Size-dependent penetration of nanoemulsions into epidermis and hair follicles: implications for transdermal delivery and immunization

Isotretinoin-Loaded Topical Lipid Liquid Crystal for the Treatment of Acne: In-Vitro and In-Vivo Evaluations

Effective acne treatment is critical due to its profound impact on physical and psychological well-being. It was shown that severe systemic side effects, including teratogenicity, ovarian reserve reduction, depression, dry skin, hypertriglyceridemia, and intracranial hypertension limited oral isotretinoin usage. Therefore, this study addresses these challenges by developing isotretinoin-loaded lipid liquid crystal (LLC-IT) nanoparticles for topical application, aiming to enhance localized delivery while minimizing systemic exposure. LLC-IT nanoparticles were prepared using a top-down method and evaluated for their physicochemical properties, photostability, cytotoxicity, antimicrobial activity, in-vitro drug release, and in-vivo therapeutic efficacy. A testosterone-induced acne mouse model was used to compare LLC-IT treatment with untreated and commercial isotretinoin gel-treated groups. LLC-IT nanoparticles exhibited a uniform particle size (69.57 ± 0.51 nm), low polydispersity index (0.264 ± 0.01), and stable zeta potential (- 19.3 ± 0.2 mV). High encapsulation efficiency (95% ± 3) and effective loading capacity (1.15% ± 0.13) were achieved. Drug release was diffusion-controlled with minimal UV-induced degradation. Stability assessments over 12 months confirmed consistent properties across varying storage temperatures. LLC-IT displayed significant antibacterial activity and reduced skin irritation in Draize tests compared to commercial gels. In-vivo, LLC-IT reduced inflammation significantly more than untreated or commercial gel-treated groups, indicating enhanced therapeutic efficacy of LLC-IT formulation. The isotretinoin-loaded lipid liquid crystal formulation shows superior stability and efficacy with reduced side effects compared to conventional treatments, offering a more effective and patient-friendly solution, as well as a promising alternative for industrial production in acne management.

Targeting Acne: Development of Monensin-Loaded Nanostructured Lipid Carriers

Purpose

The emergence of antimicrobial resistance (AMR) has made treating acne vulgaris increasingly challenging, thus underscoring the urgent need for new antibacterial therapies. This research aimed to discover, for the first time, the efficacy of monensin (MON) against acne pathogens by encapsulating MON in nanostructured lipid carriers (NLCs) to achieve targeted topical delivery.

Methods

MON-loaded NLCs were formulated and optimized using the Design of Experiments (DoE) approach and incorporated in a gel formulation. The potential of MON, MON-NLCs, and its gel formulation was investigated against resistant human isolates of C. acnes, Staphylococcus aureus (S. aureus), and Staphylococcus epidermidis (S. epidermidis) using the agar dilution method. Using the porcine ear skin, the ex vivo deposition of MON was evaluated in different skin layers. The cytotoxicity assay was also performed at antibacterial concentrations using the keratinocyte cell line.

Results

MON-loaded NLCs were developed using stearic acid, oleic acid, and Tween® 80 and optimized with particle size, polydispersity index, and zeta potential of 96.65 ± 0.94 nm, 0.13 ± 0.01, and -36.50 ± 0.30 mV, respectively. The ex vivo deposition experiments showed that MON did not penetrate any skin layer using its water dispersion. However, a significant amount of MON was deposited into the epidermal layer using MON-NLC (4219.86 ± 388.32 ng/cm²) and gel formulation (8180.73 ± 482.37 ng/cm²), whereas no MON permeated to the dermis layer using gel formulation. The antibacterial study revealed the potential of MON, MON-NLC, and gel formulation against C. acnes isolates (MIC range 0.125-4 µg/mL, 0.25-4 µg/mL, and 0.125-1 µg/mL respectively). The cell viability results suggested MON-NLC formulation as a safe topical treatment effective at antibacterial concentrations.

Conclusion

This research highlights the novel ability of MON against resistant acne-causing pathogens and the potential of MON-NLCs to deliver MON to the targeted epidermal skin layer effectively.

Modulating metal-organic frameworks by surface engineering of stearic acid modification for follicular drug delivery and enhanced hair growth promotion

Cyclodextrin metal-organic frameworks (CD-MOF) as delivery carriers have gained great attention in the biomedical field. However, limited by challenges of moisture-sensitive nature, the design and application of CD-MOF-based hair follicle delivery for androgenic alopecia (AGA) has rarely been explored. We developed the metal-organic frameworks as hair follicle-targeted delivery system (SA-MOF), stearic acid (SA) was used to modify metal-organic frameworks to form a protective hydrophobic layer on the surface and provide the additional hair growth-promoting effect. Cardamonin (CAR), a newly discovered biosafety natural product, was encapsulated in SA-MOF (CAR@SA-MOF) to promote the therapeutic efficacy on AGA. CD-MOF surface-engineered nanoparticles modified by SA avoided the rapid hydration and disintegration of CD-MOF in water, which improved the drug release and follicular deposition of drug. Assisted by the delivery of SA-modified CD-MOF carriers, the drug significantly promoted cell proliferation and migration, achieving the promoting effect on hair follicle differentiation and hair regeneration in testosterone-challenged C57BL/6 mice. Simultaneously, SA modification provided additional promoting effects on human dermal papilla cell proliferation, regulating effect on keratinocyte growth factor, and activating effect of key signaling pathways. The surface engineering design of CD-MOF hair follicle drug delivery based on SA modification exhibits significant potential for the treatment of hair follicle and sebaceous gland-related diseases.

Nanoparticle-Encapsulated Plant Polyphenols and Flavonoids as an Enhanced Delivery System for Anti-Acne Therapy

This study conducted a literature review by searching for articles related to the treatment of skin infections/wrinkles using nano-delivery systems containing natural compounds. The search was conducted in various databases for articles published in the last 10 years, with strict inclusion and exclusion criteria. Of the 490 articles found, 40 were considered relevant. Acne vulgaris is a common dermatological disorder characterised by inflammation of the sebaceous glands, often resulting in the development of pimples, cysts, and scarring. Conventional treatments, including antibiotics and topical retinoids, frequently demonstrate limitations such as side effects, resistance, and insufficient skin absorption. Recent advancements in nanotechnology have enabled the creation of innovative drug-delivery systems that enhance the effectiveness and reduce the adverse effects of anti-acne medications. Polyphenols and flavonoids, natural bioactive compounds with notable anti-inflammatory, antioxidant, and antibacterial properties, are recognised for their therapeutic effectiveness in acne treatment. However, their practical application is hindered by insufficient solubility, stability, and bioavailability. The incorporation of these compounds into nanoparticle-based delivery systems has shown promise in resolving these challenges. Various nanoparticle platforms, including lipid-based nanoparticles, polymeric nanoparticles, and solid lipid nanoparticles, are evaluated for their ability to improve the stability, controlled release, and targeted delivery of polyphenols and flavonoids to the skin. The advent of polyphenol and flavonoid-loaded nanoparticles marks a new acne therapy era.

Artemisinin emulgel ameliorates cartilage degradation in knee osteoarthritis: in vitro and in vivo studies

Aim: Laboratory scale-up of artemisinin-loaded emulgel (ART-emulgel) was carried out and characterized for therapeutic performance in osteoarthritis (OA).Materials & methods: The solubility of ART in various oils, surfactants and co-surfactants were screened for construction of pseudo ternary phase diagram (TPD), followed by scale-up of artemisinin loaded nanoemulsion (ART-NE). ART-NE was amalgamated with Carbopol Ultrez 10-NF to prepare ART-emulgel that was later characterized in vitro and in vivo to analyze therapeutic efficacy in monosodium-iodoacetate (MIA) induced knee OA.Results: The droplet diameter of ART-NE was estimated to be 104.3 ± 2.593 nm with a polydispersity index of 0.245 ± 0.019 in addition to ζ-potential of 0.434 ± 0.028 mV. Steady-state flux and permeability coefficient for ART-emulgel were estimated to be 0.651 ± 0.031 µg.cm2/h and 0.245 ± 0.011 cm/h, respectively. ART-emulgel demonstrated 43.18% reduction in COX-2 level; 52.28% drop in IL-1β, and 88.78% alleviation of Tumor Necrosis Factor-α (TNF-α) level when compared with monosodium-iodoacetate induced OA rats. ART-emulgel and injectable ART (intra-articular; I.A) portrayed minor synovial erosion compared with blank and diclofenac emulgel. Histopathological evidences indicated restoration of cartilage integrity followed by reduction of OARSI scores in ART-emulgel when compared with disease control animals.Conclusion: ART-emulgel is a potential dosage form for translating into a clinically viable product for the management of OA.

Differences in the permeation of Licoricchalcone A-polysaccharide self-assembled nanoparticles on healthy and DNCB-induced atopic dermatitis in Balb/c mice

Nanoformulation have been widely used in skin and transdermal drug delivery. However, the differences in integral nanoparticles absorption in healthy and diseased skin have not yet fully analyzed. The present study attempted to explore the percutaneous absorption of drugs via lesional skin by using atopic dermatitis (AD) as a model, dinitrochlorobenzene (DNCB) induced AD-like skin. In here, the small molecules of insoluble Licoricchalcone A (LA) and macromolecules glycyrrhizin polysaccharide were used to prepare LA-polysaccharide self-assembled nanoparticles (GPA-SANs) by micro-precipitation. An environment-responsive dye, P4, was loaded into SAN to track the transdermal translocation of the nanoparticles, while the drug marked with coumarin 6 (C6). Compared to healthy skin, the permeability of GPA-SANs on AD-like skin is stronger, which may be due to damage to the stratum corneum of the AD-like skin and increased intercellular spaces, resulting in an increased permeability coefficient. Therefore, the storage of nanoparticles and their diffusion at the lesion site also increased accordingly. CLSM shown that the fluorescence of P4 and C6 is observed to concentrate around the hair follicles and disseminate in the surrounding area in both AD-affected and healthy skin. It can be clearly seen that fluorescence signal of C6 in the intercellular spaces of the dermis and epidermis of AD-like skin, indicating that nano-drug on the disease skin can penetrate through the intercellular pathway to achieve therapeutic. The focus of the present study is to assess the permeability of healthy and disease skin, discuss their characteristics and discrepancy, aiming to provide a reference for the further study of nano-formulations in transdermal delivery.

Cardamonin-loaded liposomal formulation for improving percutaneous penetration and follicular delivery for androgenetic alopecia

Androgenic alopecia (AGA) has a considerable impact on the physical and mental health of patients. Nano preparations have apparent advantages and high feasibility in the treatment of AGA. Cardamonin (CAR) has a wide range of pharmacological activities, but it has the problems of poor solubility in water and low bioavailability. There are few, if any, researches on the use of nano-loaded CAR to improve topical skin delivery of AGA. In this study, a CAR-loaded liposomal formulation (CAR@Lip and CAR@Lip Gel) was developed and characterized. The prepared CAR@Lip exhibited a uniform and rounded vesicle in size. CAR@Lip and CAR@Lip Gel can significantly improve the cumulative release of CAR. Additionally, CAR@Lip can obviously promote the proliferation and migration of human dermal papilla cells (hDPCs). Cell uptake revealed that the uptake of CAR@Lip significantly increased compared with the free drug. Furthermore, both CAR@Lip and CAR@Lip Gel groups could markedly improve the transdermal performance of CAR, and increase the topical content of the drug in the hair follicle compared with CAR. The ratchet effect of hair follicles could improve the skin penetration depth of nanoformulations. Notably, Anti-AGA tests in the mice showed that CAR@Lip and CAR@Lip Gel groups could promote hair growth, and accelerate the transition of hair follicles to the growth stage. The anti-androgen effect was revealed by regulating the expression of IGF-1, VEGF, KGF, and TGF-β, participating in SHH/Gli and Wnt/β-catenin pathways. Importantly, the nanoformulations had no obvious skin irritation. Thus, our study showed that CAR-loaded liposomal formulation has potential application in the treatment of AGA.

Clinical Efficacy in Skin Hydration and Reducing Wrinkles of Nanoemulsions Containing Macadamia integrifolia Seed Oil

This study aimed to assess natural oils for their antioxidant and anti-hyaluronidase properties and select the most effective candidate for development into nanoemulsions (NE) for clinical evaluations. The oils were assessed using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS•+) and ferric thiocyanate assays for antioxidant properties and an enzyme-substrate reaction assay for anti-hyaluronidase activity. The most potent oil was formulated into conventional emulsions (CE) and NE, which were characterized and evaluated for their stability, both in accelerated and long-term conditions. The irritation potential was assessed using both the hen's eggs chorioallantoic membrane test and a clinical trial. Skin hydration enhancement and skin wrinkle reduction efficacy were clinically assessed. Macadamia integrifolia oil exhibited significant potency as an ABTS•+ radical scavenger, lipid peroxidation inhibitor, and hyaluronidase inhibitor (p < 0.05). Both the CE and NE, comprising 15% w/w oil, 5% w/w Tween® 80 and Span® 80, and 80% w/w DI water, were found to be optimal. NE with an internal droplet size of 112.4 ± 0.8 nm, polydispersity index of 0.17 ± 0.01, and zeta potential of -31.5 ± 1.0 mV, had good stability and induced no irritation. Both CE and NE enhanced skin hydration and reduced skin wrinkles in human volunteers, while NE was outstanding in skin hydration enhancement.

Microemulsions and Nanoemulsions for Topical Delivery of Tripeptide-3: From Design of Experiment to Anti-Sebum Efficacy on Facial Skin

The targeted delivery of a hydrophilic Tripeptide-3 to the skin using microemulsions or nanoemulsions for facial oil reduction was the focus of this study. The impact factors affecting oil/water transparent dispersion formation, such as the surfactant system, HLB value, and co-solvent, were identified through the water titration method and pseudoternary phase diagram plots. The interfacial tension between caprylic/capric triglyceride (CCT oil) and water was significantly reduced by the surfactant/co-surfactant combination (Smix) of Cremophore® RH40 and a double-tails co-surfactant, polyglycerol-3-diisostearate, at an HLB of 13 together with a water-to-co-solvent (PG) ratio of 1:1. A two-level full factorial design of experiment (FFD-DoE) emphasized the independent variables of the HLB value, co-solvent, and CCT oil contents affecting the optimal compositions for micro- or nanoemulsion formation. The low-energy spontaneous emulsification of the optimized combination at a low Smix content (10%) yielded the translucent oil-in-water Tripeptide-3 nanoemulsions with an internal droplet size of 25.7 ± 1.20 nm, a narrow polydispersity index of 0.237 ± 0.129, and 70.6 ± 0.58% transmittance. The in vitro skin permeation study revealed a significantly higher skin penetration and retention of the Tripeptide-3 nanoemulsions compared to the high surfactant microemulsions and coarse emulsions. Skin irritation and oil control efficacy were evaluated in healthy volunteers before and after product application for 28 days. The obtained nanoemulsions not only decreased sebum production but also enhanced skin moisture levels. In conclusion, the meticulously designed nanoemulsions, incorporating suitable excipients, show a promising delivery system for hydrophilic peptides to control sebum overproduction in oily facial skin.

Carrageenan-xanthan nanocomposite film with improved bioadhesion and permeation profile in human skin: A cutaneous-friendly platform for ketoprofen local delivery

Ketoprofen (KET), commonly used for inflammation in clinical settings, leads to systemic adverse effects with prolonged use, mitigated by topical administration. Nanotechnology-based cutaneous forms, like films, may enhance KET efficacy. Therefore, this study aimed to prepare and characterize films containing KET nanoemulsions (F-NK) regarding mechanical properties, chemical composition and interactions, occlusive potential, bioadhesion, drug permeation in human skin, and safety. The films were prepared using a κ-carrageenan and xanthan gum blend (2 % w/w, ratio 3: 1) plasticized with glycerol through the solvent casting method. Non-nanoemulsioned KET films (F-K) were prepared for comparative purposes. F-NK was flexible and hydrophilic, exhibited higher drug content and better uniformity (94.40 ± 3.61 %), maintained the NK droplet size (157 ± 12 nm), and was thinner and lighter than the F-K. This film also showed increased tensile strength and Young's modulus values, enhanced bioadhesion and occlusive potential, and resulted in more of the drug in the human skin layers. Data also suggested that nano-based formulations are homogeneous and more stable than F-KET. Hemolysis and chorioallantoic membrane tests suggested the formulations' safety. Thus, the nano-based film is suitable for cutaneous KET delivery, which may improve the drug's efficacy in managing inflammatory conditions.

Hydrogel of Thyme-Oil-PLGA Nanoparticles Designed for Skin Inflammation Treatment

Thyme oil (THO) possesses excellent antibacterial and antioxidant properties which are suitable for skin inflammatory disorders such as acne vulgaris. However, THO is insoluble in water and its components are highly volatile. Therefore, these drawbacks may be overcome by its encapsulation in biodegradable PLGA nanoparticles (THO-NPs) that had been functionalized using several strategies. Moreover, cell viability was studied in HaCat cells, confirming their safety. In order to assess therapeutic efficacy against acne, bacterial reduction capacity and antioxidant properties were assessed. Moreover, the anti-inflammatory and wound-healing abilities of THO-NPs were also confirmed. Additionally, ex vivo antioxidant assessment was carried out using pig skin, demonstrating the suitable antioxidant properties of THO-NPs. Moreover, THO and THO-NPs were dispersed in a gelling system, and stability, rheological properties, and extensibility were assessed. Finally, the biomechanical properties of THO-hydrogel and THO-NP-hydrogel were studied in human volunteers, confirming the suitable activity for the treatment of acne. As a conclusion, THO has been encapsulated into PLGA NPs, and in vitro, ex vivo, and in vivo assessments had been carried out, demonstrating excellent properties for the treatment of inflammatory skin disorders.

Chitosan and its amphiphilic derivative nanoparticles loaded with Minoxidil for induction of hair growth: In vitro and in vivo evaluation

Minoxidil is widely used for treating Androgenic Alopecia, but its low hydrophilicity promotes the use of co-solvents in commercial formulations, which could then cause skin irritations. Nano-drug delivery systems have been developed to improve the solubility of lipophilic molecules and increase the concentration of drugs in hair follicles, thereby minimizing side effects. Chitosan (CS) and Methylated Aminobenzyl Carboxymethyl Chitosan (MCS) nanoparticles containing Minoxidil were prepared and evaluated for their physicochemical properties, drug release profile, skin permeation, cytotoxicity, and animal hair growth. The results showed that MCS nanoparticles had a 60 % drug release compared to CS nanoparticles, with almost complete release in 2 h. MCS nanoparticles also showed a 20 % drug permeation from skin compared to 70 % for CS nanoparticles in 24 h. In 48 and 72 h, CS and MCS nanoparticles didn't exhibit any significant cytotoxicity. Animal study revealed a significant increase in hair growth from MCS nanoparticles compared to the commercial formulation in fourteen days. However, MCS nanoparticles were less efficient compared to CS nanoparticles. The use of MCS in nano-drug delivery systems is expected to continue to gain importance due to its ability to enhance the solubility of hydrophobic drugs, particularly in the treatment of skin diseases.

Phytosterol-mediated glycerosomes combined with peppermint oil enhance transdermal delivery of lappaconitine by modulating the lipid composition of the stratum corneum

Although the introduction of glycerosomes has enriched strategies for efficient transdermal drug delivery, the inclusion of cholesterol as a membrane stabilizer has limited their clinical application. The current study describes the development and optimization of a new type of glycerosome (S-glycerosome) that is formed in glycerol solution with β-sitosterol as the stabilizer. Moreover, the transdermal permeation properties of lappaconitine (LA)-loaded S-glycerosomes and peppermint oil (PO)-mediated S-glycerosomes (PO-S-glycerosomes) are evaluated, and the lipid alterations in the stratum corneum are analyzed via lipidomics. The LA-loaded S-glycerosomes prepared by the preferred formulation from the uniform design have a mean size of 145.3 ± 7.81 nm and an encapsulation efficiency of 73.14 ± 0.35%. Moreover, the addition of PO positively impacts transdermal flux, peaking at 0.4% (w/v) PO. Tracing of the fluorescent probe P4 further revealed that PO-S-glycerosomes penetrate deeper into the skin than S-glycerosomes and conventional liposomes. Additionally, treatment with PO-S-glycerosomes alters the isoform type, number, and composition of sphingolipids, glycerophospholipids, glycerolipids, and fatty acids in the stratum corneum, with the most notable effect observed for ceramides, the main component of sphingolipids. Furthermore, the transdermal administration of LA-loaded PO-S-glycerosomes improved the treatment efficacy of xylene-induced inflammation in mice without skin irritation. Collectively, these findings demonstrate the feasibility of β-sitosterol as a stabilizer in glycerosomes. Additionally, the inclusion of PO improves the transdermal permeation of S-glycerosomes, potentially by altering the stratum corneum lipids.

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.

Chondroitin Sulphate-Chitosan polyelectrolyte complexes for etorocoxib transdermal delivery: in silico, in vitro and in vivo studies

Rheumatoid arthritis (RA) is a chronic autoimmune disease which affects around 1% globally leading to joint inflammation and disability. Etorocoxib (ETR) is a potent COX-2 inhibitor traditionally used orally to alleviate RA induced inflammation, yet it causes hepatic side effects on prolonged use. This study aims for in silico optimization of ETR polyelectrolyte complex (PEC) utilizing chondroitin sulphate (CS) and chitosan (CH) for transdermal delivery to RA-inflamed joints with a synergistic anti-inflammatory action owing to CS. An artificial neural network (ANN) combined with 22 factorial design was used to optimize the PEC formula according to particle size (PS) and entrapment efficiency (%EE) by varying CS and CH concentrations. The optimum ETR PEC was incorporated in a gel and examined for its in vitro release, ex vivo permeation, in vivo inflammatory biomarkers, and histopathological evaluation in rats. The optimized formula (F3) with 0.1 CH% w/w and 0.5 CS %w/w showed a PS of 214.98 ± 17.24 nm, %EE 75.31 ± 1.67%, and enhanced in vitro release profile, ex vivo permeation and in vivo anti-inflammatory effect compared to ETR gel via suppressing the expression of IL-6, TNF-α, and TGF-β pro-inflammatory cytokines as well as the additional anti-inflammatory effect of CS. In conclusion, ETR-PEC gel holds promise as transdermal therapy for managing RA-induced inflammation.

Nanotechnology and narasin: a powerful combination against acne

Acne vulgaris is widely regarded as the most prevalent skin disorder characterized by painful, inflammatory skin lesions that are primarily attributed to the pathogenic actions of Cutibacterium acnes (C. acnes). To improve the clinical management of this disease, there is a pressing clinical demand to develop innovative antibacterial therapies that utilize novel mechanisms. The current research aimed to discover the antibacterial efficacy of narasin (NAR), a polyether ionophore, against drug-resistant acne bacteria. In addition, the study aimed to formulate self-nanomicellizing solid dispersions (SNMSD), utilizing Soluplus® (SOL), as a drug delivery system to incorporate NAR and selectively target the lipophilic C. acnes abundant environments within the skin. Furthermore, the study aimed to investigate the ex vivo deposition and permeation of NAR into the various layers of the skin using full-thickness porcine ear skin as a model skin. By encapsulating NAR within spherical polymeric micelles (dn < 80 nm) aqueous solubility was significantly increased by approximately 100-fold (from <40 μg mL-1 to 4600 μg mL-1). Following optimization, the micelle solution was integrated into a gel formulation (containing 0.2% w/v NAR) and evaluated for stability over 4 weeks at room temperature (drug content >98%). Results from drug deposition and permeation experiments demonstrated that the deposition of NAR from the NAR-micelle solution and its gel formulation into the lipophilic stratum corneum (19 835.60 ± 6237.89 ng cm-2 and 40 601.14 ± 3736.09 ng cm-2) and epidermis (19 347 ± 1912.98 ng cm-2 and 18 763.54 ± 580.77 ng cm-2) was superior to that of NAR in solution, which failed to penetrate any skin layers. In conclusion, the outcomes of this study provide evidence that NAR exhibits promising activity against antimicrobial resistant strains of C. acnes (MIC range ≤0.008-0.062) and that micelle nanocarriers can improve the aqueous solubility of poorly water-soluble drugs. Furthermore, our results highlight the ability of nanomicelles to enable selective and targeted drug delivery to the lipophilic skin layers.

Size-Dependence of the Skin Penetration of Andrographolide Nanosuspensions: In Vitro Release-Ex Vivo Permeation Correlation and Visualization of the Delivery Pathway

Particle size is a key parameter to determine the capacity of nanoparticles to overcome the skin barrier; however, such effect and the possible mechanism remain only partially understood for nanosuspensions. In this work, we examined the skin delivery performance of andrographolide nanosuspensions (AG-NS) ranging in diameter from 250 nm to 1000 nm and analyzed the role of particle size in influencing their ability of skin penetration. The AG-NS with particle sizes of about 250 nm (AG-NS250), 450 nm (AG-NS450), and 1000 nm (AG-NS1000) were successfully prepared by ultrasonic dispersion method and characterized by transmission electron microscopy. The drug release and penetration via the intact and barrier-removed skin were compared by the Franz cell method, and the related mechanisms were probed using laser scanning confocal microscopy (LSCM) via visualization of penetration routes and histopathological study via observation of structural change of the skin. Our finding revealed that drug retention in the skin or its sub-layers was increased with the reduction of particle size, and the drug permeability through the skin also exhibited an obvious dependence on the particle size from 250 nm to 1000 nm. The linear relationship between the in vitro drug release and ex vivo permeation through the intact skin was well established among different preparations and in each preparation, indicating the skin permeation of the drug was mainly determined by the release process. The LSCM indicated that all these nanosuspensions could deliver the drug into the intercellular lipid space, as well as block the hair follicle in the skin, where a similar size dependence was also observed. The histopathological investigation showed that the formulations could make the stratum corneum of the skin loose and swelling without severe irritation. In conclusion, the reduction of particle size of nanosuspension would facilitate topical drug retention mainly via the modulation of drug release.

Formulation, and Optimization of Transdermal Atorvastatin Calcium-Loaded Ultra-flexible Vesicles; Ameliorates Poloxamer 407-caused Dyslipidemia

Atorvastatin calcium (AC), a cholesterol-lowering medication, has limited oral bioavailability (14%) and adverse impacts on the gastrointestinal tract (GIT), liver, and muscle. So, in an effort to improve the poor availability and overcome the hepatotoxicity complications attendant to peroral AC administration, transdermal transfersomal gel (AC-TFG) was developed as a convenient alternative delivery technique. The impact of utilizing an edge activator (EA) and varying the phosphatidylcholine (PC): EA molar ratio on the physico-chemical characteristics of the vesicles was optimized through a Quality by Design (QbD) strategy. The optimal transdermal AC-TFG was tested in an ex-vivo permeation study employing full-thickness rat skin, Franz cell experiments, an in-vivo pharmacokinetics and pharmacodynamics (PK/PD) evaluation, and a comparison to oral AC using poloxamer-induced dyslipidemic Wister rats. The optimized AC-loaded TF nanovesicles predicted by the 2³-factorial design strategy had a good correlation with the measured vesicle diameter of 71.72 ± 1.159 nm, encapsulation efficiency of 89.13 ± 0.125%, and cumulative drug release of 88.92 ± 3.78% over 24 hours. Ex-vivo data revealed that AC-TF outperformed a free drug in terms of permeation. The pharmacokinetic parameters of optimized AC-TFG demonstrated 2.5- and 13.3-fold significant improvements in bioavailability in comparison to oral AC suspension (AC-OS) and traditional gel (AC-TG), respectively. The transdermal vesicular technique preserved the antihyperlipidemic activity of AC-OS without increasing hepatic markers. Such enhancement was proven histologically by preventing the hepatocellular harm inflicted by statins. The results showed that the transdermal vesicular system is a safe alternative way to treat dyslipidemia with AC, especially when given over a long period of time.

Synthesis and characterization of a novel hydrogel based on carboxymethyl chitosan/sodium alginate with the ability to release simvastatin for chronic wound healing

Since wound dressing has been considered a promising strategy to improve wound healing, recent attention has been focused on the development of modern wound dressings based on synthetic and bioactive polymers. In this study, we prepared a multifunctional wound dressing based on carboxymethyl chitosan (CMC)/sodium alginate (Alg) hydrogel containing a nanostructured lipid carrier (NLC) in which simvastatin (SIM) has been encapsulated. This dressing aimed to act as a barrier against pathogens, eliminate excess exudates, and accelerate wound healing. Among various fabricated composites of dressing, the hydrogel composite with a CMC/sodium Alg ratio of 1:2 had an average pore size of about 98.44 ± 26.9 μm and showed 707 ± 31.9% swelling and a 2116 ± 79.2 g m-2per day water vapor transfer rate (WVTR), demonstrating appropriate properties for absorbing exudates and maintaining wound moisture. The NLC with optimum composition and properties had a spherical shape and uniform particle size distribution (74.46 ± 7.9 nm). The prepared nanocomposite hydrogel displayed excellent antibacterial activity againstEscherichia coliandStaphylococcus aureusas well as high biocompatibility on L929 mouse fibroblast cells. It can release the loaded SIM drug slowly and over a prolonged period of time. The highest drug release occurred (80%) within 14 d. The results showed that this novel nanocomposite could be a promising candidate as a wound dressing for treating various chronic wounds in skin tissues.

Cosmetic Formulations with Melaleuca alternifolia Essential Oil for the Improvement of Photoaged Skin: A Double-Blind, Randomized, Placebo-Controlled Clinical Study

This aim of this study was to evaluate the penetration depth, antioxidant capacity and the clinical efficacy of Melaleuca alternifolia pure essential oil and in a nanoemulsion to prevent skin photoaging. For this, 2% of pure essential oil or 2% of this essential oil in a nanoemulsion were vehiculated in a formulation. The skin penetration was evaluated using confocal Raman microspectroscopy. The radical protection factor was evaluated using electron paramagnetic resonance spectroscopy. For a clinical study, 40 male participants, aged 18-28 years, were enrolled, being divided into three groups: vehicle formulation, M. alternifolia pure essential oil and M. alternifolia Nanoemulsion. All the participants also received a sunscreen SPF 50 to use during the day. Before and after 90 days of study, skin hydrolipidics and morphological characteristics were performed by skin imaging and biophysical techniques. The nanoemulsion presented a lower antioxidant capacity and a higher penetration through the stratum corneum, reaching the viable epidermis, improving the stratum granulosum morphology. The groups presented an increase in the papillary depth, improving in the dermis echogenicity and the collagen fibers. Melaleuca alternifolia essential provides the potential to improve photoaged skin, being the application of nanoemulsion able to reach deeper skin layers.

Development of New Health Risk Assessment of Nanoparticles: EPA Health Risk Assessment Revised

The concentration of nanoparticles in the ambient air can lead to induced toxicities; however, it appears that nanoparticles’ unique properties are completely omitted when assessing health risks. This paper aims to enhance the EPA health risk assessment by incorporating two new variables that consider the size of nanoparticles: the toxicity multiplier and the size multiplier. The former considers the qualitative aspect of the size of particles within a concentration, whilst the latter takes into account the effects associated with the number of particles of the specific i-th size distribution interval. To observe the impact of the new variables, a case study was performed. The studied element was cadmium, which was measured using ICP-MS to discover concentrations of size fractions, ranging from <15.1 to <9830 nm. Next, the cadmium concentration is assessed using both the current state-of-the-art method and the proposed method with adjustments. Based on the new approach, the final risk was 1.1 × 10−5, which was almost 24 times higher compared with the current method. The contribution of nanoparticles to the risk value grew from barely 6% to an alarming 88%. Therefore, the enhanced method can lead to more realistic results when assessing the health risks of nanoparticles.

Development and Skin Penetration Pathway Evaluation Using Confocal Laser Scanning Microscopy of Microemulsions for Dermal Delivery Enhancement of Finasteride

This study aimed to develop microemulsions using poloxamer 124 as a surfactant to improve the skin penetration of finasteride and to investigate the skin penetration pathways of these microemulsions by colocalization techniques using confocal laser scanning microscopy (CLSM). The prepared finasteride-loaded microemulsions had average particle sizes ranging from 80.09 to 136.97 nm with particle size distributions within acceptable ranges and exhibited negative surface charges. The obtained microemulsions could significantly increase the skin penetration of finasteride compared to a finasteride solution. According to the skin penetration pathway evaluation conducted with CLSM, the microemulsions were hair follicle-targeted formulations due to penetration via the transfollicular pathway as a major skin penetration pathway. Additionally, this study found that the microemulsions also penetrated via the intercluster pathway more than via the intercellular pathway and transcellular pathway. The intercluster pathway, intercellular pathway, and transcellular pathway were considered only minor pathways.

Trans ethosomal hybrid composites of naproxen-sulfapyridine in hydrogel carrier: anti-inflammatory response in complete Freund's adjuvant induced arthritis rats

Current treatment for Rheumatoid arthritis (RA) utilizes Disease-modifying antirheumatic drugs, non-steroidal anti-inflammatory drugs or its combination, to decrease joint inflammation. In the present study, naproxen (NAP) and sulfapyridine (SULF) ethosomes were prepared by a thin-film hydration technique using PL90G and cholesterol, later crosslinked with carbopol®934. The ethosomes and ethosomal hydrogel were evaluated for rheological properties, physico-chemical analysis, in vitro and in vivo study. The results show, NAP and SULF ethosomes exhibited an average vesicle size between 251.1 ± 1.80-343.5 ± 3.23 nm and 269.0 ± 1.17-358.8 ± 1.22 nm, respectively, with good stability (zeta potential > 30 mV) and polydispersity index. Differential scanning calorimeter and Fourier transform infrared studies reveal no significant changes in the drug properties of ethosomes. Transmission electron microscopy analysis discloses spherical shape vesicles below 200 nm. The entrapment efficiency of NAP and SULF ethosomes was above 66%, and NAP-SULF ethosomes-hydrogel (EH) exhibited a sustained release effect (>8 h). In vivo studies on NAP-SULF EH shows significant inhibition of inflammation (84.63%), with less paw volume (0.1935 ± 0.08 ml) on induced arthritis Albino Wistar rats, (p < .01). NAP-SULF EH was stable at 25 °C ± 0.5 for 3-months. To conclude, a hybrid composite of NAP-SULF in hydrogel carrier prevents inflammation effectively, and could be novel for trans delivery of drugs in RA.

Bioengineered polyester nanoparticles for the synergistic treatment of androgenic alopecia via the suppression of 5α-reductase and knockdown of androgen receptor

Androgenic alopecia (AGA) is a common disease that negatively affects patients’ physical and mental health. AGA can be treated with drugs that improve the perifollicular microenvironment, such as 5α-reductase inhibitors (e.g., dutasteride [DUT]), androgen receptor blockers, and minoxidil. However, the efficacy of these treatments is limited. Therefore, this study aimed to show that nanoparticles are effective as stable carriers with high curative benefits and little adverse effects. The in vitro study showed that PLGA-DUT/siAR@DPCM NPs could deliver both DUT and siAR to dermal papilla cells. They could successfully suppress 5α-reductase and knock down androgen receptor, respectively, and thereby promote cell proliferation. In the in vivo study, PLGA-DUT/siAR@DPCM NPs showed a significant therapeutic effect in an AGA mouse model. They successfully penetrated the stratum corneum and showed a clear targeting effect on hair follicles and surrounding tissues. PLGA-DUT/siAR@DPCM NPs could enable the targeted delivery of DUT and siAR through percutaneous penetration, enhancing phagocytosis and decreasing adverse effects. Thus, they have great potential in the clinical treatment of AGA.

Gold nanoparticles for skin drug delivery

Nanoparticle-based drug carriers are being pursued intensely to overcome the skin barrier and improve even hydrophilic or macromolecular drug delivery into or across the skin efficiently. Over the past few years, the application of gold nanoparticles as a novel kind of drug carrier for skin drug delivery has attracted increasing attention because of their unique properties and versatility. In this review, we summarized the possible factors contributing to the penetration behaviors of gold nanoparticles, including size, surface chemistry, and shape. Drug loading, release, and penetration patterns were captured towards implicating the design of gold nanoparticles for dermal or transdermal drug delivery. Physical methods applicable for future enhancing the delivery efficacy of GNPs were also presented, which mainly included microneedles and iontophoresis. As a promising "drug", the inherent activities of GNPs were finally discussed, especially regarding their application in the treatment of skin disease. Thus, this paper provided a comprehensive review of the use of gold nanoparticles for skin drug delivery, which would help the design of multifunctional systems for skin drug delivery based on gold nanoparticles.

Enhancement of the Transdermal Delivery of Nonsteroidal Anti-inflammatory Drugs Using Liposomes Containing Cationic Surfactants

New hybrid liposomes based on cationic amphiphiles with different structures of the head group (cetyltrimethylammonium bromide (CTAB), 3-hexadecyl-1-hydroxyethylimidazolium bromide (IA-16(OH)), 1-(butylcarbamoyl)oxyethyl-3-hexadecylimidazolium bromide (IAC 16(Bu)), and hexadecylmethylpyrrolidinium bromide (PR-16)) were developed for transdermal administration of nonsteroidal anti-inflammatory drugs. The different surfactant/lipid compositions were studied to obtain stable liposomes with high functionality. The hydrodynamic diameter of cationic liposomes was ∼110 nm. An admixture of cationic surfactants and PC liposomes improves the physicochemical properties of vesicles and transdermal diffusion rate and prolongs the release of drugs. Liposomal diclofenac sodium (DS) and ketoprofen (KP) were tested (using Franz cells) for transdermal penetration. Drug diffusion monitoring for 48 h demonstrated that the maximum DS and KP penetration through the synthetic membranes (Strat-M) is characterized by values of 255 ± 2 and 186 ± 3 μg/cm², respectively. The influence of the surfactant head group on the properties (stability, release profile, permeability) of cationic liposomes was shown for the first time. While the drug specificity is evident for the rate of release, the permeability increases as follows: conventional liposomes < CTAB/PC < PR-16/PC < IAC-16(Bu)/PC < IA-16(OH)/PC for both medicines. The rat paw edema model was used to assess the anti-inflammatory effect of the IA-16(OH)/PC leader formulation in vivo. It was found that liposomal DS and KP are effective for relieving rat paw edema. It should be noted that DS-loaded hybrid liposomes demonstrated the highest therapeutic efficacy compared to conventional vesicles.

Biological and Intracellular Fates of Drug Nanocrystals through Different Delivery Routes: Recent Development Enabled by Bioimaging and PK Modeling

Nanocrystals have contributed to exciting improvements in the delivery of poorly water-soluble drugs. The biological and intracellular fates of nanocrystals are currently under debate. Due to the remarkable commercial success in enhancing oral bioavailability, nanocrystals have originally been regarded as a simple formulation approach to enhance dissolution. However, the latest findings from novel bioimaging tools lead to an expanded view. Intact nanocrystals may offer long-term durability in the body and offer drug delivery capabilities like those of other nano-carriers. This review renews the understanding of the biological fates of nanocrystals administered via oral, intravenous, and parenteral (e.g., dermal, ocular, and pulmonary) routes. The intracellular pathways and dissolution kinetics of nanocrystals are explored. Additionally, the future trends for in vitro and in vivo quantification of nanocrystals, as well as factors impacting the biological and intracellular fates of nanocrystals are discussed. In conclusion, nanocrystals present a promising and underexplored therapeutic opportunity with immense potential.

Tamoxifen Citrate Containing Topical Nanoemulgel Prepared by Ultrasonication Technique: Formulation Design and In Vitro Evaluation

The present study aims to design and develop a nanoemulgel formulation of Tamoxifen citrate (TAM), a water-insoluble, potent anticancer drug, using the spontaneous emulsification method to improve topical delivery, achieve high accumulation at the tumour site, and spare the healthy tissues. The oil-based selection was related to the TAM solubility, while the surfactant and co-surfactant were chosen based on the droplets’ thermodynamic stability and size. Afterwards, a pseudo-ternary phase diagram was built for the most promising formulation using two oils, olive and sesame, with a varied mix of Tween 40 as the surfactant and Trascutol HP as the co-surfactant (Smix), by the optimisation of experiments. The nanoemulsion (NE) formulations that were prepared were found to have an average droplet size of 41.77 ± 1.23 nm and 188.37 ± 3.53 nm, with suitable thermodynamic stability and physicochemical properties. Both olive and sesame oils are natural food additives due to their associated antioxidant effects; therefore, they showed no toxicity profile on breast cell lines (MCF-7, ATCC number HTB-22). The TAM-NE preparations revealed a prolonged and doublings superior cumulative percentage of in vitro release of TAM compared to TAM plain gel suspension over 24 h. The release data suggested that the Higuchi model was the best fitting kinetical model for the developed formulations of NE1, NE9, and NE18. The extended release of the drug as well as an acceptable amount of the drug permeated TAM via nanogel preparations suggested that nanoemulgel (NEG) is suitable for the topical delivery of TAM in breast cancer management. Thus, this work suggests that a nanogel of TAM can improve anticancer properties and reduce systemic adverse effects compared to a suspension preparation of TAM when applied in the treatment of breast cancer.

Adapting Clofazimine for Treatment of Cutaneous Tuberculosis by Using Self-Double-Emulsifying Drug Delivery Systems

Although chemotherapeutic treatment regimens are currently available, and considerable effort has been lavished on the development of new drugs for the treatment of tuberculosis (TB), the disease remains deeply intractable and widespread. This is due not only to the nature of the life cycle and extraordinarily disseminated habitat of the causative pathogen, principally Mycobacterium tuberculosis (Mtb), in humans and the multi-drug resistance of Mtb to current drugs, but especially also to the difficulty of enabling universal treatment of individuals, immunocompromised or otherwise, in widely differing socio-economic environments. For the purpose of globally eliminating TB by 2035, the World Health Organization (WHO) introduced the "End-TB" initiative by employing interventions focusing on high impact, integrated and patient-centered approaches, such as individualized therapy. However, the extraordinary shortfall in stipulated aims, for example in actual treatment and in TB preventative treatments during the period 2018-2022, latterly and greatly exacerbated by the COVID-19 pandemic, means that even greater pressure is now placed on enhancing our scientific understanding of the disease, repurposing or repositioning old drugs and developing new drugs as well as evolving innovative treatment methods. In the specific context of multidrug resistant Mtb, it is furthermore noted that the incidence of extra-pulmonary TB (EPTB) has significantly increased. This review focusses on the potential of utilizing self-double-emulsifying drug delivery systems (SDEDDSs) as topical drug delivery systems for the dermal route of administration to aid in treatment of cutaneous TB (CTB) and other mycobacterial infections as a prelude to evaluating related systems for more effective treatment of CTB and other mycobacterial infections at large. As a starting point, we consider here the possibility of adapting the highly lipophilic riminophenazine clofazimine, with its potential for treatment of multi-drug resistant TB, for this purpose. Additionally, recently reported synergism achieved by adding clofazimine to first-line TB regimens signifies the need to consider clofazimine. Thus, the biological effects and pharmacology of clofazimine are reviewed. The potential of plant-based oils acting as emulsifiers, skin penetration enhancers as well as these materials behaving as anti-microbial components for transporting the incorporated drug are also discussed.

Nanoemulsion-based dosage forms for the transdermal drug delivery applications: A review of recent advances

INTRODUCTION

Nanoemulsion-based drug delivery approaches have witnessed massive acceptance over the years and acquired a significant foothold owing to their tremendous benefits over the others. It has widely been used for transdermal delivery of hydrophobic and hydrophilic drugs with solubility, lipophilicity, and bioavailability issues.

AREAS COVERED

The review highlights the recent advancements and applications of transdermal nanoemulsions. Their utilities and characteristics, clinical pertinence showcasing intellectual properties and advancements, potential in treating disorders accompanying liquid, semisolid, and solid dosage forms, the ability to modulate a drug's physicochemical properties, and regulatory status are thoroughly summarized.

EXPERT OPINION

Despite tremendous therapeutic utilities and extensive investigations, this field of transdermal nanoemulsion-based technologies yet tackles several challenges such as optimum use of surfactant mixtures, economic burden due to high energy consumption during production, lack of concrete regulatory requirement, etc. Provided with the concrete guidelines on the safe use of surfactants, stability, use of scalable and economical methods, and the use of NE as a transdermal system would solve the purpose best as nanoemulsion shows remarkable improvement in drug release profiles and bioavailability of many drugs. Nevertheless, a better understanding of nanoemulsion technology holds a promising outlook and would land more opportunities and better delivery outcomes.

The technology of transdermal delivery nanosystems: from design and development to preclinical studies

Transdermal administration has gained much attention due to the remarkable advantages such as patient compliance, drug escape from first-pass elimination, favorable pharmacokinetic profile and prolonged release properties. However, the major limitation of these systems is the limited skin penetration of the stratum corneum, the skin's most important barrier, which protects the body from the insertion of substances from the environment. Transdermal drug delivery systems are aiming to the disruption of the stratum corneum in order for the active pharmaceutical ingredients to enter successfully the circulation. Therefore, nanoparticles are holding a great promise because they can act as effective penetration enhancers due to their small size and other physicochemical properties that will be analyzed thoroughly in this report. Apart from the investigation of the physicochemical parameters, a comparison between the different types of nanoparticles will be performed. The complexity of skin anatomy and the unclear mechanisms of penetration should be taken into consideration to reach some realistic conclusions regarding the way that the described parameters affect the skin permeability. To the best of the authors knowledge, this is among the few reports on the literature describing the technology of transdermal delivery systems and how this technology affects the biological activity.

Overcoming hydrolytic degradation challenges in topical delivery: non-aqueous nano-emulsions

INTRODUCTION

Non-aqueous nano-emulsions (NANEs) are colloidal lipid-based dispersions with nano-sized droplets formed by mixing two immiscible phases, none of which happens to be an aqueous phase. Their ability to incorporate water and oxygen sensitive drugs without any susceptibility to degradation makes them the optimum dosage form for such candidates. In NANEs, polar liquids or polyols replace the aqueous phase while surfactants remain same as used in conventional emulsions. They are a part of the nano-emulsion family albeit with substantial difference in composition and application.

AREAS COVERED

The present review provides a brief insight into the strategies of loading water-sensitive drugs into NANEs. Further advancement in these anhydrous systems with the use of solid particulate surfactants in the form of Pickering emulsions is also discussed.

EXPERT OPINION

NANEs offer a unique platform for delivering water-sensitive drugs by loading them in anhydrous formulation. The biggest advantage of NANEs vis-à-vis the other nano-cargos is that they can also be prepared without using equipment-intensive techniques. However, the use of NANEs in drug delivery is quite limited. Looking at the small number of studies available in this direction, a need for further research in this field is required to explore this delivery system further.

Optimization and Transfollicular Delivery of Finasteride-Loaded Proniosomes for Hair Growth Stimulation in C57BL/6Mlac Mice

The study aimed to develop the finasteride-loaded proniosome (FLP) to enhance the transfollicular delivery of finasteride (FN). The response surface methodology (RSM) combined with central composite design (CCD) with three independent variables (FN concentrations, total lipid content, and cholesterol content) was used to optimize the FLP preparation. The particles size, zeta potential, entrapment efficiency, and drug loading capacity of the FLP were analyzed. The transfollicular delivery of the optimum formulation was investigated in vitro. In vivo hair growth stimulation study was performed on C57BL/6Mlac mice dorsal areas. The Draize primary skin irritation test for erythema and edema was performed in the New Zealand white rabbit skin. The optimum FLP consists of 5.0 mM of FN, 10.1 mM of total lipid content, and 50.0% of the cholesterol in the total lipid. The prepared proniosome delivered the FN significantly (p < 0.05), compared to the naked finasteride solution in a dose- and time-dependent manner. The FLP treatment significantly increases the number and size of hair follicles in a dose-dependent manner. The efficiency of 1% FLP was comparable to the 2% minoxidil solution. The FLP exhibited no skin irritation after 72 h. Therefore, the results demonstrated that the FLP could stimulate hair growth via a transfollicular delivery system.

The Importance of Nanocarrier Design and Composition for an Efficient Nanoparticle-Mediated Transdermal Vaccination

The World Health Organization estimates that the pandemic caused by the SARS-CoV-2 virus claimed more than 3 million lives in 2020 alone. This situation has highlighted the importance of vaccination programs and the urgency of working on new technologies that allow an efficient, safe, and effective immunization. From this perspective, nanomedicine has provided novel tools for the design of the new generation of vaccines. Among the challenges of the new vaccine generations is the search for alternative routes of antigen delivery due to costs, risks, need for trained personnel, and low acceptance in the population associated with the parenteral route. Along these lines, transdermal immunization has been raised as a promising alternative for antigen delivery and vaccination based on a large absorption surface and an abundance of immune system cells. These features contribute to a high barrier capacity and high immunological efficiency for transdermal immunization. However, the stratum corneum barrier constitutes a significant challenge for generating new pharmaceutical forms for transdermal antigen delivery. This review addresses the biological bases for transdermal immunomodulation and the technological advances in the field of nanomedicine, from the passage of antigens facilitated by devices to cross the stratum corneum, to the design of nanosystems, with an emphasis on the importance of design and composition towards the new generation of needle-free nanometric transdermal systems.

Transdermal Drug Delivery Systems and Their Use in Obesity Treatment

Transdermal drug delivery (TDD) has recently emerged as an effective alternative to oral and injection administration because of its less invasiveness, low rejection rate, and excellent ease of administration. TDD has made an important contribution to medical practice such as diabetes, hemorrhoids, arthritis, migraine, and schizophrenia treatment, but has yet to fully achieve its potential in the treatment of obesity. Obesity has reached epidemic proportions globally and posed a significant threat to human health. Various approaches, including oral and injection administration have widely been used in clinical setting for obesity treatment. However, these traditional options remain ineffective and inconvenient, and carry risks of adverse effects. Therefore, alternative and advanced drug delivery strategies with higher efficacy and less toxicity such as TDD are urgently required for obesity treatment. This review summarizes current TDD technology, and the main anti-obesity drug delivery system. This review also provides insights into various anti-obesity drugs under study with a focus on the recent developments of TDD system for enhanced anti-obesity drug delivery. Although most of presented studies stay in animal stage, the application of TDD in anti-obesity drugs would have a significant impact on bringing safe and effective therapies to obese patients in the future.

Yeast cell microcarriers for delivery of a model bioactive compound in skin

This study aimed at developing a cell-based encapsulation carrier for topical delivery of bioactives to the skin. The overall objectives were to evaluate affinity of the yeast-cell based carrier to bind to the skin surface following topical application and to quantify controlled release of curcumin as a model bioactive in ex-vivo skin models using a combination of imaging, modeling and analytical measurements. Both porcine skin tissue and clinically obtained human skin biopsies were studied. The results demonstrated that upon incubation with the ex-vivo skin tissues, the cell carriers rapidly bound to the skin surface following topical delivery and provided sustained release of encapsulated curcumin. The microcarrier binding and penetration of curcumin in the dermal compartment also showed to increase with incubation time. The average flux of curcumin in human skin biopsies J_p was 0.89 ± 0.02 μg/cm²/h. These results illustrated the potential of a novel cell-based carrier for high affinity binding to skin surface, efficient encapsulation of a model bioactive and controlled release from the cell carrier to the skin with enhanced permeation to the dermis section. Overall, this study demonstrated a new class of cost-effective carriers for improving delivery of bioactives to the skin and potentially other epithelial tissues.

The Factors Determining the Skin Penetration and Cellular Uptake of Nanocarriers: New Hope for Clinical Development

The skin provides a protective barrier against toxic environments and also offers a valuable route for topical drug delivery. The stratum corneum (SC) is the outermost layer of the skin and serves as the major barrier to chemical transfer through the skin. The human skin barrier is particularly difficult to overcome because of the complex composition and structure of the SC. Nanoparticulate carriers have gained widespread attention in topical drug delivery due to their tunable and versatile properties. The present review summarizes the main factors involved in skin penetration of nanocarriers containing the drug. Employment of nanotechnology in topical delivery has grown progressively during recent years; however, it is important to monitor the skin penetration of nanocarriers prior to their use to avoid possible toxic effects. Nanocarriers can act as a means to increase skin permeation of drugs by supporting direct interaction with the SC and increasing the period of permanence on the skin. Skin penetration is influenced by the physicochemical characteristics of nanocarriers such as composition, size, shape, surface chemistry, as well as skin features. Considering that the target of topical systems based on nanocarriers is the penetration of therapeutic agents in the skin layers, so a detailed understanding of the factors influencing skin permeability of nanocarriers is essential for safe and efficient therapeutic applications.

Dermal Drug Delivery of Phytochemicals with Phenolic Structure via Lipid-Based Nanotechnologies

Phenolic compounds are a large, heterogeneous group of secondary metabolites found in various plants and herbal substances. From the perspective of dermatology, the most important benefits for human health are their pharmacological effects on oxidation processes, inflammation, vascular pathology, immune response, precancerous and oncological lesions or formations, and microbial growth. Because the nature of phenolic compounds is designed to fit the phytochemical needs of plants and not the biopharmaceutical requirements for a specific route of delivery (dermal or other), their utilization in cutaneous formulations sets challenges to drug development. These are encountered often due to insufficient water solubility, high molecular weight and low permeation and/or high reactivity (inherent for the set of representatives) and subsequent chemical/photochemical instability and ionizability. The inclusion of phenolic phytochemicals in lipid-based nanocarriers (such as nanoemulsions, liposomes and solid lipid nanoparticles) is so far recognized as a strategic physico-chemical approach to improve their in situ stability and introduction to the skin barriers, with a view to enhance bioavailability and therapeutic potency. This current review is focused on recent advances and achievements in this area.

Anti-Melanogenic Mechanism of Tetrahydrocurcumin and Enhancing Its Topical Delivery Efficacy Using a Lecithin-Based Nanoemulsion

Tetrahydrocurcumin (THC) has been well known for its superior antioxidant properties. Therefore, it is speculated that it might be effective to relieve oxidative stress-induced diseases, such as skin hyperpigmentation. In this work, an in vitro B16F10 melanoma cell model was used to study the impact of THC on the melanogenic process under stressed conditions. It was demonstrated that THC could effectively inhibit the α-MSH (melanocyte-stimulating hormone) induced melanin production in B16F10 melanoma cells and the expressions of three key enzymes involved with the biosynthetic process of melanin, tyrosinase (TYR), tyrosinase-related protein 1 (TRP-1), and tyrosinase-related protein 2 (TRP-2), were all significantly reduced. In addition, an in vitro human keratinocyte cell model was used to investigate the potential protective role of THC on H₂O₂-induced cytotoxicity. It was found that THC could prevent H₂O₂-induced oxidative stress based on the results of both the cell viability study and the intracellular ROS (reactive oxygen species) study assessed by the flow cytometry. Last, THC was formulated into a lecithin based nanoemulsion, and an in vitro Franz diffusion cell study using Strat-M^® membrane concluded that the nanoemulsion could significantly enhance the membrane permeation compared to the unformatted THC suspension. This research demonstrated the anti-melanogenic benefits of THC on the melanoma and keratinocyte cell models and the topical delivery efficacy could be significantly enhanced using a lecithin based nanoemulsion.

Physical properties of gold nanoparticles affect skin penetration via hair follicles

Drug penetration through the skin is significant for both transdermal and dermal delivery. One mechanism that has attracted attention over the last two decades is the transport pathway of nanoparticles via hair follicle, through the epidermis, directly to the pilosebaceous unit and blood vessels. Studies demonstrate that particle size is an important factor for drug penetration. However, in order to gain more information for the purpose of improving this mode of drug delivery, a thorough understanding of the optimal physical particle properties is needed. In this study, we fabricated fluorescently labeled gold nanoparticles (GNP) with a tight control over the size and shape. The effect of the particles' physical parameters on follicular penetration was evaluated histologically. We used horizontal human skin sections and found that the optimal size for polymeric particles is 0.25 μm. In addition, shape penetration experiments revealed gold nanostars' superiority over spherical particles. Our findings suggest the importance of the particles' physical properties in the design of nanocarriers delivered to the pilosebaceous unit.

Cationic zinc (II) phthalocyanine nanoemulsions for photodynamic inactivation of resistant bacterial strains

BACKGROUND

The growing emergence of microbial resistance to antibiotics represents a worldwide challenge. Antimicrobial photodynamic inactivation (aPDI) has been introduced as an alternative technique, especially when combined with nanotechnology. Therefore, this study was designed to investigate the therapeutic merits of combined aPDI and nanoemulsion in infections caused by resistant bacterial strains.

METHODS

Cationic zinc (II) phthalocyanine nanoemulsions (ZnPc-NE) were prepared using isopropyl myristate (IPM) as oil phase, egg phosphatidylcholine (egg PC) as emulsifier, and N-cetyl-N,N,N-trimethyl ammonium bromide (CTAB). Nanoemulsions were characterized for particle size, polydispersity, zeta potential, viscosity, and skin deposition. The in-vitro aPDI was investigated on human resistant pathogens; gram-positive methicillin-resistant Staphylococcus aureus (MRSA) and gram-negative Multidrug-resistant strain of Escherichia coli (MDR E. coli), under different experimental conditions. In addition, in-vivo model of abrasion wound infected by MDR E. coli was induced in rats to investigate the therapeutic potential of the selected formulation.

RESULTS

It was evident that the selected ZnPc formulation (20 % IPM, 2 % egg PC and 0.5 % CTAB) displayed a particle size of 209.9 nm, zeta potential +73.1 mV, and 23.66 % deposition of ZnPc in skin layers. Furthermore, the selected formulation combined with light achieved almost 100 % eradication of the two bacterial strains, with superior bacterial load reduction and wound healing propertiesin-vivo, compared to either the nanoemulsion formulation or laser alone.

CONCLUSION

ZnPc nanoemulsion improved antimicrobial photodynamic therapy in inactivating resistant bacterial infections and provided a promising therapeutic means of treating serious infections, and hence could be applied in diseases caused by other bacterial strains.

Development of a gel-in-oil emulsion as a transdermal drug delivery system for successful delivery of growth factors

Growth factors (GFs) are indispensable in regenerative medicine because of their high effectiveness. However, as GFs degenerate easily, the development of a suitable carrier with improved stability for GFs is necessary. In this study, we developed a gel-in-oil (G/O) emulsion technology for the transdermal delivery of growth factors. Nanogel particles prepared with heparin-immobilized gelatin that can bind growth factors were dispersed in isopropyl myristate. The particle size of the G/O emulsion could be controlled by changing the surfactant concentration, volume ratio of the water phase to the oil phase, and gelatin concentration. In vitro skin penetration studies showed better penetration through the stratum corneum of fluorescent proteins containing G/O emulsions than of the aqueous solution of GF. Similarly, an in vivo study showed an angiogenesis-inducing effect after transdermal application of GF-immobilized G/O emulsion. Angiogenesis in mice was confirmed owing to both an increased blood vessel network and higher hemoglobin content in the blood. Therefore, the G/O emulsion could be a promising carrier for GFs with better stability and can effectively deliver GFs at the target site.

Uptake and trafficking of different sized PLGA nanoparticles by dendritic cells in imiquimod-induced psoriasis-like mice model

Psoriasis is an autoimmune inflammatory disease, where dendritic cells (DCs) play an important role in its pathogenesis. In our previous work, we have demonstrated that topical delivery of curcumin-loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) could treat Imiquimod (IMQ)-induced psoriasis-like mice. The objective of this study is to further elucidate biofate of PLGA NPs after intradermal delivery including DCs uptake, and their further trafficking in psoriasis-like mice model by using fluorescence probes. Two-sized DiO/DiI-loaded PLGA NPs of 50 ± 4.9 nm (S-NPs) and 226 ± 7.8 nm (L-NPs) were fabricated, respectively. In vitro cellular uptake results showed that NPs could be internalized into DCs with intact form, and DCs preferred to uptake larger NPs. Consistently, in vivo study showed that L-NPs were more captured by DCs and NPs were firstly transported to skin-draining lymph nodes (SDLN), then to spleens after 8 h injection, whereas more S-NPs were transported into SDLN and spleens. Moreover, FRET imaging showed more structurally intact L-NPs distributed in skins and lymph nodes. In conclusion, particle size can affect the uptake and trafficking of NPs by DCs in skin and lymphoid system, which needs to be considered in NPs tailing to treat inflammatory skin disease like psoriasis.

Physicochemical Characterization of Finasteride Nanosystem for Enhanced Topical Delivery

INTRODUCTION

The current work aimed to formulate a novel chitosan-based finasteride nanosystem (FNS-NS) for skin delivery to optimize the drug availability in skin for a longer time and enhance ex vivo performance of finasteride against androgenic alopecia.

METHODS

Both undecorated and chitosan decorated FNS-NSs were synthesized by a high energy emulsification technique. All the prepared nanosystems were further subjected to physicochemical characterizations like pH, viscosity, encapsulation efficiency, surface morphology and in vitro drug release behavior. The influence of the nanosystem on the drug permeation and retention in rat skin was examined using Franz diffusion cell apparatus.

RESULTS

The droplet size of developed nanosystems ranged from 41 to 864 nm with a low polydispersity index. The zeta potential of the nanosystems was between -10 mV and +56 mV. This chitosan decorated nanosystem exhibited controlled drug release, ie about 78-97% in 24 h. Among all the nanosystems, our chitosan decorated formulation (F5) had low drug permeation (16.35 µg/cm2) and higher drug retention (10.81 µg/cm2).

CONCLUSION

The abovementioned results demonstrate satisfactory in vitro drug release, skin retention profiles and ex vivo performance with chitosan decorated FNS-NS (F5). This optimized formulation could increase drug availability in skin and could become a promising carrier for topical delivery to treat androgenic alopecia.

Systematic study of liposomes composition towards efficient delivery of plasmid DNA as potential application of dermal fibroblasts targeting

The use of non-viral DNA vectors to topically treat skin diseases has demonstrated a high potential. However, vectors applied on the skin face extracellular barriers including the stratum corneum and intracellular barriers such as the endosomal escape and the nuclear targeting of the plasmid DNA. The aim of this study was to develop a formulation suitable for dermal application and effective for delivering plasmid DNA into cells. Different formulations were prepared using different cationic lipids (DOTAP, DC-Chol, DOTMA) and co-lipids (DOPE, DSPE). Lipoplexes were produced by complexing liposomes with plasmid DNA at different pDNA/CL (w/w) ratios. Our results showed that appropriate pDNA/CL ratios allowing total complexation of plasmid DNA differed depending on the structure of the lipid used. The transfection rates showed that (i) higher rates were obtained with DOTMA lipoplexes, (ii) DC-Chol lipoplexes provided a transfection twice as important as DOTAP lipoplexes and (iii) when DSPE was added, the cytotoxicity decreased while transfection rates were similar. We found that formulations composed of DC-Chol:DOPE:DSPE or DOTMA:DOPE were appropriate to complex plasmid DNA and to transfect human primary dermal fibroblasts with efficacy and limited cytotoxicity. Therefore, these formulations are highly promising in the context of gene therapy to treat skin diseases.

Development, Characterization and Use of Liposomes as Amphipathic Transporters of Bioactive Compounds for Melanoma Treatment and Reduction of Skin Inflammation: A Review

The skin is the largest organ in the human body, providing a barrier to the external environment. It is composed of three layers: epidermis, dermis and hypodermis. The most external epidermis is exposed to stress factors that may lead to skin conditions such as photo-aging and skin cancer. Some treatments for skin disease utilize the incorporation of drugs or bioactive compounds into nanocarriers known as liposomes. Liposomes are membranes whose sizes range from nano to micrometers and are composed mostly of phospholipids and cholesterol, forming similar structures to cell membranes. Thus, skin treatments with liposomes have lower toxicity in comparison to traditional treatment routes such as parenteral and oral. Furthermore, addition of edge activators to the liposomes decreases the rigidity of the bilayer structure making it deformable, thereby improving skin permeability. Liposomes are composed of an aqueous core and a lipidic bilayer, which confers their amphiphilic property. Thus, they can carry hydrophobic and hydrophilic compounds, even simultaneously. Current applications of these nanocarriers are mainly in the cosmetic and pharmaceutic industries. Nevertheless, new research has revealed promising results regarding the effectiveness of liposomes for transporting bioactive compounds through the skin. Liposomes have been well studied; however, additional research is needed on the efficacy of liposomes loaded with bioactive peptides for skin delivery. The objective of this review is to provide an up-to-date description of existing techniques for the development of liposomes and their use as transporters of bioactive compounds in skin conditions such as melanoma and skin inflammation. Furthermore, to gain an understanding of the behavior of liposomes during the process of skin delivery of bioactive compounds into skin cells.