cream and oily BNZ solution. According to the drug release studies, BNZ release from the microemulsion and the BNZ solution showed a similar profile (p > 0.05), while FA release from the microemulsion had a higher drug release compared to Fucidin cream (p < 0.001). The microemulsion presented lower drug permeation (p > 0.05) for both active ingredients, on the other hand, provided higher drug accumulation compared to the control preparations. Moreover, according to the results of in vitro wound healing activity, the microemulsion indicated a dose-dependent wound healing potential with the highest wound healing activity at the highest concentrations. To the best of our knowledge, this developed BNZ- and FA-loaded microemulsion would be a promising candidate to create new opportunities for wound healing thanks to present the active ingredients, which have low water solubility, in a single formulation and achieved higher accumulation than control preparations.

Nanoemulsions: Summary of a Decade of Research and Recent Advances

Nanoemulsions consist of a combination of several components such as oil, water, emulsifiers, surfactants and cosurfactants. Various techniques for producing nanoemulsions include high-energy and low-energy approaches such as high-pressure homogenization, microfluidization, jet disperser and phase inversion methods. The properties of a formulation can be influenced by elements such as the composition, concentration, size and charge of droplets, which in turn can affect the technique of manufacture. Characterization is conducted by the assessment of several factors such as physical properties, pH analysis, viscosity measurement and refractive index determination. This article offers a thorough examination of the latest developments in nanoemulsion technology, with a focus on their wide-ranging applications and promising future possibilities. It also discusses the administration of nanoemulsions through several methods.

Enhanced in vitro and ex vivo transdermal permeation of microemulsion gel of tapentadol hydrochloride

Aim of the current study is to develop a microemulsion gel for transdermal delivery of tapentadol hydrochloride. Microemulsion was developed using phase diagram and subjected to assay, globule size, PDI, zeta potential, TEM and in vitro drug release studies. The optimized microemulsion was converted into gel using carbopol 934 NF and evaluated for viscosity, spreadability, in vitro, ex vivo, FTIR, DSC, stability and skin irritation studies. The mean globule size, PDI, zeta potential and in vitro drug release of microemulsion were found 247.3 nm, 0.298, -17.6 mV and 98.42% respectively. In vitro and ex vivo drug release of gel was found 92.2% and 88.6% in 24 h. Viscosity and spreadability results indicated ease of application and no incompatibility was observed from FTIR studies. The skin irritation studies showed absence of erythema. Key findings from the current research concluded that microemulsion gel was suitable for effective transdermal delivery.

Development of microemulgel formulations with varied permeation enhancers for transungual delivery of luliconazole in onychomycosis management

Luliconazole-loaded microemulgels containing different permeation enhancers were formulated for transungual drug delivery for the management of onychomycosis, onychomycosis, which affects nails. The physicochemical properties like droplet size, zeta potential, pH, viscosity, spreadability, extrudability, oil binding capacity, drug content, and microscopic study were evaluated. The Pseudo-ternary phase diagram was constructed for the formulation of microemulsions (MEs) by keeping the Km ratio constant at 3:1 and characterized for clarity, mean droplet size, zeta potential, viscosity, pH, transmittance, refractive index, and stability. The ME mean droplet size and zeta potential were found in the range of 38.78 to 171.4 nm, and 0.00 to - 6.6 mV, respectively. Prepared MEs were converted into microemulgel by adding a 2.5% gelling agent (Carbapol 934) in the external phase, and a drug release study was conducted. Formulation E3 showed better drug release and was chosen as the control. Four different penetration enhancers were added separately within E3 and further evaluated for pH, viscosity, spreadability, extrudability, oil binding capacity, drug content, microscopic study, Compatibility study, XRD, and DSC. A favorable docking score was observed between luliconazole and Lanosterol 14-alpha-demethylase. In-vitro cumulative drug release at the end of 24 h from E3-SS, containing sodium sulfide as a penetration enhancer, was found to be 94.70% and was 2 times more than the control formulation. Ex-vivo transungual permeation studies through cutting nail clippings were found to be in the range of 28.18 - 36.52 µg/mm2. The microemulgels tagged as E3, E3-SS, and E3-SL showed a significant zone of inhibition against Candida albicans and Aspergillus fumigatus as compared to the marketed formulation.

Sustained release gel (polymer-free) of itraconazole-loaded microemulsion for oral candidiasis treatment: time-kill kinetics and cellular uptake

Itraconazole (ICZ) was prepared in a self-microemulsifying (SM) gel. This gel was intended for use in the oral mucosa, where low volume and flow of saliva result in limited solubility and absorption of drugs that are poorly water-soluble. The drug-loaded gel formulation (ICZ-SM) was selected as a clear solution in the ternary phase diagram to improve the solubility of ICZ. Seven ratios (S1-S7) were prepared by mixing polyoxyl 35 castor oils (P35), a medium chain with a blend of mono-, di-, and triglycerides (MCT), and water. Phase separation of large-sized emulsions by countering with artificial saliva were observed in dilution tests for the formulation contained MCT, P35, and water at the ratios of 70:20:10 (S1), 10:80:10 (S3), and 20:60:20 (S4). Formulations in the ratios of 15:50:35 (S5) and 19:43:38 (S6) produced strong ICZ-SM gels, as shown by rheology tests, whereas the formulations at the ratios of 30:60:10 (S2) and 10:43:47 (S7) exhibited no elasticity. A model of zero-order kinetic (S5) and first-order kinetic (S6) were found to best fit the release kinetics of ICZ from the gels. Time-killing assays revealed that S5 and S6 required less time compared with S2 and the ICZ solution. Furthermore, S5 exhibited the highest increase in cell uptake compared with S2, S6, and the ICZ solution. These findings suggest that the ICZ-SM gel was a free polymer capable of delivering an ICZ for the treatment of oral candidiasis, and that ICZ-SM gels applied locally exhibit enhanced absorption into cells.

Sustained delivery of triamcinolone acetonide from a thermosensitive microemulsion gel system for the treatment of sensorineural hearing loss

Intratympanic administration for the delivery of steroids has been extensively studied but limited because of low permeability of the drug through the row window membrane. Here, to effectively deliver poorly soluble triamcinolone acetonide (TA), microemulsions (ME) were prepared from Capmul MCM (oil), Cremophor RH40 (surfactant), and tetraglycol (cosurfactant) based on solubility studies, emulsifying ability test, and pseudoternary phase diagrams. Microemulsion gel (MEG) was prepared by mixing TA-ME with a poloxamer hydrogel base. The physicochemical properties of ME and MEG formulations were characterized, and the toxicity and oto-protective effectiveness were evaluated in vitro and in vivo. The ME-3 formulation showed a small droplet size (16.5 ± 0.2 nm), narrow PDI (0.067 ± 0.041), and enhanced TA solubility (2619.7 ± 57.6 μg/g). The optimized MEG demonstrated temperature-dependent gelation with a gelation time of 208 ± 10 sec at 37 °C. Slow degradation of the gel matrix sustained release of TA from MEG compared to the ME formulation. Both TA-ME and TA-MEG were found to be nontoxic to NIH3T3 cells at the test concentrations (0 to 5 µg/mL), and biocompatible after intratympanic administration to mice. The incorporation of ME into thermosensitive hydrogels prolonged retention of TA at the site of administration until 6 days. As a consequence, the enhanced drug absorption into the cochlea in TA-MEG group (approximately 2 times higher than other groups) protected hair cells, spiral ganglion neurons, and stria vascular cells from cisplatin-induced damage. Therefore, this injectable TA-loaded MEG is an effective and safe vehicle for the sustained delivery of triamcinolone acetonide into the inner ear.

Applications and recent advances in transdermal drug delivery systems for the treatment of rheumatoid arthritis

Rheumatoid arthritis is a chronic, systemic autoimmune disease predominantly based on joint lesions with an extremely high disability and deformity rate. Several drugs have been used for the treatment of rheumatoid arthritis, but their use is limited by suboptimal bioavailability, serious adverse effects, and nonnegligible first-pass effects. In contrast, transdermal drug delivery systems (TDDSs) can avoid these drawbacks and improve patient compliance, making them a promising option for the treatment of rheumatoid arthritis (RA). Of course, TDDSs also face unique challenges, as the physiological barrier of the skin makes drug delivery somewhat limited. To overcome this barrier and maximize drug delivery efficiency, TDDSs have evolved in terms of the principle of transdermal facilitation and transdermal facilitation technology, and different generations of TDDSs have been derived, which have significantly improved transdermal efficiency and even achieved individualized controlled drug delivery. In this review, we summarize the different generations of transdermal drug delivery systems, the corresponding transdermal strategies, and their applications in the treatment of RA.

The Application of Nanogels as Efficient Drug Delivery Platforms for Dermal/Transdermal Delivery

The delivery of active molecules via the skin seems to be an efficient technology, given the various disadvantages of oral drug administration. Skin, which is the largest human organ of the body, has the important role of acting as a barrier for pathogens and other molecules including drugs; in fact, it serves as a primary defense system blocking any particle from entering the body. Therefore, to overcome the skin barriers and poor skin permeability, researchers implement novel carriers which can effectively carry out transdermal delivery of the molecules. Another significant issue which medical society tries to solve is the effective dermal delivery of molecules especially for topical wound delivery. The application of nanogels is only one of the available approaches offering promising results for both dermal and transdermal administration routes. Nanogels are polymer-based networks in nanoscale dimensions which have been explored as potent carriers of poorly soluble drugs, genes and vaccines. The nanogels present unique physicochemical properties, i.e., high surface area, biocompatibility, etc., and, importantly, can improve solubility. In this review, authors aimed to summarize the available applications of nanogels as possible vehicles for dermal and transdermal delivery of active pharmaceutical ingredients and discuss their future in the pharmaceutical manufacturing field.

The Skin and Natural Cannabinoids-Topical and Transdermal Applications

The chemical constituents of the Cannabis plant known as cannabinoids have been extensively researched for their potential therapeutic benefits. The use of cannabinoids applied to the skin as a potential method for both skin-related benefits and systemic administration has attracted increasing interest in recent years. This review aims to present an overview of the most recent scientific research on cannabinoids used topically, including their potential advantages for treating a number of skin conditions like psoriasis, atopic dermatitis, and acne. Additionally, with a focus on the pharmacokinetics and security of this route of administration, we investigate the potential of the transdermal delivery of cannabinoids as a method of systemic administration. The review also discusses the restrictions and difficulties related to the application of cannabinoids on the skin, emphasizing the potential of topical cannabinoids as a promising route for both localized and systemic administration. More studies are required to fully comprehend the efficacy and safety of cannabinoids in various settings.

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.

Exploring the Versatility of Microemulsions in Cutaneous Drug Delivery: Opportunities and Challenges

Microemulsions are novel drug delivery systems that have garnered significant attention in the pharmaceutical research field. These systems possess several desirable characteristics, such as transparency and thermodynamic stability, which make them suitable for delivering both hydrophilic and hydrophobic drugs. In this comprehensive review, we aim to explore different aspects related to the formulation, characterization, and applications of microemulsions, with a particular emphasis on their potential for cutaneous drug delivery. Microemulsions have shown great promise in overcoming bioavailability concerns and enabling sustained drug delivery. Thus, it is crucial to have a thorough understanding of their formulation and characterization in order to optimize their effectiveness and safety. This review will delve into the different types of microemulsions, their composition, and the factors that affect their stability. Furthermore, the potential of microemulsions as drug delivery systems for skin applications will be discussed. Overall, this review will provide valuable insights into the advantages of microemulsions as drug delivery systems and their potential for improving cutaneous drug delivery.

Preparation and In Vitro Characterization of Alkyl Polyglucoside-Based Microemulsion for Topical Administration of Curcumin

The skin is a complex and selective system from the perspective of permeability to substances from the external environment. Microemulsion systems have demonstrated a high performance in encapsulating, protecting and transporting active substances through the skin. Due to the low viscosity of microemulsion systems and the importance of a texture that is easy to apply in the cosmetic and pharmaceutical fields, gel microemulsions are increasingly gaining more interest. The aim of this study was to develop new microemulsion systems for topical use; to identify a suitable water-soluble polymer in order to obtain gel microemulsions; and to study the efficacy of the developed microemulsion and gel microemulsion systems in the delivery of a model active ingredient, namely curcumin, into the skin. A pseudo-ternary phase diagram was developed using AKYPO^® SOFT 100 BVC, PLANTACARE^® 2000 UP Solution and ethanol as a surfactant mix; caprylic/capric triglycerides, obtained from coconut oil, as the oily phase; and distilled water. To obtain gel microemulsions, sodium hyaluronate salt was used. All these ingredients are safe for the skin and are biodegradable. The selected microemulsions and gel microemulsions were physicochemically characterized by means of dynamic light scattering, electrical conductivity, polarized microscopy and rheometric measurements. To evaluate the efficiency of the selected microemulsion and gel microemulsion to deliver the encapsulated curcumin, an in vitro permeation study was performed.

Design, development and evaluation of Resveratrol transdermal patches for breast cancer therapy

Resveratrol (RVT) is a polyphenolic phytoestrogen which has shown antiproliferative activity in breast cancer. However, its low bioavailability and short half-life have restricted its use. The current study aimed to develop transdermal patches of RVT and evaluate its site-specific delivery for breast cancer therapy. Different penetration enhancers were screened using a computational tool, quantitative structure propery relationship (QSPR). The best permeation of RVT was observed in a patch comprising hydroxypropyl methylcellulose (HPMC) E15LV: HPMC-K4M: polyvinyl pyrrolidone (PVP) K30 in the ratio of 3:1:2 as release controlling polymers with Glycerol:Capryol 90 (4:1) as penetration enhancer and plasticizer. To assess the localized delivery of RVT, the patch was applied to the breast of female rats. Higher breast tissue disposition with lower systemic concentration was observed compared to oral administration, demonstrated by increased AUC and MRT. Further, the optimized RVT patches were tested in 7,12-Dimethylbenz[a]anthracene (DMBA) induced rat mammary cancer. Compared to oral RVT, the application of RVT tansdermal patches significantly reduced the tumor volume and serum CA 15-3, a cancer biomarker. Thus, the RVT transdermal patch may be a viable approach for ensuring high local concentration of drug for site-specific delivery in breast cancer therapy.

Exploration of novel drug delivery systems in topical management of osteoarthritis

Osteoarthritis is one of the foremost disabling disorders in the world. There is no definitive treatment to prevent the progression of osteoarthritis. Hence, palliative treatment aims at minimizing pain, disability and improving function, performance and quality of life. Oral administration of nonsteroidal anti-inflammatory drug is associated with number of adverse effects and reduced therapeutic efficacy. Intra-articular injection has been the preferred route of drug administration. However, the clearance of drug from the arthritic site, risk of infections, cost and the pain associated with frequent injections make this route highly non-compliant to patients. Since osteoarthritis is a chronic condition which requires treatment for prolonged duration, there is an urgent need for another administration route which circumvents the hindrances linked with intra-articular route. Transdermal route across the skin locally at the osteoarthritis site could help in surpassing the disadvantages associated with intra-articular route. However, traversing skin barrier and reaching the chondrocytes with sufficient amount of the drug is extremely difficult. Nanocarrier-based approaches could hold an answer to the said shortcomings owing to their reduced size, targeting tunability and site specificity. In this article, we discuss the pathophysiology of osteoarthritis, molecular targets, and utilization of nanocarrier-based approaches to strategize the treatment of osteoarthritis in a new direction, i.e. topical delivery of nanocarriers in osteoarthritis.

Nanoemulgel: A Novel Nano Carrier as a Tool for Topical Drug Delivery

Nano-emulgel is an emerging drug delivery system intended to enhance the therapeutic profile of lipophilic drugs. Lipophilic formulations have a variety of limitations, which includes poor solubility, unpredictable absorption, and low oral bioavailability. Nano-emulgel, an amalgamated preparation of different systems aims to deal with these limitations. The novel system prepared by the incorporation of nano-emulsion into gel improves stability and enables drug delivery for both immediate and controlled release. The focus on nano-emulgel has also increased due to its ability to achieve targeted delivery, ease of application, absence of gastrointestinal degradation or the first pass metabolism, and safety profile. This review focuses on the formulation components of nano-emulgel for topical drug delivery, pharmacokinetics and safety profiles.

Microemulsion Delivery Systems with Low Surfactant Concentrations: Optimization of Structure and Properties by Glycol Cosurfactants

Extensive use of microemulsions as delivery systems raises interest in the safe ingredients that can form such systems. Here, we assessed the use of two glycols, i.e., propylene glycol and pentylene glycol, and their mixtures to manipulate the properties and structure of microemulsions. Obtained systems with glycols were extensively characterized in terms of capacity to incorporate water phase, droplet size, polydispersity, structure type, and rheological and thermal properties. The results of these studies indicate that the composition, structure, and viscosity of the microemulsions can be changed by appropriate quantification of glycols. It has been shown that the type of glycol used and its amount may favor or worsen the formation of microemulsions with the selected oils. In addition, a properly selected composition of oils and glycols resulted in the formation of microemulsions with a reduced content of surfactants and consequently improved the safety of using microemulsions as delivery systems.

Curcumin-loaded microemulsion: formulation, characterization, and in vitro skin penetration

OBJECTIVE

Formulation of curcumin in a microemulsion with a high loading capacity and that favors its penetration into the skin.

SIGNIFICANCE

Take advantage of the properties of microemulsions to promote the penetration of curcumin into the skin, with the aim of enhancing its therapeutic effects.

METHODS

Curcumin was formulated in microemulsions based on oleic acid (oil phase), Tween® 80 (surfactant), and Transcutol^® HP (cosurfactant). The microemulsion formation area was mapped by constructing pseudo-ternary diagrams for surfactant:co-surfactant ratios 1:1, 1:2, and 2:1. Microemulsions were characterized through measurements of specific weight, refractive index, conductivity, viscosity, droplet size, and in vitro skin permeation studies.

RESULTS

Nine microemulsions were prepared and characterized, showing clear, stable formulations with globule size dependent on the proportion of the components. The microemulsion with the highest loading capacity (60 mg/mL), based on Tween^® 80, Transcutol^® HP, oleic acid, and water (40:40:10:10) was able to penetrate the viable epidermis, finding a total amount of curcumin in the receptor medium at 24 h of 10.17 ± 9.7 µg/cm². The distribution of curcumin in the skin, visualized by confocal laser scanning microscopy, showed that the maximum amount was located between 20 and 30 µm.

CONCLUSION

The inclusion of curcumin in a microemulsion allows its passage into and through the skin. The localization of curcumin, especially in the viable epidermis, would be important for those cases where local conditions are sought to be treated.

Nano and Microemulsions for the Treatment of Depressive and Anxiety Disorders: An Efficient Approach to Improve Solubility, Brain Bioavailability and Therapeutic Efficacy

Most drugs used for the treatment of depression, anxiety and related disorders have low absorption, high metabolism, low brain targeting and/or low water solubility, which can make it hard to formulate them at high strength and can also lead to decreased bioavailability. Incorporating these drugs into nanometric emulsions can solve these issues. Hence, the aim of the present review was to assess the potential of nano and micro emulsions for the delivery of antidepressant and anxiolytic drugs. The results from several studies showed that nanometric emulsions were able to increase drug strength up to 20,270-fold (compared to aqueous solubility). Moreover, in general, the formulations showed droplet size, polydispersity index, zeta potential, viscosity, osmolality, pH, in vitro drug release and ex vivo drug permeation as adequate for the intended effect and administration route. In vivo animal pharmacokinetic experiments showed that nanometric emulsions improved systemic drug bioavailability and/or brain targeting, and in vivo pharmacodynamic studies showed that they had antidepressant and/or anxiolytic effects, also being apparently safe. Hence, the current review provides proof of the potential of nano and microemulsions for improving solubilization and increasing the overall bioavailability of antidepressant and/or anxiolytic drugs, providing evidence of a possible useful strategy for future therapies.

Overcoming skin barriers through advanced transdermal drug delivery approaches

Upon exhaustive research, the transdermal drug delivery system (TDDS) has appeared as a potential, well-accepted, and popular approach to a novel drug delivery system. Ease of administration, easy handling, minimum systemic exposure, least discomfort, broad flexibility and tunability, controlled release, prolonged therapeutic effect, and many more perks make it a promising approach for effective drug delivery. Although, the primary challenge associated is poor skin permeability. Skin is an intact barrier that serves as a primary defense mechanism to preclude any foreign particle's entry into the body. Owing to the unique anatomical framework, i.e., compact packing of stratum corneum with tight junction and fast anti-inflammatory responses, etc., emerged as a critical physiological barrier for TDDS. Fusion with other novel approaches like nanocarriers, specially designed transdermal delivery devices, permeation enhancers, etc., can overcome the limitations. Utilizing such strategies, some of the products are under clinical trials, and many are under investigation. This review explores all dimensions that overcome poor permeability and allows the drug to attain maximum potential. The article initially compiles fundamental features, components, and design of TDDS, followed by critical aspects and various methods, including in vitro, ex vivo, and in vivo methods of assessing skin permeability. The work primarily aimed to highlight the recent advancement in novel strategies for effective transdermal drug delivery utilizing active methods like iontophoresis, electroporation, sonophoresis, microneedle, needleless jet injection, etc., and passive methods such as the use of liposomes, SLN, NLC, micro/nanoemulsions, dendrimers, transferosomes, and many more nanocarriers. In all, this compilation will provide a recent insight on the novel updates along with basic concepts, the current status of clinical development, and challenges for the clinical translation of TDDS.

Liposome and microemulsion loaded with ibuprofen: from preparation to mechanism of drug transport

To compare the difference between liposome (LP) and microemulsion (ME) in delivering ibuprofen (IBU) transdermally and explore relative mechanism. IBU-LP and IBU-ME were prepared by ethanol injection and spontaneous emulsification, respectively. The percutaneous delivery was evaluated using Franz diffusion cells. Fourier transform infra-red spectroscopy (FTIR), differential scanning calorimetry (DSC), activation energy (Ea), and confocal laser scanning microscopy (CLSM) were used to investigate the transdermal mechanism. The particle size and encapsulation efficiency were 228.00 ± 8.60 nm, 86.68 ± 1.43%(w/w) for IBU-LP, and 56.74 ± 7.11 nm, 91.08 ± 3.27%(w/w) for IBU-ME. Percutaneous study showed that formulations enhanced permeation and drug retention in the skin. FTIR and DSC showed that the permeation occurred due to the interaction of the formulations with the lipid bilayer and the protein. The decrease in Ea (1.506 and 0.939 kcal/mol) revealed that the stratum corneum (SC) lipid bilayers were significantly disrupted and this destructive effect of IBU-LP was stronger. IBU-LP was superior to IBU-ME in the aspects of transdermal delivery of IBU.

Appraisal on the Wound Healing Potential of Deverra tortuosa DC. and Deverra triradiata Hochst Essential Oil Nanoemulsion Topical Preparation

Deverra tortuosa (Desf.) DC. and Deverra. triradiata Hochst. ex Bioss are perennial desert shrubs widely used traditionally for many purposes and they are characteristic for their essential oil. The objective of the present study was to investigate the in vivo wound healing activity of the essential oil (EO) of D. tortuosa and D. triradiata through their encapsulation into nanoemulsion. EO nanoemulsion was prepared using an aqueous phase titration method, and nanoemulsion zones were identified through the construction of phase diagrams. The EO was prepared by hydrodistillation (HD), microwave-assisted hydrodistillation (MAHD), and supercritical fluid extraction (SFE) and analyzed using GC/MS. D. tortuosa oil is rich in the non-oxygenated compound, representing 74.54, 73.02, and 41.19% in HD, MADH, and SFE, respectively, and sabinene represents the major monoterpene hydrocarbons. Moreover, D. triradiata is rich in oxygenated compounds being 69.77, 52.87, and 61.69% in HD, MADH, and SFE, respectively, with elemicin and myristicin as major phenylpropanoids. Topical application of the nanoemulsion of D. tortuosa and D. triradiata (1% or 2%) exhibited nearly 100% wound contraction and complete healing at day 16. Moreover, they exhibit significant antioxidant and anti-inflammatory effects and a significant increase in growth factors and hydroxyproline levels. Histopathological examination exhibited complete re-epithelialization accompanied by activated hair follicles and abundant collagen fibers, especially at a concentration of 2%. Therefore, the incorporation of the two Deverra species into nanoemulsion could professionally endorse different stages of wound healing.

A Cosmeceutical Topical Water-in-Oil Nanoemulsion of Natural Bioactives: Design of Experiment, in vitro Characterization, and in vivo Skin Performance Against UVB Irradiation-Induced Skin Damages

Introduction

Damage to human skin occurs either chronologically or through repetitive exposure to ultraviolet (UV) radiation, where collagen photodegradation leads to the formation of wrinkles and skin imperfections. Consequently, cosmeceutical products containing natural bioactives to restore or regenerate collagen have gained a remarkable attention as an ameliorative remedy.

Methods

This study aimed to develop and optimize collagen-loaded water-in-oil nanoemulsion (W/O NE) through a D-optimal mixture design to achieve an ideal multifunctional nanosystem containing active constituents. Vit E was included as a constituent of the formulation for its antioxidant properties to minimize the destructive impact of UV radiation. The formulated systems were characterized in terms of their globule size, optical clarity, and viscosity. An optimized system was selected and evaluated for its physical stability, in vitro wound healing properties, and in vivo permeation and protection against UV radiation. In addition, the effect of collagen-loaded NE was compared to Vit C-loaded NE and collagen-/Vit C-loaded NEs mixture as Vit C is known to enhance collagen production within the skin.

Results

The optimized NE was formulated with 25% oils (Vit E: safflower oil, 1:3), 54.635% surfactant/cosurfactant (Span 80: Kolliphor EL: Arlasolve, 1:1:1), and 20.365% water. The optimized NE loaded with either collagen or Vit C exhibited a skin-friendly appearance with boosted permeability, and improved cell viability and wound healing properties on fibroblast cell lines. Moreover, the in vivo study and histopathological investigations confirmed the efficacy of the developed system to protect the skin against UV damage. The results revealed that the effect of collagen-/Vit C-loaded NEs mixture was more pronounced, as both drugs reduced the skin damage to an extent that it was free from any detectable alterations.

Conclusion

NE formulated using Vit E and containing collagen and/or Vit C could be a promising ameliorative remedy for skin protection against UVB irradiation.

Microemulsions formed by PPG-5-CETETH-20 at low concentrations for transdermal delivery of nifedipine: Structural and in vitro study

Nifedipine is a potent anti-hypertensive, which is poorly orally bioavailable on account of first-pass metabolism, short half-life, and low water solubility. This study aimed to develop a microemulsified system with low surfactant concentration and to evaluate the influence of microemulsion (ME) phase behavior on skin permeation of nifedipine, as drug model. Thereafter, MEs were obtained using PPG-5-CETETH-20, oleic acid, and phosphate buffer at pH 5.0. The selected MEs were isotropic, with droplet diameters less than 10 nm, polydispersity index < 0.25, and pH between 5.0 and 5.2. MEs presented low viscosity and Newtonian behavior. SAXS results confirmed bicontinuous and oil-in-water (o/w) MEs formation. The presence of the drug promoted only very slight modifications in the ME structure. The MEs presented ability to deliver nifedipine via the transdermal route when in comparison with the control. Nevertheless, the skin permeated and retained amounts from the o/w and bicontinuous formulations did not differ significantly. The ATR-FTIR demonstrated that both formulations promoted fluidization and disorganization of lipids and increased the drug diffusion and partition coefficients in the skin. In conclusion, PPG-5-CETETH-20 MEs obtained proved to be effective skin permeation enhancers, acting by rising the coefficients of partition and diffusion of the nifedipine in the skin.

Anti-ageing peptides and proteins for topical applications: a review

Skin ageing is a cumulative result of oxidative stress, predominantly caused by reactive oxygen species (ROS). Respiration, pollutants, toxins, or ultraviolet A (UVA) irradiation produce ROS with 80% of skin damage attributed to UVA irradiation. Anti-ageing peptides and proteins are considered valuable compounds for removing ROS to prevent skin ageing and maintenance of skin health. In this review, skin ageing theory has been illustrated with a focus on the mechanism and relationship with anti-ageing peptides and proteins. The effects, classification, and transport pathways of anti-ageing peptides and proteins across skin are summarized and discussed. Over the last decade, several novel formulations and advanced strategies have been developed to overcome the challenges in the dermal delivery of proteins and peptides for skin ageing. This article also provides an in-depth review of the latest advancements in the dermal delivery of anti-ageing proteins and peptides. Based on these studies, this review prospected several semi-solid dosage forms to achieve topical applicability for anti-ageing peptides and proteins.

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.

Development of Licorice Flavonoids Loaded Microemulsion for Transdermal Delivery Using CCD-Optimal Experimental Approach: Formulation Development and Characterization

In this research, we sought to surmount the poor dissolvability and transdermal absorption rate of licorice flavonoids (LFs) by fabricating a LFs microemulsion. LFs content was determined using high performance liquid chromatography. Initial studies such as dissolution testing, emulsification testing, and pseudo ternary phase diagram generation were implemented for screening components and optimized adopting the central composite design. While the tested responses were solubility, droplet size and PDI, thirteen trials were performed using two different variables, oil percentage and optimized emulsifier and co-emulsifier ratio. Microemulsions were then characterized for droplet size, PDI, transmission electron microscopy, viscosity, electrical conductivity, pH, entrapment efficiency, drug content and stability. Additionally, skin release profile, percutaneous absorption and retention were investigated adopting Franz diffusion cell. The optimal formulation was found to compose of laureth-9 (emulsifier, 6.72 g), propylene glycol (co-emulsifier, 1.80 g), isopropyl myristate (IPM, oil, 1.48 g), LFs (1.50 g) and at least more than 85% deionized water. The optimized and storage for 3 months of microemulsion was found to clear, light yellow color without phase separation or precipitation indicated the stability of the preparation to long-term placement. The mean droplet size, PDI, entrapment efficiency and drug content were discovered as 12.68 ± 0.12 nm, 0.049 ± 0.005, 97.28 ± 0.13% and 122.67 ± 0.40 mg·g−1, respectively. Furthermore, the optimal formulation sustained release LFs, remarkably deliver more LFs through the skin layer (644.95 ± 6.73 μg cm−2) and significantly retained LFs in the skin layer (9.98 μg cm−2). The study concluded that optimized microemulsion has potential and enhanced the dissolvability and cumulative penetration amount of LFs.

Polysorbate-Based Drug Formulations for Brain-Targeted Drug Delivery and Anticancer Therapy

Polysorbates (PSs) are synthetic nonionic surfactants consisting of polyethoxy sorbitan fatty acid esters. PSs have been widely employed as emulsifiers and stabilizers in various drug formulations and food additives. Recently, various PS-based formulations have been developed for safe and efficient drug delivery. This review introduces the general features of PSs and PS-based drug carriers, summarizes recent progress in the development of PS-based drug formulations, and discusses the physicochemical properties, biological safety, P-glycoprotein inhibitory properties, and therapeutic applications of PS-based drug formulations. Additionally, recent advances in brain-targeted drug delivery using PS-based drug formulations have been highlighted. This review will help researchers understand the potential of PSs as effective drug formulation agents.

Recent progress in micro and nano-encapsulation of bioactive derivatives of the Brazilian genus Pterodon

In the last few decades, utilization of medicinal plants by the pharmaceutical industry has led to the identification of many new bioactive compounds. The genus Pterodon, native of the Brazilian Flora, is known for the therapeutic properties attributed to its species, which are widely used in popular medicine for their anti-inflammatory, anti-rheumatic, tonic, and depurative properties. The intrinsic low water solubility of the plant derivatives from the genus, including diterpenes with vouacapane skeletons that are partially associated with the pharmacological activities, impairs the bioavailability of these bioactive compounds. Recent studies have aimed to encapsulate Pterodon products to improve their water solubility, achieve stability, increase their efficacy, and allow clinical applications. The purpose of this paper is to review recent research on the use of nanotechnology for the development of new products from plant derivatives of the Pterodon genus in different types of micro- and nanocarriers. Therapeutic properties of their different products are also presented. Finally, an update about the current and future applications of encapsulated formulations is provided.

Jojoba oil-based microemulsion for transdermal drug delivery

Background and purpose:

Microemulsions are gaining an increased interest in transdermal drug delivery. Microemulsions are stable, easy to prepare, and provide high solubilizing capacity for various drugs. The aim of this work was to prepare microemulsions from jojoba oil for transdermal delivery of ketorolac and lidocaine HCl with improved permeation.

Experimental approach:

Microemulsions based on jojoba oil as the oil phase were formulated for transdermal delivery of lidocaine HCl and ketorolac. Brij 97 was selected as surfactant and hexanol as cosurfactant. Pseudoternary phase diagrams were constructed. Selected microemulsion formulations were characterized for their physical properties and in vitro drug permeation.

Findings/Results:

Water-in-oil microemulsions were obtained with droplet sizes not more than 220 nm. The viscosity of the microemulsions was linked to the viscosity of the surfactant used. Improved drug permeation rates were observed for both model drugs. The significant increase in permeation rate in presence of hexanol was due to its impact on skin integrity as indicated by the histopathological study. Drug permeation enhancements were caused by the surfactant, the cosurfactant used, jojoba oil itself, and the microemulsion formulation. Higher surfactant content showed lower lag times and better flux.

Conclusion and implications:

Jojoba oil microemulsions are considered promising vehicles for transdermal delivery of ketorolac and lidocaine HCl with improved drug permeation. Jojoba oil-based microemulsion would present a safe and effective means for delivering drugs through the skin.

Permeation, stability and acute dermal irritation of miroestrol and deoxymiroestrol from Pueraria candollei var. mirifica crude extract loaded transdermal gels

In this study, permeation behaviors and chemical stability of miroestrol and deoxymiroestrol from Pueraria candollei var. mirifica (PM), Thai traditional medicine, crude extract containing transdermal gels were firstly evaluated. Three different PM extract containing gels were formulated, including hydroalcoholic and microemulsion gels using carbomer, and silicone gel using silicone elastomer. In vitro permeation through porcine ear skin demonstrated that the flux and 24 h cumulative permeation of miroestrol and deoxymiroestrol were in the order of hydroalcoholic > silicone > microemulsion gels. Hydroalcoholic gel provided the highest partition coefficient from gel onto skin, and thus the skin permeability coefficient. After 24 h permeation, no miroestrol and deoxymiroestrol remained deposited in the skin. Accelerated study using heating-cooling revealed insignificant difference between the remaining percentages of miroestrol and deoxymiroestrol in aqueous and non-aqueous based gels. Long-term stability study showed that miroestrol contents remained constant for 90 d and 30 d under 5 ± 3 °C and 30 ± 2 °C, 75 ± 5%RH, respectively; whereas the percentage of deoxymiroestrol decreased significantly after 30 d storage, irrespective of storage conditions. Acute dermal irritation test on New Zealand White rabbits showed that PM hydroalcoholic gels were non-irritant, with no signs of erythema or oedema.[Figure: see text].

Design, optimization and evaluation of a microemulsion-based hydrogel with high malleability for enhanced transdermal delivery of levamisole

The objective of the present study was to prepare and evaluate a microemulsion-based hydrogel with high malleability as a transdermal delivery carrier for levamisole (LMS). A pseudo-ternary phase diagram and D-optimal mixture design were utilized to screen and optimize the microemulsion, and the formulation comprised 7.5% Maisine^TM35-1, 33% S_mix and 59.5% water. The microemulsion was physically stable with an average size of 19.3 ± 0.1 nm and zeta potential of -3.84 ± 0.05 mV. Moreover, a highly malleable alginate-boronic acid (alginate-BA) gel was prepared and could come into close contact with highly curved skin. The optimized microemulsion was loaded into alginate-BA gel and subjected to ex vivo and in vivo investigation. The microemulsion-based gel had desirable characterization, good stability and negligible skin irritation. The results of ex vivo permeation study showed that LMS achieved a significantly higher cumulative amount from the LMS-loaded microemulsion-based gel than that from the LMS-gel. The pharmacokinetic study showed a twofold increase in relative bioavailability compared to the commercial liniment. These results provide insight into the capability of the developed malleable microemulsion-based gel to enhance the transdermal permeation and bioavailability of LMS.

Development of a novel cannabinoid-loaded microemulsion towards an improved stability and transdermal delivery

The aim of this study was to develop a stable microemulsion (ME) for transdermal delivery of tetrahydrocannabinolic acid (THCA) and cannabidiolic acid (CBDA). The lipid-based vehicles were selected by screening cannabinoid solubility and the emulsifying ability of surfactants. Pseudo-ternary phase diagrams were constructed by formulation of cannabinoids with Capryol® 90 as oil phase, Tween® 80, Solutol® HS15, Procetyl® AWS, and Cremophor® RH40 as surfactants, ethanol as cosurfactant, and distilled water as the aqueous phase. A significant improvement in transmembrane flux (J_ss), permeability coefficient (K_p), and enhancement ratio (E_R) was found in one system compared to other formulations. This ME consisted of 1.0% (w/w) of cannabinoids, 5% (w/w) of Capryol® 90, 44% (w/w) S_mix (2:1, Procetyl® AWS and Ethanol) and 50.0% (w/w) of distilled water. Additionally, the effects of pH on the permeation of the cannabinoids were investigated. Based on the pH value THCA and CBDA-loaded ME exhibited the highest permeation at pH 5.17 and pH 5.25. After storing the pH-adjusted P2 ME and the optimized P2 ME for 180 days at 4℃ and 25℃, the content of cannabinoids was over 95%. Consequently, the cannabinoid-loaded ME system is a promising option for solubilizing and stabilizing lipophilic drugs like cannabinoids and utilize them for transdermal delivery.

Oleuropein as a novel topical antipsoriatic nutraceutical: formulation in microemulsion nanocarrier and exploratory clinical appraisal

Introduction: Oleuropein is a promising nutraceutical found in abundance in olive leaf, with reported antioxidant and anti-inflammatory properties, and hence could be a valuable treatment for dermatological diseases such as psoriasis.Areas covered: In order to overcome the poor skin penetration of oleuropein, it was formulated in a microemulsion nanocarrier. The selected microemulsion formulation displayed a particle size of 30.25 ± 4.8 nm, zeta potential 0.15 ± 0.08 mV and polydispersity index 0.3 ± 0.08, with storage stability for 1 year in room temperature and total deposition in skin layers amounting to 95.67%. Upon clinical examination in psoriatic patients, the oleuropein microemulsion formulation was proven superior to the marketed Dermovate cream composed of clobetasol propionate, in terms of reduction of Psoriasis Area and Severity Index (PASI) scores, as well dermoscopic imaging and morphometric analysis of the psoriasis lesions, in which oleuropein microemulsion exhibited marked improvement in the clinical manifestations of psoriasis.Expert opinion: The findings of this study further prove the promising role of nutraceuticals, as well as nanoparticles in enhancing the therapeutic outcome of treatments, and open new era of applications in a variety of diseases.

Microemulsion-based gel for the transdermal delivery of rasagiline mesylate: In vitro and in vivo assessment for Parkinson's therapy

Rasagiline mesylate (RSM) is a selective and irreversible monoamine oxidase B inhibitor used for the treatment of Parkinson's disease (PD). However, its unfavorable biopharmaceutical properties, such as extensive degradation in the gastrointestinal tract and first-pass metabolism are responsible for its low oral bioavailability and suboptimal therapeutic efficacy. Here, we report the feasibility of delivering RSM via the transdermal route using RSM containing microemulsion-based gel (RSM-MEG) to achieve effective management of PD. Our in vitro skin permeation studies of RSM-MEG showed significantly higher (at least ~1.5-fold) permeation across rat skin compared to the conventional RSM hydrogel. Our skin irritation studies in rabbits showed that RSM-MEG is safe for transdermal application. Finally, using the rat model of rotenone-induced Parkinsonism, we demonstrated that the topical application of RSM-MEG was equally effective in reversing PD symptoms when compared to oral RSM therapy. Thus, our study confirmed the feasibility and potential of transdermal delivery of RSM via simple topical application of RSM-MEG, and this approach could be an alternative therapeutic intervention for the treatment of Parkinson's disease.

Novel Gel Microemulsion as Topical Drug Delivery System for Curcumin in Dermatocosmetics

Gel microemulsion combines the advantages of the microemulsion, which can encapsulate, protect and deliver large quantities of active ingredients, and the gel, which is so appreciated in the cosmetic industry. This study aimed to develop and characterize new gel microemulsions suitable for topical cosmetic applications, using grape seed oil as the oily phase, which is often employed in pharmaceuticals, especially in cosmetics. The optimized microemulsion was formulated using Tween 80 and Plurol^® Diisostearique CG as a surfactant mix and ethanol as a co-solvent. Three different water-soluble polymers were selected in order to increase the viscosity of the microemulsion: Carbopol^® 980 NF, chitosan, and sodium hyaluronate salt. All used ingredients are safe, biocompatible and biodegradable. Curcumin was chosen as a model drug. The obtained systems were physico-chemically characterized by means of electrical conductivity, dynamic light scattering, polarized microscopy and rheometric measurements. Evaluation of the cytotoxicity was accomplished by MTT assay. In the final phase of the study, the release behavior of Curcumin from the optimized microemulsion and two gel microemulsions was evaluated. Additionally, mathematical models were applied to establish the kinetic release mechanism. The obtained gel microemulsions could be effective systems for incorporation and controlled release of the hydrophobic active ingredients.

Preparation of Microemulsion from an Alkyl Polyglycoside Surfactant and Tea Tree Oil

Preparation and characterization of microemulsions consisting of a plant-derived alkyl polyglycoside (APG) surfactant and the essential oil of Melaleuca alternifolia (tea tree) was studied. This nonionic APG surfactant used was Triton CG-110 with a CMC at 1748 ppm at 25 °C. Tea tree oil (TTO) was extracted from tea tree leaves by Triton CG-110-assisted hydrodistillation method. The preparation of the microemulsion was aided by the construction of pseudo-ternary phase diagrams, which were investigated at the different weight ratios of surfactant mixtures (S_mix = Triton CG-110/PPG) as 0.6:1, 1.8:1, 1:0 with hydrodistilled and commercial TTO by water titration method at room temperature. Particularly, structure of microemulsion was identified by electrical conductivity and viscosity. Moreover, shelf stability of some microemulsion made of 1% TTO with various concentration of Triton CG-110/PPG (1.8:1 w/w) were monitored for over a two-month period with dynamic light scattering. These results showed that microemulsion made of 1% TTO, 9% Triton CG-110/PPG (1.8:1 w/w) was insensitive with time and temperature of storage.