Background and different treatment modalities for melasma: Conventional and nanotechnology-based approaches

Strategies for transportation of peptides across the skin for treatment of multiple diseases

An established view in genetic engineering dictates an increase in the discovery of therapeutic peptides to enable the treatment of multiple diseases. The use of hypodermic needle for delivery of proteins and peptides occurs due to the hydrophilic nature, sensitivity toward proteolytic enzymes and high molecular weight. The non-invasive nature of the transdermal delivery technique offers multiple advantages over the invasive route to release drugs directly into the systemic circulation to enhance bioavailability, better patient compliance, reduced toxicity and local irritability. The transdermal route seems highly desirable from the pharmaco-therapeutic and patient compliance point of view, however, the lipophilic barrier of skin restricts the application. The use of several techniques like electrical methods (iontophoresis, sonophoresis etc.), chemical penetration enhancers (e.g. protease inhibitors, penetration enhancers, etc.) and nanocarriers (dendrimers, lipid nanocapsules, etc.) are utilized to improve the passage of drug molecules across the biomembranes. Additionally, such clinical interventions facilitate the physicochemical characteristics of peptides, to enable effective preservation, conveyance and release of therapeutic agents. Moreover, strategies ensure the attainment of the intended targets and enhance treatment outcomes for multiple diseases. This review article focuses on the techniques of peptide transportation across the skin to advance the delivery approaches and therapeutic efficiency.

Nano-vesicular systems for melanocytes targeting and melasma treatment: In-vitro characterization, ex-vivo skin retention, and preliminary clinical appraisal

Melasma represents an acquired melanogenesis disorder resulting in skin's hyperpigmentation effect. Although several approaches are adopted for melasma treatment, nanotechnology presents the most convenient one. Therefore, the present work aimed to formulate and characterize three nano-vesicular systems namely, liposomes, penetration enhancer containing vesicles (PEVs) and invasomes to enhance the topical delivery of the skin whitening agent; alpha arbutin (α-arbutin) for the treatment of melasma. Liposomes were prepared according to a 23 full factorial design and the selected formula was further employed for the preparation of PEVs and invasomes. Results showed that the three vesicular systems exhibited nano-sizes ranging from 151.95 to 672.5 nm, negative charges ranging from -12.50 to -28.20 mV, high entrapment efficiencies ranging from 80.59 to 99.53 %, good stability and prolonged-release of α-arbutin for 24 h after dispersion in hydrogel form. The deposition study from the vesicular hydrogel confirmed their effectiveness for the drug's accumulation in the skin reaching an average of 1.6-fold higher in the stratum corneum, 1.6-1.8-fold higher in the epidermis, and 1.6-1.8-fold higher in the dermis compared to the free drug dispersion in hydrogel. A preliminary clinical split-face study on patients suffering from melasma revealed that α-arbutin-loaded liposomes and PEVs in hydrogel forms showed better clinical outcomes compared to the free α-arbutin hydrogel as well as to the previously published α-arbutin encapsulated in chitosan nanoparticles and dispersed in hydrogel form. This delineates the aforementioned nano-vesicular systems as effective and clinically superior delivery means for melasma management.

Recent progress in nanoparticulate-based intranasal delivery for treating of different central nervous system diseases

Drug administration to the central nervous system (CNS) has become a great obstacle because of several biological barriers, such as the blood-brain barrier, therefore, brain targeting insights are a light for scientists to move forward for treating neurogenerative diseases using advanced non-invasive methods. The current demand is to use a potential direct route as the nasal administration to transport drugs into the brain enhancing the BBB permeability and hence, increasing the bioavailability. Interestingly, recent techniques have been implanted in formulating nanocarriers-based therapeutics for targeting and treating ischemic stroke using lipid or polymeric-based materials. Nanoparticulate delivery systems are set as an effective platform for brain targeting as polymeric nanoparticles and polymeric micelles or nanocarriers based on lipids for preventing drug efflux to promote optimal therapeutic medication concentration in the brain-diseased site. In recent years, there has been a notable increase in research publications and ongoing investigations on the utilization of drug-loading nanocarriers for the treatment of diverse CNS diseases. This review comprehensively depicts these dangerous neurological disorders, drug targeting challenges to CNS, and potential contributions as novel intranasal nano-formulations are being used to treat and regulate a variety of neurological diseases.

Global research trends on melasma: a bibliometric and visualized study from 2014 to 2023

Melasma, a prevalent pigmentary disorder, is characterized by its complex etiology, propensity for recurrence, and resistance to treatment. However, there is currently no research on melasma through bibliometrics and visualisation. This study analyses the hotspots and trends in the field based on 2,709 publications from the Web of Science Core Collection (WOSCC). We carried out bibliometric analyses using Citespace software for different countries/regions, institutions, authors, and keywords. References were also analysed using VoSviewer. The results indicate that overall, there has been an increase in publications related to melasma since 2014. According to the analysis of the collaborative network diagram, the United States, Egyptian Knowledge Bank, and Benjakul Soottawat are the most contributing countries, institutions, and authors, respectively. Reference and keyword analyses have identified the pathogenesis and treatment of melasma as a prevalent topic in recent years. And how to find new treatment options and more effective therapeutic drugs is a future research trend. This is the first bibliometric and visual analysis of melasma-related literature to explore research hotspots and trends.

Nanosystems with potential application as carriers for skin depigmenting actives

Hyperpigmentation is a skin disorder characterized by excessive production of melanin in the skin and includes dyschromias such as post-inflammatory hyperchromias, lentigens, melasma and chloasma. Topical products containing depigmenting agents offer a less aggressive treatment option for hyperpigmentation compared to methods like chemical peels and laser sessions. However, some of these agents can cause side effects such as redness and skin irritation. Encapsulating these actives in nanosystems shows promise in mitigating these effects and improving product safety and efficacy. In addition, nanocarriers have the ability to penetrate the skin, potentially allowing for targeted delivery of actives to the affected areas. The most commonly investigated nanosystems are nanoemulsions, vesicular nanosystems and nanoparticles, in which different materials can be used to generate different compositions in order to improve the properties of these nanocarriers. Nanocarriers have already been widely explored, but it is necessary to understand the evolution of these technologies when applied to the treatment of skin hyperchromias. Therefore, this literature review aims to present the state of the art over the last 15 years on the use of nanosystems as a potential strategy for encapsulating depigmenting actives for potential application in cosmetic products for skin hyperchromia. By providing a comprehensive overview of the latest research findings and technological advances, this article can contribute to improving the care and quality of life of people affected by this skin condition.

Different therapeutic approaches in melasma: advances and limitations

Melasma is a chronic hyperpigmentation skin disorder that is more common in the female gender. Although melasma is a multifactorial skin disorder, however, sun-exposure and genetic predisposition are considered as the main etiologic factors in melasma occurrence. Although numerous topical and systemic therapeutic agents and also non-pharmacologic procedural treatments have been considered in melasma management, however, the commonly available therapeutic options have several limitations including the lack of sufficient clinical effectiveness, risk of relapse, and high rate of unwanted adverse drug reactions. Recruitment of nanotechnology for topical drug delivery in melasma management can lead to enhanced skin penetration, targeted drug delivery to the site of action, longer deposition at the targeted area, and limit systemic absorption and therefore systemic availability and adverse drug reactions. In the current review, first of all, the etiology, pathophysiology, and severity classification of melasma have been considered. Then, various pharmacologic and procedural therapeutic options in melasma treatment have been discussed. Afterward, the usage of various types of nanoparticles for the purpose of topical drug delivery for melasma management was considered. In the end, numerous clinical studies and controlled clinical trials on the assessment of the effectiveness of these novel topical formulations in melasma management are summarized.

A comprehensive review on lipid nanocarrier systems for cancer treatment: fabrication, future prospects and clinical trials

Over the last few decades, cancer has been considered a clinical challenge, being among the leading causes of mortality all over the world. Although many treatment approaches have been developed for cancer, chemotherapy is still the most utilized in the clinical setting. However, the available chemotherapeutics-based treatments have several caveats including their lack of specificity, adverse effects as well as cancer relapse and metastasis which mainly explains the low survival rate of patients. Lipid nanoparticles (LNPs) have been utilized as promising nanocarrier systems for chemotherapeutics to overcome the challenges of the currently applied therapeutic strategies for cancer treatment. Loading chemotherapeutic agent(s) into LNPs improves drug delivery at different aspects including specific targeting of tumours, and enhancing the bioavailability of drugs at the tumour site through selective release of their payload, thus reducing their undesired side effects on healthy cells. This review article delineates an overview of the clinical challenges in many cancer treatments as well as depicts the role of LNPs in achieving optimal therapeutic outcomes. Moreover, the review contains a comprehensive description of the many LNPs categories used as nanocarriers in cancer treatment to date, as well as the potential of LNPs for future applications in other areas of medicine and research.

Clinical Applications of Polypodium leucotomos (Fernblock®): An Update

Exposure to sun radiation leads to higher risk of sunburn, pigmentation, immunosuppression, photoaging and skin cancer. In addition to ultraviolet radiation (UVR), recent research indicates that infrared radiation (IR) and visible light (VIS) can play an important role in the pathogenesis of some of these processes. Detrimental effects associated with sun exposure are well known, but new studies have shown that DNA damage continues to occur long after exposure to solar radiation has ended. Regarding photoprotection strategies, natural substances are emerging for topical and oral photoprotection. In this sense, Fernblock^®, a standardized aqueous extract of the fern Polypodium Leucotomos (PLE), has been widely administered both topically and orally with a strong safety profile. Thus, this extract has been used extensively in clinical practice, including as a complement to photodynamic therapy (PDT) for treating actinic keratoses (AKs) and field cancerization. It has also been used to treat skin diseases such as photodermatoses, photoaggravated inflammatory conditions and pigmentary disorders. This review examines the most recent developments in the clinical application of Fernblock^® and assesses how newly investigated action mechanisms may influence its clinical use.

Fungal production of kojic acid and its industrial applications

Kojic acid has gained its importance after it was known worldwide that the substance functions primarily as skin-lightening agent. Kojic acid plays a vital role in skin care products, as it enhances the ability to prevent exposure to UV radiation. It inhibits the tyrosinase formation which suppresses hyperpigmentation in human skin. Besides cosmetics, kojic acid is also greatly used in food, agriculture, and pharmaceuticals industries. Conversely, according to Global Industry Analysts, the Middle East, Asia, and in Africa especially, the demand of whitening cream is very high, and probably the market will reach to $31.2 billion by 2024 from $17.9 billion of 2017. The important kojic acid-producing strains were mainly belongs to the genus Aspergillus and Penicillium. Due to its commercial potential, it continues to attract the attention for its green synthesis, and the studies are still widely conducted to improve kojic acid production. Thus, the present review is focused on the current production processes, gene regulation, and limitation of its commercial production, probable reasons, and possible solutions. For the first time, detailed information on the metabolic pathway and the genes involved in kojic acid production, along with illustrations of genes, are highlighted in the present review. Demand and market applications of kojic acid and its regulatory approvals for its safer use are also discussed. KEY POINTS: • Kojic acid is an organic acid that is primarily produced by Aspergillus species. • It is mainly used in the field of health care and cosmetic industries. • Kojic acid and its derivatives seem to be safe molecules for human use.

Decrypting the Potential of Nanotechnology-Based Approaches as Cutting-Edge for Management of Hyperpigmentation Disorder

The abundant synthesis and accretion of melanin inside skin can be caused by activation of melanogenic enzymes or increase in number of melanocytes. Melasma is defined as hyperpigmented bright or dark brown spots which are symmetrically distributed and have serrated and irregular borders. The three general categories of pigmentation pattern include centro facial pattern, malar pattern, and mandibular pattern. Exposure to UV rays, heat, use of cosmetics and photosensitizing drugs, female sex hormonal therapies, aberrant production of melanocyte stimulating hormone, and increasing aesthetic demands are factors which cause the development of melasma disease. This review gives a brief overview regarding the Fitzpatrick skin phototype classification system, life cycle of melanin, mechanism of action of anti-hyperpigmenting drugs, and existing pharmacotherapy strategies for the treatment of melasma. The objectives of this review are focused on role of cutting-edge nanotechnology-based strategies, such as lipid-based nanocarriers, i.e., lipid nanoparticles, microemulsions, nanoemulsions, liposomes, ethosomes, niosomes, transfersomes, aspasomes, invasomes penetration-enhancing vesicles; inorganic nanocarriers, i.e., gold nanoparticles and fullerenes; and polymer-based nanocarriers i.e., polymeric nanoparticles, polymerosomes, and polymeric micelles for the management of hyperpigmentation.

Biological activities and safety data of kojic acid and its derivatives - a review

Kojic acid presents a variety of applications for human use, especially as a depigmenting agent. Its derivatives are also proposed in order to prevent chemical degradation, prevent adverse effects and improve efficacy. The aim of this study was to peer review the current scientific literature concerning the biological activities and safety data of kojic acid or its derivatives, aiming at human use, and trying to elucidate the action mechanisms. Three different databases were assessed and the word "kojic" was crossed with "toxicity", "adverse effect", "efficacy", "effect", "activity" and "safety". Articles were selected according to pre-defined criteria. Besides the depigmenting activity, kojic acid and derivatives can act as antioxidant, antimicrobial, anti-inflammatory, radioprotector, anticonvulsant and obesity management agents, and present potential as antitumor substances. Depigmenting activity is due to the molecules, after penetrating the cell, binding to tyrosinase active site, regulating melanogenesis factors, leucocytes modulation and free radical scavenging activity. Hence, polarity, size and ligands are also important factors for activity. Kojic acid and derivatives present cytotoxicity to some cancerous cell lines, including melanoma, hepatocellular carcinoma, ovarian cancer, breast cancer and colon cancer. Regarding safety, kojic acid or its derivatives are safe molecules for human use in the concentrations tested. Kojic acid and its derivatives have great potential for cosmetic, pharmaceutical and medical applications.

Nanoliposome Use to Improve the Stability of Phenylethyl Resorcinol and Serve as a Skin Penetration Enhancer for Skin Whitening

Phenylethyl resorcinol (PR) is a potent tyrosinase inhibitor and a cosmeceutical skin lightening agent. However, the application of PR is limited by photoinstability and poor solubility. In this study, we formulated and optimized phenylethyl resorcinol loaded nanoliposomes (PR-NLPs) to improve the stability and effective delivery of PR. PR-NLPs were prepared by the ethanol injection method and optimized by a single factor experimental and Box–Behnken design. In addition, Diethylamino Hydroxybenzoyl Hexyl Benzoate (DHHB) as the UBA absorber was added to PR-NLPs, which significantly improved the photostability of PR. The mean size, polydispersity index (PDI), and zeta potential of the optimized PR-NLPs were 130.1 ± 3.54 nm, 0.225 ± 0.02, and −43.9 ± 3.44 mV, respectively. The drug encapsulation efficiency (EE) and loading efficiency (LC) of PR-NLPs were 96.81 ± 3.46% and 8.82 ± 0.6%, respectively. These PR-NLPs showed good physicochemical stability for 3 months at 4 °C and 25 °C in the dark. They showed typical sustained and prolonged drug-release behavior in vitro. The in vitro cytotoxicity assay and cellular uptake demonstrated that the PR-NLPs had excellent biocompatibility and cell transport ability. It significantly inhibited tyrosinase activity and reduced melanin production in B16F10 cells at concentrations of 20 or 30 μg/mL. Moreover, the PR-NLPs enhanced the PR into the skin. These results indicate that PR-NLPs can be used as a nanocarrier to improve the transdermal delivery of PR.

Insightful exploring of advanced nanocarriers for the topical/transdermal treatment of skin diseases

Dermatological products constitute a big segment of the pharmaceutical market. From conventional products to more advanced ones, a wide variety of dosage forms have been developed till current date. A representative of the advanced delivery means is carrier-based systems, which can load large number of drugs for treatment of dermatological diseases, or simply for cosmeceutical purposes. To make them more favorable for topical delivery, further incorporation of these carriers in a topical vehicle, such as gels or creams is made. Therefore in this review article, an overview is compiled of the most commonly encountered novel carrier based topical delivery systems; namely lipid based (nanoemulsions, microemulsions, solid lipid nanoparticles [SLNs] and nanostructured lipid carriers [NLCs]), and vesicular carriers (non-deformable, such as liposomes, niosomes, emulsomes and cerosomes, and deformable, such as transfersomes, ethosomes, transethosomes, and penetration enhancer vesicles), with special emphasis on those loaded in a secondary gel vehicle. A special focus was made on the commonly encountered dermatological diseases, such as bacterial and fungal infections, psoriasis, dermatitis, eczema, vitiligo, oxidative damage, aging, alopecia, and skin cancer.

Conventional and hybrid nanoparticulate systems for the treatment of hepatocellular carcinoma: An updated review

Hepatocellular carcinoma (HCC) is considered a serious malignancy which affects a large number of people worldwide. Despite the presence of some diagnostic techniques for HCC, the fact that its symptoms somehow overlap with other diseases causes it to be diagnosed at a late stage, hence negatively affecting the prognosis of the disease. The currently available treatment strategies have many shortcomings such as high cost, induction of serious side effects as well as multiple drug resistance, hence resulting in therapeutic failure. Accordingly, nanoformulations have been developed in order to overcome the clinical challenges, enhance the therapeutic efficacy, and elicit chemotherapy tailor-ability. Hybrid nanoparticulate carriers in particular, which are composed of two or more drug vehicles with different physicochemical characteristics combined together in one system, have been recently reported to advance nanotechnology-based therapies. Therefore, this review sheds the light on HCC, and the role of nanotechnology and hybrid nanoparticulate carriers as well as the latest developments in the use of conventional nanoparticles in combating this disease.