Emollients in dermatological creams: Early evaluation for tailoring formulation and therapeutic performance

The targeted choice of the emollient of a cream determines its physicochemical properties and clinical effectiveness. This work researched the effects of emollient properties on the final characteristics and potential performance of oil-in-water dermatological creams. Seven emollients with different chemical characteristics and structures (alkane, triglyceride, ether, silicone, vegetable oils, and mineral oil) were tested in a model formulation. Early stability, pH, droplet size distribution, rheology, tackiness, adhesivity, spreadability, tribology, and release profile of a lipophilic substance model (in Franz cells, through a synthetic membrane, for six hours) were assessed. The creams had acid epicutaneous pH and a "shear-thinning" "solid-like" viscoelastic behavior. Among the seven emollients' properties, polarity, density, and viscosity were the most influential. Droplet parameters were the most impacted, pH and release were moderately affected, and the textural properties were lowly to moderately impacted. The emollient substitution in the model formulation affected the experimental parameters differently, allowing formulation optimization and tailoring its potential therapeutic performance regarding drug release, coadjutant effects, and dwell time on the skin. By looking at the creams' characteristics, it was possible to select the best-suited emollients for releasing a lipophilic drug, applying on painful skin, and formulation in wash-off products or leave-on protective barrier creams.

Combining protection with skin health: In vivo studies of an innovative gelatin/tannic acid-based hydrogel patch to prevent PPE-related skin lesions

The prolonged use of Personal Protective Equipment (PPE) can lead to skin problems due to persistent pressure, friction, and tension. This issue has prompted the exploration of solutions to protect the skin while maintaining the effectiveness of the PPE. This study aimed to evaluate the in vivo effectiveness of a gelatin/tannic acid-based hydrogel patch positioned beneath a mask to alleviate skin damage resulting from mask-wearing. To understand the pressure exerted by PPE, in vitro tests were conducted to measure the tensile strength of three types of facial masks. The FFP2 masks exhibited the highest tensile strength and were selected for subsequent in vivo biometric investigations. Biometric parameters were evaluated using the Flir E50bx® thermographic camera, Corneometer®, MoistureMap®, Sebumeter®, Tewameter®, and VISIA® systems. The results showed that when the hydrogel patch was used under the mask, there were no significant differences in facial skin temperature, sebum levels, or TEWL values (p > 0.05). However, a statistically significant increase in skin hydration and a decrease in frontal redness (p < 0.05) were observed. Consumer acceptance was assessed through sensory analysis questionnaires. In summary, the observed attenuation of physiological changes in the facial area and the positive consumer feedback suggest that this polymeric film-forming system is a simple yet effective solution to prevent PPE use-related skin issues.

New Horizons in Dermal and Transdermal Drug Delivery Systems

Dermal and transdermal drug delivery represents an important strategy to target drugs towards the site of action or to noninvasively enhance treatment activity, circumventing the hepatic first passage and reducing toxicity [...].

Primary Prevention of Canine Atopic Dermatitis: Breaking the Cycle-A Narrative Review

Canine atopic dermatitis (cAD) is a common and distressing skin condition in dogs, affecting up to 30% of the canine population. It not only impacts their quality of life but also that of their owners. Like human atopic dermatitis (hAD), cAD has a complex pathogenesis, including genetic and environmental factors. Current treatments focus on managing clinical signs, but they can be costly and have limitations. This article emphasizes the importance of preventing cAD from developing in the first place. Understanding the role of the skin's protective barrier is crucial, as its dysfunction plays a vital role in both hAD and cAD. hAD prevention studies have shown promising results in enhancing the skin barrier, but more research is needed to support more robust conclusions. While hAD primary prevention is currently a focal point of intensive investigation in human medicine, research on cAD primary prevention remains under-researched and almost non-existent. Pioneering effective prevention strategies for cAD holds immense potential to enhance the quality of life for both dogs and their owners. Additionally, it bears the promise of a translational impact on human research. Hence, further exploration of this crucial topic is not only relevant but also timely and imperative, warranting support and encouragement.

Biomimetic Adhesive Micropatterned Hydrogel Patches for Drug Release

The optimized physical adhesion between bees' leg hairs and pollen grains-whereby the latter's diameter aligns with the spacing between the hairs-has previously inspired the development of a biomimetic drug dressing. Combining this optimized process with the improved natural mussels' adhesion in wet environments in a dual biomimetic process, it is herein proposed the fabrication of a natural-derived micropatterned hydrogel patch of methacrylated laminarin (LAM-MET), with enriched drug content and improved adhesiveness, suitable for applications like wound healing. Enhanced adhesion is accomplished by modifying LAM-MET with hydroxypyridinone groups, following the patch microfabrication by soft lithography and UV/vis-irradiation, resulting in a membrane with micropillars with a high aspect ratio. Following the biomimetics rational, a drug patch is engineered by combining the microfabricated dressing with drug particles milled to fit the spaces between pillars. Controlled drug release is achieved, together with inherent antibacterial activity against Escherichia coli and Pseudomonas aeruginosa, and enhanced biocompatibility using the bare micropatterned patches. This new class of biomimetic dressings overcomes the challenges of current patches, like poor mechanical properties and biocompatibility, limited adhesiveness and drug dosage, and lack of prolonged antimicrobial activity, opening new insights for the development of high drug-loaded dressings with improved patient compliance.

New Insights into the Dermocosmetic Potential of the Red Seaweed Gelidium corneum

This work addresses the potential of the red seaweed Gelidium corneum as a source of bioactive ingredients for skin health and wellness in response to the growing awareness regarding the significance of sustainable strategies in developing new nature-based dermocosmetic products. Hydroalcoholic extracts from the dried biomass were subjected to sequential liquid-liquid partitions, affording five different fractions (F1-F5). Their cosmetic potential was assessed through a set of in vitro assays concerning their antioxidant, photoprotective, and healing properties. Additionally, their cytotoxicity in HaCaT cells and their capacity to induce inflammation in RAW 264.7 cells were also evaluated. As a proof-of-concept, O/W emulsions were prepared, and emulsion stability was assessed by optical microscopy, droplet size analysis, centrifugation tests, and rheology analysis. Furthermore, in vivo tests were conducted with the final formulation to assess its antioxidant capacity. At subtoxic concentrations, the most lipophilic fraction has provided photoprotection against UV light-induced photooxidation in HaCaT cells. This was conducted together with the aqueous fraction, which also displayed healing capacities. Regarding the physical and stability assays, the best performance was achieved with the formulation containing 1% aqueous extract, which exhibited water retention and antioxidant properties in the in vivo assay. In summary, Gelidium corneum displayed itself as a potential source of bioactive ingredients with multitarget properties for dermatological use.

Design and Characterization of an Ethosomal Gel Encapsulating Rosehip Extract

Rising environmental awareness drives green consumers to purchase sustainable cosmetics based on natural bioactive compounds. The aim of this study was to deliver Rosa canina L. extract as a botanical ingredient in an anti-aging gel using an eco-friendly approach. Rosehip extract was first characterized in terms of its antioxidant activity through a DPPH assay and ROS reduction test and then encapsulated in ethosomal vesicles with different percentages of ethanol. All formulations were characterized in terms of size, polydispersity, zeta potential, and entrapment efficiency. Release and skin penetration/permeation data were obtained through in vitro studies, and cell viability was assessed using an MTT assay on WS1 fibroblasts. Finally, ethosomes were incorporated in hyaluronic gels (1% or 2% w/v) to facilitate skin application, and rheological properties were studied. Rosehip extract (1 mg/mL) revealed a high antioxidant activity and was successfully encapsulated in ethosomes containing 30% ethanol, having small sizes (225.4 ± 7.0 nm), low polydispersity (0.26 ± 0.02), and good entrapment efficiency (93.41 ± 5.30%). This formulation incorporated in a hyaluronic gel 1% w/v showed an optimal pH for skin application (5.6 ± 0.2), good spreadability, and stability over 60 days at 4 °C. Considering sustainable ingredients and eco-friendly manufacturing technology, the ethosomal gel of rosehip extract could be an innovative and green anti-aging skincare product.

Prevention of skin lesions caused by the use of protective face masks by an innovative gelatin-based hydrogel patch: design and in vitro studies

The recent Covid-19 pandemics led to the increased use of facial masks, which can cause skin lesions due to continuous pressure, tension and friction forces on the skin. A preventive approach is the inclusion of dressings between the face and the mask. However, there are still uncertainties about the protective effect of dressings and whether their use compromises the efficiency of masks. The current study aimed to develop and test the efficacy of a gelatin-based hydrogel patch to be placed between the mask and the facial area. Design of Experiment with a Quality by Design approach tools were used in the patch development and in vitro characterization was performed through rheological evaluation, ATR-FTIR and molecular docking studies. Furthermore, tribology studies were performed to test the patch performance. The results showed that the addition of excipients enhanced gelation temperature, elasticity and adhesiveness parameters. The interactions between excipients were confirmed by ATR-FTIR and molecular docking. The tribology assay revealed similar friction values at room and physiological temperature, and when testing different skin types. In conclusion, the physical properties and the performance evaluation reported in this study indicate that this innovative film-forming system can be used to prevent skin lesions caused by the continuous use of protective masks.

Fabrication of antibacterial and biocompatible 3D printed Manuka-Gelatin based patch for wound healing applications

Development of multifunctional 3D patches with appropriate antibacterial and biocompatible properties is needed to deal with wound care regeneration. Combining gelatin-based hydrogel with a well-known natural antibacterial honey (Manuka honey, MH) in a 3D patch can provide improved printability and at the same time provide favourable biological effects that may be useful in regenerative wound treatment. In this study, an antibacterial Manuka-Gelatin 3D patches was developed by an extrusion-based printing process, with controlled porosity, high shape fidelity, and structural stability. It was demonstrated the antibacterial activity of Manuka-Gelatin 3D patches against both gram-positive bacteria (S. epidermidis and S. aureus) and gram-negative (E. coli), common in wound infection. The 3D Manuka-Gelatin base patches demonstrated antibacterial activity, and moreover enhanced the proliferation of human dermal fibroblasts and human epidermal keratinocytes, and promotion of angiogenesis. Moreover, the ease of printing achieved by the addition of honey, coupled with the interesting biological response obtained, makes this 3D patch a good candidate for wound healing applications.

Repurposing of Marine Raw Materials in the Formulation of Innovative Plant Protection Products

Over the years, the growth of the world population has caused a huge agricultural production to support the population's needs. Since plant protection products are essential to preserve agricultural crops and to optimize vital plant processes, it is crucial to use more sustainable, biodegradable, and biocompatible raw materials, without harming the environment and human health. Although the development of new plant protection products is a costly process, the environmental benefits should be considered. In this context, marine raw materials obtained as byproducts of fishing industries, possessing a wide variety of physicochemical and biological properties, can serve as a promising source of such materials. They have a high potential for developing alternative and safe formulations for agricultural applications, not only as biocompatible excipients but also as effective and selective, or even both. It is also possible to promote a synergistic effect between an active substance and the biological activity of the marine polymer used in the formulation, enabling plant protection products with lower concentrations of the active substances. Thus, this review addresses the repurposing of marine raw materials for the development of innovative plant protection products, focusing on micro- and nanoparticulate formulations, to protect the environment through more ecological and sustainable strategies.

Innovative, Sugar-Free Oral Hydrogel as a Co-administrative Vehicle for Pediatrics: a Strategy to Enhance Patient Compliance

Palatability and swallowability in the pediatric population are perceived as true challenges in the oral administration of medication. Pediatric patients have high sensitivity to taste and reduced ability to take solid dosage forms, which can often lead to a poor therapeutic compliance. It is crucial to find new strategies to simplify the oral administration of drugs to children. The present paper reports the development of a new hydrogel vehicle adapted to the pediatric population. Several polymers with similar properties were selected and adjustments were made to obtain the desired characteristics of the final product. The developed formulations were studied for organoleptic properties, rheology, mucoadhesion properties, preservative efficacy, and stability. Physical and chemical compatibilities between the vehicle and several drugs/medicines, at the time of administration, were also studied. Six final formulations with different polymers, odor, and color were chosen, and no known interactions with medications were observed. The proposed new oral vehicles are the first sugar-free vehicle hydrogels designed to make the intake of oral solid forms a more pleasant and safer experience for pediatric patients.

Nanomaterials in hair care and treatment

Hair care and treatment has evolved significantly through the years as new formulations are continuously being explored in an attempt to meet the demand in cosmetic and medicinal fields. While standard hair care procedures include hair washing, aimed at hair cleansing and maintenance, as well as hair dyeing and bleaching formulations for hair embellishment, modern hair treatments are mainly focused on circumventing hair loss conditions, strengthening hair follicle properties and treat hair infestations. In this regard, active compounds (ACs) included in hair cosmetic formulations include a vast array of hair cleansing and hair dye molecules, and typical hair treatments include anti-hair loss ACs (e.g. minoxidil and finasteride) and anti-lice ACs (e.g. permethrin). However, several challenges still persist, as conventional AC formulations exhibit sub-optimal performance and some may present toxicity issues, calling for an improved design of formulations regarding both efficacy and safety. More recently, nano-based strategies encompassing nanomaterials have emerged as promising tailored approaches to improve the performance of ACs incorporated into hair cosmetics and treatment formulations. The interest in using these nanomaterials is based on account of their ability to: (1) increase stability, safety and biocompatibility of ACs; (2) maximize hair affinity, contact and retention, acting as versatile biointerfaces; (3) enable the controlled release of ACs in both hair and scalp, serving as prolonged AC reservoirs; besides offering (4) hair follicle targeting features attending to the possibility of surface tunability. This review covers the breakthrough of nanomaterials for hair cosmetics and hair treatment, focusing on organic nanomaterials (polymer-based and lipid-based nanoparticles) and inorganic nanomaterials (nanosheets, nanotubes and inorganic nanoparticles), as well as their applications, highlighting their potential as innovative multifunctional nanomaterials towards maximized hair care and treatment. STATEMENT OF SIGNIFICANCE: This manuscript is focused on reviewing the nanotechnological strategies investigated for hair care and treatment so far. While conventional formulations exhibit sub-optimal performance and some may present toxicity issues, the selection of improved and suitable nanodelivery systems is of utmost relevance to ensure a proper active ingredient release in both hair and scalp, maximize hair affinity, contact and retention, and provide hair follicle targeting features, warranting stability, efficacy and safety. This innovative manuscript highlights the advantages of nanotechnology-based approaches, particularly as tunable and versatile biointerfaces, and their applications as innovative multifunctional nanomaterials towards maximized hair care and treatment.

Open-source human skin model with an in vivo-like barrier for drug testing

There is a global trend towards the development of physiologically relevant in vitro skin models to reduce or replace animal testing in the evaluation of therapeutic drug candidates. However, only commercial reconstructed human epidermis models (RHEms) have undergone formal validation. Although these commercial models are suitable for a wide range of applications, they are costly, lack flexibility, and the protocols used to generate them are not transparent. In this study, we present an open-source full-thickness skin model (FTSm) and assess its potential for drug testing. The FTSms were developed using endogenous extracellular matrix to recreate the dermal compartment, avoiding animal-derived hydrogels. An RHEm based on an open-source protocol was also evaluated in parallel. The integrity of the skin barrier was analysed by challenging the surface with detergents and measuring cell viability as well as through trans-epithelial electrical resistance (TEER) measurements. Skin irritation studies were performed based on OECD guidelines and complemented with an evaluation of the impact on the skin barrier using TEER. The comparative permeation study of the developed models and a commercial membrane (Strat-M®) was performed using Franz diffusion cells and an infinite dose approach. The FTSm demonstrated structural and barrier properties comparable to the native human skin. Although the RHEm showed an overall better performance during drug testing, the FTSm presented better barrier properties than commercial models reported in the literature. These skin models can be a valuable contribution to accelerating the development and dissemination of alternatives to animal testing, circumventing the limitations of commercial models.

Nano- and microparticle-stabilized Pickering emulsions designed for topical therapeutics and cosmetic applications

Pickering emulsions are systems composed of two immiscible fluids, which are stabilized by solid organic or inorganic particles. These solid particles include a broad range of particles that can be used to stabilize Pickering emulsions. An improved resistance against coalescence and lower toxicity, against conventional emulsions stabilized by surfactants, make Pickering emulsions suitable candidates for numerous applications, such as catalysis, food, oil recovery, cosmetics, and pharmaceutical industries. In this article, we give an overview of Pickering emulsions focusing on topical applications. First, we reference the parameters that influence the stabilization of Pickering emulsions. Second, we discuss some of the already investigated topical applications of nano- and microparticles used to stabilize Pickering emulsions. Afterwards, we consider some of the most promising stabilizers of Pickering emulsions for topical applications. Ultimately, we carried out a brief analysis of toxicity and advances in future perspectives, highlighting the promising use of these emulsions in cosmetics and dermopharmaceutical formulations.

Palatability of pediatric formulations: do rats predict aversiveness?

BACKGROUND

The brief-access taste aversion (BATA) model has been used as an alternative taste assessment tool to human taste panels and became an important element of pharmaceutical drug development, especially regarding pediatric patient's compliance. This model has been validated, demonstrating a concentration-dependent sensitivity to drug aversiveness, as well as the capacity to evaluate the taste-masking effects of cyclodextrins. In the BATA model, samples are presented randomly to rodents in numerous sipper tubes and a lickometer is used for the electronic record of licks in a sophisticated approach.

OBJECTIVES

The aim of this study was to test possible drug taste-masking strategies. Additionally, we have used an alternative approach to measure the animal lick number in the presence of different compounds, non-simultaneously.

RESULTS

In the present work we show for the first time the licking profile of different compounds during the time course of the experiment, with each animal being exposed to only one bottle of testing product. To validate the experiments, quinine hydrochloride dihydrate (QHD) was used as a bitter reference compound.

CONCLUSION

The results obtained using this simple approach showed that aversiveness is dependent on the assay duration, and that it is possible to predict the aversiveness just by measuring the mass of the tested substance consumption. Moreover, some taste-masking strategies, such as those used in pediatric formulations and corresponding to the addition of sweeteners or flavors, cannot be predicted from rodents BATA model.

Diving into 3D (bio)printing: A revolutionary tool to customize the production of drug and cell-based systems for skin delivery

The incorporation of 3D printing technologies in the pharmaceutical industry can revolutionize its R&D, by providing a simple and rapid method to produce tailored one-off batches, each with customized dosages, different compounds, shapes, sizes, and adjusted release rates. Particularly, this type of technology can be advantageous for the development of topical and transdermal drug delivery systems, including patches and microneedles. The use of both systems as drug carriers offers advantages over the oral administration, but the possibility of skin irritation and sensitization, and the high production costs, may hinder the expansion of this market. In this context, 3D printing, a high-resolution technique, allows the design of high quality, personalized, complex and sophisticated structures, thus reducing the production costs and improving the patient compliance. This review covers the 3D printing concept and discusses the relevance of this technology to the pharmaceutical industry, with a special focus on the development of topical and transdermal products - patches and microneedles. The potential of 3D bioprinting for skin applications is also presented, highlighting the development of patch-like skin constructs for wound and burn treatment, and skin equivalents for in vitro research and drug development. Several recent studies were selected to support the relevance of the subjects addressed herein. Additionally, the limitations of these printing technologies are discussed, including regulatory, quality and safety issues.

A mathematical modeling strategy to predict the spreading behavior on skin of sustainable alternatives to personal care emollients

Spreadability is one of the most important physicochemical properties of cosmetic products, according to the consumer. Thus, it is fundamental to develop strategies with the aim to improve the knowledge and predict the behavior of alternatives to synthetic emollients. The main goal of this research article was to correlate different physicochemical attributes, namely spreading value, apparent viscosity, density, saponification value, iodine value, peroxide value, acid value and melting range, with the spreading behavior of sustainable alternatives for petrolatum and dimethicone. The sensitivity and adequacy of each parameter were statistically analyzed, and the models were built by forward selection. The two adjusted and optimized models include viscosity and density as parameters and, in the petrolatum case, the model further includes the melting range, which was also validated as a significant predictor. Furthermore, it was also possible to compare the data obtained with the consumer's perception of the spreading behavior of the studied raw materials. A strong correlation was observed, suggesting that these tools mirror the consumer opinion. The application of these mathematical models is a valuable tool to assist the entire replacement process, which usually is a time-consuming procedure.

Complying with the Guideline for Quality and Equivalence for Topical Semisolid Products: The Case of Clotrimazole Cream

Semisolids constitute a significant proportion of topical pharmaceutical dosage forms available on the market, with creams being considered profitable systems for releasing active substances into the skin. This work aimed at the development of a generic Clotrimazole topical cream, based on the assumptions that assist the development of such formulations. First, the critical parameters to obtain a final formulation as similar as possible to the reference product were defined. Then, the percentages of cetyl palmitate and octyldodecanol were identified as critical variables and chosen for optimization in further studies. A "quality by design" approach was then used to identify the effect of process variability on the structural and functional similarity (Q3) of the generic product qualitatively (Q1) and quantitatively (Q2). A two-factor central composite orthogonal design was applied and eleven different formulations were developed and subjected to physicochemical characterization and product performance studies. The results were used to estimate the influence of the two variables in the variation of the responses, and to determine the optimum point of the tested factors, using a design space approach. Finally, an optimized formulation was obtained and analysed in parallel with the reference. The obtained results agreed with the prediction of the chemometric analysis, validating the reliability of the developed multivariate models. The in vitro release and permeation results were similar for the reference and the generic formulations, supporting the importance of interplaying microstructure properties with product performance and stability. Lastly, based on quality targets and response constraints, optimal working conditions were successfully achieved.

Investigations of Olive Oil Industry By-Products Extracts with Potential Skin Benefits in Topical Formulations

The by-products of olive oil industry are a major ecological issue due to their phenolic content, highly toxic organic load, and low pH. However, they can be recovered and reused, since their components have antioxidant, anti-inflammatory, and photoprotector properties. In this work, oil-in-water creams containing three different olive oil industry by-products extracts were produced without the use of organic solvents. First, the extracts were thoroughly characterized in vitro for cytotoxicity, inhibition of skin enzymes, and antioxidant and photoprotection capacities. Safety studies were then performed, including ocular and skin irritation tests, ecotoxicity evaluation, and in vivo Human Repeat Insult Patch Test. The results obtained in this initial characterization supported the incorporation of the extracts in the cream formulations. After preparation, the creams were characterized for their organoleptic, physicochemical, droplet size and rheological properties, and microbial contamination. The results showed that all formulations were semi-solid creams, with stable pH, compatible with the skin, without microbial contamination, and with the expected droplet size range. The rheological analysis showed shear-thinning behavior with yield stress, with the viscosity decreasing with increasing shear rate. The oscillatory results suggest that the creams have a strong network structure, being easily rubbed into the skin. Finally, compatibility, acceptability and antioxidant efficacy were evaluated in vivo, in human volunteers. No adverse reactions were observed after application of the formulations on skin and the cream with the highest concentrations of phenolic compounds showed the highest antioxidant efficiency. In conclusion, the results suggest that olive oil industry by-products extracts have valuable properties that favor their re-use in the cosmetic industry. The example presented here showed their successful incorporation into creams and their impact in these formulations' appearance, pH, and rheological performance, as well as their in vivo compatibility with skin and antioxidant efficiency.

Amphotericin B-loaded deformable lipid vesicles for topical treatment of cutaneous leishmaniasis skin lesions

Cutaneous leishmaniasis (CL), the most common clinical form of human leishmaniasis, is a non-fatal chronic and disabling disease characterized by erythema and nodular or ulcerative skin lesions that may cause permanent scars and disfigurement. Topical drug delivery represents a simple and efficacious approach to treat CL skin lesions. The association of drugs with nanocarrier systems enhances their permeation properties and increases the drug amount available in the dermis. Here, a deformable lipid vesicle (DLV) was optimized for the topical administration of Amphotericin B (AmB), with the aim of studying and understanding the advantages of this type of delivery system in the transport of a drug through the skin layers. AmB-DVL were characterized in terms of incorporation parameters, stability, and elasticity, and evaluated in vitro for their permeation properties, cytotoxicity, and anti-leishmanial activity. The AmB-DVL exhibited a translucent fluid gel-like aspect and a yellow color, a mean size of 132 nm (PdI ≤ 0.1), zeta potential values around zero (mV), and an AmB incorporation efficiency of 95%. Permeation and penetration assays suggest that AmB-DLV are suitable for topical administration since AmB was detected in the epidermal and dermal skin layers. AmB-DVL was able to reduce promastigote viability in a dose-dependent manner, as well as the number of intracellular amastigotes in THP-1 macrophages. Selectivity index (SI) value for AmB-DLV was considerably higher than that observed for free AmB. Results suggest that DLV may represent an attractive vehicle for dermal delivery of AmB and a new low-cost and safe therapeutic option in CL treatment.

Effect of α-tocopherol on the physicochemical, antioxidant and antibacterial properties of levofloxacin loaded hybrid lipid nanocarriers

Non-toxic hybrid lipidic nanoparticles become a promising tool for enhanced lung delivery of levofloxacin in combination with antioxidant properties.

Effects of Starch Incorporation on the Physicochemical Properties and Release Kinetics of Alginate-Based 3D Hydrogel Patches for Topical Delivery

The development of printable hydrogel inks for extrusion-based 3D printing is opening new possibilities to the production of new and/or improved pharmaceutical forms, specifically for topical application. Alginate and starch are natural polysaccharides that have been extensively exploited due to their biocompatibility, biodegradability, viscosity properties, low toxicity, and relatively low cost. This research work aimed to study the physicochemical and release kinetic effects of starch incorporation in alginate-based 3D hydrogel patches for topical delivery using a quality by design approach. The incorporation of a pregelatinized starch is also proposed as a way to improve the properties of the drug delivery system while maintaining the desired quality characteristics. Critical material attributes and process parameters were identified, and the sensitivity and adequacy of each parameter were statistically analyzed. The impact of alginate, starch, and CaCl₂·2H₂O amounts on relevant quality attributes was estimated crosswise. The amount of starch revealed a synergetic impact on porosity (p = 0.0021). An evident increase in the size and quantity of open pores were detected in the as printed patches as well as after crosslinking (15.6 ± 5.2 µm). In vitro drug release studies from the optimized alginate-starch 3D hydrogel patch, using the probe Rhodamine B, showed an initial high burst release, followed by a controlled release mechanism. The results obtained also showed that the viscoelastic properties, printing accuracy, gelation time, microstructure, and release rates can be modulated by varying the amount of starch added to the system. Furthermore, these results can be considered an excellent baseline for future drug release modulation strategies.

The Brain-Skin Connection and the Pathogenesis of Psoriasis: A Review with a Focus on the Serotonergic System

Psoriasis is a common non-communicable chronic immune-mediated skin disease, affecting approximately 125 million people in the world. Its pathogenesis results from a combination of genetic and environmental factors. The pathogenesis of psoriasis seems to be driven by the interaction between innate immune cells, adaptive immune cells and keratinocytes, in a process mediated by cytokines (including interleukins (IL)-6, IL-17 and IL-22, interferon and tumor necrosis factor) and other signaling molecules. This leads to an inflammatory process with increased proliferation of epidermal cells, neo-angiogenesis and infiltration of dendritic cells in the skin. Dysfunctional de novo glucocorticoid synthesis in psoriatic keratinocytes and the skin microbiome have also been suggested as mediators in the pathogenesis of this disease. To understand psoriasis, it is essential to comprehend the processes underlying the skin immunity and neuroendocrinology. This review paper focuses on the skin as a neuroendocrine organ and summarizes what is known about the skin immune system, the brain-skin connection and the role played by the serotonergic system in skin. Subsequently, the alterations of neuroimmune processes and of the serotonergic system in psoriatic skin are discussed, as well as, briefly, the genetic basis of psoriasis.

Fragaria vesca L. Extract: A Promising Cosmetic Ingredient with Antioxidant Properties

Fragaria vesca L. (F. vesca), popularly known as wild strawberry, is a plant from the Rosaceae family, found in temperate and subtropical areas of the northern hemisphere. F. vesca leaves have been shown to have antiseptic, emollient, and dermatological protection properties, due to the presence of bioactive compounds, such as flavonoids, phenolic acids, ellagitannins, and proanthocyanidins. In this study, a F. vesca extract was obtained by an optimized extraction process, and was characterized by HPLC, ROS scavenging activity, cytotoxicity assays in HaCaT cells, and tyrosinase inhibitory activity determination. The most active extract was then incorporated in a hydrogel with hydroxyethylcellulose at 2% (w/w), which was characterized at the physicochemical, stability, cytotoxicity, and ROS scavenging activity levels to evaluate its quality, safety, and efficacy. In vivo studies, human repeat insult patch testing, and an assay to determine their antioxidant efficacy, were also performed. The results showed that the Fragaria vesca extracts had antioxidant activity and that the F. vesca extract-based hydrogel exhibited cutaneous compatibility, acceptability and antioxidant efficacy, being stable, and suitable for topical application.

Flavonoid-Enriched Plant-Extract-Loaded Emulsion: A Novel Phytocosmetic Sunscreen Formulation with Antioxidant Properties

The aim of this study was to develop a phytocosmetic sunscreen emulsion with antioxidant effect, containing a blend of flavonoid-enriched plant extracts. In vitro sun protection factor, antioxidant activity, skin irritation, photostability, cutaneous permeation, and retention of flavonoids were evaluated. Thermodynamically stable emulsions were obtained and tested for sensorial analysis after loading the blend of extracts. The selected emulsion was stable when stored at low temperatures (5 °C), for which after 120 days the concentration of quercetin and rutin were above their limit of quantification, i.e., 2.8 ± 0.39 μg/mL and 30.39 ± 0.39 μg/mL, respectively. Spreadability, low rupture strength and adhesiveness were shown to be similar to a conventional topical product. Higher brittleness, pseudo-plastic, and viscoelastic behaviors were also recorded for the developed phytocosmetic sunscreen. The product presented a critical wavelength of 387.0 nm and ultraviolet rays A and B (UVA/UVB) rate of 0.78, confirming that the developed formulation shows capacity for UVA/UVB protection, protecting skin against damages caused by ultraviolet (UV) radiation. Rutin was shown to permeate the skin barrier and was also quantified in the stratum corneum (3.27 ± 1.92 μg/mL) by tape stripping and retention test (114.68 ± 8.70 μg/mL). The developed flavonoid-enriched phytocosmetic was shown to be non-irritant to skin by an in vitro assay. Our results confirm the antioxidant activity, sun protection, and physical properties of the developed phytocosmetic for topical application.

Starch-Based Pickering Emulsions as Platforms for Topical Antibiotic Delivery: In Vitro and In Vivo Studies

The present study investigated a new approach to treat superficial skin infections by topical application of minocycline hydrochloride (MH) formulated in a novel starch-based Pickering emulsion (ASt-emulsions). The emulsions were fully characterized in terms of efficacy, as well as in vitro release and permeation studies. The emulsions provided a prolonged MH release, always above its minimum inhibitory concentration against Staphylococcus aureus, although the drug did not permeate through the entire skin layer. The in vitro antibacterial activity of MHASt-emulsions against S. aureus was confirmed and their therapeutic efficacy was assessed using an in vitro skin-adapted agar diffusion test. In vivo antibacterial activity, evaluated using the tape-stripping infection model in mice, showed the topical administration of MH was effective against superficial infections caused by S. aureus. This study supports the potential of ASt-emulsions as promising platforms for topical antibiotic delivery, contributing to a new perspective on the treatment of superficial bacterial infections.

In vitro SPF and Photostability Assays of Emulsion Containing Nanoparticles with Vegetable Extracts Rich in Flavonoids

The aim of study was to determine the in vitro sun protection factor (SPF) and the photostability profile of a topical formulation composed of nanoparticles loaded with vegetable extracts and to assess its physicochemical properties. Chitosan/tripolyphosphate (TPP) nanoparticles loaded with flavonoids-enriched vegetable extracts (Ginkgo biloba L., Dimorphandra mollis Benth, Ruta graveolens, and Vitis vinifera L.) were produced and characterized for their morphology, mean particle size, zeta potential, and encapsulation efficiency. A final topical formulation was obtained by dispersing chitosan/TPP nanoparticles in an o/w emulsion. Results showed that nanoparticles dispersion exhibited yellowish color, spherical shape, and uniform appearance. Extract-loaded chitosan/TPP nanoparticles showed a mean particle size of 557.11 ± 3.1 nm, polydispersity index of 0.39 ± 0.27, zeta potential of + 11.54 ± 2.1 mV, and encapsulation efficiency of 75.89% of rutin. The recorded texture parameters confirm that the developed formulation is appropriate for skin application. The SPF obtained was 2.3 ± 0.4, with a critical wavelength of 387.0 nm and 0.69 UVA/UVB ratio. The developed formulation exhibited photostability, allowing the release of flavonoids from nanoparticles while retaining rutin into the skin in a higher extension.

Polyurethanes as New Excipients in Nail Therapeutics

Onychomycosis affects about 15% of the population. This disease causes physical and psychosocial discomfort to infected patients. Topical treatment (creams, solutions, gels, colloidal carriers, and nail lacquers) is usually the most commonly required due to the high toxicity of oral drugs. Currently, the most common topical formulations (creams and lotions) present a low drug delivery to the nail infection. Nail lacquers appear to increase drug delivery and simultaneously improve the effectiveness of treatment with increased patient compliance. These formulations leave a polymer film on the nail plate after solvent evaporation. The duration of the film residence in the nail constitutes an important property of nail lacquer formulation. In this study, a polyurethane polymer was used to delivery antifungals drugs, such as terbinafine hydrochloride (TH) and ciclopirox olamine (CPX) and the influence of its concentration on the properties of nail lacquer formulations was assessed. The nail lacquer containing the lowest polymer concentration (10%) was the most effective regarding the in vitro release, permeation, and antifungal activity. It has also been demonstrated that the application of PU-based nail lacquer improves the nail plate, making it smooth and uniform and reduces the porosity contributing to the greater effectiveness of these vehicles. To conclude, the use of polyurethane in nail formulations is promising for nail therapeutics.

Starch nanocapsules containing a novel neutrophil elastase inhibitor with improved pharmaceutical performance

Psoriasis and atopic dermatitis patients show an excessive amount of elastase in peripheral blood neutrophils due to an imbalance between this proteolytic enzyme and its endogenous inhibitors, the search for new human neutrophil elastase (HNE) inhibitors are required. The HNE is an attractive therapeutic target and inhibitors with new molecular architectures have been extensively investigated. In this context a promising novel synthetic human neutrophil elastase inhibitor (ER143) was associated to a starch-based nanoparticulate system (StNC) with improved pharmaceutical performance, using a quality by design approach to support product development and optimization. The resulting formulation was characterized in terms of and in vitro release, permeation and retention studies in newborn pig skin, using Franz diffusion cells revealing the StNC have the ability to control the drug release rate and contribute to a high skin retention and/or permeation profiles. The anti-inflammatory activity accessed in vivo using the croton oil-induced ear inflammation model in mice showed that erythema and edema were attenuated in 98% following local application. These observations suggest the association of ER143 to the StNC promotes a deeper skin penetration and retention, also confirming StNC as a potential topical delivery system.

Betamethasone dipropionate compounding for cutaneous T-cell lymphoma management

Background

Primary cutaneous lymphomas (extranodular non-Hodgkin lymphomas) are rare (incidence 1:100 000). Mycosis fungoides is the most common cutaneous T-cell lymphoma (CTCL) subtype. Treatment options are based on the diagnosis and the stage of the disease. Skin-directed therapies are useful for the initial stages and include topical treatments such as corticosteroids. Betamethasone dipropionate (BD) is a synthetic glucocorticoid with high anti-inflammatory activity, potency and immunosuppressant effects. It is used for topical treatment of CTCL within the following dosage 0.025-0.1% (w/w). In the Portuguese market only one topical cream contains BD at 0.05% (w/w).

Objectives

To develop a new and stable emulsion containing 0.1% of BD.

Methods

To accomplish this aim, development, stability, in vitro release and clinical studies of a new topical water-in-oil emulsion containing BD 0.1% w/w were assessed for the topical treatment of CTCL.

Results

The three batches prepared were physically, chemically and microbiologically stable over a period of 90 days. 40% of BD was released over 6 hours and evaluation of skin lesions showed a favourable clinical effect (less itching, less infiltration, fewer patches and a reduced area of plaque).

Conclusions

The clinical results show the effective cutaneous improvement of skin barrier conditions during the study.

Chitosan Nanoparticles as a Mucoadhesive Drug Delivery System for Ocular Administration

Pharmaceutical approaches based on nanotechnologies and the development of eye drops composed of the mucoadhesive polymers chitosan and hyaluronic acid are emerging strategies for the efficient treatment of ocular diseases. These innovative nanoparticulate systems aim to increase drugs’ bioavailability at the ocular surface. For the successful development of these systems, the evaluation of mucoahesiveness (the interaction between the ocular delivery system and mucins present on the eye) is of utmost importance. In this context, the aim of the present work was to investigate the mucoadhesivity of a novel nanoparticle eye drop formulation containing an antibiotic (ceftazidime) intended to treat eye infections. Eye drop formulations comprised a polymer (hydroxypropyl) methyl cellulose (HPMC) 0.75% (w/v) in an isotonic solution incorporating chitosan/sodium tripolyphosphate (TPP)-hyaluronic acid-based nanoparticles containing ceftazidime. The viscosity of the nanoparticles, and the gels incorporating the nanoparticles were characterized in contact with mucin at different mass ratios, allowing the calculation of the rheological synergism parameter (∆η). Results showed that at different nanoparticle eye formulation:mucin weight ratios, a minimum in viscosity occurred which resulted in a negative rheological synergism. Additionally, the results highlighted the mucoadhesivity of the novel ocular formulation and its ability to interact with the ocular surface, thus increasing the drug residence time in the eye. Moreover, the in vitro release and permeation studies showed a prolonged drug release profile from the chitosan/TPP-hyaluronic acid nanoparticles gel formulation. Furthermore, the gel formulations were not cytotoxic on ARPE-19 and HEK293T cell lines, evaluated by the metabolic and membrane integrity tests. The formulation was stable and the drug active, as shown by microbiological studies. In conclusion, chitosan/TPP-hyaluronic acid nanoparticle eye drop formulations are a promising platform for ocular drug delivery with enhanced mucoadhesive properties.

Development and characterization of new and scalable topical formulations containing N-acetyl-d-glucosamine-loaded solid lipid nanoparticles

N-Acetyl-d-glucosamine (NAG) has been recently considered for topical treatment of hyperpigmentation disorders due to its inhibitory effect on thyrosinase enzymes in melanocytes. NAG is a precursor of hyaluronic acid, increasing its amount in skin, and consequently, preserving the skin hydration and elasticity. It may also act as an emulsion stabilizer. Solid lipid nanoparticles (SLN) are advanced delivery systems successfully used in pharmaceutical and cosmetic formulations for the improvement of active molecules penetration into the skin. Therefore, this work aimed to develop and characterize stable and scalable topical formulations containing NAG-loaded SLN. NAG was incorporated in SLN which were prepared by two high shear homogenizers and characterized regarding its morphology and particle size by transmission electron microscopy and photon correlation spectroscopy, respectively. Oil emulgel and hydrogel were used as carriers of NAG-loaded SLN. Several parameters were evaluated, including the droplet size distribution, rheology, pH and topical delivery by different techniques. It was observed that SLN size was significantly dependent on NAG incorporation and homogenization process. Most tested SLN parameters appeared to be quite suitable, that is, spherical and well-defined SLN with approximately 258 nm and -30 mV. Hereafter, both gels containing SLN presented a pseudoplastic flow. Emulgel formulation containing NAG-loaded SLN allowed a higher NAG permeation through the SC compared to the respective control (about 0.8 μgcm^-2h^-1). According to the results obtained, it can be suggested that NAG acts as an emulsion stabilizer. This stabilization was also particularly dependent on the homogenizer type which is quite important for scale-up process. This study demonstrated the potential of scalable SLN formulations to improve NAG topical delivery contributing to the improvement of skin properties on several skin disorders.

Ethosomes for enhanced skin delivery of griseofulvin

Griseofulvin (GRF) is an important antifungal drug with low bioavailability and, for this reason, a topical formulation with a targeted action and minimal systemic effects, appears to be a preferable solution. GRF poor solubility has limited the development of topical formulations and their release to the market. The aim of this work was to prepare a new GRF formulation for topical application using lipid-based nanosystems; to study its permeation and penetration, cell viability and to evaluate its therapeutic action. Ethosomal systems composed of soy bean phosphatidylcholine, ethanol and water were prepared for incorporating GRF. After the characterization of the vesicles in terms of size, charge and penetrability, permeation through newborn pig using Franz diffusion cells was conducted. Cell viability at different concentrations of the chosen formulation was determined. At last, skin adapted agar diffusion test was performed to assess the therapeutic efficacy of the formulation. GRF vesicles had mean size of 130nm. Permeation and penetration assays revealed that GRF-loaded ethosomes have an adequate profile to be used in a topical formulation since drug retention in the stratum corneum was achieved. Cell viability tests proved this formulation presented no cytotoxicity to HaCaT cells for concentrations below 50μg/mL. The skin diffusion test evidenced the potential of developed formulation to target skin dermatophytes. The results obtained in this study contribute to a new perspective in topical treatment of fungal infections.

A Quality by design (QbD) approach on starch-based nanocapsules: A promising platform for topical drug delivery

Exploring novel applications for approved excipients with a history of safe use in therapeutics is a smart strategy to obtain improved pharmaceutical products. The present study aimed at developing a novel starch-based nanoparticulate carrier system (StNC) for topical delivery of lipophilic bioactive molecules. The role of the different factors that affect the particle size distribution and zeta potential of StNC prepared by the emulsification-solvent evaporation method was assessed using a quality by design approach. An optimal formulation was selected and fully characterized in terms of molecular interactions (DSC and FTIR), morphology (TEM and AFM), as well as in vitro and in vivo biological properties, including biological sensitivity/irritation studies performed in human volunteers. Results show the surfactant and lipid contents play a major role in StNC particle size distribution. In addition, all tested formulations presented a zeta potential of ca. +33.6±6.7 mV, indicating a good physical stability, while revealing an excellent compromise between stability, safety and cosmeticity, evidencing that StNC are suitable nanocarriers for topical use. Finally, the design planning methodology has clearly shown its usefulness for optimizing the formulation, being also crucial for the understanding of StNC formation process. The StNC proved to be a promising formulation strategy and a potential nanocarrier for topical lipophilic bioactive molecules.

Melatonin-based pickering emulsion for skin's photoprotection

CONTEXT

Based on its antioxidant activity, melatonin was recently found to have a protection effect against photocarcinogenesis.

OBJECTIVE

This work aimed to develop an innovative sunscreen formulation based on the Pickering emulsions concept, stabilized by physical UV filters, modified starch and natural oils associated to melatonin as a key strategy for prevention against UV-induced skin damage.

MATERIALS AND METHODS

For this purpose, melatonin was incorporated in Pickering emulsions that were characterized using physicochemical, in vitro and in vivo testing. Physicochemical studies included physical and chemical stability by a thorough pharmaceutical control. The possible protective effects of melatonin against UV-induced cell damage in HaCaT cell lines were investigated in vitro. The safety assessment and the in vivo biological properties of the final formulations, including Human Repeat Insult Patch Test and sunscreen water resistance tests were also evaluated.

RESULTS AND DISCUSSION

These studies demonstrated that melatonin sunscreen Pickering emulsion was beneficial and presented a powerful protection against UVB-induced damage in HaCat cells, including inhibition of apoptosis. The inclusion of zinc oxide, titanium dioxide, green coffee oil and starch ensured a high SPF (50+) against UVA and UVB.

CONCLUSION

The combination of melatonin, multifunctional solid particles and green coffee oil, contributed to achieve a stable, effective and innovative sunscreen with a meaningful synergistic protection against oxidative stress.

Topical gels of etofenamate: in vitro and in vivo evaluation

Non-steroid anti-inflammatory drugs (NSAIDs), such as etofenamate, are among the most prescribed drugs used for their analgesic, anti-rheumatic, antipyretic and anti-inflammatory properties. Topical formulations have the main advantage of targeted delivery. However, drugs must overcome the skin due to its role as a physical and chemical barrier against the penetration of chemicals and microorganisms. This barrier must be altered to allow the permeation of drugs at a suitable rate to the desired site of activity. Permeation modulators can intercalate the skin outer layers causing structure disruption, opening an energetically favourable route for the drug to diffuse through. The aim of this work was the development of hydroalcoholic gels containing 5.0% (w/w) of etofenamate for topical administration with anti-inflammatory activity and enhanced drug delivery. The physical and chemical characterization, in vitro release and permeation studies and in vivo anti-inflammatory activity were assessed. The gel with 30% ethanol showed in vivo anti-inflammatory activity with suitable physical chemical and microbiologic characteristics. In vitro release and permeation studies revealed that the different amounts of ethanol used influenced the release profiles of etofenamate. Moreover, it was demonstrated that this formulation is an adequate vehicle for the etofenamate skin permeation.