Development of a quercetin-loaded nanostructured lipid carrier formulation for topical delivery

SLN and NLC for topical, dermal, and transdermal drug delivery

Introduction: From a biopharmaceutical standpoint, the skin is recognized as an interesting route for drug delivery. In general, small molecules are able to penetrate the stratum corneum, the outermost layer of the skin. In contrast, the delivery of larger molecules, such as peptides and proteins, remains a challenge. Nanoparticles have been exploited not only to enhance skin penetration of drugs but also to expand the range of molecules to be clinically used.Areas covered: This review focus on Solid lipid nanoparticles (SLN) and Nanostructured lipid carriers (NLC) for skin administration. We discuss the selection criteria for lipids, surfactants, and surface modifiers commonly in use in SLN/NLC, their production techniques, and the range of drugs loaded in these lipid nanoparticles for the treatment of skin disorders.Expert opinion: Depending on the lipid and surfactant composition, different nanoparticle morphologies can be generated. Both SLN and NLC are composed of lipids that resemble those of the skin and sebum, which contribute to their enhanced biocompatibility, with limited toxicological risk. SLN and NLC can be loaded with very chemically different drugs, may provide a tunable release profile, can be produced in a sterilized environment, and be scaled-up without the need for organic solvents.

Novel Approach for Transdermal Delivery of Rifampicin to Induce Synergistic Antimycobacterial Effects Against Cutaneous and Systemic Tuberculosis Using a Cationic Nanoemulsion Gel

Purpose

This study demonstrated improved transdermal delivery of rifampicin-loaded cationic nanoemulsion gel to treat systemic and cutaneous tuberculosis using capmul, labrasol, and acconon, which exert anti-Mycobacterium activities. This approach enhanced drug permeation across the skin, increased therapeutic efficacy, and reduced dose-related side effects.

Methods

Design Expert^® was used to optimize formulations (S_mix ratio and capmul as independent factors), which were prepared using a slow spontaneous titration method. The optimized nanoemulsion was incorporated into carbopol gel to allow for topical application and comparative assessments. Nanoemulsions and gels were evaluated for size, size distribution, shape, zeta potential, percent spread, viscosity, in vitro hemolysis, in vitro release, and ex vivo skin permeation and deposition. A mechanistic evaluation was performed using scanning electron microscopy. Furthermore, in vivo pharmacokinetic and irritation studies were performed.

Results

The optimized cationic nanoemulsion (OCNE-1) was characterized by small particle size (≤100 nm), had optimal viscosity, percent spread, zeta potential, and percent drug release, and was hemocompatible. The OCNE-1T gel exhibited higher permeation flux (51.32 ± 0.5 µg/cm² hr), permeation coefficient (2.566 ± 0.08 cm/hr), drug deposition (994.404 µg/cm²), and enhancement ratio (7.16) than those of the OCNE-1 nanoemulsion or drug solution. Scanning electron microscopy was used to characterize the mechanism of enhanced permeation. An In vivo study showed that the C_max and area under the curve following transdermal application were 4.34- and 4.74-fold higher than those following oral administration.

Conclusion

Transdermal delivery of rifampicin could be a promising alternative to conventional approaches to treat systemic and local tuberculosis, and other bacterial infections.

Development of Topical Nanocarriers for Skin Cancer Treatment Using Quality by Design Approach

BACKGROUND

One of the most compelling medical challenges of this century is the treatment of cancer and among them, skin cancer is the most common type. Thus, current treatments need to be renewed continuously to handle this challenge.

OBJECTIVE

This review presents considerations which can be employed during the development of nanosized formulations dedicated to the topical treatment of skin cancer. We aimed to collect and organize literature data on the treatment options for skin cancer in order to determine the required quality attributes of an effective dermal anticancer formulation.

METHOD

With the consideration of the Quality by Design (QbD) approach related to the development of new pharmaceutical formulations, a cost-saving process ensuring a high-quality product taking into account patient expectations, industrial and regulatory aspects can be achieved. Furthermore, this concept is highly recommended by regulatory agencies.

RESULTS

Our work discusses the current therapies, active agents, drug carrier systems, and evaluation methods in connection with the treatment of skin cancer and outlines Critical Quality Attributes which need to be considered during the development of a nanosized dermal anticancer formulation.

CONCLUSION

The first part of this review summarizes the most important topical treatment therapies for skin cancer and highlights the future therapeutic perspectives, focusing on the benefits of nanotechnology and dermal administration. The second part outlines the critical points of nanosized dermal anticancer formulation development in the view of QbD approach. Our research emphasizes the application of QbD method for a rationalized and more effective anticancer formulation development process.

Enhancing the potential preclinical and clinical benefits of quercetin through novel drug delivery systems

Quercetin is reported to have numerous pharmacological actions, including antidiabetic, anti-inflammatory and anticancer activities. The main mechanism responsible for its pharmacological activities is its ability to quench reactive oxygen species (ROS) and, hence, decrease the oxidative stress responsible for the development of various diseases. Despite its proven therapeutic potential, the clinical use of quercetin remains limited because of its low aqueous solubility, bioavailability, and substantial first-pass metabolism. To overcome this, several novel formulations have been reported. In this review, we focus on the applications of quercetin extract as well as its novel formulations for treating different disorders. We also examine its proposed mechanism of action of quercetin.

Lipid Nanoparticles and Active Natural Compounds: A Perfect Combination for Pharmaceutical Applications

Phytochemicals represent an important class of bioactive compounds characterized by significant health benefits. Notwithstanding these important features, their potential therapeutic properties suffer from poor water solubility and membrane permeability limiting their approach to nutraceutical and pharmaceutical applications. Lipid nanoparticles are well known carrier systems endowed with high biodegradation and an extraordinary biocompatible chemical nature, successfully used as platform for advanced delivery of many active compounds, including the oral, topical and systemic routes. This article is aimed at reviewing the last ten years of studies about the application of lipid nanoparticles in active natural compounds reporting examples and advantages of these colloidal carrier systems.

A comparative study: the prospective influence of nanovectors in leveraging the chemopreventive potential of COX-2 inhibitors against skin cancer

Introduction

This study was conducted to elucidate the chemopreventive potential, cytotoxic, and suppression of cellular metastatic activity of etodolac (ETD)-loaded nanocarriers.

Methods

To esteem the effect of charge and composition of the nanovectors on their performance, four types of vectors namely, negative lipid nanovesicles; phosalosomes (N-Phsoms), positive phosalosomes (P-Phsoms), nanostructured lipid carriers (NLCs) and polymeric alginate polymer (AlgNPs) were prepared and compared. ETD was used as a model cyclo-oxygenase-2 (COX-2) inhibitor to evaluate the potency of these nanovectors to increase ETD permeation and retention through human skin and cytotoxicity against squamous cell carcinoma cell line (SCC). Moreover, the chemopreventive activity of ETD nanovector on mice skin cancer model was evaluated.

Results

Among the utilized nanovectors, ETD-loaded N-Phsoms depicted spherical vesicles with the smallest particle size (202.96±2.37 nm) and a high zeta potential of −24.8±4.16 mV. N-Phsoms exhibited 1.5, and 3.6 folds increase in the ETD amount deposited in stratum corneum, epidermis and dermis. Moreover, cytotoxicity studies revealed a significant cytotoxic potential of such nanovector with IC₅₀=181.76 compared to free ETD (IC₅₀=982.75), correlated to enhanced cellular internalization. Its efficacy extended to a reduction in the relative tumor weight with 1.70 and 1.51-fold compared to positive control and free ETD, that manifested by a 1.72-fold reduction in both COX-2 and proliferating cell nuclear antigen mRNA (PCNA-mRNA) levels and 2.63-fold elevation in caspase-3 level in skin tumors relative to the positive control group with no hepato-and nephrotoxicity.

Conclusion

Encapsulation of ETD in nanovector enhances its in-vitro and in-vivo anti-tumor activity and opens the door for encapsulation of more relevant drugs.

Polyoxazolines based mixed micelles as PEG free formulations for an effective quercetin antioxidant topical delivery

This study aims to prove the value of the polyoxazolines polymer family as surfactant in formulations for topical application and as an alternative to PEG overuse. The amphiphilic polyoxazolines (POx) were demonstrated to have less impact on cell viability of mice fibroblasts (NIH3T3) than their PEG counterparts. Mixed micelles, made of POx and phosphatidylcholine, were manufactured using thin film and high pressure homogenizer process. The mixed micelles were optimized to produce nanosized vesicles of about 20 nm with a spherical shape and stable over 28 days. The natural lipophilic antioxidant, quercetin, was successfully encapsulated (encapsulation efficiency 94 ± 4% and drug loading 3.6 ± 0.2%) in the mixed micelles with no morphological variation. Once loaded in the formulation, the quercetin impact on cell viability of NIH3T3 was decreased while its antioxidant activity remained unchanged. This work highlights the capacity of amphiphilic POx to create, in association with phospholipids, stable nanoformulations which show promise for topical delivery of antioxidant and ensure skin protection against oxidative stress.

Vitis vinifera L. Leaf Extract Inhibits In Vitro Mediators of Inflammation and Oxidative Stress Involved in Inflammatory-Based Skin Diseases

Psoriasis is a chronic cutaneous condition characterized by the release of pro-inflammatory mediators and oxidative stress. The reduction of these factors is currently the most effective strategy to inhibit the symptoms of pathology. Antioxidants from natural sources are increasingly used to improve skin conditions. Dried red leaves from grapevine (Vitis vinifera L., cv Teinturiers) showed anti-inflammatory and anti-bacterial activities, but their possible effects on keratinocytes have not been previously investigated. In this study we tested the ability of a water extract from grapevine leaves (VVWE) to inhibit inflammatory conditions in human keratinocytes (HaCaT cells), challenged with proinflammatory (tumor necrosis factor-α (TNF-α) or lipopolysaccharide (LPS)) or prooxidant (ultraviolet B radiation (UVB) or H₂O₂) mediators. VVWE inhibited interleukin-8 (IL-8) secretion induced by proinflammatory stimuli, acting on the IL-8 promoter activity, but the effect was lower when prooxidant mediators were used. The effect was partly explained by the reduction of nuclear factor-κB (NF-κB)-driven transcription and nuclear translocation. Furthermore, vascular endothelial growth factor (VEGF) secretion, a regulator of angiogenesis, was inhibited by VVWE, but not matrix metalloproteinase-9 (MMP-9), a protease involved in matrix remodeling. VVWE, assayed on Franz diffusion cell system, showed a marked reduction of High Performance Liquid Chromatography (HPLC)-identified compounds. Pure molecules individually failed to reduce TNF-α-induced IL-8 release, suggesting synergistic effects or the presence of other bioactive compounds still unknown.

In Vitro Drug Dissolution/Permeation Testing of Nanocarriers for Skin Application: a Comprehensive Review

This review highlights in vitro drug dissolution/permeation methods available for topical and transdermal nanocarriers that have been designed to modulate the propensity of drug release, drug penetration into skin, and permeation into systemic circulation. Presently, a few of USFDA-approved in vitro dissolution/permeation methods are available for skin product testing with no specific application to nanocarriers. Researchers are largely utilizing the in-house dissolution/permeation testing methods of nanocarriers. These drug release and permeation methods are pending to be standardized. Their biorelevance with reference to in vivo plasma concentration-time profiles requires further exploration to enable translation of in vitro data for in vivo or clinical performance prediction.

Application of pH-Responsive Fucoidan/Chitosan Nanoparticles to Improve Oral Quercetin Delivery

Polymeric nanoparticles based on fucoidan and chitosan were developed to deliver quercetin as a novel functional food. Through the polyelectrolyte self-assembly method, fucoidan/chitosan (F/C) nanoparticles were obtained with three different weight ratios (1/1, 3/1, and 5/1). The content of quercetin in the fucoidan/chitosan nanoparticles was in the range 110 ± 3 to 335 ± 4 mg·mL^-1, with the increase of weight ratio of fucoidan to chitosan in the nanoparticle. Physicochemically stable nanoparticles were obtained with a particle size within the 300⁻400 nm range and surface potential higher than +30 mV for the 1F/1C ratio nanoparticle and around -30 mV for the 3F/1C and 5F/1C ratios nanoparticles. The 1F/1C ratio nanoparticle became larger and more unstable as the pH increased from 2.5 to 7.4, while the 3F/1C and 5F/1C nanoparticles retained their initial characteristics. This result indicates that the latter nanoparticles were stable along the gastrointestinal tract. The quercetin-loaded fucoidan/chitosan nanoparticles showed strong antioxidant activity and controlled release under simulated gastrointestinal environments (in particular for the 3F/1C and 5F/1C ratios), preventing quercetin degradation and increasing its oral bioavailability.

Stimuli-responsive lipid-based magnetic nanovectors increase apoptosis in glioblastoma cells through synergic intracellular hyperthermia and chemotherapy

In this study, taking into consideration the limitations of current treatments of glioblastoma multiforme, we fabricated a biomimetic lipid-based magnetic nanovector with a good loading capacity and a sustained release profile of the encapsulated chemotherapeutic drug, temozolomide. These nanostructures demonstrated an enhanced release after exposure to an alternating magnetic field, and a complete release of the encapsulated drug after the synergic effect of low pH (4.5), increased concentration of hydrogen peroxide (50 μM), and increased temperature due to the applied magnetic field. In addition, these nanovectors presented excellent specific absorption rate values (up to 1345 W g-1) considering the size of the magnetic component, rendering them suitable as potential hyperthermia agents. The presented nanovectors were progressively internalized in U-87 MG cells and in their acidic compartments (i.e., lysosomes and late endosomes) without affecting the viability of the cells, and their ability to cross the blood-brain barrier was preliminarily investigated using an in vitro brain endothelial cell-model. When stimulated with alternating magnetic fields (20 mT, 750 kHz), the nanovectors demonstrated their ability to induce mild hyperthermia (43 °C) and strong anticancer effects against U-87 MG cells (scarce survival of cells characterized by low proliferation rates and high apoptosis levels). The optimal anticancer effects resulted from the synergic combination of hyperthermia chronic stimulation and the controlled temozolomide release, highlighting the potential of the proposed drug-loaded lipid magnetic nanovectors for treatment of glioblastoma multiforme.

Cellular Uptake and Intracellular Antioxidant Activity of Zein/Chitosan Nanoparticles Incorporated with Quercetin

In this work, zein/chitosan nanoparticles (ZCPs-Q) were developed for encapsulating quercetin to overcome its lower water solubility and instability, and to concomitantly enhance its cellular uptake and intracellular antioxidant activity. This strategy enhanced quercetin solubility 753.6 and 9.95 times in water and PBS (7.4), respectively, and quercetin encapsulated in ZCPs remained stable after UV irradiation and heat treatment. ZCPs-Q could significantly attenuate AAPH induced erythrocyte hemolysis through the inhibition of ROS generation. It restored intracellular antioxidant enzyme (SOD and GSH-Px) activities to normal levels and inhibited intracellular malondialdehyde (MDA) formation. Simultaneously, ZCPs-Q showed a strong antioxidant activity in HepG2 cells with an EC₅₀ value of 31.18 μg/mL, which was lower than free quercetin's 41.02 μg/mL. ZCPs enhanced the uptake efficiency of quercetin in Caco-2 cells, which contributed to the improvement of cellular antioxidant activities (CAA) evaluated with the CAA assay and AAPH-induced erythrocyte hemolysis assay. The designed route is particularly suitable for the encapsulation of water-insoluble nutraceuticals and for enhancing cell uptake and CAA.

Nanostructured lipid carriers: A potential use for skin drug delivery systems

Skin application of pharmaceutical products is one of the methods used for drug administration. The problem of limited drug penetration via topical application makes searching for safe drug carriers that will provide an expected therapeutic effect of utmost importance. Research into safe drug carriers began with liposome structures, paving the way for work with nanocarriers, which currently play a large role as drug vehicles. Nanostructured lipid carriers (NLC) consist of blended solid and liquid lipids (oils) dispersed in an aqueous solution containing a surfactant. These carriers have many advantages: good biocompatibility, low cytotoxicity, high drug content; they enhance a drug's stability and have many possibilities of application (oral, intravenous, pulmonary, ocular, dermal). The following article presents properties, methods of preparation and tests to assess the quality and toxicity of NLC. This analysis indicates the possibility of using NLC for dermal and transdermal drug application.

Enhancing the Delivery of Chemotherapeutics: Role of Biodegradable Polymeric Nanoparticles

While pharmaceutical drugs have revolutionized human life, there are several features that limit their full potential. This review draws attention to some of the obstacles currently facing the use of chemotherapeutic drugs including low solubility, poor bioavailability and high drug dose. Overcoming these issues will further enhance the applicability and potential of current drugs. An emerging technology that is geared towards improving overall therapeutic efficiency resides in drug delivery systems including the use of polymeric nanoparticles which have found widespread use in cancer therapeutics. These polymeric nanoparticles can provide targeted drug delivery, increase the circulation time in the body, reduce the therapeutic indices with minimal side-effects, and accumulate in cells without activating the mononuclear phagocyte system (MPS). Given the inroads made in the field of nanodelivery systems for pharmaceutical applications, it is of interest to review and emphasize the importance of Polymeric nanocarrier system for drug delivery in chemotherapy.

Nanosized soy phytosome-based thermogel as topical anti-obesity formulation: an approach for acceptable level of evidence of an effective novel herbal weight loss product

PURPOSE

Herbal supplements are currently available as a safer alternative to manage obesity, which has become a rising problem over the recent years. Many chemical drugs on the market are designed to prevent or manage obesity but high cost, low efficacy, and multiple side effects limit its use. Nano lipo-vesicles phytosomal thermogel of Soybean, Glycine max (L.) Merrill, was formulated and evaluated in an attempt to investigate its anti-obesity action on body weight gain, adipose tissue size, and lipid profile data.

METHODS

Three different techniques were used to prepare phytosome formulations including solvent evaporation, cosolvency, and salting out. The optimized phytosome formulation was then selected using Design Expert® (version 7.0.0) depending on the highest entrapment efficiency, minimum particle size (PS), and maximum drug release within 2 hours as responses for further evaluation. The successful phytosome complex formation was investigated by means of Fourier-transform infrared spec troscopy and determination of PS and zeta potential. Phytosome vesicles' shape was evaluated using transmission electron microscope to ensure its spherical shape. After characterization of the optimized phytosome formulation, it was incorporated into a thermogel formulation. The obtained phytosomal thermogel formulation was evaluated for its clarity, homogeneity, pH, and gel transformation temperature besides rheology behavior and permeation study. An in vivo study was done to investigate the anti-weight-gain effect of soy phytosomal ther mogel.

RESULTS

EE was found to be >99% for all formulations, PS ranging from 51.66-650.67 while drug release was found to be (77.61-99.78) in range. FTIR and TEM results confirmed the formation of phytosome complex. In vivo study showed a marked reduction in body weight, adipose tissue weight and lipid profile.

CONCLUSION

Concisely, soy phytosomal thermogel was found to have a local anti-obesity effect on the abdomen of experimental male albino rats with a slight systemic effect on the lipid profile data.

Estimating the Aqueous Solubility of Pharmaceutical Hydrates

Estimation of crystalline solute solubility is well documented throughout the literature. However, the anhydrous crystal form is typically considered with these models, which is not always the most stable crystal form in water. In this study, an equation which predicts the aqueous solubility of a hydrate is presented. This research attempts to extend the utility of the ideal solubility equation by incorporating desolvation energetics of the hydrated crystal. Similar to the ideal solubility equation, which accounts for the energetics of melting, this model approximates the energy of dehydration to the entropy of vaporization for water. Aqueous solubilities, dehydration and melting temperatures, and log P values were collected experimentally and from the literature. The data set includes different hydrate types and a range of log P values. Three models are evaluated, the most accurate model approximates the entropy of dehydration (ΔSd) by the entropy of vaporization (ΔSvap) for water, and utilizes onset dehydration and melting temperatures in combination with log P. With this model, the average absolute error for the prediction of solubility of 14 compounds was 0.32 log units.

Formulations based on solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) for cutaneous use: A review

Cutaneous use of lipid nanoparticles (solid lipid nanoparticles, SLN and nanostructured lipid carriers, NLC) has been showing promising results. These systems consist of low viscosity aqueous dispersions, being usually employed by means of semi-solid formulations with adequate consistency for skin application. This review addresses the cutaneous use of lipid nanoparticles for therapeutic and cosmetic applications. Initially, general information related to pharmaceutical semi-solid formulations is presented. Afterwards, the effects of SLN and NLC on the skin, and technological aspects related to semi-solid systems based on SLN or NLC are described. Finally, the most relevant studies related to the formulations based on SLN and NLC, for cosmetic and therapeutic applications, are reported. Notwithstanding the cutaneous use of SLN and NLC has been proposed for both local and transdermal delivery, the reported studies show promising results only for local application. In this sense, more research is required to better understanding the interaction mechanisms of lipid nanoparticles with skin lipids. Furthermore, the development of standard methods for skin experiments with nanoparticles is necessary.

Advances in the design of solid lipid nanoparticles and nanostructured lipid carriers for targeting brain diseases

Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) comprise a category of versatile drug delivery systems that have been used in the biomedical field for >25years. SLNs and NLCs have been used for the treatment of various diseases including cardiovascular and cerebrovascular, and are considered a standard treatment for the latter, due to their inherent ability to cross the blood brain barrier (BBB). In this review, a presentation of the most important brain diseases (brain cancer, ischemic stroke, Alzheimer's disease, Parkinson's disease and multiple sclerosis) is approached, followed by the basic fabrication techniques of SLNs and NLCs. A detailed description of the reported studies of the last seven years, of active and passive targeting SLNs and NLCs for the treatment of glioblastoma multiforme and of other brain cancers, as well as for the treatment of neurodegenerative diseases is also carried out. Finally, a brief description of the advantages, the disadvantages, and the future perspectives in the use of these nanocarriers is reported, aiming at giving an insight of the limitations that have to be overcome in order to result in a delivery system with high therapeutic efficacy and without the limitations of the existing nano-systems.

In vitro evaluation of α-lipoic acid-loaded lipid nanocapsules for topical delivery

This study aimed at in vitro evaluation of α-lipoic acid-loaded lipid nanocapsules for topical delivery, which was prepared by hot high-pressure homogenisation. Stable particles could be formed and particle size was 148.54 ± 2.31 nm with polydispersity index below 0.15. Encapsulation efficiency and drug loading of α-lipoic acid were 95.23 ± 0.45% and 2.81 ± 0.37%. Antioxidant study showed α-lipoic acid could be protected by lipid nanocapsules without loss of antioxidant activity. Sustained release of α-lipoic acid from lipid nanocapsules was obtained and cumulative release was 62.18 ± 1.51%. In vitro percutaneous study showed the amount of α-lipoic acid distributed in skin was 1.7-fold than permeated. Cytotoxicity assay and antioxidant activity on L929 cells indicated this formulation had low cytotoxicity and ability of protecting cells from oxidative damage within specific concentration. These studies suggested α-lipoic acid-loaded lipid nanocapsules could be potential formulation for topical delivery.

Promises of a biocompatible nanocarrier in improved brain delivery of quercetin: Biochemical, pharmacokinetic and biodistribution evidences

In various neurological disorders, antioxidants are frequently prescribed along with the specific treatment modalities. One such promising natural flavonoid is quercetin, offering better outcomes than established vitamins E and C. Though with immense promises, various challenges like poor oral-bioavailability (<2%), extensive first-pass metabolism, poor brain permeability, hydrophobic nature and physiological pH instability hinder its proper usage. Hence, it was planned to prepare quercetin-loaded nano lipidic carriers (NLCs) employing biocompatible components like phospholipids and tocopherol acetate for enhanced brain delivery. The outcomes were also compared with solid lipid nanoparticles (SLNs) of comparable composition. Both the nanocolloids offered better drug loading and controlled drug release with appreciable stability. In vitro antioxidant performance was improved after encapsulation in nanoparticles and the nanoparticles were substantially uptaken by Caco-2 cells. The difference in outcomes was vivid in pharmacokinetic studies, where nanoparticles, esp. NLCs substantially enhanced the relative bioavailability (approx. 6 folds), biological residence (2.5 times) and appreciably retarded the drug clearance (approx. 6 folds). On the other hand, both nanoparticles were able to substantially deliver the drug to brain. NLCs were observed to enhance the brain permeability of drug in a noticeable manner. In Conclusion, SLNs/NLCs can offer a better-platform for brain-delivery of quercetin.

Polymeric nanospheres for topical delivery of vitamin D3

This study investigates the potential application of polymeric nanospheres (known as TyroSpheres) as a formulation carrier for topical delivery of cholecalciferol (i.e., Vitamin D3, VD3) with the goal to improve the skin delivery and stability of VD3. High drug loading and binding efficiencies were obtained for VD3 when loaded in TyroSpheres. VD3 was released from TyroSpheres in a sustained manner and was delivered across the stratum corneum, which occurred independent of the initial drug loading. An ex vivo skin distribution study showed that TyroSphere formulations delivered 3-10μg of active into the epidermis which was significantly higher than that delivered from Transcutol^® (the control vehicle). In addition, an in vitro cytotoxicity assay using keratinocytes confirmed that VD3 encapsulation in the nanoparticles did not alter the drug activity. Photodegradation of VD3 followed zero-order kinetics. TyroSpheres were able to protect the active against hydrolysis and photodegradation, significantly enhancing the stability of VD3 in the topical formulation.

Development and evaluation of nanostructured lipid carrier-based hydrogel for topical delivery of 5-fluorouracil

The aim of this study was to develop a nanostructured lipid carrier (NLC)-based hydrogel and study its potential for the topical delivery of 5-fluorouracil (5-FU). Precirol® ATO 5 (glyceryl palmitostearate) and Labrasol® were selected as the solid and liquid lipid phases, respectively. Poloxamer 188 and Solutol® HS15 (polyoxyl-15-hydroxystearate) were selected as surfactants. The developed lipid formulations were dispersed in 1% Carbopol® 934 (poly[acrylic acid]) gel medium in order to maintain the topical application consistency. The average size, zeta potential, and polydispersity index for the 5-FU-NLC were found to be 208.32±8.21 nm, -21.82±0.40 mV, and 0.352±0.060, respectively. Transmission electron microscopy study revealed that 5-FU-NLC was <200 nm in size, with a spherical shape. In vitro drug permeation studies showed a release pattern with initial burst followed by sustained release, and the rate of 5-FU permeation was significantly improved for 5-FU-NLC gel (10.27±1.82 μg/cm2/h) as compared with plain 5-FU gel (2.85±1.12 μg/cm2/h). Further, skin retention studies showed a significant retention of 5-FU from the NLC gel (91.256±4.56 μg/cm2) as compared with that from the 5-FU plain gel (12.23±3.86 μg/cm2) in the rat skin. Skin irritation was also significantly reduced with 5-FU-NLC gel as compared with 5-FU plain gel. These results show that the prepared 5-FU-loaded NLC has high potential to improve the penetration of 5-FU through the stratum corneum, with enormous retention and with minimal skin irritation, which is the prerequisite for topically applied formulations.

Current application of phytocompound-based nanocosmeceuticals for beauty and skin therapy

Phytocompounds have been used in cosmeceuticals for decades and have shown potential for beauty applications, including sunscreen, moisturizing and antiaging, and skin-based therapy. The major concerns in the usage of phyto-based cosmeceuticals are lower penetration and high compound instability of various cosmetic products for sustained and enhanced compound delivery to the beauty-based skin therapy. To overcome these disadvantages, nanosized delivery technologies are currently in use for sustained and enhanced delivery of phyto-derived bioactive compounds in cosmeceutical sectors and products. Nanosizing of phytocompounds enhances the aseptic feel in various cosmeceutical products with sustained delivery and enhanced skin protecting activities. Solid lipid nanoparticles, transfersomes, ethosomes, nanostructured lipid carriers, fullerenes, and carbon nanotubes are some of the emerging nanotechnologies currently in use for their enhanced delivery of phytocompounds in skin care. Aloe vera, curcumin, resveratrol, quercetin, vitamins C and E, genistein, and green tea catechins were successfully nanosized using various delivery technologies and incorporated in various gels, lotions, and creams for skin, lip, and hair care for their sustained effects. However, certain delivery agents such as carbon nanotubes need to be studied for their roles in toxicity. This review broadly focuses on the usage of phytocompounds in various cosmeceutical products, nanodelivery technologies used in the delivery of phytocompounds to various cosmeceuticals, and various nanosized phytocompounds used in the development of novel nanocosmeceuticals to enhance skin-based therapy.

Molecular targets of quercetin with anti-inflammatory properties in atopic dermatitis

Atopic dermatitis (AD) is an inflammatory skin disease. Over the past few decades, AD has become more prevalent worldwide. Quercetin, a naturally occurring polyphenol, shows antioxidant, anti-inflammatory, and antiallergic activities. Several recent clinical and preclinical findings suggest quercetin as a promising natural treatment for inflammatory skin diseases. Significant progress in elucidating the molecular mechanisms underlying the anti-AD properties of quercetin has been achieved in the recent years. Here, we discuss the use of quercetin as treatment for AD, with a particular focus on the molecular basis of its effect. We also briefly discuss the approaches to improve the bioavailability of quercetin.

Quality by design case study 1: Design of 5-fluorouracil loaded lipid nanoparticles by the W/O/W double emulsion - Solvent evaporation method

With Quality by Design (QbD), a systematic approach involving design and development of all production processes to achieve the final product with a predetermined quality, you work within a design space that determines the critical formulation and process parameters. Verification of the quality of the final product is no longer necessary. In the current study, the QbD approach was used in the preparation of lipid nanoparticle formulations to improve skin penetration of 5-Fluorouracil, a widely-used compound for treating non-melanoma skin cancer. 5-Fluorouracil-loaded lipid nanoparticles were prepared by the W/O/W double emulsion - solvent evaporation method. Artificial neural network software was used to evaluate the data obtained from the lipid nanoparticle formulations, to establish the design space, and to optimize the formulations. Two different artificial neural network models were developed. The limit values of the design space of the inputs and outputs obtained by both models were found to be within the knowledge space. The optimal formulations recommended by the models were prepared and the critical quality attributes belonging to those formulations were assigned. The experimental results remained within the design space limit values. Consequently, optimal formulations with the critical quality attributes determined to achieve the Quality Target Product Profile were successfully obtained within the design space by following the QbD steps.

Solid-State and Solution Characterization of Myricetin

Myricetin (MYR) is a natural compound that has been investigated as a chemopreventative agent. MYR has been shown to suppresses ultraviolet B (UVB)-induced cyclooxygenase-2 (COX-2) protein expression and reduce the incidence of UVB-induced skin tumors in mice. Despite MYR's promise as a therapeutic agent, minimal information is available to guide the progression of formulations designed for future drug development. Here, data is presented describing the solid-state and solution characterization of MYR. Investigation into the solid-state properties of MYR identified four different crystal forms, two hydrates (MYR I and MYR II) and two metastable forms (MYR IA and MYR IIA). From solubility studies, it was evident that all forms are very insoluble (<5 μg/ml) in pure water. MYR I was found to be the most stable form at 23, 35, and 56°C. Stability determination indicated that MYR undergoes rapid apparent first-order degradation under basic pH conditions, and that degradation was influenced by buffer species. Apparent first-order degradation was also seen when MYR was introduced to an oxidizing solution. Improved stability was achieved after introducing 0.1% antioxidants to the solution. MYR was found to have good stability following exposure to ultraviolet radiation (UVR), which is a consideration for topical applications. Finally, a partitioning study indicated that MYR possess a log P of 2.94 which, along with its solid-state properties, contributes to its poor aqueous solubility. Both the solid-state properties and solution stability of MYR are important to consider when developing future formulations.