Topical delivery of clobetasol propionate loaded microemulsion based gel for effective treatment of vitiligo – Part II: Rheological characterization and in vivo assessment through dermatopharmacokinetic and pilot clinical studies

Biodegradable calcium carbonate carriers for the topical delivery of clobetasol propionate

Inflammatory dermatoses represent a global problem with increasing prevalence and recurrence among the world population. Topical glucocorticoids (GCs) are the most commonly used anti-inflammatory drugs in dermatology due to a wide range of their therapeutic actions, which, however, have numerous local and systemic side effects. Hence, there is a growing need to create new delivery systems for GCs, ensuring the drug localization in the pathological site, thus increasing the effectiveness of therapy and lowering the risk of side effects. Here, we propose a novel topical particulate formulation for the GC clobetasol propionate (CP), based on the use of porous calcium carbonate (CaCO3) carriers in the vaterite crystalline form. The designed carriers contain a substantially higher CP amount than conventional dosage forms used in clinics (4.5% w/w vs. 0.05% w/w) and displayed a good biocompatibility and effective cellular uptake when studied in fibroblasts in vitro. Hair follicles represent an important reservoir for the GC accumulation in skin and house the targets for its action. In this study, we demonstrated successful delivery of the CP-loaded carriers (CP-CaCO3) into the hair follicles of rats in vivo using optical coherent tomography (OCT). Importantly, the OCT monitoring revealed the gradual intrafollicular degradation of the carriers within 168 h with the most abundant follicle filling occurring within the first 48 h. Biodegradability makes the proposed system especially promising when searching for new CP formulations with improved safety and release profile. Our findings evidenced the great potential of the CaCO3 carriers in improving the dermal bioavailability of this poorly water-soluble GC.

Implementation of the vitiligo area scoring index in clinical studies of patients with vitiligo: a scoping review

The vitiligo area scoring index (VASI) is a validated, reliable clinician-reported outcome measure widely used to assess the extent of skin depigmentation seen in patients with vitiligo and to measure patient responses to therapies for vitiligo in clinical trials. However, its implementation in studies is inconsistent and makes comparing results across different studies difficult. The aim of this scoping review is to summarize interventional clinical studies that applied the VASI to measure vitiligo and identify variability in VASI implementation. A systematic search of Ovid Medline, Embase, Web of Science, Cochrane, and ClinicalTrials.gov was performed. Interventional studies published between January 1946 and October 2020 that used the VASI as an outcome measure for assessing vitiligo response were reviewed for methodological approach. Great heterogeneity was found within the 55 included interventional studies that used VASI as an outcome measure. A total of 9 VASI subtypes were described by the authors within 10 intervention categories. VASI determined study eligibility in one study. Body surface area was most frequently established using inconsistent methods. We found unclear or ambiguously scaled assessments of depigmentation. Most VASI outcomes were reported as mean absolute difference, percentage VASI improvement, and percentage of patients who achieved the VASI endpoint. The VASI score was over 100 in one study. Our scoping review revealed many VASI methodology variations in interventional clinical studies of vitiligo. While VASI is a standard method to measure vitiligo changes, substantial heterogeneity in methodology limits reliable comparison and interpretation of findings from different clinical trials. Our findings may be used as a foundation to standardize the VASI outcome measure methodology, allowing for improved clinician training and rigorous data analysis across vitiligo research groups worldwide.

Microemulsion-Based Keratin-Chitosan Gel for Improvement of Skin Permeation/Retention and Activity of Curcumin

Curcumin (Cur) is a kind of polyphenol with a variety of topical pharmacological properties including antioxidant, analgesic and anti-inflammatory activities. However, its low water solubility and poor skin bioavailability limit its effectiveness. In the current study, we aimed to develop microemulsion-based keratin-chitosan gel for the improvement of the topical activity of Cur. The curcumin-loaded microemulsion (CME) was formulated and then loaded into the keratin-chitosan (KCS) gel to form the CME-KCS gel. The formulated CME-KCS gel was evaluated for its characterization, in vitro release, in vitro skin permeation and in vivo activity. The results showed that the developed CME-KCS gel had an orange-yellow and gel-like appearance. The particle size and zeta potential of the CME-KCS gel were 186.45 ± 0.75 nm and 9.42 ± 0.86 mV, respectively. The CME-KCS gel showed desirable viscoelasticity, spreadability, bioadhesion and controlled drug release, which was suitable for topical application. The in vitro skin permeation and retention study showed that the CME-KCS gel had better in vitro skin penetration than the Cur solution and achieved maximum skin drug retention (3.75 ± 0.24 μg/cm²). In vivo experimental results confirmed that the CME-KCS gel was more effective than curcumin-loaded microemulsion (Cur-ME) in analgesic and anti-inflammatory activities. In addition, the CME-KCS gel did not cause any erythema or edema based on a mice skin irritation test. These findings indicated that the developed CME-KCS gel could improve the skin penetration and retention of Cur and could become a promising formulation for topical delivery to treat local diseases.

Nanoparticles for Topical Application in the Treatment of Skin Dysfunctions-An Overview of Dermo-Cosmetic and Dermatological Products

Nanomaterials (NM) arouse interest in various fields of science and industry due to their composition-tunable properties and the ease of modification. They appear currently as components of many consumer products such as sunscreen, dressings, sports clothes, surface-cleaning agents, computer devices, paints, as well as pharmaceutical and cosmetics formulations. The use of NPs in products for topical applications improves the permeation/penetration of the bioactive compounds into deeper layers of the skin, providing a depot effect with sustained drug release and specific cellular and subcellular targeting. Nanocarriers provide advances in dermatology and systemic treatments. Examples are a non-invasive method of vaccination, advanced diagnostic techniques, and transdermal drug delivery. The mechanism of action of NPs, efficiency of skin penetration, and potential threat to human health are still open and not fully explained. This review gives a brief outline of the latest nanotechnology achievements in products used in topical applications to prevent and treat skin diseases. We highlighted aspects such as the penetration of NPs through the skin (influence of physical-chemical properties of NPs, the experimental models for skin penetration, methods applied to improve the penetration of NPs through the skin, and methods applied to investigate the skin penetration by NPs). The review summarizes various therapies using NPs to diagnose and treat skin diseases (melanoma, acne, alopecia, vitiligo, psoriasis) and anti-aging and UV-protectant nano-cosmetics.

Novel Dermal Delivery Cargos of Clobetasol Propionate: An Update

Dermal disorders such as psoriasis and eczema are associated with modifications in the chemical and molecular composition of the skin. Clobetasol propionate (CP), a superpotent topical glucocorticoid, is widely used for the therapeutic management of various skin conditions, owing to its strong anti-inflammatory, antipruritic, vasoconstrictive, and antiproliferative activities. Safety studies demonstrated that CP is safer for a shorter period, however, with prolonged application, it shows secondary side effects such as photosensitivity, Cushing-like syndrome, allergic contact dermatitis, osteonecrosis, hypopigmentation, steroid acne, and skin atrophy. Therefore, the US FDA (United States Food and Drug Administration) has restricted the usage of CP to not more than 15 days. Research scientists addressed its several formulations and drug delivery issues, such as low water solubility, less stability, photodegradation, and poor absorption, by incorporating them into novel nanobased delivery platforms. With the utilization of these technologies, these drawbacks of CP have been resolved to a large extent to reestablish this moiety. This article explores the physicochemical properties and mechanism of action of CP. Additionally, an attempt has been made to discover and highlight the possible features of the novel nanosystems, including nanoemulsions, nanosponges, solid lipid nanoparticles, nanostructured lipid carriers, and nanogels, reported for CP. The stability and safety concerns of CP, along with its commercial status, are also discussed.

Multi-component clobetasol-loaded monolithic lipid-polymer hybrid nanoparticles ameliorate imiquimod-induced psoriasis-like skin inflammation in Swiss albino mice

Lipid-polymer hybrid nanoparticles (LPNs) exhibit several advantages over polymeric and non-polymeric systems in terms of improved drug loading, controlled release, stability, and cellular uptake. Herein we report a scalable and stable monolithic lipid-polymer hybrid nanoparticles (LPNs) consisting of a combination of lipids (solid and liquid) and an amphiphilic copolymer, mPEG-PLA. Clobetasol propionate, a topical corticosteroid, was encapsulated in the hydrophobic core of these LPNs that showed spherical shaped particles with a z-average size of 94.8 nm (PDI = 0.213) and encapsulation efficiency of 84.3%. These clobetasol loaded LPNs (CP/LPNs) were formulated into a topical hydrogel using carbopol 974P. CP/LPNs gel showed a sustained in vitro clobetasol release for 7 days with no burst release and 6 month stability at 2-8°C and room temperature. Further, CP/LPNs showed an improved cellular uptake with significant growth inhibition of HaCaT cells. In ex vivo studies, these LPNs penetrated into the viable epidermis and dermis region of the psoriatic skin with undetectable quantities leaching to the reservoir. Further, the topical application of CP/LPNs gel on Swiss albino mice with psoriasis-like inflammation showed negligible leaching of clobetasol into the systemic circulation. Efficacy assessment showed significantly improved PASI score, reduced skin damage and proliferation after treatment with CP/LPNs gel as compared to marketed product (Clobetamos™). Collectively, the enhanced cellular uptake, high skin penetration with increased skin retention, and improved efficacy demonstrate the potential of these LPNs for future clinical application.

Bicontinuous microemulsions containing Melaleuca alternifolia essential oil as a therapeutic agent for cutaneous wound healing

The Melaleuca alternifolia essential oil (MEO) has been widely used due to its healing and antimicrobial action. Its incorporation into drug delivery systems is a reality, and numerous studies have already been developed for this purpose. In this regard, the aim of this work was to develop, characterize, and evaluate the in vivo pharmacological activity of bicontinuous microemulsions (BME) containing MEO. Through diagram construction, a formulation consisting of Kolliphor® HS 15 (31.05%), Span® 80 (3.45%), isopropyl myristate (34.5%), and distilled water (31%) was selected and MEO was incorporated in the proportion of 3.45% (v/v). Morphological analysis characterization confirms that the system studied herein is a BME. The evaluated formulation showed physicochemical characteristics that allow its topical use. Rheologically, samples were characterized as pseudo-plastic non-Newtonian thixotropic fluids. The chromatographic method developed is in accordance with the current recommendations. The extraction method used assured a 100% recovery of the pharmacological marker (terpinen-4-ol). In vivo studies suggest that BME loaded with MEO may contribute to the healing process of skin wounds. In addition, it demonstrated antibacterial activity for Gram-positive and Gram-negative bacteria. Therefore, the BME system loaded with MEO is promising as a healing and antimicrobial agent for skin wounds.Graphical abstract.

Recent Progress and Future Directions: The Nano-Drug Delivery System for the Treatment of Vitiligo

Vitiligo is a depigmentation disease that seriously affects the physical health, mental health and quality of life of a patient. Therapeutic aim at control immunoreaction by relieving oxidative stress. Unfortunately, the cuticle barrier function and lack of specific accumulation lead to unsatisfactory therapeutic outcomes and side effects. The introduction and innovation of nanotechnology offers inspiration and clues for the development of new strategies to treat vitiligo. However, not many studies have been done to interrogate how nanotechnology can be used for vitiligo treatment. In this review, we summarize and analyze recent studies involving nano-drug delivery systems for the treatment of vitiligo, with a special emphasis on liposomes, niosomes, nanohydrogel and nanoparticles. These studies made significant progress by either increasing drug loading efficiency or enhancing penetration. Based on these studies, there are three proposed principles for topical nano-drug delivery systems treatment of vitiligo including the promotion of transdermal penetration, enhancement of drug retention and facilitation of melanin regeneration. The presentation of these ideas may provide inspirations for the future development of topical drug delivery systems that will conquer vitiligo.

Biomedical applications of microemulsion through dermal and transdermal route

Microemulsions are thermodynamically stable, transparent, colloidal drug carrier system extensively used by the scientists for effective drug delivery across the skin. It is a spontaneous isotropic mixture of lipophilic and hydrophilic substances stabilized by suitable surfactant and co-surfactant. The easy fabrication, long-term stability, enhanced solubilization, biocompatibility, skin-friendly appearance and affinity for both the hydrophilic and lipophilic drug substances make it superior for skin drug delivery over the other carrier systems. The topical administration of most of the active compounds is impaired by limited skin permeability due to the presence of skin barriers. In this sequence, the microemulsion represents a cost-effective and convenient drug carrier system which successfully delivers the drug to and across the skin. In the present review work, we compiled various attempts made in last 20 years, utilizing the microemulsion for dermal and transdermal delivery of various drugs. The review emphasizes the potency of microemulsion for topical and transdermal drug delivery and its effect on drug permeability.

Prolonged skin retention of clobetasol propionate by bio-based microemulsions: a potential tool for scalp psoriasis treatment

Novel effective and cosmetically acceptable formulations are needed for the treatment of scalp psoriasis, due to the poor efficacy of the current products. The challenge in developing safe, efficient, and convenient delivery systems for this drug was addressed in the present work by formulating clobetasol propionate-loaded W/O microemulsions (MEs). Pseudo-ternary phase diagrams were constructed by using a combination of biocompatible and biodegradable excipients. Characterization studies demonstrated that selected MEs had suitable technological features such as being Newtonian fluids, possessing low viscosity, and high thermodynamic stability. Photomicrographs showed a significant alteration of the skin structure after treatment with MEs, and a preferential concentration of these in the stratum corneum and epidermis. These data, together with ex vivo permeation results, suggested an enhanced topical targeted effect due to an increased drug retention efficacy in the upper skin layers, as desired. Moreover, the bio-based excipients selected could contribute to the healing of the psoriatic scalp. In this way, the improvement of clobetasol efficacy is combined with the useful properties of the microemulsion components and with environmental safety.

Preparation and Characterization of Minoxidil Loaded Nanostructured Lipid Carriers

Nanostructured lipid carriers (NLCs) are interesting delivery systems for enhancing the penetration of an active substance through the skin after topical administration. The present paper described the development of a novel NLCs for minoxidil (MXD) topical delivery. Stearic acid and oleic acid that showed the highest solubility for MXD were selected as solid lipid and liquid lipid, respectively, and the NLCs were prepared by hot high pressure homogenization method. The minoxidil loaded NLCs prepared accordingly to the optimal formulation exhibited spherical shape with a mean diameter of 281.4 ± 7.4 nm, polydispersity of 0.207 ± 0.009, zeta potential of -32.90 ± 1.23 mV, drug entrapment efficiency of 92.48 ± 0.31%, and drug loading of 13.85 ± 0.47%. Storage stability studies demonstrated that the particle size and entrapment efficiency of the MXD-NLCs were not changed during 3 months both at 4°C and room temperature. Moreover, the release of MXD from the NLCs was faster than drug release from SLNs. In vitro skin permeability test demonstrated that MXD-NLCs had a more pronounced permeation and retention profile than MXD-SLNs. Furthermore, no erythema was observed after administration of MXD-NLCs. All these results indicated that the developed MXD-NLCs could be a promising and effective nanocarrier for topical delivery of MXD.

Preparation of a mixed-matrix hydrogel of vorinostat for topical administration on the rats as experimental model

Oral vorinostat has the remarkable curative effect on aggravated and recurrent cutaneous T-cell lymphoma (CTCL), but is accompanied by serious adverse effects. Therefore, oral vorinostat is not applicable to the treatment of early stage CTCL. The aim of this study is to develop a novel vorinostat formulation which is effective for early stage CTCL and free of the serious adverse effects. A mixed-matrix hydrogel of vorinostat was prepared and characterized as a potential topical skin delivery system. Moisture retention, swelling behavior, viscosity, real-time morphology and differential scanning calorimeter analysis (DSC) of hydrogel were evaluated to select the solvent, matrix and humectant. The optimal HPMC/HPC ratio, pH, additive, dose and drug loading of vorinostat hydrogel were determined by evaluating the cumulative vorinostat amount of skin retention and transdermal amount of vorinostat through the skin in vitro. The optimal hydrogel presented a low transdermal amount of vorinostat through the skin, suggesting that the hydrogel reduced the amount of vorinostat that was absorbed in the systemic circulation. More importantly, in vivo percutaneous permeation experiments were also performed to evaluate the permeation behavior of vorinostat into the skin. The topical application with a much lower dose showed higher AUC (the cumulative vorinostat amount of skin retention) than oral application and the hydrogel achieved a sustained permeation of vorinostat in the skin for 24h in vivo. It indicated that a higher relative bioavailability for hydrogel was achieved compared with oral vorinostat. Moreover, there was no damage, inflammation or cell swelling of the skin after administration. Thus, the mixed-matrix vorinostat hydrogel prepared in this study could deliver vorinostat into local skin more efficiently than oral administration.

A novel topical targeting system of caffeine microemulsion for inhibiting UVB-induced skin tumor: characterization, optimization, and evaluation

The purpose of the present study was to develop an optimal microemulsion (ME) formulation as topical nanocarrier of caffeine (CAF) to enhance CAF skin retention and subsequently improve its therapeutic effect on UVB-induced skin carcinogenesis. The pseudo-ternary phase diagram was developed composing of Labrafil M 1944 CS as oil phase, Cremophor EL as surfactant, tetraglycol as cosurfactant, and water. Four ME formulations at water content of 50, 60, 70, and 80% were prepared along the water dilution line of oil to surfactant ratio of 1:3 and characterized in terms of morphology, droplet size, and electric conductivity. A gel at the same drug loads (1%, w/w) was used as control. Ex vivo skin permeation studies were conducted for ME optimization. The optimized formulation (ME4) was composed of 5% (w/w) Labrafil M 1944 CS, 15% (w/w) Smix (2/1, Cremophor EL and tetraglycol), and 80% (w/w) aqueous phase. The skin location amount of CAF from ME4 was nearly 3-fold higher than control (P < 0.05) with improved permeated amount through the skin. The skin targeting localization of hydrophilic substance from ME4 was further visualized through fluorescent-labeled ME by a confocal laser scanning microscope. In pharmacodynamics studies, CAF-loaded ME4 was superior in terms of increasing apoptotic sunburn cells (P < 0.05) as compared with control. Overall results suggested that the ME4 might be a promising vehicle for the topical delivery of CAF.