Ultrasonic synthesis of green lipid nanocarriers loaded with Scutellaria barbata extract: a sustainable approach for enhanced anticancer and antibacterial therapy

Ultrasonic manufacturing has emerged as a promising eco-friendly approach to synthesize lipid-based nanocarriers for targeted drug delivery. This study presents the novel ultrasonic preparation of lipid nanocarriers loaded with Scutellaria barbata extract, repurposed for anticancer and antibacterial use. High-frequency ultrasonic waves enabled the precise self-assembly of DSPE-PEG, Span 40, and cholesterol to form nanocarriers encapsulating the therapeutic extract without the use of toxic solvents, exemplifying green nanotechnology. Leveraging the inherent anticancer and antibacterial properties of Scutellaria barbata, the study demonstrates that lipid encapsulation enhances the bioavailability and controlled release of the extract, which is vital for its therapeutic efficacy. Dynamic light scattering and transmission electron microscopy analyses confirmed the increase in size and successful encapsulation post-loading, along with an augmented negative zeta potential indicating enhanced stability. A high encapsulation efficiency of 91.93% was achieved, and in vitro assays revealed the loaded nanocarriers' optimized release kinetics and improved antimicrobial potency against Pseudomonas aeruginosa, compared to the free extract. The combination of ultrasonic synthesis and Scutellaria barbata in an eco-friendly manufacturing process not only advances green nanotechnology but also contributes to sustainable practices in pharmaceutical manufacturing. The data suggest that this innovative nanocarrier system could provide a robust platform for the development of nanotechnology-based therapeutics, enhancing drug delivery efficacy while aligning with environmental sustainability.

Advances in microscopy characterization techniques for lipid nanocarriers in drug delivery: a comprehensive review

This review paper provides an in-depth analysis of the significance of lipid nanocarriers in drug delivery and the crucial role of characterization techniques. It explores various types of lipid nanocarriers and their applications, emphasizing the importance of microscopy-based characterization methods such as light microscopy, confocal microscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The paper also delves into sample preparation, quantitative analysis, challenges, and future directions in the field. The review concludes by underlining the pivotal role of microscopy-based characterization in advancing lipid nanocarrier research and drug delivery technologies.

Promises of Lipid-Based Nanocarriers for Delivery of Dimethyl Fumarate to Multiple Sclerosis Brain

Multiple sclerosis (MS) is a neurodegenerative autoimmune disorder of the central nervous system (CNS) infecting 2.5 million people worldwide. It is the most common nontraumatic neurological impairment in young adults. The blood-brain barrier rupture for multiple sclerosis pathogenesis has two effects: first, during the onset of the immunological attack, and second, for the CNS self-sustained "inside-out" demyelination and neurodegeneration processes. In addition to genetic variations, environmental and lifestyle variables can also significantly increase the risk of developing MS. Dimethyl fumarate (DMF) and sphingosine-1-phosphate (S1P) receptor modulators that may pass the blood-brain barrier and have positive direct effects in the CNS with quite diverse mechanisms of action raise the possibility that a combination therapy could be successful in treating MS. Lipid nanocarriers are recognized as one of the best drug delivery techniques to the brain for effective brain delivery. Numerous scientific studies have shown that lipid nanoparticles can enhance the lipid solubility, oral bioavailability, and brain availability of the drugs. Nanolipidic carriers for DMF delivery could be derived through vitamin D, tocopherol acetate, stearic acid, quercetin, cell-mimicking platelet-based, and chitosan-alginate core-shell-corona-shaped nanoparticles. Clinical and laboratory diagnosis of MS can be performed mainly through magnetic resonance imaging. The advancements in nanotechnology have enabled the clinicians to cross the blood-brain barrier and to target the brain and central nervous system of the patient with multiple sclerosis.

Lipid Nano-System Based Topical Drug Delivery for Management of Rheumatoid Arthritis: An Overview

The overall purpose of rheumatoid arthritis (RA) treatment is to give symptomatic alleviation; there is no recognized cure for RA. Frequent use of potent drugs like non-steroidal anti-inflammatory drugs (NSAIDs) and disease-modifying antirheumatic drugs (DMARDs), lead to various adverse effects and patient compliance suffers. On the other hand, there are many drawbacks associated with traditional methods, such as high first pass, high clearance rate, and low bioavailability. Drug administration through the skin can be a promising alternative to cope with these drawbacks, increasing patient compliance and providing site-specific action. The stratum corneum, the uppermost non-viable epidermal layer, is one of the primary limiting barriers to skin penetration. Various nanocarrier technologies come into play as drug vehicles to help overcome these barriers. The nanocarrier systems are biocompatible, stable, and have a lower cytotoxic impact. The review discusses several lipid-based nanocarrier systems for anti-rheumatic medicines for topical administration it also discusses in-vivo animal models for RA and provides information on patents granted.

The diffusion-driven microfluidic process to manufacture lipid-based nanotherapeutics with stealth properties for siRNA delivery

Our study investigated the manufacturing of lipid-based nanotherapeutics with stealth properties for siRNA delivery by employing a diffusion-driven microfluidic process in one or two-steps strategies to produce siRNA-loaded lipid nanocarriers and lipoplexes, respectively. In the one-step synthesis, siRNA in the aqueous phase is introduced from one inlet, while phospholipids dispersed in anhydrous ethanol are introduced from other inlets, generating the lipid nanocarriers. In the two-steps strategies, the pre-formed liposomes are complexed with siRNA. The process configuration with an aqueous diffusion barrier exerts a significant effect on the nanoaggregates synthesis. Dynamic light scattering data showed that lipid nanocarriers had a bigger particle diameter (298 ± 24 nm) and surface charge (43 ± 6 mV) compared to lipoplexes (194 ± 7 nm and 37.0 ± 0.4 mV). Moreover, DSPE-PEG(2000) was included in the formulation to synthesize lipid-based nanotherapeutics containing siRNA with stealth characteristics. The inclusion of PEG-lipid resulted in an increase in the surface charge of lipoplexes (from 33.7 ± 4.4-54.3 ± 1.6 mV), while a significant decrease was observed in the surface charge of lipid nanocarriers (30.3 ± 8.7 mV). The different structural assemblies were identified for lipoplex and lipid nanocarriers using Synchrotron SAXS. Lipid nanocarriers present a lower amount of multilayers than lipoplexes. Lipid-PEG insertion significantly influenced lipid nanocarriers' characteristics, drastically decreasing the number of multilayers. This effect was not observed in lipoplexes. The association between process configuration, lipid composition, and its effect on the characteristics of lipid-based vector systems can generate fundamental insights, contributing to gene-based nanotherapeutics development.

Arginine-based cationic liposomes accelerate T cell activation and differentiation in vitro

Cationic liposomes are versatile lipid nanocarriers to improve the pharmacological properties of drug payloads. Recent advantages include the application of their intrinsic immunostimulatory effects to enhance immune activation. Herein, we report for the first time the structural effect of cationic lipids in promoting T cell activation and differentiation in vitro. Two types of cationic liposomes R3C14 and R5C14 were prepared from single type of lipids Arg-C3-Clu2C14 or Arg-C5-Clu2C14, which bear arginine head group and ditetradecyl tails but vary in the carbon number of the spacer in between. Murine CD8 or CD4 T cells were pretreated with 50 μM of each type of liposomes for 2 h, followed by stimulation with anti-CD3/CD28 antibodies for 24 h. In comparison to liposome-untreated T cells, R5C14-pretreatment induced a robust T cell activation (IL-2, CD25⁺) and differentiation into effector cells (CD44^high, CD62L^low), whereas R3C14 did not show comparable effect. Furthermore, a weak activation of nuclear factor of activated T cells (NFAT) was detected in Jurkat-Lucia NFAT cells (InvivoGen), suggesting a potential signaling pathway for the liposomal effect. Although R5C14 liposomes did not activate T cells without subsequent CD3/CD28 stimulation, this study implied a recessive effect of some cationic adjuvant in priming T cells to enhance their responsiveness to antigens.

Exploration of Lipid-Based Nanocarriers as Drug Delivery Systems in Diabetic Foot Ulcer

Diabetes mellitus is a chronic manifestation characterized by high levels of glucose in the blood resulting in several complications including diabetic wounds and ulcers, which predominantly require a longer duration of treatment and adversely affect the quality of life of the patients. Nanotechnology-based therapeutics (both intrinsic and extrinsic types) have emerged as a promising treatment in diabetic foot ulcer/chronic wounds owing to their unique characteristics and specific functional properties. In this review, we have focused on the significance of the use of lipids in the healing of diabetic ulcers, their interaction with the injured skin, and recent trends in lipid-based nanocarriers for the healing of diabetic wounds. Lipid nanocarriers are also being investigated for gene therapy in diabetic wound healing to encapsulate nucleic acids such as siRNA and miRNA, which could silence the expression of inflammatory cytokines overexpressed in chronic wounds. Additionally, these are also being explored for encapsulating proteins, peptides, growth factors, and other biological genetic material as therapeutic agents. Lipid-based nanocarriers encompassing a wide variety of carriers such as liposomes, niosomes, ethosomes, solid lipid nanoparticles, and lipidoid nanoparticles that are explored for the treatment of foot ulcers supplemented with relevant research studies have been discussed in the present review. Lipid-based nanodrug delivery systems have demonstrated promising wound healing potential, particularly in diabetic conditions due to the enhanced efficacy of the entrapped active molecules.

Lipid-Based Nanocarriers via Nose-to-Brain Pathway for Central Nervous System Disorders

Neurodegenerative disorders are distinguished by the gradual deterioration of the nervous system's structure and function due to oxidative stress, mitochondrial dysfunction, protein misfolding, excitotoxicity, and neuroinflammation. Among these NDs, Alzheimer's disease, Huntington's disease, Parkinson's disease, and amyotrophic lateral sclerosis characterized an increasing dysfunction and loss of neuronal structure leading to neuronal cell death. Although there is currently no drug to totally reverse the effects of NDs, such novel formulations and administration routes are developed for better management and nose-to-brain delivery is one of delivery for treating NDs. This review aimed to highlight advances in research on various lipid based nanocarriers such as liposomes, solid lipid nanoparticles, nanostructured lipid carriers, microemulsion, nanoemulsion, and cubosomes which are reported to treat and alleviate the symptoms of NDs via nose-to-brain route. The challenges during clinical translation of lipid nanocarriers from bench to bed side is also discussed.

Supramolecular lipid nanoparticles as delivery carriers for non-invasive cancer theranostics

Nanotheranostics is an emerging frontier of personalized medicine research particularly for cancer, which is the second leading cause of death. Supramolecular aspects in theranostics are quite allured to achieve more regulation and controlled features. Supramolecular nanotheranostics architecture is focused on engineering of modular supramolecular assemblies benefitting from their mutable and stimuli-responsive properties which confer an ultimate potential for the fabrication of unified innovative nanomedicines with controlled features. Amalgamation of supramolecular approaches to nano-based features further equip the potential of designing novel approaches to overcome limitations seen by the conventional theranostic strategies, for curing even the lethal diseases and endowing personalized therapeutics with optimistic prognosis, endorsing their clinical translation. Among many potential nanocarriers for theranostics, lipid nanoparticles (LNPs) have shown various promising advances in theranostics and their formulation can be tailored for several applications. Despite the great advancement in cancer nanotheranostics, there are still many challenges that need to be highlighted to fill the literature gap. For this purpose, herein, we have presented a systematic overview on the subject and proposed LNPs as the potential material to manage cancer via non-invasive approaches by highlighting the use of supramolecular approaches to make them robust for cancer theranostics. We have concluded the review by entailing the future perspectives of lipid nanotheranostics towards clinical translation.

Nanostructured lipid carriers (NLCs) as drug delivery platform: Advances in formulation and delivery strategies

NLCs have provoked the incessant impulsion for the development of safe and valuable drug delivery systems owing to their exceptional physicochemical and then biocompatible characteristics. Throughout the earlier period, a lot of studies recounting NLCs based formulations have been noticeably increased. They are binary system which contains both solid and liquid lipids aiming to produce less ordered lipidic core. Their constituents particularly influence the physicochemical properties and effectiveness of the final product. NLCs can be fabricated by different techniques which are classified according to consumed energy. More utilization NLCs is essential due to overcome barriers surrounded by the technological procedure of lipid-based nanocarriers' formulation and increased information of the core mechanisms of their transport via various routes of administration. They can be used in different applications and by different routes such as oral, cutaneous, ocular and pulmonary. This review article seeks to present an overview on the existing situation of the art of NLCs for future clinics through exposition of their applications which shall foster their lucid use. The reported records evidently demonstrate the promise of NLCs for innovate therapeutic applications in the future.

Dense nanolipid fluid dispersions comprising ibuprofen: Single step extrusion process and drug properties

Dense nanolipid fluid (DNLF) dispersions are highly concentrated aqueous dispersions of lipid nanocarriers (LNCs) with more than 10¹⁵ lipid particles per cubic centimeter. Descriptions of dense nanolipid fluid dispersions in the scientific literature are rare, and they have not been used to encapsulate drugs. In this paper we describe the synthesis of DNLF dispersions comprising ibuprofen using a recently described twin-screw extrusion process. We report that such dispersions are stable, bind ibuprofen tightly and yet provide high transdermal drug permeation. Ibuprofen DNLF dispersions prepared according to the present study provide up to five times greater flux of the pharmacologically active S-ibuprofen isomer through human skin than a commercially available racemic ibuprofen emulsion product. We demonstrate scaling up the twin-screw extrusion method to pilot production for a stable, highly permeating ibuprofen DNLF composition based on excipients approved by the US FDA for use in topical products as a key step towards development of a commercially viable, FDA approvable topical ibuprofen medicine to treat osteoarthritis, which has never before been accomplished.

Lipids from algal biomass provide new (nonlamellar) nanovectors with high carrier potentiality for natural antioxidants

Lipid mesophases are lyotropic liquid crystalline systems which differ from liposomes and other globular aggregates in dilute regimes due to their inner ordering. It is known that natural lipids enable to obtain a rich variety of nanosystems and many of them have been proposed as delivery agents for bioactive compounds. Due to their packing parameters, several classes of lipids found in natural sources are able to self-assemble into nonlamellar structures. Among lipids occurring in plants and algae, triglycerides display this tendency. In the present study we examine new nanosystems built with lipids extracted from the marine microalga Nannochloropsis sp and their use as carriers for lipophilic antioxidants. The antioxidants studied, curcumin and tocopherol were encapsulated with high rate in the carriers. The physico-chemical characterization of plain and loaded vectors showed their structure and localization site, as well as the structure-functionality relationship related to potential drug delivery. The results show that the cargo molecules play an active role in driving the interactions which characterize the overall structure of the aggregates. The systems studied showed several coexisting mesophases, the most predominant structure being of cubic symmetry.

One-step extrusion of concentrated lidocaine lipid nanocarrier (LNC) dispersions

Lipid nanocarriers (LNCs) have been successfully produced by many methods including high pressure homogenization, sonication and microemulsification, but it remains very difficult to produce dispersions with greater than 30% LNCs, volume average particle diameter less than 150 nm, and concentration of drugs useful for topical products. This research is the first to propose and demonstrate extrusion to manufacture highly concentrated drug containing LNC dispersions continuously and economically in a single step. By treating crude emulsions in a twin-screw extruder which has sections for homogenizing, mixing and fast-cooling inside the extruder, lidocaine-loaded LNC dispersions were successfully generated with lipid concentration up to 60% and particle diameters less than 50 nm. Electrical conductivity and birefringence measurements indicate that in the lidocaine system, lamellar microemulsions are intermediate structures and compositions with low lipid concentrations that do not present evidence of lamellar structures fail to give nanoparticles when processed. This paper also presents a new method for measuring kinetics of drug release from nanoparticles based on pH stat titration. Sufficiently precise data from pH stat titration allows determination of rate laws for release occurring on a time scale of minutes versus hours or days. The release rate of lidocaine from extruded 35% lipid nanoparticles was constant (zero order release kinetics) through the first hour (40% of drug release), a valuable property for drug delivery.

Current insights on lipid nanocarrier-assisted drug delivery in the treatment of neurodegenerative diseases

The central nervous system (CNS) is vulnerable to pathologic processes that lead to the development of neurodegenerative disorders like Alzheimer's, Parkinson's and Huntington's diseases, Multiple sclerosis or Amyotrophic lateral sclerosis. These are chronic and progressive pathologies characterized by the loss of neurons and the formation of misfolded proteins. Additionally, neurodegenerative diseases are accompanied by a structural and functional dysfunction of the blood-brain barrier (BBB). Although serving as a protection for the CNS, the existence of physiological barriers, especially the BBB, limits the access of several therapeutic agents to the brain, constituting a major hindrance in neurotherapeutics advancement. In this regard, nanotechnology-based approaches have arisen as a promising strategy to not only improve drug targeting to the brain, but also to increase bioavailability. Lipid nanocarriers such as liposomes, solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC), microemulsions and nanoemulsions, have already proven their potential for enhancing brain transport, crossing more easily into the CNS and allowing the administration of medicines that could benefit the treatment of neurological pathologies. Given the socioeconomic impact of such conditions and the advent of nanotechnology that inevitably leads to more effective and superior therapeutics for their management, it is imperative to constantly update on the current knowledge of these topics. Herein, we provide insight on the BBB and the pathophysiology of the main neurodegenerative disorders. Moreover, this review seeks to highlight the several approaches that can be used to improve the delivery of therapeutic agents to the CNS, while also offering an extensive overview of the latest efforts regarding the use of lipid-based nanocarriers in the management of neurodegenerative diseases.

Lipid-based nano delivery of antimicrobials to control food-borne bacteria

Direct application of antibacterial agents into foods gives limited advantages because bioactive ingredients may be partially inactivated, neutralized, or easily diffused when contacting with the food matrix. Hence, the aim of this study is to investigate the application of lipid-based nanocarriers as delivery systems for antibacterial ingredients. In this regard, several types of these carriers such as nanoliposomes, nanoemulsions, solid lipid nanoparticles (SLNs), and nanostructured lipid carriers (NLCs) are explored. This study seeks to cover the important challenges of lipid-based nanocarriers including structures and characteristics, properties, production methods, advantages and drawbacks, and their applications to encapsulate antibacterial compounds effectively, particularly in food systems. However, for more scrutiny inspection of the functionality of lipid-based nanocarriers, we have gathered and discussed the studies related to the antibiotic-loaded lipid-based nanoparticles. Also, the role of such nanocarriers in active packaging systems when combining with edible coatings or films is discussed.

Lipid-based Nanosized Delivery Systems for Fluoroquinolones: a Review

BACKGROUND

The class of fluoroquinolone antibiotics, due to its core chemical modifications, is considered as wide-spectrum antibacterial drugs with useful pharmacokinetic and pharmacodynamic properties. However, because of their poor solubility in water, they are used as salts (lactates or hydrochlorides). Fluoroquinolones, bacterial membranes and eukaryotic cell membranes interactions are well known and their permeation properties are well investigated. In fact, they are concentrated inside the cells and intracellular compartments. Nanotechnology in Drug Delivery has developed many supra-molecular structures that have been used to improve both pharmacokinetic and pharmacodynamic properties. The main results of the published papers showed reduction of toxicity, higher intracellular concentrations (both bacteria and eukaryotic), enhancement of antimicrobial activity, prolonged drug release, decreased mortality in animal model studies, improved water solubility and improved in vitro efficacy against intracellular pathogens.

METHODS

a literature search was performed in the NCBI-PUBMED database, with no time range, using the keywords "solid lipid nanoparticles" and 'quinolones' or the name of single antibiotics.

RESULTS

the most important aspects of lipid-based nanocarrier technology used for fluoroquinolones have been highlighted, with a focus on the latest formulation developments that have led to significant improvements of pharmacokinetics and pharmacodynamics. Both technological and microbiological aspects of published papers have been discussed.

CONCLUSION

the potentiality of using lipid nanoparticles to improve the efficacy and potency of quinolone antibiotics has been supported by recent scientific publications, although some criticism appeared due to the microbiological investigative methods used and because of lack of systematic evaluation about the influence of technological approaches to the in vitro and in vivo drug activity.

Cytotoxicity and genotoxicity of lipid nanocapsules

Lipid nanocapsules (LNCs) offer a promising method for the entrapment and nanovectorisation of lipophilic molecules. This new type of nanocarrier, formulated according to a solvent-free process and using only regulatory-approved components, exhibits many prerequisites for being well tolerated. Although toxicological reference values have already been obtained in mice, interaction of LNCs at the cell level needs to be elucidated. LNCs, measuring from 27.0±0.1nm (25nm LNCs) and 112.1±1.8nm (100nm LNCs) and with a zeta potential between -38.7±1.2mV and +9.18±0.4mV, were obtained by a phase inversion process followed by post-insertion of carboxy- or amino-DSPE-PEG. Trypan blue, MTS and neutral red uptake (NRU) assays were performed to evaluate the cytotoxicity of LNCs on mouse macrophage-like cells RAW264.7 after 24h of exposure. The determination of 50% lethal concentration (LC50) showed a size effect of LNCs on toxicity profiles: LC50 ranged from 1.036mg/L (MTS) and 0.477mg/mL (NRU) for 25nm LNCs, to 4.42mg/mL (MTS) and 2.18mg/mL (NRU) for 100nm LNCs. Surfactant Solutol® HS15 has been shown to be the only constituent to exhibit cytotoxicity; its LC50 reached 0.427mg/mL. Moreover, LNCs were not more toxic than their components in simple mixtures. At sublethal concentration, 100nm LNCs only were able to induce a significant production of nitric oxide (NO) by RAW264.7 cells, as assessed by the Griess reaction. Again, surfactant was the only component responsible for an increased NO release (1.8±0.2-fold). Genotoxicity assays revealed no DNA damage on human lymphocytes in both the in vitro Comet and micronucleus assays using 4-hour and 24-hour treatments, respectively.

Transdermal Lipid Nanocarriers: A Potential Delivery System for Lornoxicam

BACKGROUND

Lornoxicam, is a NSAID of the oxicam class. Its short duration of action owing to rapid elimination and gastrointestinal side effects limits its usefulness when administered orally.

OBJECTIVE

The primary objective of the proposed work is to develop suitable lipid nanocarriers for transdermal delivery of Lornoxicam with increased drug residence time at local site of inflamation and in systemic circulation, overcoming undesired gastrointestinal side effects.

METHOD

Lornoxicam loaded lipid nanocarriers like solid lipid nanocarriers (SLN), nano-structured lipid carriers (NLC) & nanoemulsions (NE) were prepared by high-speed homogenization technique.

RESULT

The particle size, zeta potential, and polydispersity index as obtained, were in the range of 140- 193 nm, -22 to -32 mV, and 0.354-0.301 for SLN formulations and 146-201 nm, -23 to -30 mV, and 0.355-0.354 for NLC formulations respectively. Characterization of stable NE revealed that globule size, zeta potential and polydispersity index were within the range of 138 to 195 nm, -26.1±0.123 mV and 0.195 ± 1.231 respectively. It was also observed that entrapment efficacy and drug loading improved as the lipid concentration was increased. The results obtained from the in vitro permeation study and in vivo anti-inflammatory study showed controlled drug permeation, increased bioavailability, longer retention and better therapeutic potential of Lornoxicam after transdermal application of lipid nanoparticles as compared to conventional gel.

CONCLUSION

It can be concluded that the developed lipid nanoparticle loaded gel was found to be a suitable drug delivery carrier for transdermal delivery of Lornoxicam to increase the residence time of drug in systemic circulation and to combat the gastrointestinal side effects.

How can lipid nanocarriers improve transdermal delivery of olanzapine?

The development of a transdermal nanocarrier drug delivery system with potential for the treatment of psychiatric disorders, such as schizophrenia and bipolar disorder, is described. Lipid nanocarriers (LN), encompassing various solid:liquid lipid compositions were formulated and assessed as potential nanosystems for transdermal delivery of olanzapine. A previously optimized method of hot high pressure homogenization (HPH) was adopted for the production of the LN, which comprised solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC) and nanoemulsions (NE). Precirol^® was selected as the solid lipid for progression of studies. SLN exhibited the best performance for transdermal delivery of olanzapine, based on in vitro release and permeation studies, coupled with results from physicochemical characterization of several solid:liquid lipid formulations. Stability tests, performed to give an indication of long-term storage behavior of the formulations, were in good agreement with previous studies for the best choice of solid:liquid lipid ratio. Overall, these findings highlight the SLN-based formulation as promising for the further inclusion in and production of transdermal patches, representing an innovative therapeutic approach.

Integrity of lipid nanocarriers in bloodstream and tumor quantified by near-infrared ratiometric FRET imaging in living mice

Lipid nanocarriers are considered as promising candidates for drug delivery and cancer targeting because of their low toxicity, biodegradability and capacity to encapsulate drugs and/or contrasting agents. However, their biomedical applications are currently limited because of a poor understanding of their integrity in vivo. To address this problem, we report on fluorescent nano-emulsion droplets of 100 nm size encapsulating lipophilic near-infrared cyanine 5.5 and 7.5 dyes with a help of bulky hydrophobic counterion tetraphenylborate. Excellent brightness and efficient Förster Resonance Energy Transfer (FRET) inside lipid NCs enabled for the first time quantitative fluorescence ratiometric imaging of NCs integrity directly in the blood circulation, liver and tumor xenografts of living mice using a whole-animal imaging set-up. This unique methodology revealed that the integrity of our FRET NCs in the blood circulation of healthy mice is preserved at 93% at 6 h of post-administration, while it drops to 66% in the liver (half-life is 8.2 h). Moreover, these NCs show fast and efficient accumulation in tumors, where they enter in nearly intact form (77% integrity at 2 h) before losing their integrity to 40% at 6 h (half-life is 4.4 h). Thus, we propose a simple and robust methodology based on ratiometric FRET imaging in vivo to evaluate quantitatively nanocarrier integrity in small animals. We also demonstrate that nano-emulsion droplets are remarkably stable nano-objects that remain nearly intact in the blood circulation and release their content mainly after entering tumors.

Parenteral formulation of an antileishmanial drug candidate--tackling poor solubility, chemical instability, and polymorphism

The paullon chalcone derivative KuRei300 is active against Leishmania donovani, the protozoans causing visceral leishmaniasis. The aim of this study was the development of a parenteral formulation of the virtually water insoluble compound in order to enable future studies in mice. Mixed lecithin/bile salt micelles, liposomes, supercooled smectic cholesterol myristate nanoparticles, cubic phase nanoparticles and a triglyceride emulsion were screened for their solubilizing properties. Due to the limited available amount of KuRei300 a passive loading approach with pre-formulated carriers that were incubated with drug substance deposited onto the walls of glass vials was used. The loading capacities of the nanocarriers, the influence of the solid state properties of the drug and its deposits on the loading results and chemical stability aspects of KuRei300 were investigated. Employed methods included HPLC, UV spectroscopy, (1)H NMR, XRPD, and DSC. All nanocarriers substantially improved the solubility of KuRei300; the mixed micelles exhibited the highest drug load. Related to the lipid matrix, however, the smectic nanoparticles solubilized the significantly highest amount of drug. Loading from physically altered drug deposits improved the obtainable concentration to the threefold compared with untreated drug powder. Formulations with KuRei300 must be stored excluded from light under a nitrogen atmosphere as the substance is susceptible to photoisomerization and decomposition.