Lucia Grifoni

Central nervous system (CNS) disorders remain difficult to treat because many pharmacologically active molecules do not achieve adequate exposure in the brain. The blood–brain barrier (BBB), blood-cerebrospinal fluid (CSF) barrier, efflux transporters, extracellular matrix, and local clearance mechanisms impose different constraints according to the target compartment and administration route. Nanocarriers can protect unstable payloads, alter pharmacokinetics, and support receptor-mediated or local delivery, but the same properties that promote transport can also increase immune recognition, tissue retention, and neurotoxicity. This review critically examines how nanoparticles (NPs) size, surface charge, composition, degradability, ligand density, and release kinetics should be matched to intravenous, intranasal, intrathecal, intracranial, and oral administration. Rather than treating these routes as interchangeable, we compare the barriers encountered by each route, the payloads for which it is best suited, and the experimental conditions that limit interpretation of reported brain uptake. Particular attention is given to the weak correspondence between many rodent efficacy studies and human delivery constraints, including protein-corona formation after systemic dosing, species differences in BBB and nasal anatomy, limited parenchymal penetration from cerebrospinal fluid, and the procedural risks of direct administration. The resulting route-specific framework is intended to support application-driven formulation design and more informative preclinical evaluation of CNS nanomedicines.

This review reports on the huge potential of natural products (NPs) as drugs due to their pleiotropic activities and discusses the recent research and development of nanoscale drug delivery systems loaded with NPs. Indeed, the number of publications is dramatically increased in the last years and excellent biopharmaceutical properties of nanosized vectors loaded with NPs have been reported, however on the market the number of products based on nanoscale drug delivery systems are limited essentially to food supplements and cosmetics. The difficulties of NPs loaded nanovectors to reach the market as medicine is mainly due to the lack of dedicated regulatory frameworks, a specialized "nano" legal context. Instead, nanovectors are evaluated on a case-by-case basis under existing broad pharmaceutical regulations under traditional benefit/risk frameworks. This manuscript would be a comprehensive collection of the reviews on nanovectors loaded with some paradigmatic NPs, namely curcumin, quercetin, resveratrol, epigallocatechin-3-gallate, thymoquinone, cannabidiol, and silybin, all developed to overcome their biopharmaceutical restrictions, mainly solubility and stability. The study highlights the challenges and limitations of the reported studies, evidencing in many cases the lack of complete knowledge of the mechanistic of nano–bio interactions, the lack of some basic requirements as the encapsulation efficiency and drug loading efficiency, as well as the very limited number of the clinical studies. Finally, NPs are presented as multifunctional excipients of nanovectors to improve nanocarrier structure, function and drug biopharmaceutical properties, mainly represented by ginseng and quillaja saponins, escin and glycyrrhizin to form micelles or vesicles such as escinosomes.

The search for harmless alternative solutions to protect crops has become urgent and has recently attracted widespread attention from researchers around the world focusing on natural polyphenols, which represent a treasure chest of molecules with potent activities. Due to the low water solubility of polyphenols, microemulsions were selected as nanovectors. Curcumin and mangiferin solubility in different excipients was evaluated by HPLC. Microemulsion was developed using pseudo-ternary phase diagrams. Sizes and polydispersity of microemulsion globules were evaluated by dynamic light scattering. Activity against Fusarium verticillioides was evaluated by a microdilution method. Vitamin E acetate was selected as the oily phase, Transcutol P as cosurfactant and Tween 80 as surfactant. S_mix was composed of Transcutol P and Tween 80 in a 1:2 gravimetric ratio and combined with oil-phase vitamin E acetate at a weight ratio of 3:1. Microemulsions were loaded with 5 mg/mL of each polyphenol and recovery results were 99.5% and 99.3% for curcumin and mangiferin, respectively. Sizes of the lipid phase were 121.7 ± 29.2 nm and 172.6 ± 19.3 nm, respectively, for mangiferin and curcumin microemulsions. F. verticillioides was very susceptible to both microemulsions with a very high activity at a dose of 0.9 mg/mL (log-4 reduction), evidencing a possible use of these nanoformulations to protect crops from F. verticillioides.

Background/objectives Search for harmless alternative solutions to protect crops has become urgent and has recently attracted widespread attention from researchers around the world focusing on natural polyphenols, which represent a treasure chest of molecules with potent activities. Due to the low water solubility of polyphenols, microemulsions, were selected as nanovectors. Methods Curcumin and mangiferin solubility in different excipients was evaluated by HPLC. Microemulsion was developed using pseudo-ternary phase diagrams. Sizes and polydispersity of microemulsion globules were evaluated by dynamic light scattering. Activity against Fusarium verticillioides was evaluated by a microdilution method. Results Vitamin E acetate was selected as the oily phase, Transcutol P as cosolvent and Tween 80 as surfactant. S_mix was composed of Transcutol P and Tween 80 in a 1:2 gravimetric ratio and combined with vitamin E acetate oil phase at weight ratio 3:1. Microemulsions were loaded with 5 mg/mL of each polyphenol and recovery resulted 99.5% and 99.3% for curcumin and mangiferin respectively. Sizes of the lipid phase was 121.7±29.2 nm and 172.6±19.3 nm, respectively for mangiferin and curcumin microemulsions. Conclusions F. verticillioides was very susceptible to both microemulsions with a very high activity at a dose of 0.9 mg/ml (log-4 reduction), evidencing a possible use of these nanoformulations to protect crops from F. verticillioides.

Background: Cannabidiol (CBD) is a highly lipophilic compound with potential therapeutic applications in neurological disorders. However, its poor aqueous solubility and bioavailability, coupled with instability in physiological conditions, significantly limit its clinical use. Objectives: This study aimed to develop and characterize nanovesicles incorporating Tween 20 to enhance CBD encapsulation, stability, and the performance across the blood–brain barrier (BBB). Methods: Nanovesicles were prepared via thin-film hydration followed by sonication and optimized for size, polydispersity index, and zeta potential. Stability studies were conducted under physiological conditions and during storage at 4 °C. In vitro release studies employed the dialysis bag method, while permeability across the BBB was assessed using PAMPA-BBB and the hCMEC/D3-BBB cell line, characterized for brain endothelial phenotype and largely employed as a model of human blood–brain barrier (BBB) function. Cytotoxicity was evaluated via MTT and LDH assays. Results: The quantification of CBD was carried out by HPLC-DAD and HPLC-MS/MS. Nanovesicles with Tween 20 (VS-CBD) exhibited smaller size (65.27 ± 1.27 nm vs. 90.7 ± 0.2), lower polydispersity (0.230 ± 0.005 vs. 0.295 ± 0.003), and higher stability compared to conventional liposomes (L-CBD). VS-CBD achieved high encapsulation efficiency (96.80 ± 0.96%) and recovery (99.89 ± 0.52%). Release studies showed sustained CBD release with Higuchi model fitting (R² = 0.9901). Both PAMPA-BBB and hCMEC/D3-BBB cell lines demonstrated an improved controlled permeability of the formulation compared to free CBD. Cytotoxicity tests confirmed the good biocompatibility of VS-CBD formulations. The addition of Tween 20 to nanovesicles enhanced CBD encapsulation, stability, and controlled release. Conclusions: These nanovesicles represent a promising strategy to improve CBD delivery to the brain, offering sustained therapeutic effects and reduced dosing frequency, potentially benefiting the treatment of neurological disorders.

Resins are complex mixtures of natural constituents containing non-volatile and volatile terpenes, in combination with gums and polyphenols, used since ancient times for their medicinal properties. Current research has evidenced their therapeutic value with a plethora of activities. The main limits of resins and their constituents for their clinical use are low water solubility, poor stability and bioavailability. Therefore, nanovectors including vesicles, solid lipid nanoparticles, micelles, nanoemulsions, microemulsions and mesoporic nanoparticles have been investigated to optimize the biopharmaceutical properties after topical or oral administration of resins or fractions from them, including essential oils or single constituents. In this review, we report the results evidencing that developed nanovectors were able to entrap high amounts of resins or their components, modify the release properties, enhance their cellular uptake and penetration across biological barriers and optimize the biopharmaceutical properties. In addition, the resins or their fractions as enhancer penetration molecules can optimize the architecture and properties of nanovectors in their capacity to circumvent biological barriers. Although no clinical studies have been reported until now, nanovectors represent a huge platform for upgrading therapies and emerging new treatments of resins such as wound healing therapy.

Essential oils (EOs) are reported to be natural pesticides, but their use to protect crops is very limited due to EOs’ high instability and great volatility. Nanovectors represent a very smart alternative, and in this study, EOs from Artemisia annua (AEO) and Salvia fruticosa (SEO) were formulated into microemulsions and tested against Fusarium verticillioides. The EOs were extracted by steam distillation and analyzed by GC–MS. The main constituents of AEO were camphor, artemisia ketone, and 1,8-cineole; the main constituents of SEO were 1,8-cineole, camphor, α-pinene, and β-pinene. Artemisia ketone and 1,8-cineole were used to calculate the recovery and chemical stability of the microemulsions. The microemulsions were loaded with 10 mg/mL of EOs, and the recoveries were 99.8% and 99.6% for AEO and SEO, respectively. The sizes of the lipid phases were 255.3 ± 0.6 nm and 323.7 ± 2.3 nm for the AEO and SEO microemulsions, respectively. Activity against F. verticillioides was tested using amphotericin B as the positive control. F. verticillioides was very susceptible to both EOs. When loaded in the microemulsions, AEO and SEO remained very active at a dose of 1.4 and 1.2 mg, with a 99.99% reduction of F. verticillioides. The findings suggest AEO and SEO microemulsions are suitable carriers for the protection of crops against F. verticillioides.

The purpose of this study was to investigate the loading properties of the non-psychoactive cannabidiol (CBD) in a new nanostructured lipid carrier (NLC), evaluating its bioaccessibility in gastric and intestinal simulated physiological media. CBD has a low water solubility, as well as high instability in simulated physiological conditions and in the acidic media, which results in a very low bioavailability—less than 6%. NLCs containing CBD (10 mg/mL), Compritol 888 ATO, Lauroglycol 90, Labrafil 2125, Tween 20, and Poloxamer 188 were formulated. This resulted in them being suitable for oral administration because the size was less than 200 nm, polydispersity index 0.152, and ζ-potential −39.21 ± 1.89 mV. Recovery and encapsulation efficiency were 100% and 93%, respectively. After two hours of incubation in simulated gastric fluid (SGF), NLCs remained unchanged, protecting CBD from acidic medium. Indeed, CBD is also reported to be not stable in media with pH = 7.4 at 37 °C, but our studies evidenced that in the presence of the intestinal fluid, the NLC was digested and formed an emulsion, which can protect and preserve the CBD chemical structure, as confirmed by the 100% recovery found after six hours. Accordingly, CBD-loaded NLCs are a promising oral formulation that optimize bioaccessibility in the small intestine.

Oleanolic acid (OA) is the main triterpenic acid of olive leaves known for numerous pharmacological properties, including antioxidant activity. However, it is poorly soluble in water and consequently with low bioavailability, which limits its pharmacological application. Microemulsions (MEs) are dispersed systems consisting of two immiscible phases that promote rapid solubilization and absorption in the gastrointestinal tract. To improve both solubility and intestinal permeability of this molecule, OA has been formulated in two different microemulsions (ME-1 and ME-2). A solubility screening was carried out to select the ME components, and pseudoternary phase diagrams were constructed to evaluate the region of existence and select the appropriate amount of the constituents. ME-1 was prepared using Capmul PG-8/NF as the oily phase, and Transcutol and Tween 20 (7:3) as surfactants, while ME-2 contained Nigella oil and Isopropil myristate as the oily phase, and Transcutol HP and Cremophor EL (2:1) as surfactants. The OA solubility was increased by 1000-fold and 3000-fold in ME-1-OA and ME-2-OA, respectively. The MEs’ droplet size and the PdI were evaluated, and the stability was assessed for 8 weeks by monitoring chemical and physical parameters. The parallel artificial membrane permeability assay (PAMPA) also demonstrated an enhanced intestinal permeability of both OA formulations compared with free OA. The potential ability of both MEs to enhance the bioactivity of OA against LPS-induced oxidative stress in RAW 264.7 murine macrophages was also investigated. Overall, this study suggests that both MEs promote a bio-enhancement of the protective action of OA against the LPS-induced pro-oxidant stress in macrophages. Overall, this study suggests that MEs could be an interesting formulation to improve OA oral bioavailability with potential clinical applications.