Effects of Carbopol® 934 proportion on nanoemulsion gel for topical and transdermal drug delivery: a skin permeation study

Development of a hydrogel containing bisabolol-loaded nanocapsules for the treatment of atopic dermatitis in a Balb/c mice model

α-Bisabolol (αBIS), a plant-derived compound with anti-inflammatory properties, is potentially a therapeutic agent for Atopic dermatitis. However, its poor water solubility and photoinstability limit its topical application. Therefore, the present study, aimed to develop cationic polymeric nanocapsules of αBIS to improve its skin delivery, photostability, and therapeutic efficacy. The αBIS-loaded nanocapsules were prepared using the solvent displacement technique. A Box-Behnken (BB) design was employed to statistically optimize formulation variables and αBIS-loaded nanocapsules characterized by particle size, surface charge and encapsulation efficiency. The optimal formulation was selected, and the spherical shape of the nanocapsules was confirmed by scanning electron microscopy (SEM). Furthermore, hydrogel containing αBIS-loaded nanocapsules was prepared by thickening of nanocapsule suspension with Carbopol 934 and evaluated for rheology, in vitro drug release and skin permeation. Furthermore, a mice model of atopic dermatitis was used to evaluate the anti-inflammatory potential of the hydrogels. The optimal formulation displayed a spherical morphology under scanning electron microscopy (SEM) with an optimum particle size of 133.00 nm, polydispersity index (PDI) of 0.12, high EE% of 93 %, and improved optical stability of αBIS in the prepared nanocapsules compared to the free drug. The nano-based hydrogels demonstrated non-Newtonian pseudoplastic behavior and an increased αBIS in vitro release profile without causing skin irritation in rabbits. Drug retention within the dermis and epidermis layers significantly surpassed that of drug-free hydrogel. Moreover, in vivo histopathological studies and myeloperoxidase (MPO) enzyme activity, revealed that hydrogel containing bisabolol nanocapsules exhibited The best anti-inflammatory effect. The results showed that hydrogels containing bisabolol nanocapsules markedly alleviated dermatitis-related inflammation and reduced skin thickness in Balb/c mice. Our findings support nanocapsules as an effective drug delivery system to enhance αBIS stability, bioavailability, and therapeutic efficacy in AD treatment.

Novel Therapeutic Hybrid Systems Using Hydrogels and Nanotechnology: A Focus on Nanoemulgels for the Treatment of Skin Diseases

Topical and transdermal drug delivery are advantageous administration routes, especially when treating diseases and conditions with a skin etiology. Nevertheless, conventional dosage forms often lead to low therapeutic efficacy, safety issues, and patient noncompliance. To tackle these issues, novel topical and transdermal platforms involving nanotechnology have been developed. This review focuses on the latest advances regarding the development of nanoemulgels for skin application, encapsulating a wide variety of molecules, including already marketed drugs (miconazole, ketoconazole, fusidic acid, imiquimod, meloxicam), repurposed marketed drugs (atorvastatin, omeprazole, leflunomide), natural-derived compounds (eucalyptol, naringenin, thymoquinone, curcumin, chrysin, brucine, capsaicin), and other synthetic molecules (ebselen, tocotrienols, retinyl palmitate), for wound healing, skin and skin appendage infections, skin inflammatory diseases, skin cancer, neuropathy, or anti-aging purposes. Developed formulations revealed adequate droplet size, PDI, viscosity, spreadability, pH, stability, drug release, and drug permeation and/or retention capacity, having more advantageous characteristics than current marketed formulations. In vitro and/or in vivo studies established the safety and efficacy of the developed formulations, confirming their therapeutic potential, and making them promising platforms for the replacement of current therapies, or as possible adjuvant treatments, which might someday effectively reach the market to help fight highly incident skin or systemic diseases and conditions.

Impact of miconazole nitrate ferrying cationic and anionic nanoemulsion and gels on permeation profiles of across EpiDerm, artificial membrane, and skin: Instrumental evidences

Based on our previous report, the study was extended to investigate the impact of miconazole nitrate (MCN) loaded cationic/anionic nanoemulsions and nanoemulsion gels on permeation behaviour across artificial-membrane, EpiDerm, and rat skin. Nanoemulsions and gels were evaluated for size, charge, viscosity, size-distribution, pH, and percent entrapment efficiency (%EE). In vitro drug diffusion across artificial membrane and EpiDerm were conducted to get diffusion coefficients. Permeation profiles were studied using rat skin to investigate mechanistic insight of formulated mediated permeation followed by CLSM (confocal laser scanning microscopy), SEM (scanning electron microscopy), AFM (atomic force microscopy), and irritation studies. Results showed that MCNE11-Rh (probed cationic nanoemulsion at pH ∼ 7.2) and MNE11-Rh (probed anionic nanoemulsion at pH ∼ 7.2) showed size values of 158 nm and 145 nm, respectively whereas MCNE11-GR (probed cationic nanoemulsion gel at pH ∼ 6.8) and MNE11-GR (probed anionic nanoemulsion gel at pH ∼ 6.8) exhibited size values 257 nm and 243 nm, respectively. The %EE values were found to be as 91.5 % and 89.6 % for MCNE11-Rh and MNE11-Rh, respectively. The gels (∼6000 cP) elicited relatively high viscosity than nanoemulsions (∼3300 - 3500 cP). MCNE11-GR showed the highest values of permeation flux, diffusion rate, diffusion coefficient (D), and permeation coefficient (P) across artificial membrane, EpiDerm, and rat skin which may be attributed to three potential factors (cationic charge, composition, and hydration by the hydrophilic gel) working in tandem. Transepidermal water loss (TEWL) by the MCNE11-GR was maximum (14.4 g/m2h) than control (6.1 g/m2h) indicating augmented interaction of MCNE11-Rh with skin components. Conclusively, cationic nanoemulsion gel was promising carrier for enhanced permeation and the drug access to the dermal region to treat deep seated fungal infections.

A mucoadhesive nanolipo gel containing Aegle marmelos gum to enhance transdermal effectiveness of linezolid for vaginal infection: In vitro evaluation, in vitro-ex vivo correlation, pharmacokinetic studies

Effective treatment of vaginal infections with conventional antibiotics often faces challenges like unavoidable dose-related side effects with increased risk of bacterial resistance. The study aims to deliver linezolid through natural gum based mucoadhesive nano lipogel to improve therapeutic effectiveness against vaginal infections. The linezolid loaded nanoliposomes (LNLs) were developed by thin film hydration method and were characterized by FTIR, DSC, XRD, FESEM, particle size analysis, zeta potential, drug loading capacity, in vitro release study etc. Selected LNLs was loaded into suitable gel formulation containing Aegle marmelos gum (as the mucoadhesive agent) and evaluated for in vitro, in vivo potentiality. FTIR/DSC test confirmed absence of any major interaction between selected drug and excipients. XRD showed amorphization of the drug encapsulated in NLs. FESEM studies showed spherical LNLs having smooth surface. LNLs had nanosize (51.03 nm), negative surface charge (-25.7 mV), satisfied drug loading capacity (11.5 ± 0.7 %) with sustained drug release. The experimental LNLs loaded lipogel showed desired physico-chemical properties viz. viscosity (37000 cps), spreadability (6.5 gm.cmsec-1), mucoadhesion (21.9 gf) and 61.04 % release of drug across rabbit vaginal mucosal membrane. The nanolipo gel exhibited improved antimicrobial activity against E. coli and C. albicans with respect to the pure linezolid. A good correlation was observed in between in vitro drug release and ex vivo permeation. Improved pharmacokinetic parameters like AUC, AUMC, MRT, Vd was observed for experimental nanolipo gel Vs. marketed formulation. The experimental nanolipo gel could be explored further for futuristic clinical application.

Co-delivery of amphotericin B and pentamidine loaded niosomal gel for the treatment of Cutaneous leishmaniasis

Topical drug delivery is preferable route over systemic delivery in case of Cutaneous leishmaniasis (CL). Among the available agents, amphotericin B (AmB) and pentamidine (PTM) showed promising result against CL. However, monotherapy is associated with incidences of reoccurrence and resistance. Combination therapy is therefore recommended. Thin film hydration method was employed for amphotericin B-pentamidine loaded niosomes (AmB-PTM-NIO) preparation followed by their incorporation into chitosan gel. The optimization of AmB-PTM-NIO was done via Box Behnken Design method and in vitro and ex vivo analysis was performed. The optimized formulation indicated 226 nm particle size (PS) with spherical morphology, 0.173 polydispersity index (PDI), -36 mV zeta potential (ZP) and with entrapment efficiency (EE) of 91% (AmB) and 79% (PTM), respectively. The amphotericin B-pentamidine loaded niosomal gel (AmB-PTM-NIO-Gel) showed desirable characteristics including physicochemical properties, pH (5.1 ± 0.15), viscosity (31870 ± 25 cP), and gel spreadability (280 ± 26.46%). In vitro release of the AmB and PTM from AmB-PTM-NIO and AmB-PTM-NIO-Gel showed more prolonged release behavior as compared to their respective drug solution. Higher skin penetration, greater percentage inhibition and lower IC50 against the promastigotes shows that AmB-PTM-NIO has better antileishmanial activity. The obtained findings suggested that the developed AmB-PTM-NIO-Gel has excellent capability of permeation via skin layers, sustained release profile and augmented anti-leishmanial outcome of the incorporated drugs.

Design and Development of a Topical Nanogel Formulation Comprising of a Unani Medicinal Agent for the Management of Pain

The oil of the Unani medicinal herb Baboona (Matricaria chamomilla) has shown potential in the management of pain. However, predicaments such as poor skin penetration, skin sensitization, liable to degradation, and volatile nature restrict its use. Therefore, our group for the first time has developed a carrier-based delivery system to facilitate the direct application of chamomile oil to the forehead. The developed nanogel was characterized for physical parameters such as compatibility, TEM, and stability studies. Further, it was also evaluated for pH, viscosity, spread ability, and extrudability, as well as through texture analyses, in vitro studies, and skin irritation tests. The formulation was successfully developed with all the necessary attributes. The in vitro studies revealed the enhanced skin penetration of chamomile oil nanogel. The in vivo studies were also performed in chemically induced pain models, mimicking migraine. The studies show significant improvement of the pain threshold for chamomile nanogel when compared to the positive control group and the results were comparable to marketed diclofenac formulations. Finally, the encapsulation into nanogel reduced the skin irritation property. The nanogel formulation showed promising effects in the pain management of migraine.

Development of a Nanoemulgel for the Topical Application of Mupirocin

Mupirocin (MUP) is an effective topical antibiotic with poor skin permeability; however, its skin permeability can be improved by a nanoemulsion formulation based on eucalyptus oil or eucalyptol. Despite this improvement, the nanoemulsion has limitations, such as low viscosity, low spreadability, and poor retention on the skin. To overcome these limitations, the aim of this study was to develop a nanoemulgel formulation that would enhance its rheological behaviour and physicochemical properties. The MUP nanoemulgel was prepared by incorporating a preprepared MUP nanoemulsion into Carbopol gel at a concentration of 0.75% in a 1:1 ratio. The nanoemulgel formulations were characterised and evaluated for their physicochemical and mechanical strength properties, rheological behaviour, and in vitro skin permeation and deposition, as well as antibacterial studies. Both nanoemulgels exhibited stability at temperatures of 4 and 25 °C for a period of 3 months. They had a smooth, homogenous, and consistent appearance and displayed non-Newtonian pseudoplastic behaviour, with differences in their viscosity and spreadability. However, both nanoemulgels exhibited lower skin permeability compared to the marketed control. The local accumulation efficiency of MUP from nanoemulgel after 8 h was significantly higher than that of the control, although there was no significant difference after 24 h. Micro-CT scan imaging allowed visualisation of these findings and interpretation of the deposited drug spots within the layers of treated skin. While there were no significant differences in the antibacterial activities between the nanoemulgels and the control, the nanoemulgels demonstrated superiority over the control due to their lower content of MUP. These findings support the potential use of the nanoemulgel for targeting skin lesions where high skin deposition and low permeability are required, such as in the case of topical antibacterial agents.

QbD-Optimized, Phospholipid-Based Elastic Nanovesicles for the Effective Delivery of 6-Gingerol: A Promising Topical Option for Pain-Related Disorders

In this study, elastic nanovesicles, constructed of phospholipids optimized by Quality by Design (QbD), release 6-gingerol (6-G), a natural chemical that may alleviate osteoporosis and musculoskeletal-related pain. A 6-gingerol-loaded transfersome (6-GTF) formulation was developed using a thin film and sonication approach. 6-GTFs were optimized using BBD. Vesicle size, PDI, zeta potential, TEM, in vitro drug release, and antioxidant activity were evaluated for the 6-GTF formulation. The optimized 6-GTF formulation had a 160.42 nm vesicle size, a 0.259 PDI, and a -32.12 mV zeta potential. TEM showed sphericity. The 6-GTF formulation's in vitro drug release was 69.21%, compared to 47.71% for the pure drug suspension. The Higuchi model best described 6-G release from transfersomes, while the Korsmeyer-Peppas model supported non-Fickian diffusion. 6-GTF had more antioxidant activity than the pure 6-G suspension. The optimized transfersome formulation was converted into a gel to improve skin retention and efficacy. The optimized gel had a spreadability of 13.46 ± 4.42 g·cm/s and an extrudability of 15.19 ± 2.01 g/cm². The suspension gel had a 1.5 μg/cm²/h ex vivo skin penetration flux, while the 6-GTF gel had 2.71 μg/cm²/h. Rhodamine B-loaded TF gel reached deeper skin layers (25 μm) compared to the control solution in the CLSM study. The gel formulation's pH, drug concentration, and texture were assessed. This study developed QbD-optimized 6-gingerol-loaded transfersomes. 6-GTF gel improved skin absorption, drug release, and antioxidant activity. These results show that the 6-GTF gel formulation has the ability to treat pain-related illnesses effectively. Hence, this study offers a possible topical treatment for conditions connected to pain.

Design and dermatokinetic appraisal of lornoxicam-loaded ultrafine self-nanoemulsion hydrogel for the management of inflammation: In vitro and in vivo studies

The present study aimed to evaluate the impact of ultrafine nanoemulsions on the transdermal delivery of lornoxicam (LOR) for management of the inflammation. The transdermal administration of LORNE could increase the efficacy of LOR with a reduction in side effects. Merging the beneficial properties of ultrafine nanoemulsions and their components (penetration enhancers) can lead to good solubilization, a small droplet size, and more effective LOR carriers. Therefore, this study aims to develop and evaluate the potential use of ultrafine nanoemulsions of LOR (LORNE) to elucidate their skin targeting for the treatment of inflammation. Based on solubility and pseudo ternary phase diagram tests, ultrafine LORNE composed of Labrafil M 2125 CS, Cremophor RH40, and Transcutol HP to deliver LOR was developed and characterized for its physicochemical properties, emulsification, and in vitro release. The selected LORNE was incorporated into carbopol gel (LORNE-Gel) and examined for ex vivo skin permeation, retention, dermatokinetics, anti-inflammatory efficacy, and skin irritation. The selected LORNE12-Gel could improve skin permeation, retention, and dermatokinetic results significantly (p < 0.05) with enhanced C_{Skin max} and AUC_0-48h compared to LOR-Gel. Moreover, LORNE12-Gel showed a remarkable anti-inflammatory effect compared to LOR-Gel after topical application. No signs of skin irritation were observed following treatment, indicating the safety of LORNE12-Gel. Thus, this study demonstrated that LOR-loaded LORNE12-Gel could be promising as an efficient transdermal nanocarrier for an anti-inflammatory alternative.

Dapsone-Loaded Mixed Micellar Gel for Treatment OF Acne Vulgaris

Mixed polymeric micelles are potential nanocarriers for topical drug delivery. Dapsone (DAP) is an antibacterial used as anti-acne agent, but challenged by low water solubility and poor skin permeability. In the present study, DAP-loaded mixed micellar gel was developed comprising Pluronics F-68 and F-127. Micelles were prepared by solvent evaporation method and particle size, ex vivo permeation, drug loading, and entrapment efficiency were determined. Central Composite Design was used to optimize formulation. Independent variables were concentration of Pluronics at three levels while micelle size and drug loading capacities were dependent variables. Droplet size ranged from 400 to 500 nm. Transmission electron microscopy revealed spherical morphology of micelles. Optimized micelles were incorporated into gel base using HPMC K100M, Sodium CMC, and Carbopol 980 as gelling agents. Gels were evaluated for pH, drug content, spreadability, rheology, syneresis, ex vivo permeation, and subacute dermal toxicity. Compared with solubility of free DAP (0.24+0.056 µg/ml), solubility in mixed micelles was 18.42±3.4 µg/ml in water at room temperature. Order of spreadability of gels was Na CMC < HPMC < Carbopol 980. Carbopol gels displayed thixotropy with index of 3.17. Syneresis for all gels from day 0 to day 30 was found to be in range of 4.2 to 15.6% w/w. Subacute dermal toxicity studies showed no signs of erythema and edema on rat skin until 21 days. These results suggest that mixed micelles can significantly increase solubility and permeability and sustain release of DAP and are suitable carriers for topical DAP delivery in anti-acne therapies.

Quality by Design Assisted Optimization and Risk Assessment of Black Cohosh Loaded Ethosomal Gel for Menopause: Investigating Different Formulation and Process Variables

Black cohosh (Cimicifuga racemosa) (CR) is a popular herb and is medically lauded for ameliorating myriad symptoms associated with menopause. However, its pharmaceutical limitations and non-availability of a patient-compliant drug delivery approach have precluded its prevalent use. Henceforth, the current research premise is aimed at developing an ethosomal gel incorporating triterpene enriched fraction (TEF) obtained from CR and evaluating its effectiveness through the transdermal application. TEF-loaded ethosomes were formulated using solvent injection, optimized and characterised. The optimized ethosomes were then dispersed into a polymeric gel base to form ethosomal gel which was further compared with the conventional gel by in-vitro and ex-vivo experiments. Here, the quality by design (QbD) approach was exploited for the optimization and development of ethosomal gel. The elements of QbD comprising initial risk assessment, design of experimentation (DoE), and model validation for the development of formulation have all been described in detail. The optimized ethosomes (F03) showed a nanometric size range, negative zeta potential and good entrapment. The in vitro release profile of gel revealed a burst release pattern following the Korsmeyer Peppas model having Fickian diffusion. The transdermal flux of ethosomal gel was observed to be more than that of conventional gel. Texture analysis and rheological characterization of the gel, revealed good strength showing shear thinning and pseudoplastic behaviour. The confocal microscope investigation revealed the deeper skin permeation of ethosomal gel than conventional gel. This result was further strengthened by DSC, IR and histological assessment of the animal skin (Wistar rat), treated with the optimized formulation. Conclusively, the implementation of QbD in the formulation resulted in a better understanding of the process and the product. It aids in the reduction of product variability and defects, hence improving product development efficiencies. Additionally, the ethosomal gel was found to be a more effective and successful carrier for TEF than the conventional gel through the transdermal route. Moreover, this demands an appropriate animal study, which is underway, for a stronger outcome.

Antileishmanial Agents Co-loaded in Transfersomes with Enhanced Macrophage Uptake and Reduced Toxicity

The prime objective of this study was to develop amphotericin B (AMB) and rifampicin (RIF) co-loaded transfersomal gel (AMB-RIF co-loaded TFG) for effective treatment of cutaneous leishmaniasis (CL). AMB-RIF co-loaded TF was prepared by the thin-film hydration method and was optimized based on particle size, polydispersity index (PDI), zeta potential, entrapment efficiency (%EE), and deformability index. Similarly, AMB-RIF co-loaded TFG was characterized in terms of rheology, spread ability, and pH. In vitro, ex vivo, and in vivo assays were performed to evaluate AMB-RIF co-loaded TF as a potential treatment option for CL. The optimized formulation had vesicles in nanosize range (167 nm) with suitable PDI (0.106), zeta potential (- 19.05 mV), and excellent %EE of RIF (66%) and AMB (85%). Moreover, it had appropriate deformability index (0.952). Additionally, AMB-RIF co-loaded TFG demonstrated suitable rheological behavior for topical application. AMB-RIF co-loaded TF and AMB-RIF co-loaded TFG showed sustained release of the incorporated drugs as compared to AMB-RIF suspension. Furthermore, RIF permeation from AMB-RIF co-loaded TF and AMB-RIF co-loaded TFG was enhanced fivefold and threefold, whereas AMB permeation was enhanced by eightfold and 6.6-fold, respectively. The significantly different IC₅₀, higher CC₅₀, and FIC₅₀ (p < 0.5) showed synergistic antileishmanial potential of AMB-RIF co-loaded TF. Likewise, reduced lesion size and parasitic burden in AMB-RIF co-loaded TF-treated mouse group further established the antileishmanial effect of the optimized formulation. Besides, AMB-RIF co-loaded TFG showed a better safety profile. This study concluded that TFG may be a suitable carrier for co-delivery of AMB-RIF when administered topically for the treatment of CL.

Betamethasone Dipropionate Nanocrystals: Investigation, Feasibility and In Vitro Evaluation

Corticosteroids, such as betamethasone dipropionate (BMD), have been the mainstay in topical therapy as potent glucocorticoid receptor agonist with immune suppression, anti-proliferative, and anti-inflammatory effects. Moreover, they have poor skin penetration, which is a hurdle against its potential therapeutic benefits. In present investigation, nanocrystals as carrier for effective topical delivery of BMD were explored using wet milling as technique and polysorbate 80 as a non-ionic stabilizer. Upon optimizing different process parameters, promising results were observed at stabilizer concentration of 0.9% w/v having particle size analysis (PSA) and PDI as 284 nm and 0.299, respectively. These results were supported by the FTIR and PXRD spectra of BMD-API and BMD nanocrystals, suggesting strong crystal lattice structure of BMD being reduced due to milling. The reduction in particle morphology was evident from the FESEM images. The optimized batch of BMD nanocrystals was incorporated into Carbopol gel base, showing pH 6.2 ± 0.2 and viscosity 87.00 ± 5.2 Pa s at 25°C. A drug diffusion study using Franz diffusion cell proclaimed around ~86% BMD release from nanogel across the membrane. Also, it was observed that the BMD permeation across the skin was 2.39-fold higher with marketed formulation in contrast to BMD nanogel, suggesting prolonged drug release. The skin permeation flux with nanogel was at a much lower rate along with ~50.27% drug retention in different strata of skin, resulting in retention of drug nanocrystals. Thus, in nutshell the prolonged drug release from nanogel would fulfill the aim of once a day application and would aid in reducing the adverse events associated with repeated drug applications.

Co-Combination of Pregabalin and Withaniacoagulans-Extract-Loaded Topical Gel Alleviates Allodynia and Hyperalgesia in the Chronic Sciatic Nerve Constriction Injury for Neuropathic Pain in Animal Model

The current study reports the fabrication of co-combination gel using Pregabalin and Withania coagulans fruit extract to validate its effectiveness for neuropathic pain in chronic constriction injury (CCI) rat models. Three topical gels were prepared using Carbopol 934 through a pseudo-ternary phase diagram incorporating the Pregabalin (2.5%), Withania coagulans extract (2%), and co-combination of both Pregabalin (2.5%) and Withania coagulans extract (2%). Gels were characterized. FTIR showed a successful polymeric network of the gel without any interaction. The drug distribution at the molecular level was confirmed by XRD. The AFM images topographically indicated the rough surface of gels with a size range from 0.25 to 330 nm. DSC showed the disappearance of sharp peaks of the drug and extract, showing successful incorporation into the polymeric network of gels. The in vitro drug release of co-combination gel was 73% over 48 h. The mechanism of drug release by combination gel was Higuchi+ fickian with values of n (0.282) and R2 (0.947). An in vivo study for pain assessment via four methods: (i) heat hyperalgesia, (ii) cold allodynia, (iii) mechano-hyperalgesia, and (iv) dynamic mechano-allodynia, confirmed that topical treatment with co-combination gel reduced the pain significantly as indicated by the p value: R1 (p < 0.001), R2 (p < 0.001), R3 (p < 0.015), and R4 (p < 0.0344). The significance order was R2 (****) > R1 (***) > R3 (**) > R4 (*) > R5 (ns).

Preparation, Characterization of Pregabalin and Withania coagulans Extract-Loaded Topical Gel and Their Comparative Effect on Burn Injury

The current study depicts the comparative effects of nanogel using Withania coagulans extract, pregabalin alone, and a co-combination gel. The gels prepared were then analyzed for conductivity, viscosity, spread ability, globule size, zeta potential, polydispersity index, and TEM. The globule size of the co-combination gel, determined by zeta sizer, was found to be (329 ± 0.573 nm). FTIR analysis confirms the successful development of gel, without any interaction. Drug distribution at the molecular level was confirmed by XRD. DSC revealed no bigger thermal changes. TEM images revealed spherical molecules with sizes of 200 nm for the co-combination gel. In vivo studies were carried out by infliction of third degree burn wounds on rat skin, and they confirmed that pregabalin and Withania coagulans heals the wound more effectively, with a wound contraction rate of 89.95%, compared to remaining groups. Anti-inflammatory activity (IL-6 and TNF-α), determined by the ELISA technique, shows that the co-combination gel group reduces the maximum inflammation with TNF-α value (132.2 pg/mL), compared to the control (140.22 pg/mL). Similarly, the IL-6 value was found to be (78 pg/mL) for the co-combination gel and (81 pg/mL) in the case of the control. Histopathologically, the co-combination gel heals wounds more quickly, compared to individual gel. These outcomes depict that a co-combination gel using plant extracts and drugs can be successfully used to treat burn injury.

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

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

Rhamnolipid Nano-Micelles versus Alcohol-Based Hand Sanitizer: A Comparative Study for Antibacterial Activity against Hospital-Acquired Infections and Toxicity Concerns

Hospital-acquired infections (HAIs) are considered to be a major global healthcare challenge, in large part because of the development of microbial resistance to currently approved antimicrobial drugs. HAIs are frequently preventable through infection prevention and control measures, with hand hygiene as a key activity. Improving hand hygiene was reported to reduce the transmission of healthcare-associated pathogens and HAIs. Alcohol-based hand sanitizers are commonly used due to their rapid action and broad spectrum of microbicidal activity, offering protection against bacteria and viruses. However, their frequent administration has been reported to be associated with many side effects, such as skin sensitivity, skin drying, and cracks, which promote further skin infections. Thus, there is an essential need to find alternative approaches to hand sanitation. Rhamnolipids are glycolipids produced by Pseudomonas aeruginosa, and were shown to have broad antimicrobial activity as biosurfactants. We have previously demonstrated the antimicrobial activity of rhamnolipid nano-micelles against selected drug-resistant Gram-negative (Salmonella Montevideo and Salmonella Typhimurium) and Gram-positive bacteria (Staphylococcus aureus, Streptococcus pneumoniae). To the best of our knowledge, the antimicrobial activity of rhamnolipid nano-micelles in comparison to alcohol-based hand sanitizers against microorganisms commonly causing HAIs in Egypt—such as Acinetobacter baumannii and Staphylococcus aureus—has not yet been studied. In the present work, a comparative study of the antibacterial activity of rhamnolipid nano-micelles versus alcohol-based hand sanitizers was performed, and their safety profiles were also assessed. It was demonstrated that rhamnolipid nano-micelles had a comparable antibacterial activity to alcohol-based hand sanitizer, with a better safety profile, i.e., rhamnolipid nano-micelles are unlikely to cause any harmful effects on the skin. Thus, rhamnolipid nano-micelles could be recommended to replace alcohol-based hand sanitizers; however, they must still be tested by healthcare workers in healthcare settings to ascertain their antimicrobial activity and safety.

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.

Tocotrienols-rich naringenin nanoemulgel for the management of diabetic wound: Fabrication, characterization and comparative in vitro evaluations

The present research had been attempted to formulate and characterize tocotrienols-rich naringenin nanoemulgel for topical application in chronic wound conditions associated with diabetes. In due course, different phases of the nanoemulsion were chosen based on the solubility study, where combination of Capryol 90 and tocotrienols, Solutol HS15, and Transcutol P were selected as oil, surfactant, and cosurfactant, respectively. The nanoemulsions were formulated using the spontaneous emulsification method. Subsequently, Carbopols were incorporated to develop corresponding nanoemulgels of the optimized nanoemulsions. Thermodynamically stable optimized nanoemulgels were evaluated for their globule size, polydispersity index (PDI), surface charge, viscosity, mucoadhesive property, spreadability, in vitro release and release mechanism. Further, increasing polymer concentration in the nanoemulgels was reflected with the increased mucoadhesive property with corresponding decrease in the release rate of the drug. The optimized nanoemulgel (NG1) consisted of uniform dispersion (PDI, 0.452 ​± ​0.03) of the nanometric globules (145.58 ​± ​12.5) of the dispersed phase, and negative surface charge (−21.1 ​± ​3.32 ​mV) with viscosity 297,600 ​cP and good spreadability. In vitro release of naringenin in phosphate buffer saline revealed a sustained release profile up to a maximum of 74.62 ​± ​4.54% from the formulated nanoemulgel (NG1) within the time-frame of 24 ​h. Alternatively, the release from the nanoemulsion was much higher (89.17 ​± ​2.87%), which might be due to lack of polymer coating on the dispersed oil droplets. Moreover, the in vitro release kinetics from the nanoemulgel followed the first-order release and Higuchi model with non-Fickian diffusion. Therefore, encouraging results in this research is evident in bringing a promising future in wound management, particularly associated with diabetes complications.

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Thermodynamically stable naringenin-loaded tocotrienol-rich nanoemulgels were fabricated using spontaneous method.

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Developed nanoemulgel possesses nanometric globule size with good spreadability.

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Controlled in vitro release was obtained over a period of 24 ​h.

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First-order release and Higuchi model with non-Fickian diffusion was established in the in vitro release kinetic profile.

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This nanoemulgel could be a promising tool in the management of chronic wound condition.

Development, Characterization, and Evaluation of α-Mangostin-Loaded Polymeric Nanoparticle Gel for Topical Therapy in Skin Cancer

The aim of this study was to prepare and evaluate α-mangostin-loaded polymeric nanoparticle gel (α-MNG-PLGA) formulation to enhance α-mangostin delivery in an epidermal carcinoma. The poly (D, L-lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) were developed using the emulsion-diffusion-evaporation technique with a 3-level 3-factor Box-Behnken design. The NPs were characterized and evaluated for particle size distribution, zeta potential (mV), drug release, and skin permeation. The formulated PLGA NPs were converted into a preformed carbopol gel base and were further evaluated for texture analysis, the cytotoxic effect of PLGA NPs against B16-F10 melanoma cells, and in vitro radical scavenging activity. The nanoscale particles were spherical, consistent, and average in size (168.06 ± 17.02 nm), with an entrapment efficiency (EE) of 84.26 ± 8.23% and a zeta potential of -25.3 ± 7.1 mV. Their drug release percentages in phosphate-buffered solution (PBS) at pH 7.4 and pH 6.5 were 87.07 ± 6.95% and 89.50 ± 9.50%, respectively. The release of α-MNG from NPs in vitro demonstrated that the biphasic release system, namely, immediate release in the initial phase, was accompanied by sustained drug release. The texture study of the developed α-MNG-PLGA NPs gel revealed its characteristics, including viscosity, hardness, consistency, and cohesiveness. The drug flux from α-MNG-PLGA NPs gel and α-MNG gel was 79.32 ± 7.91 and 16.88 ± 7.18 µg/cm2/h in 24 h, respectively. The confocal study showed that α-MNG-PLGA NPs penetrated up to 230.02 µm deep into the skin layer compared to 15.21 µm by dye solution. MTT assay and radical scavenging potential indicated that α-MNG-PLGA NPs gel had a significant cytotoxic effect and antioxidant effect compared to α-MNG gel (p < 0.05). Thus, using the developed α-MNG-PLGA in treating skin cancer could be a promising approach.

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.

Tacrolimus encapsulated mesoporous silica nanoparticles embedded hydrogel for the treatment of atopic dermatitis

Atopic dermatitis (AD) is a repetitive inflammatory skin disorder with limited treatment options. Innovative targeted therapies are gaining significant interest and momentum towards disease control including better ways to deliver drugs topically. Tacrolimus is one such compound which is used to manage moderate to severe AD without causing atrophy which is one of the common side effects of steroids. However, Tacrolimus suffers from poor solubility and retention in the skin when used alone in hydrogel. Therefore, we have prepared Tacrolimus loaded mesoporous silica nanoparticles (TMSNs) to overcome the issues related to its solubility and effective topical delivery. Mesoporous silica nanoparticles (MSNs) were synthesized using sol gel technique and surface functionalized using amino (-NH₂⁺) and phosphonate (-PO₃^-) groups. Tacrolimus was loaded into MSNs and the particles were characterized for particle size (TEM and DLS), zeta potential (DLS), solubility studies, FTIR, TGA, XRD, BET and cytotoxicity studies. Water solubility of Tacrolimus was increased by 7 folds with phosphonate functionalized MSNs compared to free Tacrolimus. Further the TMSNs were incorporated in to carbopol gel, and the gel formulation was evaluated for various gel characterization tests (pH, spreadability, viscosity), in vitro tests (drug release, permeability studies) and in vivo tests (skin irritation study and efficacy studies) using 1-Fluoro-2,4-dinitrobenzene (DNFB) induced dermatitis in Balb/c mice. Results of in vitro and in vivo study showed that TMSNs loaded gel showed significantly higher amount of Tacrolimus retained (ex vivo - rat skin) and much higher reduction in ear thickness and improved histology (in vivo - in mice). Our data collectively suggest that MSNs incorporated hydrogel as a promising new formulation strategy for topical delivery of poorly soluble drugs.

Chitosan-Coated 5-Fluorouracil Incorporated Emulsions as Transdermal Drug Delivery Matrices

The purpose of the present study was to develop emulsions encapsulated by chitosan on the outer surface of a nano droplet containing 5-fluorouracil (5-FU) as a model drug. The emulsions were characterized in terms of size, pH and viscosity and were evaluated for their physicochemical properties such as drug release and skin permeation in vitro. The emulsions containing tween 80 (T80), sodium lauryl sulfate, span 20, and a combination of polyethylene glycol (PEG) and T20 exhibited a release of 88%, 86%, 90% and 92%, respectively. Chitosan-modified emulsions considerably controlled the release of 5-FU compared to a 5-FU solution (p < 0.05). All the formulations enabled transportation of 5-FU through a rat's skin. The combination (T80, PEG) formulation showed a good penetration profile. Different surfactants showed variable degrees of skin drug retention. The ATR-FTIR spectrograms revealed that the emulsions mainly affected the fluidization of lipids and proteins of the stratum corneum (SC) that lead to enhanced drug permeation and retention across the skin. The present study concludes that the emulsions containing a combination of surfactants (Tween) and a co-surfactant (PEG) exhibited the best penetration profile, prevented the premature release of drugs from the nano droplet, enhanced the permeation and the retention of the drug across the skin and had great potential for transdermal drug delivery. Therefore, chitosan-coated 5-FU emulsions represent an excellent possibility to deliver a model drug as a transdermal delivery system.

Fabrication of Conductive, Adhesive, and Stretchable Agarose-Based Hydrogels for a Wearable Biosensor

Herein, a strategy is proposed to prepare a conductive, self-adhesive, and stretchable agarose gel with the merits of distinct heat resistance, freeze resistance, and long-term moisture retention. To endow the gels with conductivity, monodisperse carbon nanotubes modified by polydopamine are introduced into the gel networks, which promote both conductivity and mechanical strength of the gels. Meanwhile, further addition of glycerol enhances excellent stretchability as well as heating/freezing tolerability and moisture retention of the gels. A wearable biosensor based on the gel is fabricated to record body motions precisely with good biocompatibility, which benefits the development of smart wearable devices.

Nanoemulgel for Improved Topical Delivery of Desonide: Formulation Design and Characterization

This research aimed to develop a novel drug delivery system to improve treatment of skin disorders. The system is comprised of a Carbopol 980-based nanoemulgel (NE-gel) containing a desonide (DES; 0.05%, w/w) nanoemulsion (NE), which has a small particle size, high encapsulation efficiency, good thermodynamic stability, good permeation ability, and high skin retention. DES-loaded NE (DES-NE) was prepared by high-pressure homogenization. The developed formulation was characterized by differential scanning calorimetry (DSC), X-ray diffraction, drug release, skin permeation, and drug retention. DES in vitro release and skin permeation studies with different formulations of artificial membrane and rat abdominal skin were performed with the Franz diffusion cell system. Confocal laser scanning microscopy (CLSM) was used to detect the localization and permeation pathways of drugs in the skin. Compared with commercially available gel (CA-gel) and NE, the NE-gel release process conformed to the Higuchi release model (R² = 0.9813). NE-gel prolonged the drug release time and allowed for reduced administration dose and frequency. The unit cumulative permeation of NE and NE-gel through the skin for 12 h was 63.13 ± 2.78 and 42.53 ± 2.06 μg/cm², respectively, values significantly higher (p < 0.01) than that of the CA-gel (30.65 ± 1.25 μg/cm²) and CA-cream (15.21 ± 0.97 μg/cm²). The DES-NE and DES NE-gel skin drug retention was significantly higher than commercially available formulations (p < 0.01). Hence, the prepared NE-gel is a potential vehicle for improved topical DES delivery for better treatment of skin disorders.

Topical delivery of curcumin-loaded transfersomes gel ameliorated rheumatoid arthritis by inhibiting NF-κβ pathway

Aim: To fabricate and evaluate curcumin-loaded transfersomes (Cur-TF) for the targeted delivery and enhanced therapeutic efficacy of curcumin for the treatment of rheumatoid arthritis (RA). Methods: Modified thin-film hydration method was used to prepare Cur-TF which were then embedded into carbopol-934 gel. They were further evaluated through in vitro techniques and in an in vivo arthritis model. Results: Cur-TF had optimal particle size, spherical morphology, high encapsulation efficiency and sustained drug release profiles. The Cur-TF gel had better in vitro skin penetration than plain curcumin. In vivo findings demonstrated improved clinical, histological and x-ray scores and reduced pro-inflammatory cytokines through NF-κβ inhibition. Conclusion: Cur-TF gel delivered curcumin to the arthritic dermal tissue through a topical route and demonstrated promising therapeutic efficacy by significantly alleviating complete Freud's adjuvant (CFA)-induced arthritis.

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.

Synthetic Nanoclay Gels Do Not Cause Skin Irritation in Healthy Human Volunteers

Synthetic clays are promising biomaterials for delivery of therapeutic molecules in regenerative medicine. However, before their use can be translated into clinical applications, their safety must be assessed in human volunteers. The aim of this study was to test the hypothesis that a synthetic nanoclay (LAPONITE) does not cause irritation to the human skin. To achieve this, a nanoclay gel at two different concentrations (1.5 and 3% w/v) was applied on the forearm of healthy volunteers for 24 h. 1% sodium lauryl sulfate (SLS) and 3% (w/v) polyacrylic acid were used as the positive and negative controls, respectively. The compromise in the skin barrier function was measured by trans-epidermal water loss (TEWL), erythema by spectroscopic measurements, and skin inflammatory biomarkers (IL-1α and IL-1RA) by the enzyme-linked immunosorbent assay. We found that the nanoclay caused no prolonged increase in TEWL, erythema, or induction of inflammatory cytokines. This was in contrast to 1% SLS, a known irritant, which induced significant increases in both skin erythema and TEWL. We conclude that the nanoclay is not an irritant and is thus suitable for therapeutic interventions at the skin surface.

Antipsychotic Potential and Safety Profile of TPGS-Based Mucoadhesive Aripiprazole Nanoemulsion: Development and Optimization for Nose-To-Brain Delivery

Delivering therapeutics to the brain using conventional dosage forms is always a challenge, thus the present study was aimed to formulate mucoadhesive nanoemulsion (MNE) of aripiprazole (ARP) for intranasal delivery to transport the drug directly to the brain. Therefore, a TPGS based ARP-MNE was formulated and optimized using the Box-Behnken statistical design. The improved in vitro release profile of the formulation was in agreement to enhanced ex vivo permeation through sheep mucous membranes with a maximum rate of permeation co-efficient (62.87  cm h^-1 × 10³) and flux (31.43  μg cm^-2.h^-1). The pharmacokinetic profile following single-dose administration showed the maximum concentration of drug in the brain (C_max) of 15.19 ± 2.51  μg mL^-1 and T_max of 1 h in animals with ARP-MNE as compared to 10.57 ± 1.88  μg mL^-1 and 1 h, and 2.52 ± 0.38  μg mL^-1 and 3 h upon intranasal and intravenous administration of ARP-NE, respectively. Further, higher values of % drug targeting efficiency (96.9%) and % drug targeting potential (89.73%) of ARP-MNE through intranasal administration were investigated. The studies in Wistar rats showed no existence of extrapyramidal symptoms through the catalepsy test and forelimb retraction results. No ex vivo ciliotoxicity on nasal mucosa reflects the safety of the components and delivery tool. Further, findings on locomotor activity and hind-limb retraction test in ARP-MNE treated animals established its antipsychotic efficacy. Thus, it can be inferred that the developed ARP-MNE could effectively be explored as brain delivery cargo in the effective treatment of schizophrenia without producing any toxic manifestation.

Development and characterization of nano-emulsions and nano-emulgels for transdermal delivery of statins

BACKGROUND

Oral administration of statins for the treatment of familial hypercholesterolemia results in poor therapeutic outcomes and patient compliance. An alternative administration route is proposed to circumvent the current limitations. This research is aimed at developing nano-emulsions and nano-emulgels as the ultimate potential delivery systems of statins for administration via the transdermal route.

METHODS

Oil-in-water (o/w) nano-formulations (nano-emulsions and nano-emulgels) containing 2% (w/w) of the selected statin and 8% apricot kernel oil as oil phase were formulated. The nano-formulations were characterized using transmission electron microscopy (TEM), pH, viscosity, droplet size and zeta-potential.

RESULTS

Nano-emulsions' and nano-emulgels' droplet size ranged between 114.23-169.83 nm and 149.83-267.53 nm, respectively. The addition of Carbopol® Ultrez 20 increased the nano-emulsions' viscosity (3.59-8.38 cP) resulting in the formation of nano-emulgels (viscosity: 1911.00-46,090.00 cP). The entrapment efficiency (90.77-99.55%) confirmed the incorporation of the statins. Membrane release studies indicated that statins were released at higher flux values in nano-emulsions compared to their respective nano-emulgels. Ex vivo (skin diffusion) studies indicated higher median values in the nano-emulgels compared to their nano-emulsion counterparts.

CONCLUSIONS

The results indicate the benefits of nano-emulsions and nano-emulgels as potential alternative delivery systems for the transdermal delivery of statins.

Nicotinamide extrudates as novel anti-aging and collagen promoting platform: a comparative cosmeceutical study versus the gel form

The objective of the study was to explore the potential of a novel nicotinamide extrudate as an anti-aging platform compared to the conventional gel. Nicotinamide extrudates were prepared by hot melt extrusion and characterized pharmaceutically for their thermal behavior, mositure uptake, skin adhesion, and deposition in different skin layers. The pharmacological potential of the extrudates was explored in terms of induction of skin amino acids, cellular energy estimation, 8-hydroxy-2-deoxyguanosine content, Nitrate + nitrite content and histological chacaterization of collagen area percent. Results revealed that the extrusion technique managed to amorphize nicotinamide and enhance its skin deposition (46%) compared to the gel form which only showed about 10% deposition, owing to the mucoadhesive nature of the former. Extrudates were also found superior to the gel form as demonstrated by the increased amino acids level (glycine, proline, hydroxyproline), increased cellular energy, decreased oxidative stress and increased collagen formation. Nictotinamide extrudates were proven to be a scalable promising anti-aging platform which are worthy of entering the cosmeceutical market as products.

Stabilization of ferulic acid in topical gel formulation via nanoencapsulation and pH optimization

Ferulic acid is a potent anti-oxidant with scientifically proven skin care efficacies. However, instability of this active in the skin care products restricted its wide application in beauty and skin care industries. This study aimed to stabilize ferulic acid in topical hydrogel formulation via nanoencapsulation technique. Ferulic acid loaded nanocapsules were prepared via high pressure homogenization method and physicochemically characterized. Mean particle size of ferulic acid loaded nanocapsules was < 300 nm. TEM and SEM images exhibited spherical particles with smooth surface. DSC and XRD results indicated that ferulic acid was completely dissolved in the lipid matrix of the nanocapsules and remained in amorphous form. Two types of hydrogel formulations containing ferulic acid loaded nanocapsules were prepared: Gel A with pH higher and Gel B with pH lower than pKa of ferulic acid. Cross-polarized microscopic image of the gel formulations did not show presence of any un-encapsulated and un-dissolved crystal. Gel B showed slower and controlled release of ferulic acid than Gel A. Ferulic acid permeation through skin mimic from the gel formulation demonstrated controlled permeation. Color stability of the gel and chemical stability of ferulic acid were very good in Gel B, while poor in Gel A (although significantly better than the gel with un-encapsulated ferulic acid). The result clearly indicates that together with nanoencapsulation, low pH (less than pKa of ferulic acid) of the hydrogel was crucial for both product appearance and chemical stability of ferulic acid. In fact, it has been proved that skin care product with low pH is good for skin as it can maintain skin homeostasis and microbiome. Furthermore, the permeation result suggests that ferulic acid may penetrate into deep skin layers and at the same time avoid systemic circulation. Overall, this low pH hydrogel formulation containing nanoencapsulated ferulic acid demonstrates great promise for commercialization.

Levofloxacin nanoemulsion gel has a powerful healing effect on infected wound in streptozotocin-induced diabetic rats

The aim of this study was to develop a novel oil-in-water (o/w) nanoemulsion gel containing levofloxacin for enhanced topical efficacy. Average particle size of sesame oil nanoemulsion without (SONE) and containing levofloxacin (SONEL) was found as 25.2 and 26.3 nm, respectively. Results from scratch test showed that SONEL had better proliferation effect in comparison with negative control. Treated animals with SONEL showed significant reduction in period of epithelialization, wound contraction, and number of inflammatory cells among all groups. Also, SONEL-treated group had the greatest collagen synthesis. Immunohistochemical analysis showed high intensity of CD31 and TGF-β at wound site of treatment groups with SONEL on day 12 post-treatment (P < 0.05). Skin irritation test demonstrated safety of SONEL gel for skin topical application. In conclusion, our studies suggest that SONEL could be an effective formulation for treatment of diabetic wound infection by controlling infection and improving the healing process. Graphical Abstract .

Bromocriptine Nanoemulsion-Loaded Transdermal Gel: Optimization Using Factorial Design, In Vitro and In Vivo Evaluation

Bromocriptine mesylate (BCM), a dopaminergic agonist administered orally, exhibits retarded bioavailability owing to poor absorption and extreme first-pass metabolism. The objective of the current study was to develop, characterize, and statistically optimize BCM nanoemulsion (BCM-NE) loaded into a gel (BCM-NE gel) to evaluate its potential for improved permeation of BCM through the transdermal route, thereby improving its pharmacokinetic profile. BCM-NE was prepared by o/w spontaneous emulsification method and the effects of different formulation variables on the critical attributes of NE like globule size were investigated by implementing factorial design. The optimized formulation exhibited a mean globule size of 160 ± 6.5 nm, zeta potential of - 20.4 ± 1.23 mV, and drug content of 99.45 ± 1.9%. Ex vivo permeation studies across rat skin exhibited a significant enhancement in permeation, i.e., enhancement ratio (ER) of ~ 7.4 and 5.86 for BCM-NE and BCM-NE gel, respectively, when compared with aqueous BCM suspension gel. In vivo pharmacokinetic studies performed in rats demonstrated a higher and prolonged drug release of BCM from BCM-NE gel when compared to oral aqueous BCM suspension. The AUC_0-t for BCM-NE gel and BCM suspension was found to be 562.54 ± 77.55 and 204.96 ± 51.93 ng/ml h, respectively. The relative bioavailability (%F) of BCM was shown to be enhanced 274% by BCM-NE gel. Histopathological studies demonstrated the safety and biocompatibility of the developed system. All the above results proved that the BCM-NE gel could be a superior and patient-compliant alternative to oral delivery in the management of PD.

Development and Investigation of Vitamin C-Enriched Adapalene-Loaded Transfersome Gel: a Collegial Approach for the Treatment of Acne Vulgaris

Adapalene-loaded transfersome gel containing vitamin C as a combination therapy for the management of acne vulgaris was developed in the present study. The transfersome was prepared by reverse-phase evaporation, and the effect of various process parameters were investigated by the Design of Experiment (DOE) approach and optimized based on the particle size (PS), polydispersity index (PDI), zeta potential (ZP), and entrapment efficiency (EE). The selected tranfersomes were further evaluated for their thermal behavior and morphology by transmission electron microscopy and turbidity measurements and incorporated into a gel with/without vitamin C. The gel was evaluated and compared with the marketed product (Adiff gel) for various physicochemical parameters, and in vivo studies in testosterone-induced rat models of acne. The prepared transfersomes had PS in the range of 280 to 400 nm, PDI values of 0.416 to 0.8, ZP of - 38 to - 20 mV, and % EE of 32 to 70%. DSC studies confirmed a positive interaction of the components in the transfersome. Surface morphology confirmed that the vesicles were spherical, unilamellar, and discrete. A relative deformability study showed higher elasticity of the transfersomes compared with Adiff aqs gel. Ascorbyl-6-palmitate in adapalene-loaded transfersome gel containing vitamin C (ADVTG) was found to have a good antioxidant free radical-scavenging activity. An in vitro drug release study showed that the sustained release of the transfersomal formulations was attributed to the flexibility of the vesicles by which penetration was increased. ADVTG was found to be promising in treating acne compared with the marketed product. Graphical Abstract.

A novel Nanoformulation Development of Eugenol and their treatment in inflammation and periodontitis

OBJECTIVE

To prepare a novel nanoemulsion- Carbopol® 934 gel for Eugenol, in order to prevent the periodontitis.

MATERIAL AND METHODS

Spontaneous emulsification method was used for the preparation of nanoemulsion in which it contain Eugenol (oil phase), Tween-80 (surfactant), and PEG (co-surfactant). To the development of best nanoemulsion, three-factor three-level central composite design was used in which %oil; %Smix and % water were optimized as independent variables. An optimized-nanoemulsion were converted to nanoemulsion-Carbopol® 934 gel.

RESULTS

5.5% oil, 35.5% Smix and 59.0% water were optimized as independent and dependent variables. Finally dependent variables optimized as a particle size (nm), PDI and %transmittance were observed 79.92 ± 6.33 nm, 0.229 ± 0.019, and 98.88 ± 1.31% respectively. The values of final results for dependent variables like particle size (nm), PDI and % transmittance were evaluated as 79.92 ± 6.33 nm, 0.229 ± 0.019, and 98.88 ± 1.31%, respectively. TEM and SEM showed a spherical shape of developed nanoemulsion with refractive index (1.63 ± 0.038), zeta potential (-19.16 ± 0.11), pH (7.4 ± 0.06), viscosity (34.28 ± 6 cp), and drug content of 98.8 ± 0.09%. After that a final optimized EUG-NE-Gel was assessed on the basis of their pH measurement, drug content, syringeability, and mucoadhesion on the goat buccal mucosa. Optimized EUG-NE-Gel (Tween-80 and Carbopol® 934 used) showed the results, to improve the periodontal drug delivery of EUG in future.

CONCLUSION

EUG-NE-Gel showed a significant role in anti-inflammatory activity, analgesic, and anesthetic, antibacterial, and treatment of periodontal disease.

Preparation and in vivo evaluation of a topical hydrogel system incorporating highly skin-permeable growth factors, quercetin, and oxygen carriers for enhanced diabetic wound-healing therapy

PURPOSE

We created and evaluated an enhanced topical delivery system featuring a combination of highly skin-permeable growth factors (GFs), quercetin (QCN), and oxygen; these synergistically accelerated re-epithelialization and granulation tissue formation of/in diabetic wounds by increasing the levels of GFs and antioxidants, and the oxygen partial pressure, at the wound site.

METHODS

To enhance the therapeutic effects of exogenous administration of GFs for the treatment of diabetic wounds, we prepared highly skin-permeable GF complexes comprised of epidermal growth factor (EGF), insulin-like growth factor-I (IGF-I), platelet-derived growth factor-A (PDGF-A), and basic fibroblast growth factor (bFGF), genetically attached, via the N-termini, to a low-molecular-weight protamine (LMWP) to form LMWP-EGF, LMWP-IGF-I, LMWP-PDGF-A, and LMWP-bFGF, respectively. Furthermore, quercetin (QCN)- and oxygen-carrying 1-bromoperfluorooctane (PFOB)-loaded nanoemulsions (QCN-NE and OXY-PFOB-NE) were developed to improve the topical delivery of QCN and oxygen, respectively. After confirming the enhanced penetration of LMWP-GFs, QCN-NE, and oxygen delivered from OXY-PFOB-NE across human epidermis, we evaluated the effects of combining LMWP-GFs, QCN-NE, and OXY-PFOB-NE on proliferation of keratinocytes and fibroblasts, and the chronic wound closure rate of a diabetic mouse model.

RESULTS

The optimal ratios of LMWP-EGF, LMWP-IGF-I, LMWP-PDGF-A, LMWP-bFGF, QCN-NE, and OXY-PFOB-NE were 1, 1, 0.02, 0.02, 0.2, and 60, respectively. Moreover, a Carbopol hydrogel containing LMWP-GFs, QCN-NE, and OXY-PFOB-NE (LMWP-GFs/QCN-NE/OXY-PFOB-NE-GEL) significantly improved scratch-wound recovery of keratinocytes and fibroblasts in vitro compared to that afforded by hydrogels containing each component alone. LMWP-GFs/QCN-NE/OXY-PFOB-NE-GEL significantly accelerated wound-healing in a diabetic mouse model, decreasing wound size by 54 and 35% compared to the vehicle and LMWP-GFs, respectively.

CONCLUSION

LMWP-GFs/QCN-NE/OXY-PFOB-NE-GEL synergistically accelerated the healing of chronic wounds, exerting both rapid and prolonged effects.

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

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

Transdermal delivery of fluvastatin loaded nanoemulsion gel: Preparation, characterization and in vivo anti-osteoporosis activity

The objective of present study was to develop hydrogel based nanoemulsion (NE) drug delivery system for transdermal delivery and evaluate its potential in in vivo anti-osteoporotic activity. NE was prepared using aqueous phase titration method and characterized for droplet size, zeta potential and morphology. It was then formulated into hydrogel based NE gel using carbopol 940 as gelling agent. NE gel was evaluated for pH, viscosity, in vitro/ex vivo permeation studies and in vivo anti-osteoporotic activity. The results indicated formation of spherical, nano sized globules of NE ranging from 11.17 ± 0.24 to 128.8 ± 0.16 nm with polydispersity of <0.5. In vitro and ex vivo permeation studies showed significantly higher permeation of NE as well as NE gel in comparison to fluvastatin solution indicating that NE gel can effectively penetrate through skin layers. In vivo anti-osteoporotic results demonstrated formation of new bone in trabecular region of osteoporotic rat femurs through micro-CT scanning radiographs. Biomechanical strength testing demonstrated greater load bearing capacity of rat femurs in the treated animals in comparison with the osteoporotic group. Thus, developed NE gel formulation of fluvastatin demonstrated greater potential for transdermal delivery and in the treatment of osteoporosis.