Antimicrobial and Anesthetic Niosomal Formulations Based on Amino Acid-Derived Surfactants.

BACKGROUND: This work proposes the development of new vesicular systems based on anesthetic compounds (lidocaine (LID) and capsaicin (CA)) and antimicrobial agents (amino acid-based surfactants from phenylalanine), with a focus on physicochemical characterization and the evaluation of antimicrobial and cytotoxic properties. METHOD: Phenylalanine surfactants were characterized via high-performance liquid chromatography (HPLC) and nuclear magnetic resonance (NMR). Different niosomal systems based on capsaicin, lidocaine, cationic phenylalanine surfactants, and dipalmitoyl phosphatidylcholine (DPPC) were characterized in terms of size, polydispersion index (PI), zeta potential, and encapsulation efficiency using dynamic light scattering (DLS), transmitted light microscopy (TEM), and small-angle X-ray scattering (SAXS). Furthermore, the interaction of the pure compounds used to prepare the niosomal formulations with DPPC monolayers was determined using a Langmuir balance. The antibacterial activity of the vesicular systems and their biocompatibility were evaluated, and molecular docking studies were carried out to obtain information about the mechanism by which these compounds interact with bacteria. RESULTS: The stability and reduced size of the analyzed niosomal formulations demonstrate their potential in pharmaceutical applications. The nanosystems exhibit promising antimicrobial activity, marking a significant advancement in pharmaceutical delivery systems with dual therapeutic properties. The biocompatibility of some formulations underscores their viability. CONCLUSIONS: The proposed niosomal formulations could constitute an important advance in the pharmaceutical field, offering delivery systems for combined therapies thanks to the pharmacological properties of the individual components.

Pluronic 123 Liquid Lyotropic Crystals for Transdermal Delivery of Caffeic Acid-Insights from Structural Studies and Drug Release.

BACKGROUND: This study aims to evaluate the percutaneous permeation profiles of caffeic acid (CA) from the cubic and hexagonal liquid crystalline phases of Pluronic P123/water mixtures. METHOD: The resulting drug-loaded mesophases were subjected to characterisation through deuterium nuclear magnetic resonance spectroscopy and polarised optical microscopy observations. These analyses aimed to evaluate the structural changes that occurred in the mesophases loading with CA. Additionally, steady and dynamic rheology studies were conducted to further explore their mechanical properties and correlate them to the supramolecular structure. Finally, CA release experiments were carried out at two different temperatures to examine the behaviour of the structured systems in a physiological or hyperthermic state. RESULTS: As the concentration of the polymer increases, an increase in the viscosity of the gel is noted; however, the addition of caffeic acid increases microstructure fluidity. It is observed that the temperature effect conforms to expectations. The increase in temperature causes a decrease in viscosity and, consequently, an increase in the rate of permeation of caffeic acid. CONCLUSIONS: The CA permeation profile from the prepared formulations is mostly dependent on the structural organisation and temperature. Cubic mesophase LLC 30/CA showed greater skin permeation with good accumulation in the skin at both tested temperatures.

Liposomes Coated with Novel Synthetic Bifunctional Chitosan Derivatives as Potential Carriers of Anticancer Drugs.

In this study, liposomes coated with novel multifunctional polymers were proposed as an innovative platform for tumor targeted drug delivery. Novel Folic acid-Cysteine-Thiolated chitosan (FTC) derivatives possessing active targeting ability and redox responsivity were synthesized, characterized, and employed to develop FTC-coated liposomes. Liposomes were characterized for size, surface charge and drug encapsulation efficiency before and after coating. The formation of a coating layer on liposomal surface was confirmed by the slight increase in particle size and by zeta-potential changes. FTC-coated liposomes showed a redox-dependent drug release profile: good stability at physiological conditions and rapid release of liposome-entrapped calcein in presence of glutathione. Moreover, the uptake and cytotoxic activity of doxorubicin-loaded FTC-coated liposomes was evaluated on murine B16-F10 and human SKMEL2 melanoma cancer cells. Results demonstrated enhanced uptake and antitumor efficacy of FTC-coated liposomes compared to control chitosan-coated liposomes in both cancer lines, which is attributed to higher cellular uptake via folate receptor-mediated endocytosis and to triggered drug release by the reductive microenvironment of tumor cells. The proposed novel liposomes show great potential as nanocarriers for targeted therapy of cancer.

Lidosomes: Innovative Vesicular Systems Prepared from Lidocaine Surfadrug.

Lidocaine is a local anaesthetic drug with an amphiphilic structure able to self-associate, under certain conditions, in molecular aggregates playing the role of both carrier and drug. The aim of this study was to determine the optimal conditions for obtaining vesicular carriers, called lidosomes. The new formulations were obtained using both lidocaine and lidocaine hydrochloride and different hydration medias (distilled water, acid, and basic aqueous solution). Lidosomes formulations were characterized in terms of size, ζ-potential, drug retained, stability formulation, and ex vivo permeation profile. Moreover, lidosomes were incorporated in two different gel structures: one based on carboxymethylcellulose and one based on pluronic F-127 to achieve suitable properties for a topical application. Results obtained showed that lidocaine showed a better performance to aggregate in vesicular carriers in respect to hydrochloride form. Consequently, only formulations comprised of lidocaine were studied in terms of skin permeation performance and as carriers of another model drug, capsaicin, for a potential combined therapy. Lidocaine, when in form of vesicular aggregates, acted as percutaneous permeation enhancer showing better permeation profiles with respect to drug solutions. Moreover, lidosomes created a significant drug depot into the skin from which the drug was available for a prolonged time, a suitable feature for a successful local therapy.

Control of the Verticillium Wilt on Tomato Plants by Means of Olive Leaf Extracts Loaded on Chitosan Nanoparticles.

In this research, a new ecofriendly and sustainable fungicide agent, with the ability to control Verticillium wilt, was developed. To this purpose, a green extract of olive leaf (OLE) was prepared by ultrasound-assisted extraction (UAE) and characterized in terms of polyphenol content and antioxidant activity. Then, OLE was loaded in chitosan nanoparticles (CTNPs) to combine the antifungal activity of CTNPs and phenolic compounds to obtain an important synergic effect. Nanoparticles were synthetized using the ionic gelation technique and characterized in terms of sizes, polydispersity index, Z-potential, encapsulation efficiency, and release profile. Qualitative and quantitative analyses of OLE were performed by the HPLC method. OLE-loaded CTNPs exhibited good physicochemical properties, such as a small size and positive surface charge that significantly contributed to a high antifungal efficacy against Verticillum dahliae. Therefore, their antifungal activity was evaluated in vitro, using the minimal inhibition concentration (MIC) assay in a concentration range between 0.071 and 1.41 mg/mL. Free OLE, blank CTNPs, and OLE-loaded CTNPs possessed MIC values of 0.35, 0.71, and 0.14 mg/mL, respectively. These results suggest an important synergic effect when OLE was loaded in CTNPs. Thereafter, we tested the two higher concentrations on tomato plants inoculated with V. dahliae, where no fungal growth was observed in the in vitro experiment, 0.71 and 1.41 mg/mL. Interestingly, OLE-loaded CTNPs at the higher concentration used, diminished the symptoms of Verticillium wilt in tomato plants inoculated with V. dahliae and significantly enhanced plant growth. This research offers promising results and opens the possibility to use OLE-loaded CTNPs as safe fungicides in the control strategies of Verticillium wilt at open field.

New Nanomaterials with Intrinsic Antioxidant Activity by Surface Functionalization of Niosomes with Natural Phenolic Acids.

Nanoantioxidants have emerged as smart devices able to provide improved stability and biocompatibility and sustained and targeted release of conventional antioxidants. In the current research, a new family of nanoantioxidants has been developed by covalently grafting gallic (GA), caffeic (CF) and ferulic (FR) acid on the surfaces of Tween 80 niosomes. First, empty and curcumin (CUR)-loaded vesicles were prepared using a thin-layer evaporation technique and then functionalized with phenolic acids using carbodiimide chemistry. Nanoantioxidants obtained were characterized in terms of size, polydispersity index, zeta potential, and loading efficiency. Their antioxidant activity was studied by ABTS and DPPH assays. Surface functionalization of empty and CUR-loaded vesicles provided stable vesicles with intrinsic antioxidant properties. In vitro antioxidant assays highlighted that vesicles functionalized with FR or GA exhibited better antioxidant activity compared to CF-grafted niosomes. Furthermore, vesicles loaded with CUR and functionalized with GA and CF showed an enhanced scavenging ability of ABTS and DPPH radicals, compared to the single antioxidant-loaded formulations, highlighting an important synergic effect of CUR when used in combination with GA ad CF.

Use of Pluronic Surfactants in Gel Formulations of Photosensitive 1,4-Dihydropyridine Derivatives: A Potential Approach in the Treatment of Neuropathic Pain.

1,4-Dihydropyridines (DHPs) are the most important class of L-type calcium channel blockers that are employed for the treatment of cardiovascular diseases, particularly hypertension. Various modifications on this scaffold lead to the discovery of new DHPs blocking different types of calcium channels. Among them, the T-type calcium channel has recently attracted great interest due to its role in chronic pain conditions. In this study, we selected three newly synthesized DHPs (HM8, HM10 and MD20) with different selectivity profiles to the T-type calcium channel and formulated them in micellar solutions and micellar-in-gel matrices to be tested for potential topical use in the treatment of neuropathic pain. To prevent the well-known sensitivity to light of the DHPs, the studied compounds were entrapped in colloidal aggregates obtained by using edible Pluronic® surfactants and adding α-tocopherol as an antioxidant. All the prepared formulations were exposed to stressing light, according to international rules. Along with the degradation experiments, the concentrations of the parent compounds and by-products were calculated by multivariate curve resolution-alternating least squares (MCR-ALS) applied to the spectral data. The defined formulations proved suitable as light-stable matrices for the DHP compounds, showing an increase in stability for HM8 and MD20 and an almost complete photoprotection for HM10, compared to ethanol solutions and standard gel formulations.

Gel Formulation of Nabumetone and a Newly Synthesized Analog: Microemulsion as a Photoprotective Topical Delivery System.

Photostability studies were performed on topical formulations containing the anti-inflammatory drug Nabumetone and an analog newly synthesized in order to achieve better photostability and pharmacokinetic profile. Stability tests, according to the International Conference on Harmonization rules, were applied on ethanol solutions and topical gel formulations of both compounds. The photodegradation profiles were monitored by Multivariate curve resolution applied to the UV spectral data. The inclusion of the compounds in microemulsion was investigated to improve light stability and, at the same time, to ensure a sustained release system for skin delivery. All the formulations in solution, gel, microemulsion, and microemulsion-in-gel were exposed to a forced irradiation of 350 W/m2, corresponding to a 21 kJ/m2 min, for up to 300 min. Photostability increased significantly for both drugs in the liquid microemulsion and microemulsion-in-gel, compared to the ethanol solution and plain gel, reaching a residual drug of 97% and 98% for Nabumetone and analog in microemulsion-in-gel, respectively. Permeation experiments on the microemulsion-in-gel showed a better performance of the analog formulated at 0.2%, compared to the same formulation of Nabumetone at 0.7%. These results highlight the potential of the designed matrices as delayed drug delivery systems along with the use of lower drug doses leading to reduced side effects.

In vitro Antifungal Activity of Olive (Olea europaea) Leaf Extracts Loaded in Chitosan Nanoparticles.

Olive leaf extract is characterized by a high content of phenols and flavonoids (oleuropein, luteolin, and their derivatives). These compounds are defined as secondary metabolites and exert such as anti-inflammatory, antioxidant, and antimicrobial activities. We investigated the in vitro antifungal activity of two olive leaf extracts (named EF1 and EF2) against a Fusarium proliferatum (AACC0215) strain that causes diseases to many economically important plants and synthesizing diverse mycotoxins. In this work, we aimed to identify the most appropriate concentration between the tested two olive leaf extracts to develop a safe, stable and efficient drug delivery system. Qualitative and quantitative analyses of the two olive leaf extracts by (HPLC) were performed. Furthermore, we also evaluated the antifungal effects of the two leaf extracts when encapsulated in chitosan-tripolyphosphate nanoparticles. The major compound in both EF1 and EF2 was oleuropein, with 336 and 603 mg/g, respectively, however, high concentrations of flavonoid were also present. EF1 and EF2 showed a concentration depended effect on F. proliferatum (AACC0215) viability. Our results showed a great efficacy of EF1/nanoparticles at the higher concentration tested (12X) against the target species. In this case, we observed an inhibition rate to both germination and growth of 87.96 and 58.13%, respectively. We suggest that EF1 olive leaf extracts, as free or encapsulated in chitosan-tripolyphosphate nanoparticles, could be used as fungicides to control plant diseases. Finally, future application of these findings may allow to reduce the dosage of fungicides potentially harmful to human health.

Reverse Transcriptase Inhibitors Nanosystems Designed for Drug Stability and Controlled Delivery.

An in-depth analysis of nanotechnology applications for the improvement of solubility, distribution, bioavailability and stability of reverse transcriptase inhibitors is reported. Current clinically used nucleoside and non-nucleoside agents, included in combination therapies, were examined in the present survey, as drugs belonging to these classes are the major component of highly active antiretroviral treatments. The inclusion of such agents into supramolecular vesicular systems, such as liposomes, niosomes and lipid solid NPs, overcomes several drawbacks related to the action of these drugs, including drug instability and unfavorable pharmacokinetics. Overall results reported in the literature show that the performances of these drugs could be significantly improved by inclusion into nanosystems.

Actively Targeted and Redox Responsive Delivery of Anticancer Drug by Chitosan Nanoparticles.

The clinical efficacy of methotrexate (MTX) is limited by its poor water solubility, its low bioavailability, and the development of resistance in cancer cells. Herein, we developed novel folate redox-responsive chitosan (FTC) nanoparticles for intracellular MTX delivery. l-Cysteine and folic acid molecules were selected to be covalently linked to chitosan in order to confer it redox responsiveness and active targeting of folate receptors (FRs). NPs based on these novel polymers could possess tumor specificity and a controlled drug release due to the overexpression of FRs and high concentration of reductive agents in the microenvironment of cancer cells. Nanoparticles (NPs) were prepared using an ionotropic gelation technique and characterized in terms of size, morphology, and loading capacity. In vitro drug release profiles exhibited a glutathione (GSH) dependence. In the normal physiological environment, NPs maintained good stability, whereas, in a reducing environment similar to tumor cells, the encapsulated MTX was promptly released. The anticancer activity of MTX-loaded FTC-NPs was also studied by incubating HeLa cells with formulations for various time and concentration intervals. A significant reduction in viability was observed in a dose- and time-dependent manner. In particular, FTC-NPs showed a better inhibition effect on HeLa cancer cell proliferation compared to non-target chitosan-based NPs used as control. The selective cellular uptake of FTC-NPs via FRs was evaluated and confirmed by fluorescence microscopy. Overall, the designed NPs provide an attractive strategy and potential platform for efficient intracellular anticancer drug delivery.

Different BRIJ97 colloid systems as potential enhancers of acyclovir skin permeation and depot.

The low efficacy of Acyclovir topical therapy is due to its physicochemical properties that limit the permeation across the stratum corneum. The goal of this research was to evaluate the ability of biodegradable surfactant, Brij97, to self-assembly in different types of colloid systems which can improve the Acyclovir permeation and accumulation at the target site (the basal epidermis). New Acyclovir formulation based on Brij97 have been analyzed in order to investigate the effect of drug encapsulation on the structure. After that, the in vitro percutaneous permeation of Acyclovir has been compared with that one of the commercial specialty Zovirax® 5%. To estimate the potential of the new formulations proposed as topical delivery, it has been essential to quantify the Acyclovir in the skin layers. The results confirmed that the self-assembly of the surfactant in different nanosized structures improved the amount of permeated Acyclovir and the formation of intracutaneous drug reservoir. Furthermore, the different lipophilicity and structural organization of carriers based on Brij97 showed different influence on the promotion of permeation. The experimental data suggest that the designed carriers could be a valid alternative to improve the efficacy of the current antiviral therapy.

Thermo-Sensitive Vesicles in Controlled Drug Delivery for Chemotherapy.

Thermo-sensitive vesicles are a promising tool for triggering the release of drugs to solid tumours when used in combination with mild hyperthermia. Responsivity to temperature makes them intelligent nanodevices able to provide a site-specific chemotherapy. Following a brief introduction concerning hyperthermia and its advantageous combination with vesicular systems, recent investigations on thermo-sensitive vesicles useful for controlled drug delivery in cancer treatment are reported in this review. In particular, the influence of bilayer composition on the in vitro and in vivo behaviour of thermo-sensitive formulations currently under investigation have been extensively explored.

Innovative topical formulations from diclofenac sodium used as surfadrug: The birth of Diclosomes.

HYPOTHESIS: Due to the well-know surfactant-like properties of diclofenac sodium (DS), vesicular systems consisting exclusively of DS, named diclosomes, were designed with the aim to minimize or avoid the use of other excipients and to improve the formulation biocompatibility. EXPERIMENTS: Diclosomes were designed and characterized in terms of dimensions, polydispersity index, ξ-potential, drug retained, stability as a function of storage time and ex-vivo percutaneous permeation profiles. Additionally, diclosomes were incorporated into gel dosage forms and their performance in terms of permeation enhancement were evaluated. FINDINGS: DS was found to form nanosized vesicular systems, both alone and in presence of cholesterol. Increasing hydrophobicity (due to the presence of cholesterol) resulted in smaller vesicles, always spherical and homogeneous in shape. Permeation of DS from free solution was found to be lower respect to ones obtained for all diclosomal formulations, allowing these aggregates to be considered as percutaneous permeation enhancers. DS permeated from diclosomal gels was higher than that obtained with traditional niosomal gel, DS plain gel and commercial specialty Voltaren Emulgel® 1%, while containing a considerably lower drug amount.

Light-sensitive drugs in topical formulations: stability indicating methods and photostabilization strategies.

Photostability tests applied on commercial specialties for topical use have demonstrated a greater vulnerability of several drugs, due to greater exposure to light than other pharmaceutical forms. Photodegradation of a drug can considerably modify its pharmacokinetic behavior by varying the therapeutic index. The evaluation of the degradation profile of a drug, according to the ICH rules, is of primary importance in developing an appropriate topical formulation. Advanced strategies have been proposed to increase the protection from the light of the photolabile drugs. Supramolecular systems have been investigated to improve both pharmacokinetic profile and photostability. In this review, the more recent stability-monitoring methods for the analysis of drugs in topical formulations are collected and the main approaches for the drug photostabilization are discussed.

Pharmaceutical versatility of cationic niosomes derived from amino acid-based surfactants: Skin penetration behavior and controlled drug release.

The natural capability shown by cationic vesicles in interacting with negatively charged surfaces or biomolecules has recently attracted increased interest. Important pharmacological advantages include the selective targeting of the tumour vasculature, the promotion of permeation across cell membranes, as well as the influence of cationic vesicles on drug delivery. Accordingly, cationic amphiphiles derived from amino acids may represent an alternative to traditional synthetic cationic surfactants due to their lower cytotoxicity. The importance of a synthesized lysine-based gemini surfactant (labelledC6(LL)2) was evaluated in drug delivery by designing cationic niosomes as usable pharmaceutical tools of chemotherapeutics and antibiotics, respectively like methotrexate and tetracycline. The influence of formulation factors on the vesicles' physical-chemical properties, drug entrapment efficiency, in vitro release and ex-vivo skin permeation were investigated. A niosomal gel containing the gemini surfactant was also tested as a viable multi-component topical formulation. Results indicate that in the presence of cholesterol, C6(LL)2 was able to form stable and nanosized niosomes, loading hydrophilic or hydrophobic molecules. Furthermore, in vitro release studies and ex-vivo permeation profiles showed that C6(LL)2-based vesicles behave as sustained and controlled delivery systems in the case of parenteral administration, and as drug percutaneous permeation enhancers after topical application. Finally, cationic C6(LL)2 acts as a carrier constituent, conferring peculiar and interesting functionality to the final formulation.

Nanovesicular Formulations for Cancer Gene Therapy.

In the last decades, gene therapy has become a novel therapeutic strategy for cancer treatment, including immunologic and molecular approaches. Among molecular avenue, the design of efficient and effective gene delivery systems, like cationic liposomes and niosomes, has been widely investigated and proposed as the most promising research area. The advantages of cationic vesicles rely on their natural ability to form complexes with anionic genetic molecules and deliver them into the cells via the endosomal pathway. Obviously, cationic vesicles- mediated gene delivery is affected by numerous factors, in particular composition, that strongly affects vesicle physical-chemistry characteristics and transfection effectiveness. This review will analyse the potential of cationic nanocarriers in cancer gene therapy, focusing on the role of liposomes and niosomes as vesicular devices and giving an exhaustive collection of the most representative investigations.

Spontaneous temperature-sensitive Pluronic(®) based niosomes: Triggered drug release using mild hyperthermia.

Inclusion of lipids or polymers with a transition temperature closer to physiological body temperature (40-42°C) is a strategy used in tumor therapy for more than 30 years, because it allows induction of drug release from delivery systems by mild hyperthermia. Unfortunately, most of these thermo-sensitive carriers are removed from circulation before completion of their function. Thus, novel multi-functional niosomes possessing spontaneous stealth and thermo-sensitive properties were developed from L64 Pluronic(®) and L64ox as its derivative, in presence or absence of cholesterol. The use of L64 both as amphiphilic constituent and thermo-sensitive molecule, gave the possibility to bypass the use of additional excipients and increased the system biocompatibility. Niosomes diameter ranged from 400 to 750nm and were long term stable. Calcein and 5-FU possess great affinity to niosomal matrices rich in PEO groups. Negative Z-potential values were attributed to the negative charges onto the niosomes surface and generally change according to the temperature. The in vitro drugs release studies were performed at 25°C, 37°C and 42°C, that are representative of certain conditions (storage, physiological condition and mild hyperthermia, respectively). Results showed that L64-based niosomes possess spontaneous thermo-sensitive properties: drugs releases were found to be more pronounced at 42°C. These early results are a promising first step for the development of multi-functional devices that combine several advantages such as stealth properties and temperature controllability at the desired location and time, for a more specific and efficient pharmacological therapy.

Multi-functional vesicles for cancer therapy: The ultimate magic bullet.

Delivering chemotherapy specifically, effectively and safely to tumor remains a significant challenge in recent years. Although cancer cells are more vulnerable than normal to the effect of anticancer agents, these drugs are non-selective and can cause injury to normal tissues. Different approaches i.e. passive, active and magnetic targeting, smart devices with appropriate stimuli-sensitive properties or drugs combinations, have been already proposed as single methods, contributing to minimize severe side effects and enhancing tumor-targeting efficacy. Often, the use of a single strategy is not sufficient, whereby multi-functional approach has been suggested as further evolution of traditional "magic bullet" proposed in the early 1900s by Paul Ehrlich. Among the macromolecular systems useful for targeted drug delivery, liposomes and niosomes are the most extensively studied and they own the most suitable characteristics to be converted in multi-functional devices. Liposomes and niosomes are nanovesicles that contain amphiphilic molecules arranged in concentric bilayers, delimitating an aqueous core. These vesicular carriers are very versatile, since they can be differently designed and modified in such a way that they exhibit combinations of the following properties: longevity in blood, specific target to the tumor, respond to internal/external stimuli, promotion of drug intracellular delivery. This review will focus on the potential of multi-functional vesicular nanocarriers in cancer therapy, analizing each combination of targeting strategies, stimuli-sensitivity and drug combinations and giving an exhaustive collection of recent investigations. Many multi-functional vesicular devices have shown great promise in clinical application, indicating broad potential as therapeutics in the near future, but more needs to be done. The development of more specific and efficient carriers for a personalized cancer therapy is the next challenge.