Formulation and in vitro release evaluation of newly synthesized palm kernel oil esters-based nanoemulsion delivery system for 30% ethanolic dried extract derived from local Phyllanthus urinaria for skin antiaging

Overview of Nanocosmetics with Emphasis on those Incorporating Natural Extracts

The cosmetic industry is rapidly rising worldwide. To overcome certain deficiencies of conventional cosmetics, nanomaterials have been introduced to formulations of nails, lips, hair, and skin for treating/alleviating hyperpigmentation, hair loss, acne, dandruff, wrinkles, photoaging, etc. Innovative nanocarrier materials applied in the cosmetic sector for carrying the active ingredients include niosomes, fullerenes, liposomes, carbon nanotubes, and nanoemulsions. These exhibit several advantages, such as elevated stability, augmented skin penetration, specific site targeting, and sustained release of active contents. Nevertheless, continuous exposure to nanomaterials in cosmetics may pose some health hazards. This review features the different new nanocarriers applied for delivering cosmetics, their positive impacts and shortcomings, currently marketed nanocosmetic formulations, and their possible toxic effects. The role of natural ingredients, including vegetable oils, seed oils, essential oils, fats, and plant extracts, in the formulation of nanocosmetics is also reviewed. This review also discusses the current trend of green cosmetics and cosmetic regulations in selected countries.

Emerging Trends in the Treatment of Skin Disorders by Herbal Drugs: Traditional and Nanotechnological Approach

Since the earliest days, people have been employing herbal treatments extensively around the world. The development of phytochemical and phytopharmacological sciences has made it possible to understand the chemical composition and biological properties of a number of medicinal plant products. Due to certain challenges like large molecular weight and low bioavailability, some components of herbal extracts are not utilized for therapeutic purposes. It has been suggested that herbal medicine and nanotechnology can be combined to enhance the benefits of plant extracts by lowering dosage requirements and adverse effects and increasing therapeutic activity. Using nanotechnology, the active ingredient can be delivered in an adequate concentration and transported to the targeted site of action. Conventional therapy does not fulfill these requirements. This review focuses on different skin diseases and nanotechnology-based herbal medicines that have been utilized to treat them.

Physicochemical properties and micro-interaction between micro-nanoparticles and anterior corneal multilayer biological interface film for improving drug delivery efficacy: the transformation of tear film turnover mode

Recently, various novel drug delivery systems have been developed to overcome ocular barriers in order to improve drug efficacy. We have previously reported that montmorillonite (MT) microspheres (MPs) and solid lipid nanoparticles (SLNs) loaded with the anti-glaucoma drug betaxolol hydrochloride (BHC) exhibited sustained drug release and thus intraocular pressure (IOP) lowering effects. Here, we investigated the effect of physicochemical particle parameters on the micro-interactions with tear film mucins and corneal epithelial cells. Results showed that the MT-BHC SLNs and MT-BHC MPs eye drops significantly prolonged the precorneal retention time due to their higher viscosity and lower surface tension and contact angle compared with the BHC solution, with MT-BHC MPs exhibiting the longest retention due to their stronger hydrophobic surface. The cumulative release of MT-BHC SLNs and MT-BHC MPs was up to 87.78% and 80.43% after 12 h, respectively. Tear elimination pharmacokinetics study further confirmed that the prolonged precorneal retention time of the formulations was due to the micro-interaction between the positively charged formulations and the negatively charged tear film mucins. Moreover, the area under the IOP reduction curve (AUC) of MT-BHC SLNs and MT-BHC MPs was 1.4 and 2.5 times that of the BHC solution. Accordingly, the MT-BHC MPs also exhibit the most consistent and long-lasting IOP-lowering effect. Ocular irritation experiments showed no significant toxicity of either. Taken together, MT MPs may have the potential for more effective glaucoma treatment.

Investigating the efficacy of topical application of Ipomoea carnea herbal cream in preventing skin damage induced by UVB radiation in a rat model

Ultraviolet-B irradiation is a common environmental stressor that has detrimental effects on human skin. Natural sunscreens are well-known for their ability to benefit inflamed sunburn and dry skin. This study examined the effect of formulated Ipomoea carnea herbal cream on UVB-induced skin damage. We screened the bioactive compounds of I. carnea crude extract, showing significant antioxidant activity. Additionally, we evaluated the cytotoxicity, revealing that I. carnea extract has less toxicity to vero cells (IC50 98.45 μg/mL) than to A375 cells (IC50 48.95 μg/mL). Based on this, we formulated the I. carnea herbal cream (FIHC) at 50, 100 and 200 mg concentrations and evaluated its organoleptic characteristics. Then, the rats were exposed to UVB radiation (32,800 J/m2) four times/week (on alternate days) before the cream was applied topically to the dorsal skin surface. Under UVB stress without treatment, rats showed deep dermal damage. In contrast, rats treated with the FIHC exhibited significantly reduced sunburn. Moreover, the histopathological and biochemical assays were confirmed by the topical application of FIHC, which had potentially reduced the skin elasticity and maintained the imbalanced enzyme and non-enzymatic antioxidant activity. Our findings amply demonstrate that the FIHC significantly accelerated the recovery of UVB-induced lesions through antioxidant and down-regulation of skin photodamage.

Influence of Manufacturing Process on the Microstructure, Stability, and Sensorial Properties of a Topical Ointment Formulation

The manufacturing process for ointments typically involves a series of heating, cooling, and mixing steps. Precise control of the level of mixing through homogenization and the cooling rate, as well as temperature at different stages, is important in delivering ointments with the desired quality attributes, stability, and performance. In this work, we investigated the influence of typical plant processing conditions on the microstructure, stability, and sensorial properties of a model ointment system through a Design of Experiments (DoE) approach. Homogenization speed at the cooling stage after the addition of the solvent (propylene glycol, PG) was found to be the critical processing parameter that affects stability and the rheological and sensorial properties of the ointment. A lower PG addition temperature was also found to be beneficial. The stabilization of the ointment at a lower PG addition temperature was hypothesized to be due to more effective encapsulation by crystallizing mono- and diglycerides at the lower temperature. The in vitro release profiles were found to be not influenced by the processing parameters, suggesting that for the ointment platform studied, processing affects the microstructure, but the effects do not translate into the release profile, a key performance indicator. Our systematic study represents a Quality-by-Design (QbD) approach to the design of a robust manufacturing process for delivering stable ointments with the desired performance attributes and properties.

Nanotechnology Promoting the Development of Products from the Biodiversity of the Asteraceae Family

Biodiversity is a hallmark of the Asteraceae family. Several species are known for their pharmacological potential. The search for new substances has permeated the chemistry of natural products for years. However, the development of a final product is still a challenge. Plant extracts have physicochemical characteristics that sometimes hinder administration, requiring a formulation. In this context, nanotechnology emerges as a tool to improve the pharmacokinetic parameters of several pharmacologically active substances. Nanoemulsions, liposomes, and nanoparticles are used to carry the active ingredients and thus improve therapeutic action, especially for substances with solubility and absorption problems. This paper aimed at compiling all the studies that used nanotechnology to develop formulations from species of the Asteraceae family from 2010 to 2021 in a literature review. The search showed that nanoemulsions are the most developed formulation associated with essential oils. The use of nanotechnology promoted an improvement in the pharmacokinetic parameters of active substances.

Preparation and optimization of medicated cold cream using Caralluma adscendens var. attenuata for the treatment of Candida skin infection

Fungal skin infection is a major skin health issue worldwide. For the treatment of fungal infections, systematic antifungal therapies are frequently prescribed. The aim of this study is to prepare an antifungal cold cream from Caralluma adscendens var. attenuata to treat deep dermal fungal infection in the skin layer. To achieve this, different concentrations of plant extract-based cold cream were prepared, and their in vitro characteristic features such as color, texture, pH, viscosity, spreadability, stability, permeation, were analyzed together with ex vivo evaluation to identify their applicability in the treatment of acute rat skin irritation. After 72 h of induction of Candida albicans infection in rats (7 days, two times/day), C. adscendens var. attenuata cold cream was applied topically. In rats with C. albicans induction without any treatment, adverse skin damages were visible in the form of red rashes, whereas in those with the formulated cold cream application, significantly less skin damage and inflammation were observed on a dose-dependent basis. Moreover, the reduced microbial colonization and histopathology of the rat skin without any treatment indicated the successful invasion of C. albicans and showed the morphological changes caused by candidal infection. However, treatment with the C. adscendens var. attenuata cream significantly inhibited candida colonization and reversed the morphological changes. In addition, the formulated C. adscendens var. attenuata cold cream showed good spreadability, permeation, and viscosity. Hence, it can act as a potent antifungal topical agent for the treatment of C. albicans skin infection without any irritation, thus safeguarding the skin tissue.

Crystallization and Rheology of Mono- and Diglycerides and Their Role in Stabilization of Emulsion Droplets in Model Topical Ointments

The crystallization behavior of commercial mono- and diglycerides (MDG) in paraffin oil is studied to develop an in-depth understanding of the polymorphic transitions useful for the physical stability of petroleum oil-based topical emulsions. Optical microscopy and differential scanning calorimetry measurements showed the formation of plate-like and spherulite crystals at high and low temperatures, in sequence, while cooling a solution of MDG dissolved in oil. High-resolution NMR and X-ray scattering demonstrate that 1-monoglycerides (mixture of 1-glyceride monostearate and 1-glyceride monopalmitate) cocrystallize to an inverse-lamellar structure (L_α polymorph) that mainly forms plate-like crystals at a higher temperature. The L_α polymorph is seen to exist up to room temperature during the cooling process. At lower temperatures, 1,3-diglycerides (mixture of 1,3-glyceryl distearate and 1,3-glyceryl dipalmitate) crystallize into β-polymorphs that form spherulites. The spherulites tend to assemble into elongated strands via aggregation, leading to the formation of a percolating network structure. The sizes of both types of crystals decrease with an increasing cooling rate, leading to a higher mechanical modulus due to the increased network connectivity of spherulites. In an emulsion, monoglycerides in the form of L_α polymorphs having plate-like crystal morphology show a higher affinity to the polar liquid/oil interface, thereby providing better interfacial stability compared to the spherulitic β-polymorphs. However, diglycerides in the form of spherulites form bulk network structures which provide network stabilization to the suspended droplets. This work demonstrates that MDG, a commercially available ingredient that combines the differential functionality of monoglycerides and diglycerides, is an effective, bifunctional, emulsifying agent for petrolatum-based topical emulsions.

Formula Development of Red Palm (Elaeis guineensis) Fruit Extract Loaded with Solid Lipid Nanoparticles Containing Creams and Its Anti-Aging Efficacy in Healthy Volunteers

Palm fruits (Elaeis guineensis) comprise antioxidants that can be used as skin care agents. This study developed a cosmeceutical cream containing E. guineensis extract, loaded with solid lipid nanoparticles (SLNs), and assessed its efficacy on female volunteers. The E. guineensis extract exhibited a good antioxidant activity with high levels of vitamin E, β-carotene, and palmitic acid. Day and night creams containing E. guineensis fruit extract, loaded with SLNs, were formulated and exhibited acceptable physical characteristics and good stability. Subsequently, their clinical efficacy and safety were evaluated on female volunteers. Both creams were non-irritating and had good cutaneous compatibility. Skin hydration, transepidermal water loss (TEWL), skin elasticity, melanin index, and skin texture were measured before and 30 min after the first application, as well as after 7, 14, and 30 days of daily application. A satisfactory survey was implemented using a questionnaire, and volunteer satisfaction scores were high for the product’s performance. Overall, the results showed that skin hydration, TEWL, cutaneous elasticity, and melanin index were improved, compared to the baseline data, after 30 days. Thus, the formulated facial day and night creams made the skin moist, reduced wrinkles, increased elasticity, and cleared the skin to the consumers’ satisfaction.

Natural Antioxidants from Plant Extracts in Skincare Cosmetics: Recent Applications, Challenges and Perspectives

In recent years, interest in the health effects of natural antioxidants has increased due to their safety and applicability in cosmetic formulation. Nevertheless, efficacy of natural antioxidants in vivo is less documented than their prooxidant properties in vivo. Plant extracts rich in vitamins, flavonoids, and phenolic compounds can induce oxidative damage by reacting with various biomolecules while also providing antioxidant properties. Because the biological activities of natural antioxidants differ, their effectiveness for slowing the aging process remains unclear. This review article focuses on the use of natural antioxidants in skincare and the possible mechanisms underlying their desired effect, along with recent applications in skincare formulation and their limitations.

Investigating the influence of excipient batch variation on the structure, consistency and physical stability of polysorbate 60-based topical vehicles

Fatty alcohol-polysorbate 60-water ternary systems were used as models to represent the continuous phases of the respective semisolid oil-in-water emulsions for topical delivery of cosmetic and medicinal agents. The influence of batch variation of polysorbate 60 and fatty alcohol on structure and consistency of these systems was investigated using microscopy, rheology, differential scanning calorimetry and X-ray scattering techniques. The polysorbate 60 : cetostearyl alcohol mixed emulsifying wax showed swelling in water, that is, the lamellar repeat distance continually augmented from 93 to 125 Å with water percentage 20-90%. Cetostearyl alcohol ternary systems were thicker than cetyl alcohol ones independently of polysorbate 60 batches used. All the ternary systems showed an initial increase in consistency over the first 2 weeks of storage, which was followed by slight changes in consistency (cetostearyl alcohol systems) due to the re-allocation of polysorbate 60 molecules in the gel network or significant breakdown of structure (cetyl alcohol systems) due to the transformation of swollen α-lamellar gel phase into β, γ crystals on 25°C storage. With all fatty alcohols, the consistency of polysorbate 60 ternary system was directly dependent upon interlamellar water thickness as governed by the length and distribution of polyoxyethylene groups within polysorbate 60 molecules. In relation with the composition of polysorbate 60 batches used, the consistency of ternary systems was higher when prepared with the polysorbate 60 batch containing a greater amount of sorbitan polyoxyethylene monoesters. It was proposed that the swollen α-crystalline gel phase could be better formed by sorbitan polyoxyethylene monoesters rather than sorbitan polyoxyethylene diesters.

Effects of Black Garlic Extract and Nanoemulsion on the Deoxy Corticosterone Acetate-Salt Induced Hypertension and Its Associated Mild Cognitive Impairment in Rats

Organosulfur compounds, phenolic acids and flavonoids in raw and black garlic were determined, and followed by preparation of black garlic nanoemulsion for studying their effects on deoxycorticosterone acetate-salt-induced hypertension and associated mild cognitive impairment in rats. Three organosulfur compounds, including diallyl sulfide (87.8 μg/g), diallyl disulfide (203.9 μg/g) and diallyl trisulfide (282.6 μg/g) were detected in black garlic by GC-MS, while gallic acid (19.19 μg/g), p-coumaric acid (27.03 μg/g) and quercetin (22.77 μg/g) were detected by UPLC-MS/MS. High doses of both black garlic extract and nanoemulsion prepared using Tween-80, glycerol, grapeseed oil and water could decrease systolic blood pressure through the elevation of bradykinin and nitric oxide levels as well as diminish aldosterone and angiotensin II levels in rats. In Morris water maze test, they could significantly decrease escape latency and swimming distance and increase the time spent in the target quadrant, accompanied by a decline of acetylcholinesterase activity and malondialdehyde level in the hippocampus as well as a rise in glutathione level and activities of superoxide dismutase, catalase and glutathione peroxidase. In addition, the levels of tumor necrosis factor, interleukin-6 and interleukin-1β were reduced. Effects of lowering blood pressure and improving learning/memory ability in rats followed the order: lisinopril > black garlic nanoemulsion > black garlic extract.

In vitro kinetic release study, antimicrobial activity and in vivo toxicity profile of a kojic acid ester-based nanoemulsion for topical application

Nanoemulsions have emerged as novel vehicles for drug delivery that allow sustained or controlled release for topical application. In this study, kojic acid ester-based nanoemulsion (KAE-NA) was analyzed for in vitro permeation evaluation, kinetic release study, in vitro antimicrobial activity and in vivo toxicity profile on embryonic zebrafish (Danio rerio). Based on KAE-NA in vitro permeation evaluation, the percentage of permeation was significantly improved from 4.94% at 1 h to 59.64% at 8 h of application. The permeation rate of KAE-NA at 8 h was 4659.50 μg cm-2 h-1 (initial concentration, C 0 = 2000 μg mL-1) with a permeability coefficient (K p) value of 0.48 cm h-1. The kinetic release analysis showed the Korsmeyer-Peppas model was the best fitted kinetic model with high linearity [R 2 = 0.9964]. Antimicrobial activity of KAE-NA was studied against the skin pathogen bacteria Staphylococcus aureus ATCC 43300. The results indicated that the inhibition zone size of the KAE-NA (8.00 ± 0.0 mm) was slightly bigger than that of its active ingredient, kojic acid ester (6.5 ± 0.0 mm). The toxicity profile of KAE-NA on embryonic zebrafish revealed less toxicity with LC50 (50% lethal concentration) more than 500 μg mL-1. The survival rate of the embryonic zebrafish was more than 80% when treated at doses ranging from 7.81-250 μg mL-1 and showed normal development throughout the experiment without any observed deformation. Hence, KAE-NA proved to be less toxic on the embryonic zebrafish.

Rheology by Design: A Regulatory Tutorial for Analytical Method Validation

The increasing demand for product and process understanding as an active pursuit in the quality guideline Q8 and, more recently, on the draft guideline on quality and equivalence of topical products, has unveiled the tremendous potential of rheology methods as a tool for microstructure characterization of topical semisolid dosage forms. Accordingly, procedure standardization is a dire need. This work aimed at developing and validating a methodology tutorial for rheology analysis. A 1% hydrocortisone cream was used as model cream formulation. Through a risk assessment analysis, the impact of selected critical method variables (geometry, temperature and application mode) was estimated in a broad range of rheological critical analytical attributes-zero-shear viscosity, upper-shear thinning viscosity, lower-shear thinning viscosity, infinite-shear viscosity, rotational yield point, thixotropic relative area, linear viscoelastic region, oscillatory yield point, storage modulus, loss modulus, and loss tangent. The proposed validation of the approach included the rheometer qualification, followed by the validation of numerous operational critical parameters regarding a rheology profile acquisition. The thixotropic relative area, oscillatory yield point, flow point and viscosity related endpoints proved to be highly sensitive and discriminatory parameters. This rationale provided a standard framework for the development of a reliable and robust rheology profile acquisition.

Bioresponsive nanostructured systems for sustained naltrexone release and treatment of alcohol use disorder: Development and biological evaluation

In this study, microemulsions capable of transforming into nanostructured hexagonal phase gels in vivo upon uptake of biological fluids for naltrexone prolonged release were investigated as a strategy for management of alcohol use disorder (AUD). Microemulsions were prepared using monoolein, tricaprylin, water and propylene glycol; after preliminary characterization, one formulation was selected, which contained 55% of monoolein-tricaprylin (M-55). This microemulsion displayed size below 200 nm and Newtonian rheological behavior. Liquid crystalline gels formed in vitro upon 8 h of contact with water following a second order kinetics. After 120 h, <50% of naltrexone was released in vitro independently on drug loading (5 or 10%). In vivo, gels formed within 24 h of M-55 subcutaneous administration, and persisted locally for over 30 days providing slow release of the fluorescent marker Alexa fluor compared to a solution. Using the conditioned place preference paradigm, a test used to measure drug's rewarding effects, a single dose of M-55 containing 5% naltrexone reduced the time spent in the ethanol-paired compartment by 1.8-fold compared to saline; this effect was similar to that obtained with daily naltrexone injections, demonstrating the formulation efficacy and its ability to reduce dosing frequency. A more robust effect was observed following administration of M-55 containing 10% of naltrexone, which was compatible with aversion. These results support M-55 as a platform for sustained release of drugs that can be further explored for management of AUD to reduce dosing frequency and aid treatment adherence.

Nutraceutical Vegetable Oil Nanoformulations for Prevention and Management of Diseases

The scientific community is becoming increasingly interested in identifying, characterizing, and delivering nutraceuticals, which constitutes a multi-billion-dollar business. These bioactive agents are claimed to exhibit several health benefits, including the prevention and treatment of diseases such as arthritis, cancer, osteoporosis, cataracts, Alzheimer's, and Huntington's diseases, heart, brain and metabolic disorders, etc. Nutraceuticals are typically consumed as part of a regular human diet and are usually present within foods, comprising vegetable oil, although at low levels and variable composition. Thus, it is difficult to control the type, amount and frequency of their ingestion by individuals. Nanoformulations about vegetable oil-based bioactive compounds with nutraceutical properties are useful for overcoming these issues, while improving the uptake, absorption, and bioavailability in the body. The purpose of this current study is to review papers on such nanoformulations, particularly those relevant for health benefits and the prevention and management of diseases, as well as bioactives extracted from vegetable oils enhancing the drug effectiveness, retrieved through bibliographic databases by setting a timespan from January 2000 to April 2020 (about 1758 records).

Synthesis of physically crosslinked PVA/Chitosan loaded silver nanoparticles hydrogels with tunable mechanical properties and antibacterial effects

Limitation of antibacterial activity, low water vapour, oxygen permeation and mechanical strength are the disadvantages of existing wound dressings. The present research is focused on synthesis of Polyvinyl alcohol (PVA) and Chitosan (CH) hydrogels using freeze thaw process. The formation of AgNPs and PVA/CH hydrogels was confirmed by UV spectroscopy, particle size, morphology, spectral analysis, swelling studies, and in-vitro drug release studies. The particle size of AgNPs was found to be in the range of 20-35 nm with an intense peak at 430 nm. The results of spectral peaks showed that PVA/CH blend maintains characteristics peak of -OH and -NH in the spectrum with higher intensity. The morphology and tensile strength of hydrogels showed a wrinkled surface with an increase in force and extension values from 0.49 to 11.15 N and 45 to 129 mm, respectively. A controlled release of 84.3% (28 h) of Ocimum sanctum extract was noticed from hydrogel discs which scavenges 69.2% of free radicals as compared to raw extract 82.5% (16 h) which scavenges 63.1% of free radicals, respectively. The results of zone of inhibition (ZOI) against gram +ve and gram -ve bacteria was found to be 9.3 mm and 6.3 mm, respectively.

Topical application of omega-3-, omega-6-, and omega-9-rich oil emulsions for cutaneous wound healing in rats

Wound healing is a physiological event that generates reconstitution and restoration of granulation tissue that ends with scar formation. As omega fatty acids are part of membrane phospholipids and participate in the inflammatory response, we investigated the effects of omega-3, omega-6, and omega-9 fatty acids in the form of oils on wound healing. Linseed (LO), evening primrose (EPO), and olive oils (OO) rich in omega-3, omega-6, and omega-9 fatty acids were formulated into emulsions and were topically applied on rats with excision wounds. All omega-3-, omega-6-, and omega-9-rich oil formulations were found to accelerate wound closure compared to untreated, with significant improvement (p < 0.05) being observed at day 14. EPO induced early deposition of collagen as evaluated by Masson trichrome staining that correlated well with the hydroxyproline content assay, with the highest level at days 3 and 7. Vascular endothelial growth factor (VEGF) showed greater amount of new microvasculature formed in the EPO-treated group, while moderate improvement occurs in the LO and OO groups. EPO increased both the expression of proinflammatory cytokines and growth factors in the early stage of healing and declined at the later stage of healing. LO modulates the proinflammatory cytokines and chemokine but did not affect the growth factors. In contrast, OO induced the expression of growth factors rather than proinflammatory cytokines. These data suggest that LO, EPO, and OO emulsions promote wound healing but they accomplish this by different mechanisms.

Developing Cream Formulations: Renewed Interest in an Old Problem

This work aimed at establishing a framework to screen and understand the product variability deeming from factors that affect the quality features of cream formulations. As per Quality by Design - based approach, cream quality target profile and critical quality attributes were identified, and a risk assessment analysis was conducted to qualitatively detect the most critical variables for cream design and development. A Plackett-Burman design was used to screen out unimportant factors, avoiding collecting large amounts of data. Accordingly, 2 designs of experiments (DoE-1 and DoE-2) were performed, and the effects of independent variables on the cream formulations responses were estimated. At different factor combinations, significant variability was observed in droplet size, consistency, hardness, compressibility, and adhesiveness with values ranging from 2.6 ± 0.9 to 10 ± 6 μm, 7.93 ± 0.05 to 13.53 ± 0.14 mm, 27.6 ± 0.3 to 58.4 ± 1.1 g, 38 ± 6 to 447 ± 37 g.s, and 25.7 ± 2.1 to 286 ± 33 g.s, respectively. The statistical analysis allowed determining the most influent factors. This study revealed the potential of Quality by Design methodology in understanding product variability, recognizing the most critical independent variables for the final product quality. This systematic approach in the pharmaceutical field will yield more robust products and processes, provisioning time and cost effective developments.

Self-assembled hexagonal liquid crystalline gels as novel ocular formulation with enhanced topical delivery of pilocarpine nitrate

The aim of this paper was to develop hexagonal liquid crystalline (H_II) gels that can be used as a novel ocular delivery system for pilocarpine nitrate (PN). H_II gels were prepared by a vortex method using phytantriol/triglyceride/water (71.15: 3.85: 26, w/w) ternary system. The gels were characterized by crossed polarized light microscopy, small-angle X-ray scattering, differential scanning calorimetry and rheology. And, in vitro drug release behavior and ex vivo corneal permeation were investigated. Finally, preocular residence time evaluation, eye irritation test, histological examination and miotic tests were studied in vivo and compared with carbopol gel. Based on various characterization techniques, the inner structure of the gels were H_II mesophase and exhibited a pseudoplastic fluid behaviour. In vitro release results revealed that PN could be released continuously from H_II gel over a period of 24 h. The ex vivo apparent permeability coefficient of H_II gel was 3.15-fold (P < 0.01) higher than that of the Carbopol gel. Compared with Carbopol gel, H_II gel displayed longer residence time on the eyeballs surface using fluorescent labeling technology. Furthermore, the H_II gel caused no ocular irritation was estimated by corneal hydration levels, Draize test and histological inspection. Additionally, in vivo miotic study showed that H_II gel had a remarkably long-lasting decrease in the pupil diameter of rabbits. In conclusion, H_II gels would be a promising sustained-release formulation for ocular drug delivery.

Formulation and characterization of garlic (Allium sativum L.) essential oil nanoemulsion and its acaricidal activity on eriophyid olive mites (Acari: Eriophyidae)

Green and nanoacaricides including essential oil (EO) nanoemulsions are important compounds to provide new, active, safe acaricides and lead to improvement of avoiding the risk of synthetic acaricides. This study was carried out for the first time on eriophyid mites to develop nanoemulsion of garlic essential oil by ultrasonic emulsification and evaluate its acaricidal activity against the two eriophyid olive mites Aceria oleae Nalepa and Tegolophus hassani (Keifer). Acute toxicity of nanoemulsion was also studied on male rats. Garlic EO was analyzed by gas chromatography-mass spectrometry (GC-MS), and the major compounds were diallyl sulfide (8.6%), diallyl disulfide (28.36%), dimethyl tetrasulfide (15.26%), trisulfide,di-2-propenyl (10.41%), and tetrasulfide,di-2-propenyl (9.67%). Garlic oil nanoemulsion with droplet size 93.4 nm was formulated by ultrasonic emulsification for 35 min. Emulsification time and oil and surfactant ratio correlated to the emulsion droplet size and stability. The formulated nanoemulsion showed high acaricidal activity against injurious eriophyid mites with LC₅₀ 298.225 and 309.634 μg/ml, respectively. No signs of nanoemulsion toxicity were noted in treating rats; thus, it may be considered non-toxic to mammals. Stability of garlic oil nanoemulsion, high acaricidal activity, and the absence of organic toxic solvents make the formulation that may be a possible acaricidal product. Results suggest the possibility of developing suitable natural nanoacaricide from garlic oil.

Nanoemulsion as pharmaceutical carrier for dermal and transdermal drug delivery: Formulation development, stability issues, basic considerations and applications

The use of nanoemulsion in augmenting dermal and transdermal effectiveness of drugs has now well established. The development of nanoemulsion based semisolid dosage forms is an active area of present research. However, thickening or liquid-to-semisolid conversion of the nanoemulsions provides opportunities to the formulation scientist to explore novel means of solving instability issues during transformation. Extending knowledge about the explicit role of nature/magnitude of zeta potential, types of emulsifiers and selection of appropriate semisolid bases could place these versatile carriers from laboratory to industrial scale. This article reviews the progressive advancement in the delivery of medicament via nanoemulsion with special reference to the dermal and transdermal administration. It is attempted to explore the most suitable semi solid dosage form for the particular type of nanoemulsion (o/w, w/o and others) and effect of particle size and zeta potential on the delivery of drugs through dermal or transdermal route. Finally, this review also highlights the basic principles and fundamental considerations of nanoemulsion manufacture, application of nanoemulsion based semisolid dosage forms in the dermal/transdermal administration and basic considerations during the nanoemulsion absorption into and through skin.

Preparation and characterization of neem oil nanoemulsion formulations against Sitophilus oryzae and Tribolium castaneum adults

This study aimed to improve the efficacy of azadirachtin (Azadirachta indica. A. Juss) against two serious pest species of stored products, Sitophilus oryzae (L.) and Tribolium castaneum (Herbst), through nano-emulsion formulations. Pseudoternary phase diagrams were constructed consisting of an emulsion system of an active ingredient (neem oil), surfactant (polysorbate or alkylpolyglucoside), and water. Isotropic regions were formed in the pseudoternary phase diagrams, and four formulations were selected from the isotropic regions and characterized according to particle size, particle aging, zeta potential, stability and thermostability, surface tension, viscosity, and pH. The selected formulations showed particle sizes of 208-507 nm in diameter. The result of contact toxicity demonstrated excellent mortality of S. oryzae and T. castaneum adults, with a mortality range of 85-100% and 74-100%, respectively, at a 1% azadirachtin concentration after only 2 days of exposure. Compared to non-formulated neem oil, the nano-emulsion formulations significantly increased the mortality of the tested species.

Development of antimicrobial nanoemulsion-based delivery systems against selected pathogenic bacteria using a thymol-rich Thymus daenensis essential oil

AIMS

Thymol-rich medicinal plants have been used in traditional medicine to relieve infectious diseases. However, the application of essential oils as medicine is limited by its low water solubility and high vapour pressure. The objective of this study was to produce stable nanoemulsions of Thymus daenensis oil in water by preventing Ostwald ripening and phase separation.

METHODS AND RESULTS

The antibacterial activity of bulk and emulsified essential oil against selected pathogenic bacteria including Gram-negative (Haemophilus influenzae, Pseudomonas aeruginosa) and Gram-positive (Streptococcus pneumoniae) were investigated in the liquid and vapour phase. The optimum formulation (L2) contained 2% Tween 80 (surfactant) and 0·1% lecithin (cosurfactant) had a mean droplet diameter of 131 nm. In the liquid phase, the optimized nanoemulsion exhibited good antibacterial activity against S. pneumonia with MIC value of 0·0039 mg mL^-1 . In the vapour phase, the MIC values against S. pneumonia were similar (<7·35 μL L^-1 ) for both bulk and emulsified essential oil. However, there was no antibacterial activity in the vapour phase against H. influenzae and P. aeruginosa. Analysis of thymol concentration in the head space indicated that the nanoemulsion retarded the release of thymol into the vapour phase.

CONCLUSIONS

These findings highlight the potential applications of nanoemulsions containing essential oils as antibacterial products.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results of the current study highlight the advantages of nanoemulsification for improvement of the physicochemical properties and the antibacterial activity of T. daenensis EOs in the liquid and vapour phase for therapeutic purposes.

Potential of Non-aqueous Microemulsions to Improve the Delivery of Lipophilic Drugs to the Skin

In this study, non-aqueous microemulsions were developed because of the challenges associated with finding pharmaceutically acceptable solvents for topical delivery of drugs sparingly soluble in water. The formulation irritation potential and ability to modulate the penetration of lipophilic compounds (progesterone, α-tocopherol, and lycopene) of interest for topical treatment/prevention of skin disorders were evaluated and compared to solutions and aqueous microemulsions of similar composition. The microemulsions (ME) were developed with BRIJ, vitamin E-TPGS, and ethanol as surfactant-co-surfactant blend and tributyrin, isopropyl myristate, and oleic acid as oil phase. As polar phase, propylene glycol (MEPG) or water (MEW) was used (26% w/w). The microemulsions were isotropic and based on viscosity and conductivity assessment, bicontinuous. Compared to drug solutions in lipophilic vehicles, MEPG improved drug delivery into viable skin layers by 2.5-38-fold; the magnitude of penetration enhancement mediated by MEPG into viable skin increased with drug lipophilicity, even though the absolute amount of drug delivered decreased. Delivery of progesterone and tocopherol, but not lycopene (the most lipophilic compound), increased up to 2.5-fold with MEW, and higher amounts of these two drugs were released from MEW (2-2.5-fold). Both microemulsions were considered safe for topical application, but MEPG-mediated decrease in the viability of reconstructed epidermis was more pronounced, suggesting its higher potential for irritation. We conclude that MEPG is a safe and suitable nanocarrier to deliver a variety of lipophilic drugs into viable skin layers, but the use of MEW might be more advantageous for drugs in the lower range of lipophilicity.

An Artificial Neural Network Based Analysis of Factors Controlling Particle Size in a Virgin Coconut Oil-Based Nanoemulsion System Containing Copper Peptide

A predictive model of a virgin coconut oil (VCO) nanoemulsion system for the topical delivery of copper peptide (an anti-aging compound) was developed using an artificial neural network (ANN) to investigate the factors that influence particle size. Four independent variables including the amount of VCO, Tween 80: Pluronic F68 (T80:PF68), xanthan gum and water were the inputs whereas particle size was taken as the response for the trained network. Genetic algorithms (GA) were used to model the data which were divided into training sets, testing sets and validation sets. The model obtained indicated the high quality performance of the neural network and its capability to identify the critical composition factors for the VCO nanoemulsion. The main factor controlling the particle size was found out to be xanthan gum (28.56%) followed by T80:PF68 (26.9%), VCO (22.8%) and water (21.74%). The formulation containing copper peptide was then successfully prepared using optimum conditions and particle sizes of 120.7 nm were obtained. The final formulation exhibited a zeta potential lower than -25 mV and showed good physical stability towards centrifugation test, freeze-thaw cycle test and storage at temperature 25°C and 45°C.

Design and development of a nanoemulsion system containing copper peptide by D-optimal mixture design and evaluation of its physicochemical properties

The particle size of Virgin coconut oil nanoemulsions was optimized using D-optimal mixture design and the optimum formulation was physicochemically characterized.

Design and development of a nanoemulsion system containing extract of Clinacanthus nutans (L.) leaves for transdermal delivery system by D-optimal mixture design and evaluation of its physicochemical properties

C. nutansis a well-known medicinal plant in South-East Asia that has attracted attention for its therapeutic characteristics. In this work, nanoemulsion has been chosen to be a carrier in encapsulation ofC. nutansextract for its potential in nanotechnology application.

Development and Characterization of Cinnamon Leaf Oil Nanocream for Topical Application

Cinnamon leaf oil contains a high percentage of eugenol and has antimicrobial, antioxidant and antiinflammatory properties. However, the undiluted oil can cause irritation to the skin. Therefore, the aims of this study were to develop and evaluate cinnamon leaf oil nanocream using palm oil. Nanocream base was prepared using different ratios of oil, surfactants and water. The surfactant used were mixture of Tween 80:Carbitol or Tween 80:Span 65 at different hydrophile-lipophile balance values. The pseudoternary phase diagrams were constructed to identify the nanocream base areas and the results showed that the nanocream bases using Span 65 as co-surfactant produced bigger cream area. Fifteen formulations using mixtures of Tween 80:Span 65 were further evaluated for accelerated stability test, droplet size, zeta potential, rheological properties and apparent viscosity. The nanocream base which had an average droplet size of 219 nm and had plastic flow with thixotropic behavior was selected for incorporation of 2% cinnamon leaf oil. The nanocream containing cinnamon leaf oil had the average size of 286 nm and good rheological characteristics. The in vitro release study demonstrated that eugenol as the main constituent of cinnamon leaf oil was released for about 81% in 10 h. The short-term stability study conducted for 6 months showed that the cinnamon leaf oil nanocream was stable at a temperature of 25° and thus, cinnamon leaf oil nanocream is a promising natural based preparation to be used for topical application.

Development of an insecticidal nanoemulsion with Manilkara subsericea (Sapotaceae) extract

BACKGROUND

Plants have been recognized as a good source of insecticidal agents, since they are able to produce their own defensives to insect attack. Moreover, there is a growing concern worldwide to develop pesticides with low impact to environment and non-target organisms. Hexane-soluble fraction from ethanolic crude extract from fruits of Manilkara subsericea and its triterpenes were considered active against a cotton pest (Dysdercus peruvianus). Several natural products with insecticidal activity have poor water solubility, including triterpenes, and nanotechnology has emerged as a good alternative to solve this main problem. On this context, the aim of the present study was to develop an insecticidal nanoemulsion containing apolar fraction from fruits of Manilkara subsericea.

RESULTS

It was obtained a formulation constituted by 5% of oil (octyldodecyl myristate), 5% of surfactants (sorbitan monooleate/polysorbate 80), 5% of apolar fraction from M. subsericea and 85% of water. Analysis of mean droplet diameter (155.2 ± 3.8 nm) confirmed this formulation as a nanoemulsion. It was able to induce mortality in D. peruvianus. It was observed no effect against acetylcholinesterase or mortality in mice induced by the formulation, suggesting the safety of this nanoemulsion for non-target organisms.

CONCLUSIONS

The present study suggests that the obtained O/A nanoemulsion may be useful to enhance water solubility of poor water soluble natural products with insecticidal activity, including the hexane-soluble fraction from ethanolic crude extract from fruits of Manilkara subsericea.

Protein transduction domain-containing microemulsions as cutaneous delivery systems for an anticancer agent

In this study, we developed cationic microemulsions containing a protein transduction domain (penetratin) for optimizing paclitaxel localization within the skin. Microemulsions were prepared by mixing a surfactant blend (BRIJ:ethanol:propylene glycol 2:1:1, w/w/w) with monocaprylin (oil phase) at 1.3:1 ratio, and adding water at 30% (ME-30), 43% (ME-43), and 50% (ME-50). Electrical conductivity and viscosity measurements indicated that ME-30 is most likely a bicontinuous system, whereas ME-43 and ME-50 are water continuous. Their irritation potential, studied in bioengineered skin equivalents, decreased as aqueous content increased. Because ME-50 was not stable in the presence of paclitaxel (0.5%), ME-43 was selected for penetratin incorporation (0.4%). The microemulsion containing penetratin (ME-P) displayed zeta potential of +5.2 mV, and promoted a 1.8-fold increase in paclitaxel cutaneous (but not transdermal) delivery compared with the plain ME-43, whereas the enhancement promoted by another cationic microemulsion containing phytosphingosine was 1.3-fold. Compared with myvacet oil, ME-P promoted a larger increase on transepidermal water loss (twofold) than the plain or the phytosphingosine-containing microemulsions (1.5-fold), suggesting that penetratin addition increases the barrier-disrupting and penetration-enhancing effects of microemulsions. The ratio Δcutaneous/Δtransdermal delivery promoted by ME-P was the highest among the formulations, suggesting its potential for drug localization within cutaneous tumor lesions.