Cubic phase nanoparticles (Cubosome): principles for controlling size, structure, and stability

Hybrid crystalline bioparticles with nanochannels encapsulating acemannan from Aloe vera: Structure and interaction with lipid membranes

Smart nanocarrier-based bioactive delivery systems are a current focus in nanomedicine for allowing and boosting diverse disease treatments. In this context, the design of hybrid lipid-polymer particles can provide structure-sensitive features for tailored, triggered, and stimuli-responsive devices. In this work, we introduce hybrid cubosomes that have been surface-modified with a complex of chitosan-N-arginine and alginate, making them pH-responsive. We achieved high-efficiency encapsulation of acemannan, a bioactive polysaccharide from Aloe vera, within the nanochannels of the bioparticle crystalline structure and demonstrated its controlled release under pH conditions mimicking the gastric and intestinal environments. Furthermore, an acemannan-induced phase transition from Im3m cubic symmetry to inverse hexagonal HII phase enhances the bioactive delivery by compressing the lattice spacing of the cubosome water nanochannels, facilitating the expulsion of the encapsulated solution. We also explored the bioparticle interaction with membranes of varying curvatures, revealing thermodynamically driven affinity towards high-curvature lipid membranes and inducing morphological transformations in giant unilamellar vesicles. These findings underscore the potential of these structure-responsive, membrane-active smart bioparticles for applications such as pH-triggered drug delivery platforms for the gastrointestinal tract, and as modulators and promoters of cellular internalization.

Preparation and characterization of macrophage membrane camouflaged cubosomes as a stabilized and immune evasive biomimetic nano-DDS

This study aims to develop a biomimetic nano-drug delivery system (nano-DDS) by employing a macrophage cell membrane camouflaging strategy to modify lyotropic liquid crystal nanoparticles (LLC-NPs). The cubic-structured LLC-NPs (Cubosomes, CBs) were prepared via a top-down approach (ultra-sonification) using monoolein (MO) and doped with the cationic lipid, DOTAP. The cell membrane camouflaging procedure induced changes in the cubic lipid phase from primitive cubic phase (QIIP) to a coexistence of QIIP and diamond cubic phase (QIID). The macrophage membrane camouflaging strategy protected CB cores from the destabilization by blood plasma and enhanced the stability of CBs. The in vitro experiment results revealed that the macrophage cell membrane coating significantly reduced macrophage uptake efficacy within 8 h of incubation compared to the non-camouflaged CBs, while it had minimal impact on cancer cell uptake efficacy. The macrophage membrane coated CBs showed lower accumulation in the heart, kidney and lungs in vivo. This study demonstrated the feasibility of employing cell membrane camouflaging on CBs and confirmed that the bio-functionalities of the CBs-based biomimetic nano-DDS were retained from the membrane source cells, and opened up promising possibilities for developing an efficient and safe drug delivery system based on the biomimetic approach.

Recent Advances in the Use of Cubosomes as Drug Carriers with Special Emphasis on Topical Applications

Topical drug delivery employing drug nanocarriers has shown prominent results in treating topical ailments, especially those confined to the skin and eyes. Conventional topical formulations persist with drug and disease-related challenges during treatment. Various nanotechnology-driven approaches have been adopted to mitigate the issues associated with conventional formulations. Among these, cubosomes have shown potential applications owing to their liquid crystalline structure, which aids in bioadhesion, retention, sustained release, and loading hydrophilic and hydrophobic moieties. The phase transition behavior of glyceryl monooleate, the concentration of stabilizers, and critical packing parameters are crucial parameters that affect the formation of cubosomes. Microfluidics-based approaches constitute a recent advance in technologies for generating stable cubosomes. This review covers the recent topical applications of cubosomes for treating skin (psoriasis, skin cancer, cutaneous candidiasis, acne, and alopecia) and eye (fungal keratitis, glaucoma, conjunctivitis, and uveitis) diseases. The article summarizes the manufacturing and biological challenges (skin and ocular barriers) that must be considered and encountered for successful clinical outcomes. The patented products are successful examples of technological advancements within cosmeceuticals that support various topical applications with cubosomes in the pharmaceutical field.

Vesicular approach of cubosomes, its components, preparation techniques, evaluation and their appraisal for targeting cancer cells

Cancer has been characterized by abnormal and uncontrolled proliferation of cells. Majority of drugs given through chemotherapy produce unwanted and adverse effects of chemotherapeutic agents to the other healthy cells and tissues of body. Various nanocarriers have now been considered for treatment of cancer. Among various nanocarriers, cubosomes are the nano sized dispersions that have drawn interest of researchers recently. Cubosomes are defined as dispersions of colloidal nature containing cubic crystalline liquid formations in aqueous medium in presence of suitable surfactant molecules. The unique capacity to encapsulate lipophilic, hydrophilic, and amphiphilic compounds inside their structure distinguishes them among others. Top- down method and hydrotrope method are most often employed methods for cubosomes preparation. Cubosomes can be characterized by Polarized light microscopy Photon correlation spectroscopy X-ray scattering (SAXS), Transmission electron microscopy and various stability studies. Cubic lipid nanoparticles have a very stable cubic structure that enables slower dissociation rate, increased retention and site-specific delivery of drugs. Cubosomes containing extracts of cornelian cherry for boosting anti-cancerous effects in cancer of colorectal cells by preventing against GIT destruction. When applied for skin cancer, cubosomes have shown to be having enhanced permeation of the drug. In liver cancer, increased bioavailability of drug was observed via cubosomes. This current review elaborates the advancement of cubosomes and their effective role in the treatment of cancer. This review aims to describe vesicular approach of cubosomes, its composition and method of preparation, characterization tests as well as elaborates various applications of cubosomes in cancer.

Development and approval of novel injectables: enhancing therapeutic innovations

INTRODUCTION

Novel injectables possess applications in both local and systemic therapeutics delivery. The advancement in utilized materials for the construction of complex injectables has tremendously upgraded their safety and efficacy.

AREAS COVERED

This review focuses on various strategies to produce novel injectables, including oily dispersions, in situ forming implants, injectable suspensions, microspheres, liposomes, and antibody-drug conjugates. We herein present a detailed description of complex injectable technologies and their related drug formulations permitted for clinical use by the United States Food and Drug Administration (USFDA). The excipients used, their purpose and the challenges faced during manufacturing such formulations have been critically discussed.

EXPERT OPINION

Novel injectables can deliver therapeutic agents in a controlled way at the desired site. However, several challenges persist with respect to their genericization. Astronomical costs incurred by innovator companies during product development, complexity of the product itself, supply limitations with respect to raw materials, intricate manufacturing processes, patent evergreening, product life-cycle extensions, relatively few and protracted generic approvals contribute to the exorbitant prices and access crunch. Moreover, regulatory guidance are grossly underdeveloped and significant efforts have to be directed toward development of effective characterization techniques.

Angiopep-2-Functionalized Lipid Cubosomes for Blood-Brain Barrier Crossing and Glioblastoma Treatment

Glioblastoma multiforme (GBM) is an aggressive brain cancer with high malignancy and resistance to conventional treatments, resulting in a bleak prognosis. Nanoparticles offer a way to cross the blood-brain barrier (BBB) and deliver precise therapies to tumor sites with reduced side effects. In this study, we developed angiopep-2 (Ang2)-functionalized lipid cubosomes loaded with cisplatin (CDDP) and temozolomide (TMZ) for crossing the BBB and providing targeted glioblastoma therapy. Developed lipid cubosomes showed a particle size of around 300 nm and possessed an internal ordered inverse primitive cubic phase, a high conjugation efficiency of Ang2 to the particle surface, and an encapsulation efficiency of more than 70% of CDDP and TMZ. In vitro models, including BBB hCMEC/D3 cell tight monolayer, 3D BBB cell spheroid, and microfluidic BBB/GBM-on-a-chip models with cocultured BBB and glioblastoma cells, were employed to study the efficiency of the developed cubosomes to cross the BBB and showed that Ang2-functionalized cubosomes can penetrate the BBB more effectively. Furthermore, Ang2-functionalized cubosomes showed significantly higher uptake by U87 glioblastoma cells, with a 3-fold increase observed in the BBB/GBM-on-a-chip model as compared to that of the bare cubosomes. Additionally, the in vivo biodistribution showed that Ang2 modification could significantly enhance the brain accumulation of cubosomes in comparison to that of non-functionalized particles. Moreover, CDDP-loaded Ang2-functionalized cubosomes presented an enhanced toxic effect on U87 spheroids. These findings suggest that the developed Ang2-cubosomes are prospective for improved BBB crossing and enhanced delivery of therapeutics to glioblastoma and are worth pursuing further as a potential application of nanomedicine for GBM treatment.

Water-lipid interface in lipidic mesophases with excess water

This study investigates the influence of excess water on the lipidic mesophase during the phase transition from diamond cubic phase (Pn3̄m) to reverse hexagonal phase (HII). Using a combination of small angle X-ray scattering (SAXS), broadband dielectric spectroscopy (BDS), and Fourier transform infrared (FTIR) techniques, we explore the dynamics of lipids and their interaction with water during phase transition. Our BDS results reveal three relaxation processes originating from lipids, all of which exhibit a kink during the phase transition. With the excess water, these processes accelerate due to the plasticizing effect of water. Additionally, our results demonstrate that the headgroups in the HII phase are more densely packed than those in the Pn3̄m phase, which agrees with the FTIR results. Meanwhile, we investigate the influence of excess water on the lipid headgroups, the H-bond network of water, the lipid tail, and the interface carbonyl group between the head and tail of the lipid molecule. The results indicate that excess water permeates the lipid interface and forms additional hydrogen bonds with the carbonyl groups. As a result, the headgroups are more flexible in a lipidic mesophase with excess water than those in mesophases without excess water.

Cubosomes: An Emerging and Promising Drug Delivery System for Enhancing Cancer Therapy

Cancer and other diseases can be treated with cubosomes, which are lyotropic nonlamellar liquid crystalline nanoparticles (LCNs). These cubosomes can potentially be a highly versatile carrier with theranostic efficacy, as they can be ingested, applied topically, or injected intravenously. Recent years have seen substantial progress in the synthesis, characterization, regulation of drug release patterns, and target selectivity of loaded anticancer bioactive compounds. However, its use in clinical settings has been slow and necessitates additional proof. Recent progress and roadblocks in using cubosomes as a nanotechnological intervention against various cancers are highlighted. In the last few decades, advances in biomedical nanotechnology have allowed for the development of "smart" drug delivery devices that can adapt to external stimuli. By improving therapeutic targeting efficacy and lowering the negative effects of payloads, these well-defined nanoplatforms can potentially promote patient compliance in response to specific stimuli. Liposomes and niosomes, two other well-known vesicular systems, share a lipid basis with cubosomes. Possible applications include a novel medication delivery system for hydrophilic, lipophilic, and amphiphilic drugs. We evaluate the literature on cubosomes, emphasizing their potential use in tumor-targeted drug delivery applications and critiquing existing explanations for cubosome self-assembly, composition, and production. As cubosome dispersion has bioadhesive and compatible features, numerous drug delivery applications, including oral, ocular, and transdermal, are also discussed in this review.

Intrinsic and Dynamic Heterogeneity of Nonlamellar Lyotropic Liquid Crystalline Nanodispersions

Nonlamellar lyotropic liquid crystalline (LLC) nanoparticles are a family of versatile nano-self-assemblies, which are finding increasing applications in drug solubilization and targeted drug delivery. LLC nanodispersions are heterogeneous with discrete nanoparticle subpopulations of distinct internal architecture and morphology, frequently coexisting with micelles and/or vesicles. Diversity in the internal architectural repertoire of LLC nanodispersions grants versatility in drug solubilization, encapsulation, and release rate. However, drug incorporation contributes to the heterogeneity of LLC nanodispersions, and on exposure to biological media, LLC nanodispersions often undergo nanostructural and morphological transformations. From a pharmaceutical perspective, coexistence of multiple types of nanoparticles with diverse structural attributes, together with media-driven transformations in colloidal characteristics, brings challenges in dissecting biological and therapeutic performance of LLC nanodispersions in a spatiotemporal manner. Here, we outline innate and acquired heterogeneity of LLC nanodispersions and discuss technological developments and alternative approaches needed to improve homogeneity of LLC formulations for drug delivery applications.

Formulation and evaluation of simvastatin cubosomal nanoparticles for assessing its wound healing effect

Wound healing is one of the most challenging medical circumstances for patients. Pathogens can infect wounds, resulting in tissue damage, inflammation, and disruption of the healing process. Simvastatin was investigated recently, as a wound healing agent that may supersede the present therapies for wounds. Our goal in this paper is to focus on formulation of simvastatin cubosomes for topical delivery, as a potential approach to improve simvastatin skin permeation. By this technique its wound healing effect could be improved. Cubosomes were prepared using the top-down method and the prepared cubosomes were characterized by several techniques. The most optimal simvastatin cubosomal formulation was then included in a cubogel dosage form using different gelling agents. The results showed that the average particle size of the prepared cubosomes was 113.90 ± 0.58 nm, the entrapment efficiency was 93.95 ± 0.49% and a sustained simvastatin release was achieved. The optimized formula of simvastatin cubogel displayed pseudoplastic rheological behavior. This same formula achieved enhancement in drug permeation through excised rat skin compared to free simvastatin hydrogel with flux values of 46.18 ± 2.12 mcg cm-2 h-1 and 25.92 ± 3.45 mcg cm-2 h-1 respectively. Based on the in-vivo rat studies results, this study proved a promising potential of simvastatin cubosomes as wound healing remedy.

Preparation of Cubosomes with Improved Colloidal and Structural Stability Using a Gemini Surfactant

Cubosomes are nanoparticles with bicontinuous cubic internal nanostructures that have been considered for use in drug delivery systems (DDS). However, their low structural stability is a crucial concern for medical applications. Herein, we investigated the use of a gemini surfactant, sodium dilauramidoglutamide lysine (DLGL), which is composed of two monomeric surfactants linked with a spacer to improve the structural stability of cubosomes prepared with phytantriol (PHY). Uniform nanosuspensions comprising a specific mixing ratio of DLGL and PHY in water prepared via ultrasonication were confirmed by using dynamic light scattering. Small-angle X-ray scattering and cryo-transmission electron microscopy revealed the formation of Pn3̅m cubosomes in a range of DLGL/PHY solid ratios between 1 and 3% w/w. By contrast, cubosome formation was not observed at DLGL/PHY solid ratios of 5% w/w or higher, suggesting that excess DLGL interfered with cubosome formation and caused them to transform into small unilamellar vesicles. The addition of phosphate-buffered saline to the nanosuspension caused aggregation when the solid ratio of DLGL/PHY was less than 5% w/w. However, Im3̅m cubosomes were obtained at solid ratios of DLGL/PHY of 6, 7.5, and 10% w/w. The lattice parameters of the Pn3̅m and Im3̅m cubosomes were approximately 7 and 11-13 nm, respectively. The lattice parameters of Im3̅m cubosomes were affected by the concentration of DLGL. Pn3̅m cubosomes were surprisingly stable for 4 weeks at both 25 and 5 °C. In conclusion, DLGL, a gemini surfactant, was found to act as a new stabilizer for PHY cubosomes at specific concentrations. Cubosomes composed of DLGL are stable under low-temperature storage conditions, such as in refrigerators, making them a viable option for heat-sensitive DDS.

Cubic nanoparticles as potential carriers for a natural anticancer drug: development, in vitro and in vivo characterization

Natural compounds that elicit anticancer properties are of great interest for cancer therapy. However, the low solubility and bioavailability of these compounds limit their use as efficient anticancer drugs. To avoid these drawbacks, incorporation of these compounds into cubic nanoparticles (cubosomes) was carried out. Cubosomes containing bergapten which is a natural anticancer compound isolated from Ficus carica were prepared by the homogenization technique using monoolein and poloxamer. These cubosomes were characterized for size, zeta potential, entrapment efficiency, small angle X-ray diffraction, in vitro release, in vitro cytotoxicity, cellular uptake, and antitumor activity. Particle size of cubosomes was 220 ± 3.6 nm with almost neutral zeta potential - 5 ± 1.2 mV and X-ray measurements confirmed the existence of the cubic structure. Additionally, more than 90% of the natural anticancer drug was entrapped within the cubosomes. A sustained release over 30 h was obtained for these cubosomes. Finally, these cubosomes illustrated higher in vitro cytotoxicity and in vivo tumor inhibition compared with the free natural anticancer compound. Thus, cubosomes could be promising carriers for enhancement of antitumor efficiency of this natural compound.

Darifenacin Self-assembled Liquid Crystal Cubic Nanoparticles: a Sustained Release Approach for an Overnight Control of Overactive Bladder

The current study is regarding the development and characterization of Darifenacin-loaded self-assembled liquid crystal cubic nanoparticles (LCCN). An anhydrous approach was used for the preparation of these cubic nanoparticles using a hydrotropic agent (propylene glycol), with minimal energy input. Upon dispersion in aqueous medium, the system was successfully transformed to cubosomal nanoparticles counterpart as depicted by transmission electron micrographs. A Box-Behnken design was used to optimize formulation variables, namely A: amount of GMO, B: amount of Pluronic F127, C: amount of PG, and D: amount of HPMC. The design has generated 29 formulae which were tested regarding drug content uniformity, dispersibility in water, particle size, zeta potential, polydispersity index, and in vitro release behavior. The numerical optimization algorithms have generated an optimized formula with high desirability ≈ 1. The optimized formula displayed small particle size, good homogeneity, and zeta potential along with controlled in vitro release profile and ex vivo permeation through rabbit intestine. Thus, self-assembled LCCN might offer an alternative anhydrous approach for the preparation of cubosomal nanoparticles with controlled release profile for a possibly better control of overactive bladder syndrome which tremendously affect the overall life quality.

Lipid-Based Inhalable Micro- and Nanocarriers of Active Agents for Treating Non-Small-Cell Lung Cancer

Non-small-cell lung cancer (NSCLC) afflicts about 2 million people worldwide, with both genetic (familial) and environmental factors contributing to its development and spread. The inadequacy of currently available therapeutic techniques, such as surgery, chemotherapy, and radiation therapy, in addressing NSCLC is reflected in the very low survival rate of this disease. Therefore, newer approaches and combination therapy regimens are required to reverse this dismal scenario. Direct administration of inhalable nanotherapeutic agents to the cancer sites can potentially lead to optimal drug use, negligible side effects, and high therapeutic gain. Lipid-based nanoparticles are ideal agents for inhalable delivery owing to their high drug loading, ideal physical traits, sustained drug release, and biocompatibility. Drugs loaded within several lipid-based nanoformulations, such as liposomes, solid-lipid nanoparticles, lipid-based micelles, etc., have been developed as both aqueous dispersed formulations as well as dry-powder formulations for inhalable delivery in NSCLC models in vitro and in vivo. This review chronicles such developments and charts the future prospects of such nanoformulations in the treatment of NSCLC.

Cubosomes in Drug Delivery-A Comprehensive Review on Its Structural Components, Preparation Techniques and Therapeutic Applications

Cubosomes are lipid vesicles that are comparable to vesicular systems like liposomes. Cubosomes are created with certain amphiphilic lipids in the presence of a suitable stabiliser. Since its discovery and designation, self-assembled cubosomes as active drug delivery vehicles have drawn much attention and interest. Oral, ocular, transdermal, and chemotherapeutic are just a few of the drug delivery methods in which they are used. Cubosomes show tremendous potential in drug nanoformulations for cancer therapeutics because of their prospective advantages, which include high drug dispersal due to the structure of the cubic, large surface area, a relatively simple manufacturing process, biodegradability, ability to encapsulate hydrophobic, hydrophilic, and amphiphilic compounds, targeted and controlled release of bioactive agents, and biodegradability of lipids. The most typical technique of preparation is the simple emulsification of a monoglyceride with a polymer, followed by sonication and homogenisation. Top-down and bottom-up are two different sorts of preparation techniques. This review will critically analyse the composition, preparation techniques, drug encapsulation approaches, drug loading, release mechanism and applications relevant to cubosomes. Furthermore, the challenges faced in optimising various parameters to enhance the loading capacities and future potentialities are also addressed.

Remote Loading of Hydrophilic Drug into Cubosomes by Transmembrane pH-Gradient and Characterization of Drug-Loaded Cubosomes Prepared by Different Method

The encapsulation efficiency (EE) of hydrophobic drug into cubosomes was high by conventional methods, while poor for the hydrophilic drug. In this study, a remote loading method based on transmembrane pH-gradient was applied to prepare hydrophilic drug loaded cubosomes. Several hydrophilic drugs were selected and studied. Results showed just part of the investigated drugs were successfully loaded into cubosomes by the remote loading method, whereas all the drugs failed to be encapsulated by the high-pressure homogenization method. The EE based on remote loading method was affected by the solubility, LogP, number of rings, and polarizability of the drug independent of the number of hydrogen acceptor and hydrogen donor. And the drugs that had high EE by remote loading method were BCS class 1 or 2. In addition, the EE base on remote loading method was significantly affected by the external water pH of cubosomes and drug concentration. The size of drug-loaded cubosomes by remote loading method mainly depended on the pre-formed blank cubosomes, which was bigger than that by high-pressure homogenization method. The preparation method affected the liquid crystalline structure of acidic drug loaded cubosomes, while showed no obvious effect on that of basic drug loaded cubosomes. The release of drug was susceptible to the pH of release medium independent of the preparation method. The drug-loaded cubosomes prepared by different method all showed favorable stability during storage. The remote loading method was a promising approach for the efficient encapsulation of hydrophilic drug into cubosomes. This study laid a foundation for the application of remote loading method on the preparation of hydrophilic drug loaded cubosomes.

Comparative study on the performance of monoolein cubic nanoparticles and trimyristin solid lipid nanoparticles as carriers for docetaxel

Nowadays the application of lipid nanoparticles as carriers for the delivery of anticancer drugs gained great attention in cancer therapy. Solid lipid nanoparticles (SLN_s) and cubic nanoparticles (cubosomes) are considered as promising carriers in cancer therapy. The comparison of these two lipid nanoparticles as efficient carriers for the anticancer drug docetaxel was our main goal in this study. Both nanoparticles were prepared by the hot melt homogenization technique followed by measurement of particle size, zeta potential, entrapment efficiency and in vitro release of docetaxel. An advanced technique has been applied to measure the release of docetaxel from these nanoparticles using small unilamellar vesicles (SUV_s) as acceptor particles which resemble many compartments in our body. All prepared nanoparticles revealed a neutral zeta potential with particle sizes of about 200 nm. While SUV_s showed a negative surface charge with a zeta potential of -55 mV, cubosomes showed higher entrapment efficiency and a slower docetaxel release compared to SLN_s. Additionally, cubosomes improved in vitro cytotoxicity as well as the in vivo antitumor inhibition of docetaxel compared to SLN_s and docetaxel solution. Overall, our results showed that incorporation of docetaxel into cubosomes could enhance its in vitro and in vivo performance compared to docetaxel incorporated into SLN_s.

Characterizing the Self-Assembly Properties of Monoolein Lipid Isosteres

Living cells feature lipid compartments which exhibit a variety of shapes and structures that assist essential cellular processes. Many natural cell compartments frequently adopt convoluted nonlamellar lipid architectures that facilitate specific biological reactions. Improved methods for controlling the structural organization of artificial model membranes would facilitate investigations into how membrane morphology affects biological functions. Monoolein (MO) is a single-chain amphiphile which forms nonlamellar lipid phases in aqueous solution and has wide applications in nanomaterial development, the food industry, drug delivery, and protein crystallization. However, even if MO has been extensively studied, simple isosteres of MO, while readily accessible, have seen limited characterization. An improved understanding of how relatively minor changes in lipid chemical structure affect self-assembly and membrane topology could instruct the construction of artificial cells and organelles for modeling biological structures and facilitate nanomaterial-based applications. Here, we investigate the differences in self-assembly and large-scale organization between MO and two MO lipid isosteres. We show that replacing the ester linkage between the hydrophilic headgroup and hydrophobic hydrocarbon chain with a thioesther or amide functional group results in the assembly of lipid structures with different phases not resembling those formed by MO. Using light and cryo-electron microscopy, small-angle X-ray scattering, and infrared spectroscopy, we demonstrate differences in the molecular ordering and large-scale architectures of the self-assembled structures made from MO and its isosteric analogues. These results improve our understanding of the molecular underpinnings of lipid mesophase assembly and may facilitate the development of MO-based materials for biomedicine and as model lipid compartments.

Paclitaxel-loaded cubosome lipid nanocarriers stabilised with pH and hydrogen peroxide-responsive steric stabilisers as drug delivery vehicles

Responsive nanoparticle delivery systems hold great potential for next-generation chemotherapeutic treatment with reduced off-target side effects. In this work, we formulated responsive lipid-based cubosomes loaded with paclitaxel (PTX) as a model drug and stabilised by novel amphiphilic block copolymers (ABCs) containing the pH-responsive poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) and/or the hydrogen peroxide (H₂O₂)-responsive poly(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl acrylate) (PTBA) blocks. The results showed that these cubosomes with a particle size of around 250 nm exhibited excellent PTX encapsulation efficiency of up to 60% and had the ability to control the release rate of the drug in response to pH and H₂O₂ changes. Specifically, compared to the physiological pH of 7.4, PTX was released faster from the cubosome carriers when exposed to pH 5.5 and/or 50 mM H₂O₂ conditions, which are pathological conditions found in a tumour microenvironment. In vitro cytotoxicity and cell uptake studies further investigated the cellular interactions of these cubosomes. It was found that cubosomes containing PTX had more toxic effects than the control free PTX sample. Compared to cubosomes stabilised by the non-responsive block copolymer Pluronic® F127, the ABC-stabilised cubosomes also had higher cell internalisation efficiency demonstrated by the cytoplasmic fluorescence intensities using confocal microscopy. These results demonstrated that ABCs containing responsive moieties can stabilise lipid cubosomes and enhance controlled release of poorly soluble chemotherapeutics and cellular uptake.

Enhancing the photoluminescence and cellular uptake of fluorescent carbon nanodots via cubosome lipid nanocarriers

Carbon nanodots (C-dots) have attracted much attention for their use in the fields of bioimaging, drug delivery, and sensing due to their excellent fluorescent and photoluminescent properties, photostability, biocompatibility, and amenability to surface modification. Herein, we report a nanocomposite formulation of C-dots (<5 nm) encapsulated in lipid-based lyotropic liquid crystalline nanoparticles (∼250 nm) via either passive diffusion or electrostatic mechanisms. The physicochemical properties of the nanocomposite formulation including particle size, surface charge, internal cubic nanostructures, and pH-dependent fluorescent properties were characterised. Upon loading of C-dots into lipid nanoparticles, the highly ordered inverse bicontinuous cubic mesophase existed in the internal phase of the nanoparticles, demonstrated by synchrotron small angle X-ray scattering, molecular dynamic simulation and cryogenic transmission electron microscopy. The pH-dependent fluorescent property of the C-dots was modified via electrostatic interaction between the C-dots and cationic lipid nanoparticles, which further enhanced the brightness of C-dots through self-quenching prevention. The cytotoxicity and cellular uptake efficiency of the developed nanocomposites were also examined in an epithelial gastric adenocarcinoma cell line (AGS) and a macrophage cell line (stimulated THP-1). Compared to free C-dots, the uptake and cell imaging potential of the C-dot nanocomposites was significantly improved, by several orders of magnitude as demonstrated by cytoplasmic fluorescent intensities using confocal microscopy. Loading C-dots into mesoporous lipid nanocarriers presents a new way of modifying C-dot physicochemical and fluorescent properties, alternative to direct chemical surface modification, and advances the bioimaging potential of C-dots by enhancing cellular uptake efficiency and converging C-dot light emission.

Development of stimuli-responsive lyotropic liquid crystalline nanoparticles targeting lysosomes: Physicochemical, morphological and drug release studies

The abilities of sub-cellular targeting and stimuli-responsiveness are critical challenges in pharmaceutical nanotechnology. In the present study, glyceryl monooleate (GMO)-based non-lamellar lyotropic liquid crystalline nanoparticles were stabilized by the poly(2-(dimethylamino)ethyl methacrylate)-b-poly(lauryl methacrylate) block copolymer carrying tri-phenyl-phosphine cations (TPP-QPDMAEMA-b-PLMA), either used alone or in combination with other polymers as co-stabilizers. The systems were designed to perform simultaneously sub-cellular targeting, stimuli-responsiveness and to exhibit stealthiness. The physicochemical characteristics and fractal dimensions of the resultant nanosystems were obtained from light scattering techniques, while their micropolarity and microfluidity from fluorescence spectroscopy. Their morphology was assessed by cryo-TEM, while their thermal behavior by microcalorimetry and high-resolution ultrasound spectroscopy. The analyzed properties, including the responsiveness to pH and temperature, were found to be dependent on the combination of the polymeric stabilizers. The subcellular localization was monitored by confocal microscopy, revealing targeting to lysosomes. Subsequently, resveratrol was loaded into the nanosystems, the entrapment efficiency was investigated and in vitro release studies were carried out at different conditions, in which a stimuli-triggered drug release profile was achieved. In conclusion, the proposed multi-functional nanosystems can be considered as potentially stealth, stimuli-responsive drug delivery nanocarriers, with targeting ability to lysosomes and presenting a stimuli-triggered drug release profile.

Light-Responsive Molecular Release from Cubosomes Using Swell-Squeeze Lattice Control

Stimuli-responsive materials are crucial to advance controlled delivery systems for drugs and catalysts. Lyotropic liquid crystals (LLCs) have well-defined internal structures suitable to entrap small molecules and can be broken up into low-viscosity dispersions, aiding their application as delivery systems. In this work, we demonstrate the first example of light-responsive cubic LLC dispersions, or cubosomes, using photoswitchable amphiphiles to enable external control over the LLC structure and subsequent on-demand release of entrapped guest molecules. Azobenzene photosurfactants (AzoPS), containing a neutral tetraethylene glycol head group and azobenzene-alkyl tail, are combined (from 10-30 wt %) into monoolein-water systems to create LLC phases. Homogenization of the bulk LLC forms dispersions of particles, ∼200 nm in diameter with internal bicontinuous primitive cubic phases, as seen using small-angle X-ray scattering and cryo-transmission electron microscopy. Notably, increasing the AzoPS concentration leads to swelling of the cubic lattice, offering a method to tune the internal nanoscale structure. Upon UV irradiation, AzoPS within the cubosomes isomerizes within seconds, which in turn leads to squeezing of the cubic lattice and a decrease in the lattice parameter. This squeeze mechanism was successfully harnessed to enable phototriggerable release of trapped Nile Red guest molecules from the cubosome structure in minutes. The ability to control the internal structure of LLC dispersions using light, and the dramatic effect this has on the retention of entrapped molecules, suggests that these systems may have huge potential for the next-generation of nanodelivery.

Cubosomes: Design, Development, and Tumor-Targeted Drug Delivery Applications

Because of the extraordinary advancements in biomedical nanotechnology over the last few decades, traditional drug delivery systems have been transformed into smart drug delivery systems that respond to stimuli. These well-defined nanoplatforms can boost therapeutic targeting efficacy while reducing the side effects/toxicities of payloads, which are crucial variables for enhancing patient compliance by responding to specific internal or external triggers. Cubosomes are lipid-based nano systems that are analogous to well-known vesicular systems, such as lipo- and niosomes. They could be used as part of a unique drug delivery system that includes hydro-, lipo-, and amphiphilic drug molecules. In this review, we critically analyze the relevant literature on cubosomesregarding theories of cubosomeself-assembly, composition, and manufacturing methods, with an emphasis on tumor-targeted drug delivery applications. Due to the bioadhesive and -compatible nature of cubosome dispersion, this review also focuses on a variety of drug delivery applications, including oral, ophthalmic and transdermal.

Sustained release of azithromycin from lipid liquid-crystalline nanoparticles laden in situ gel for the treatment of periodontitis: In vitro and efficacy study

Periodontitis is a chronic inflammatory disease affecting teeth, periodontal ligament and alveolar bone. Current treatment options include surgery or oral antibiotics. Oral dosage forms shows systemic side effects due to frequent dosing and it failed to reach the therapeutic concentration in the periodontal cavity. In this work, a novel in situ gel loaded with azithromycin laden lipid liquid-crystalline nanoparticles (cubosomes) was formulated for effective treatment of periodontitis. Cubosomes were prepared using DL-α-monoolein (MO) and Pluronic^®F-127, and characterized for size, zeta potential, shape, and entrapment efficacy. In situ gel laden cubosomes were evaluated for pH, drug content, viscosity, syringeability, mucoadhesive strength, texture profile, gelation temperature, gel strength, in vitro release profile, antimicrobial activity and in vivo efficacy in rat model. Cubosomal size (137-450 nm) and entrapment efficacy (74-88%) increases with increase in the level of MO. The in situ gel-cubosomal batches showed sufficient viscosity (878-956 cp), syringeability (125-150N), mucoadhesive strength (25.7-26.2 dyne/cm²), gelation temperature (34.3-35.3^oC), gel strength (45-51 s), and texture profile for periodontal application. The in vitro release profiles showed sustain azithromycin release for 24h from the in situ gel-cubosomal gels compared to 4h from the marketed azithromycin gel. The in vivo studies (alveolar bone loss and histopathology) in rat model confirmed the efficacy of in situ gel to treat periodontitis at low frequency of dosing compared to marketed gel. In conclusion, the study demonstrated the potential of cubosomes to sustain the release of azithromycin from in situ gelling system for effective treatment of periodontitis.

Inverse ISAsomes in Bio-Compatible Oils—Exploring Formulations in Squalane, Triolein and Olive Oil

In contrast to their more common counterparts in aqueous solutions, inverse ISAsomes (internally self-assembled somes/particles) are formulated as kinetically stabilised dispersions of hydrophilic, lyotropic liquid-crystalline (LC) phases in non-polar oils. This contribution reports on their formation in bio-compatible oils. We found that it is possible to create inverse hexosomes, inverse micellar cubosomes (Fd3m) and an inverse emulsified microemulsion (EME) in excess squalane with a polyethylene glycol alkyl ether as the primary surfactant forming the LC phase and to stabilise them with hydrophobised silica nanoparticles. Furthermore, an emulsified -phase and inverse hexosomes were formed in excess triolein with the triblock-copolymer Pluronic® P94 as the primary surfactant. Stabilisation was achieved with a molecular stabiliser of type polyethylene glycol (PEG)-dipolyhydroxystearate. For the inverse hexosomes in triolein, the possibility of a formulation without any additional stabiliser was explored. It was found that a sufficiently strong stabilisation effect was created by the primary surfactant alone. Finally, triolein was replaced with olive oil which also led to the successful formation of inverse hexosomes. As far as we know, there exists no previous contribution about inverse ISAsomes in complex oils such as triolein or plant oils, and the existence of stabiliser-free (i.e., self-stabilising) inverse hexosomes has also not been reported until now.

Affimer Tagged Cubosomes: Targeting of Carcinoembryonic Antigen Expressing Colorectal Cancer Cells Using In Vitro and In Vivo Models

Nanomedicines, while having been approved for cancer therapy, present many challenges such as low stability, rapid clearance, and nonspecificity leading to off-target toxicity. Cubosomes are porous lyotropic liquid crystalline nanoparticles that have shown great premise as drug delivery vehicles; however, their behavior in vivo is largely underexplored, hindering clinical translation. Here, we have engineered cubosomes based on the space group Im3m that are loaded with copper acetylacetonate as a model drug, and their surfaces are functionalized for the first time with Affimer proteins via copper-free click chemistry to actively target overexpressed carcinoembryonic antigens on LS174T colorectal cancer cells. Unlike nontargeted cubosomes, Affimer tagged cubosomes showed preferential accumulation in cancer cells compared to normal cells not only in vitro (2D monolayer cell culture and 3D spheroid models) but also in vivo in colorectal cancer mouse xenografts, while exhibiting low nonspecific absorption and toxicity in other vital organs. Cancerous spheroids had maximum cell death compared to noncancerous cells upon targeted delivery. Xenografts subjected to targeted drug-loaded cubosomes showed a 5-7-fold higher drug accumulation in the tumor tissue compared to the liver, kidneys, and other vital organs, a significant decrease in tumor growth, and an increased survival rate compared to the nontargeted group. This work encompasses the first thorough preclinical investigation of Affimer targeted cubosomes as a cancer therapeutic.

Topological defects in polycrystalline hexosomes from β-cyclodextrin fatty esters

Colloidal nanoparticles were prepared by aqueous self-assembly of amphiphilic β-cyclodextrins (βCDs) acylated on their secondary face with C₁₄ chains to a total degree of substitution of 7.0, via a thermolysin-catalyzed transesterification process. The small-angle X-ray scattering pattern of the nanoparticles was consistent with a reverse hexagonal organization. Cryo-transmission electron microscopy images revealed particles with spectacular tortuous shapes and consisting of misoriented domains with a regular columnar hexagonal structure, separated by sharp interfaces. Edge dislocations as well as a variety of stepped tilt grain boundaries (GBs) composed of symmetrical and asymmetrical sections, together with one twist GB, were identified from axial views of the columnar organization. The tilt GB structure was analyzed using the concepts of coincidence site lattice and structural units developed to describe the atomic structure of interfaces in various types of polycrystals. The tilt GBs were described using sequences of βCD-C₁₄ columns that differed by the number of neighboring columns (5, 6 or 7) and exhibiting distinctive contrasts. To our knowledge, this is the first time that these types of topological defects are described at the nanometric scale by direct observation of colloidal polycrystalline hexosomes of self-organized amphiphiles.

Ion exchange column technique as a novel method for evaluating the release of docetaxel from different lipid nanoparticles

Lipid nanoparticles with their unique characters showed many advantages as carriers for anticancer drugs. To compare between these nanoparticles as carriers for anticancer drugs, it was important to evaluate and characterize their drug retention and release properties. In this study, ion exchange column is used as a new evaluation technique. Solid lipid nanoparticles (SLN), nanostructured lipid carrier (NLC), and cubic nanoparticles were prepared using the homogenization technique. Characterization of these nanoparticles was carried out by measuring particle size, zeta potential, and entrapment efficiency. The ion exchange column was used to evaluate docetaxel release from the different nanoparticles as donors to acceptor liposomes that mimic the cell membranes. Both populations were mixed and at different time points, separated using the columns. The amounts of docetaxel in the eluted nanoparticles and retained liposomes were calculated. The particle size of all donors was in the nanometer range with almost neutral zeta potential. The particle size of the acceptor liposomes was 135 nm with a high negative zeta potential -55 mV. Ion exchange columns showed excellent retention of the negative acceptor liposomes while less than 1% of the different donors were retained on the columns. Cubic nanoparticles showed the highest entrapment efficiency (95%) and the slowest drug transfer in comparison with SLN and NLC. In conclusion, the ion exchange column technique can be applied successfully to evaluate the release of docetaxel from the different lipid nanoparticles to acceptor liposomes. Cubic nanoparticles showed advantageous docetaxel incorporation and transfer over SLN and NLC.

Cubosomes as an emerging platform for drug delivery: a state-of-the-art review

Lipid-based drug delivery nanoparticles, including non-lamellar type, mesophasic nanostructured materials of lyotropic liquid crystals (LLCs), have been a topic of interest for researchers for their applications in encapsulation of drugs...

Electroformation of Particulate Emulsions Using Lamellar and Nonlamellar Lipid Self-Assemblies

We report on the development of an electroformation technique for the preparation of particulate (particle-based) emulsions. These oil-in-water (here, lipid phase acts as an "oil") emulsions were prepared using nonlamellar lipid phases. Such emulsion particles offer high hydrophobic volumes compared to conventional lipid particles based on lamellar phases (vesicles/liposomes). In addition, the tortuous internal nanostructure contributes through greater surface area per volume of lipid particles allowing an enhanced loading of payloads. The electroformation method makes use of a capacitor formed from two indium tin oxide coated conductive glass surfaces separated by a dielectric aqueous medium. This capacitor setup is enclosed in a custom-designed 3D-printed unit. Lipid molecules, deposited on conductive surfaces, self-assemble into a nanostructure in the presence of an aqueous medium, which when subjected to an alternating current electric field forms nano- and/or microparticles. Optical microscopy, dynamic light scattering, and small-angle X-ray scattering techniques were employed for micro- and nanostructural analyses of electroformed particles. With this method, it is possible to produce particulate emulsions at a very low (e.g., 0.0005 wt % or 0.5 mg/mL) lipid concentration. We demonstrate an applicability of the electroformation method for drug delivery by preparing lipid particles with curcumin, which is a highly important but water-insoluble medicinal compound. As the method employs gentle conditions, it is potentially noninvasive for the delivery of delicate biomolecules and certain drugs, which are prone to decomposition or denaturation due to the high thermomechanical energy input and/or nonaqueous solvents required for existing methods.

Lipid Nanoparticles─From Liposomes to mRNA Vaccine Delivery, a Landscape of Research Diversity and Advancement

Lipid nanoparticles (LNPs) have emerged across the pharmaceutical industry as promising vehicles to deliver a variety of therapeutics. Currently in the spotlight as vital components of the COVID-19 mRNA vaccines, LNPs play a key role in effectively protecting and transporting mRNA to cells. Liposomes, an early version of LNPs, are a versatile nanomedicine delivery platform. A number of liposomal drugs have been approved and applied to medical practice. Subsequent generations of lipid nanocarriers, such as solid lipid nanoparticles, nanostructured lipid carriers, and cationic lipid-nucleic acid complexes, exhibit more complex architectures and enhanced physical stabilities. With their ability to encapsulate and deliver therapeutics to specific locations within the body and to release their contents at a desired time, LNPs provide a valuable platform for treatment of a variety of diseases. Here, we present a landscape of LNP-related scientific publications, including patents and journal articles, based on analysis of the CAS Content Collection, the largest human-curated collection of published scientific knowledge. Rising trends are identified, such as nanostructured lipid carriers and solid lipid nanoparticles becoming the preferred platforms for numerous formulations. Recent advancements in LNP formulations as drug delivery platforms, such as antitumor and nucleic acid therapeutics and vaccine delivery systems, are discussed. Challenges and growth opportunities are also evaluated in other areas, such as medical imaging, cosmetics, nutrition, and agrochemicals. This report is intended to serve as a useful resource for those interested in LNP nanotechnologies, their applications, and the global research effort for their development.

Metformin dampens cisplatin cytotoxicity on leukemia cells after incorporation into cubosomal nanoformulation

Acute lymphoblastic leukemia (ALL) is one of the most common type of leukemia in children. It is caused by abnormal cell division of the lymphoid progenitor cells in the bone marrow. In the past decade, metformin has gained increased attention for its anti-leukemic potential. Moreover, other chemotherapeutic agents were investigated for the possible superior efficacy over the existing treatments in treating ALL. Several studies examined the effect of cisplatin as a potential candidate for therapy. Here, we investigate the anti-leukemic effect of metformin and cisplatin on 697 cells. Both compounds revealed significant cytotoxic effects. Specifically designed lipid-based cubosomal nanoformulations were used as drug carriers to facilitate compound entry in low doses. Our results indicate that the use of the carrier did not affect cytotoxicity significantly. In addition, combining the drugs in different carriers demonstrated an antagonistic effect through damping the efficacy of both drugs. This was evident from experiments investigating cellular viability, annexin V/PI staining, mitochondrial membrane potential and caspase-3 activity. Taken together, it appears that metformin does not represent a suitable option for sensitizing leukemia cells to cisplatin.

Balanced lipase interactions for degradation-controlled paclitaxel release from lipid cubic phase formulations

Lipid cubic phase (LCP) formulations enhance the intestinal solubility and bioavailability of hydrophobic drugs by reducing precipitation and facilitating their mass transport to the intestinal surface for absorption. LCPs with an ester linkage connecting the acyl chain to the glycerol backbone (monoacylglycerols), are susceptible to chemical digestion by several lipolytic enzymes including lipases, accelerating the release of hydrophobic agents from the lipid bilayers of the matrix. Unlike regular enzymes that transform soluble substrates, lipolytic enzymes act at the interface of water and insoluble lipid. Therefore, compounds that bind to this interface can enhance or inhibit the activity of enzymes to varying extent. Here, we explore how the lipolysis rate can be tuned by the interfacial interaction of porcine pancreatic lipase with monoolein LCPs containing a known lipase inhibitor, tetrahydrolipstatin. Release of the Biopharmaceutical Classification System (BCS) class IV drug, paclitaxel, from the inhibitor-modified LCP was examined in the presence of lipase and its effectors colipase and calcium. By combining experimental dynamic digestion studies, thermodynamic measurements and molecular dynamics simulations of the competitive inhibition of lipase by tetrahydrolipstatin, we reveal the role and mode of action of lipase effectors in creating a precisely-balanced degradation-controlled LCP release system for the poorly soluble paclitaxel drug.

Controlling the pH dependent transition between monoolein Fd3m micellar cubosomes and hexosomes using fatty acetate and fatty acid additive mixtures

HYPOTHESIS

Cubosomes made from the inverse micellar cubic mesophase (I₂) with Fd3m symmetry possess a unique structure of closely packed inverse micelles. These have prospective functionality in sustained drug release. In this study, we hypothesised that similar to fatty acids, various fatty acetate compounds can induce the formation of micellar Fd3m cubosomes in monoolein (MO) nanoparticles. They are different to micellar cubosomes made of MO and a fatty acid, which are pH responsive and can transition from an Fd3m phase to an inverse hexagonal phase (H₂) as pH increases. We hypothesised that by co-doping a fatty acetate and fatty acid into MO, precise control of the Fd3m-H₂ phase transition pH in nanoparticles can be achieved.

EXPERIMENTS

Five unsaturated fatty acetates with hydrocarbon chain lengths between 18 and 24 were added to MO at a weight ratio of 0.45 - 0.60 to form nanoparticles. The nanoparticles were prepared using high-throughput formulation and characterised with synchrotron small angle X-ray scattering (SAXS). MO nanoparticles doped with vaccenyl acetate and vaccenic acid were used to demonstrate the fine control over Fd3m-H₂ phase transition pH.

FINDINGS

Micellar cubosomes (Fd3m phase) were found in MO nanoparticles doped with fatty acetates. The Fd3m structure was stable in a wide pH range of 2.6 - 8 and at temperatures up to 45 °C. In MO nanoparticles doped with the acetate/acid mixture, the Fd3m-H₂ phase transition pH was tuned between pH 5 and pH 7 by adjusting the ratio of vaccenyl acetate and vaccenic acid. As a H₂ phase generally offers faster drug release than an Fd3m phase, the pH responsive lipid nanoparticles developed here may find application in orally administrated formulation, where the vehicles must pass a low pH environment in the stomach before reaching neutral pH in the blood.

Revealing the complex self-assembly behaviour of sodium deoxycholate in aqueous solution

HYPOTHESIS

Sodium deoxycholate is a natural bile salt produced by animals and fulfilling important physiological processes. It is also used as dispersive surfactant and building block for self-assembled architectures in biology and material science. Although long debated, the study of its self-assembly in water is hereto incomplete and the models of the known aggregates are still controversial. This background suggests a complex scenario likely missing of additional mesophases.

EXPERIMENTS

Electron and optical microscopy techniques were crossed with SAXS data for the research.

FINDINGS

Novel rod, sponge, vesicle, lamellae, nanotube phases and reversible transitions among them arise at conditions (concentration, pH, temperature, ionic strength, ionic composition) fitting the physiological working environment of sodium deoxycholate. These findings enlarge the perspective towards different directions. The integration of the previous literature with this work removes any interpretative contradiction since all the structures cover the entire spectrum of phases expected for surfactants, thus being explained according to the Israelachvili's scheme. It is not trivial that a single molecule can show such a high structural variability. This fact highlights a very versatile system. Probably it is not a coincidence that it occurs in a multitasking biomolecule. These results furnish fundamental knowledge to clarify the bile salts' role in vivo.

Novel Amphiphilic Block Copolymers for the Formation of Stimuli-Responsive Non-Lamellar Lipid Nanoparticles

Non-lamellar lyotropic liquid crystalline (LLC) lipid nanoparticles contain internal multidimensional nanostructures such as the inverse bicontinuous cubic and the inverse hexagonal mesophases, which can respond to external stimuli and have the potential of controlling drug release. To date, the internal LLC mesophase responsiveness of these lipid nanoparticles is largely achieved by adding ionizable small molecules to the parent lipid such as monoolein (MO), the mixture of which is then dispersed into nanoparticle suspensions by commercially available poly(ethylene oxide)-poly(propylene oxide) block copolymers. In this study, the Reversible Addition-Fragmentation chain Transfer (RAFT) technique was used to synthesize a series of novel amphiphilic block copolymers (ABCs) containing a hydrophilic poly(ethylene glycol) (PEG) block, a hydrophobic block and one or two responsive blocks, i.e., poly(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl acrylate) (PTBA) and/or poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA). High throughput small angle X-ray scattering studies demonstrated that the synthesized ABCs could simultaneously stabilize a range of LLC MO nanoparticles (vesicles, cubosomes, hexosomes, inverse micelles) and provide internal particle nanostructure responsiveness to changes of hydrogen peroxide (H2O2) concentrations, pH and temperature. It was found that the novel functional ABCs can substitute for the commercial polymer stabilizer and the ionizable additive in the formation of next generation non-lamellar lipid nanoparticles. These novel formulations have the potential to control drug release in the tumor microenvironment with endogenous H2O2 and acidic pH conditions.

Norfloxacin loaded nano-cubosomes for enhanced management of otitis externa: In vitro and in vivo evaluation

The research's goal is to design and formulate nano-structured cubosomes loaded with norfloxacin (NFX)formanagement of otitis externa. In this study, glyceryl monooleate (GMO) as lipid phase, Cremophor EL as surfactant and either Pluronic F108 or Pluronic F127 as stabilizer were the used ingredients. The nano-cubosomal formulation "CUB 1" (its dispersed phase is composed of GMO (95%), Cremophor EL (2.5%) and Pluronic F108 (2.5%)) was the best achieved one. It had small particles size (216.75 ± 2.47 nm), good polydispersity index (0.339 ± 0.012) and acceptable zeta potential (-41.2 ± 2.262 mV). Images obtained after transmission electron microscopy examination ensured nearly cubic shape of formed nanoparticles with excellent dispersibility. Moreover, micrographs of rabbit ear skin specimens examined by confocal laser microscopy ensured good permeation capability of nano-structured cubosomes.In addition, in vivoskin deposition results revealed that higher amount of NFX was deposited in the rabbit ear skin throughout the study period (10 h) compared to drug suspension. Additionally, histopathological results proved that NFX loaded cubosomes can be safely applied topically on ear skin without any signs of inflammation nor skin irritation. Accordingly, these results anticipated the nano-structured cubosomal capabilities as a favorable nano-carrier for dermal NFX delivery to external ear skin for enhancing the management of otitis externa.

Latanoprost-loaded phytantriol cubosomes for the treatment of glaucoma

Glaucoma is a degenerative optic neuropathy characterized by increased intraocular pressure that if untreated can result in blindness. Ophthalmological drug therapy is a challenge of great clinical importance due to the diversity of ocular biological barriers which commonly causes limited or no effectiveness for drugs delivered through the eye. In this work, we proposed the development of nanosized cubic liquid crystals (cubosomes) as a new drug carrier system for latanoprost, an anti-glaucoma drug. Latanoprost-loaded phytantriol cubosomes (CubLnp) were prepared using a top-down method. Latanoprost concentration in the formulations ranged from 0.00125% to 0.02% w/v. All cubosomes displayed an average size around 200 nm, a low polydispersity index of 0.1 and zeta potential values around -25 mV, with an encapsulation efficiency of about 90%. Structural studies revealed that cubosomes displayed a double-diamond surface, Pn3m cubic-phase structure, and was not affected by drug loading. Calorimetric studies revealed a fast and exothermic interaction between latanoprost and cubosomes. According to in vitro essays, latanoprost release from cubosomes was slow in time, evidencing a sustained release profile. Based on this behavior, the in vivo hypotensive intraocular effect was evaluated by means of the subconjunctival administration of CubLnp in normotensive rabbits. We obtained promising results in comparison with a marketed latanoprost formulation (0.005% w/v).

Physicochemical characterization of green sodium oleate-based formulations. Part 1. Structure and rheology

HYPOTHESIS

The structure, rheology and other physicochemical properties of dilute aqueous dispersions of sodium oleate (NaOL) are well known. This paper is the first report in which a moderately concentrated (13% w/w) dispersion of NaOL in water is investigated. In fact, at this concentration the phase and rheology behavior of the surfactant remarkably deviates from those of its dilute solutions in water and a significant effect is imparted by the addition of potassium chloride.

EXPERIMENTAL

The structural, thermal and rheological properties of a 13% w/w dispersion of NaOL in water were investigated by cryo-TEM, rheology, and DSC experiments with and without the addition of potassium chloride. The system is comprised of elongated wormlike micelles that turn into a gel-like more disordered viscous material upon addition of small amounts of KCl (4% w/w).

FINDINGS

This paper illustrates the multifaceted behavior of sodium oleate dispersions at intermediate concentrations that depends on the presence of other cosolutes (such as KCl). The results show that viscoelastic aqueous dispersions of NaOL are excellent candidates for the preparation of stimuli-responsive green materials to be used in a number of different applications. We also discuss the genesis of wormlike micelles (WLMs) in terms of the general theory of self-assembly.

Liquid crystalline nanoparticles for drug delivery: The role of gradient and block copolymers on the morphology, internal organisation and release profile

Amphiphilic polymers represent one of the main class of stabilizers for non-lamellar lyotropic liquid crystalline nanoparticles, being essential for their formation and stability. In the present study, poly(ethylene oxide)-block-poly(ε-caprolactone) (PEO-b-PCL) block copolymers and poly(2-methyl-2-oxazoline)-grad-poly(2-phenyl-2-oxazoline) (MPOx) gradient copolymers were incorporated as stabilizers in liquid crystalline nanoparticles prepared from glyceryl monooleate. The polymers were chosen according to their high biocompatibility and promising stealth properties, in order to develop safe and efficient drug delivery nanosystems. The physicochemical characteristics and fractal dimension of the resultant nanosystems were obtained from light scattering techniques, while their micropolarity and microfluidity from fluorescence spectroscopy. The effect of temperature, serum proteins and ionic strength on the physicochemical behavior was monitored. Their morphology was assessed by cryo-TEM, while their thermal behavior by microcalorimetry and high-resolution ultrasound spectroscopy. Their properties were dependent on the stabilizer chemistry and topology (block/gradient copolymer) and its concentration. Subsequently, resveratrol, as model hydrophobic drug, was loaded into the nanosystems, the entrapment efficiency was calculated and in vitro release studies were carried out, highlighting how the different stabilizer can differentiate the drug release profile. In conclusion, the proposed copolymers broaden the toolbox of polymeric stabilizers for the development of liquid crystalline nanoparticles intended for drug delivery applications.