Sterically stabilized liposomes

Immune Implications of Cholesterol-Containing Lipid Nanoparticles

The majority of clinically approved nanoparticle-mediated therapeutics are lipid nanoparticles (LNPs), and most of these LNPs are liposomes containing cholesterol. LNP formulations significantly alter the drug pharmacokinetics (PK) due to the propensity of nanoparticles for uptake by macrophages. In addition to readily engulfing LNPs, the high expression of cholesterol hydroxylases and reactive oxygen species (ROS) in macrophages suggests that they will readily produce oxysterols from LNP-associated cholesterol. Oxysterols are a heterogeneous group of cholesterol oxidation products that have potent immune modulatory effects. Oxysterols are implicated in the pathogenesis of atherosclerosis and certain malignancies; they have also been found in commercial liposome preparations. Yet, the in vivo metabolic fate of LNP-associated cholesterol remains unclear. We review herein the mechanisms of cellular uptake, trafficking, metabolism, and immune modulation of endogenous nanometer-sized cholesterol particles (i.e., lipoproteins) that are also relevant for cholesterol-containing nanoparticles. We believe that it would be imperative to better understand the in vivo metabolic fate of LNP-associated cholesterol and the immune implications for LNP-therapeutics. We highlight critical knowledge gaps that we believe need to be addressed in order to develop safer and more efficacious lipid nanoparticle delivery systems.

Liposomal delivery of organoselenium-cisplatin complex as a novel therapeutic approach for colon cancer therapy

Cisplatin is a widely-used chemotherapeutic agent for the treatment of various solid neoplasms including colon cancer. Cisplatin-induced DNA damage is restricted due to dose-related adverse reactions as well as primary resistance mechanisms. Therefore, it is imperative to utilize novel therapeutic approaches to circumvent cisplatin limitations and attenuate its normal tissues toxicity. In this study, we exploited a novel PEGylated liposomes with greater efficiency to treat colon cancer. For this, an organoselenium compound (diselanediylbis decanoic acid (DDA)) was synthesized, and liposomes composed of Egg PC or HSPC, as well as DOPE, mPEG2000-DSPE, cholesterol and DDA at varying molar ratios were prepared by using thin-film method. Cisplatin loading was performed through incubation with liposomes. Characterization of nanoliposomes indicated a favarable size range of 91-122 nm and negative zeta potential of -9 to -22 mv. The organoselenium compound significantly improved cisplatin loading efficiency within the liposomes (83.4 %). Results also revealed an efficient bioactivity of cisplatin liposome on C26 cells compared to the normal cells. Further, DDA bearing liposomes significantly improved drug residence time in circulation, reduced toxicity associated with the normal tissues, and enhanced drug accumulation within the oxidative tumor microenvironment. Collectively, results indicated that cisplatin encasement within liposomes by using this method could significantly improve the therapeutic efficacy in vivo, and merits further investigations.

The 60-year evolution of lipid nanoparticles for nucleic acid delivery

Delivery of genetic information to the interior of target cells in vivo has been a major challenge facing gene therapies. This barrier is now being overcome, owing in part to dramatic advances made by lipid-based systems that have led to lipid nanoparticles (LNPs) that enable delivery of nucleic acid-based vaccines and therapeutics. Examples include the clinically approved COVID-19 LNP mRNA vaccines and Onpattro (patisiran), an LNP small interfering RNA therapeutic to treat transthyretin-induced amyloidosis (hATTR). In addition, a host of promising LNP-enabled vaccines and gene therapies are in clinical development. Here, we trace this success to two streams of research conducted over the past 60 years: the discovery of the transfection properties of lipoplexes composed of positively charged cationic lipids complexed with nucleic acid cargos and the development of lipid nanoparticles using ionizable cationic lipids. The fundamental insights gained from these two streams of research offer potential delivery solutions for most forms of gene therapies.

The impact of phospholipids with high transition temperature to enhance redox-sensitive liposomal doxorubicin efficacy in colon carcinoma model

In this study, we have developed a redox-sensitive (RS) liposomal doxorubicin formulation by incorporating 10,10'-diselanediylbis decanoic acid (DDA) organoselenium compound as the RS moiety. Hence, several RS liposomal formulations were prepared by using DOPE, HSPC, DDA, mPEG2000-DSPE, and cholesterol. In situ drug loading using a pH gradient and citrate complex yielded high drug to lipid ratio and encapsulation efficiency (100%) for RS liposomes. Liposomal formulations were characterized in terms of size, surface charge and morphology, drug loading, release properties, cell uptake and cytotoxicity, as well as therapeutic efficacy in BALB/c mice bearing C26 tumor cells. The formulations showed an average particle size of 200 nm with narrow size distributions (PDI < 0.3), and negative surface charges varying from -6 mV to -18.6 mV. Our study confirms that the presence of the DDA compound in liposomes is highly sensitive to hydrogen peroxide at 0.1% w/v, resulting in a significant burst release of up to 40%. The in vivo therapeutic efficacy study in BALB/c mice bearing C26 colon carcinoma confirmed the promising function of RS liposomes in the tumor microenvironment which led to a prolonged median survival time (MST). The addition of hydrogenated soy phosphatidylcholine (HSPC) with a high transition temperature (Tm: 52-53.5°C) extended the MST of our 3-component formulation of F14 (DOPE/HSPC/DDA) to 60 days in comparison to Caelyx (PEGylated liposomal Dox), which is not RS-sensitive (39 days). Overall, HSPC liposomes bearing RS-sensitive moiety enhanced therapeutic efficacy against colon cancer in vitro and in vivo. This achievement unequivocally underscores the criticality of high-TM phospholipids, particularly HSPC, in significantly enhancing liposome stability within the bloodstream. In addition, RS liposomes enable the on-demand release of drugs, leveraging the redox environment of tumor cells, thereby augmenting the efficacy of the formulation.

QbD Enabled Development and Evaluation of Pazopanib Loaded Nanoliposomes for PDAC Treatment

Pancreatic ductal adenocarcinoma (PDAC) is one of the highly fatal types of cancer with high mortality/incidence. Considering the crucial role of vascular endothelial growth factor (VEGF) in PDAC progression, its inhibition can be a viable strategy for the treatment. Pazopanib, a second-generation VEGF inhibitor, is approved for the treatment of various oncological conditions. However, due to associated limitations like low oral bioavailability (14-39%), high inter/intra-subject variability, stability issues, etc., high doses (800 mg) are required, which further lead to non-specific toxicities and also contribute toward cancer resistance. Thus, to overcome these challenges, pazopanib-loaded PEGylated nanoliposomes were developed and evaluated against pancreatic cancer cell lines. The nanoliposomes were prepared by thin-film hydration method, followed by characterization and stability studies. This QbD-enabled process design successfully led to the development of a suitable pazopanib liposomal formulation with desirable properties. The % entrapment of PZP-loaded non-PEGylated and PEGylated nanoliposomes was found to be 75.2% and 84.9%, respectively, whereas their particle size was found to be 129.7 nm and 182.0 nm, respectively. The developed liposomal formulations exhibited a prolonged release and showed desirable physicochemical properties. Furthermore, these liposomal formulations were also assessed for in vitro cell lines, such as cell cytotoxicity assay and cell uptake. These studies confirm the effectiveness of developed liposomal formulations against pancreatic cancer cell lines. The outcomes of this work provide encouraging results and a way forward to thoroughly investigate its potential for PDAC treatment.

Elastic Liposomes Containing Calcium/Magnesium Ferrite Nanoparticles Coupled with Gold Nanorods for Application in Photothermal Therapy

This work reports on the design, development, and characterization of novel magneto-plasmonic elastic liposomes (MPELs) of DPPC:SP80 (85:15) containing Mg0.75Ca0.25Fe2O4 nanoparticles coupled with gold nanorods, for topical application of photothermal therapy (PTT). Both magnetic and plasmonic components were characterized regarding their structural, morphological, magnetic and photothermal properties. The magnetic nanoparticles display a cubic shape and a size (major axis) of 37 ± 3 nm, while the longitudinal and transverse sizes of the nanorods are 46 ± 7 nm and 12 ± 1.6 nm, respectively. A new methodology was employed to couple the magnetic and plasmonic nanostructures, using cysteine as bridge. The potential for photothermia was evaluated for the magnetic nanoparticles, gold nanorods and the coupled magnetic/plasmonic nanoparticles, which demonstrated a maximum temperature variation of 28.9 °C, 33.6 °C and 37.2 °C, respectively, during a 30 min NIR-laser irradiation of 1 mg/mL dispersions. Using fluorescence anisotropy studies, a phase transition temperature (Tm) of 35 °C was estimated for MPELs, which ensures an enhanced fluidity crucial for effective crossing of the skin layers. The photothermal potential of this novel nanostructure corresponds to a specific absorption rate (SAR) of 616.9 W/g and a maximum temperature increase of 33.5 °C. These findings point to the development of thermoelastic nanocarriers with suitable features to act as photothermal hyperthermia agents.

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.

Stealth and pseudo-stealth nanocarriers

The stealth effect plays a central role on capacitating nanomaterials for drug delivery applications through improving the pharmacokinetics such as blood circulation, biodistribution, and tissue targeting. Here based on a practical analysis of stealth efficiency and a theoretical discussion of relevant factors, we provide an integrated material and biological perspective in terms of engineering stealth nanomaterials. The analysis surprisingly shows that more than 85% of the reported stealth nanomaterials encounter a rapid drop of blood concentration to half of the administered dose within 1 h post administration although a relatively long β-phase is observed. A term, pseudo-stealth effect, is used to delineate this common pharmacokinetics behavior of nanomaterials, that is, dose-dependent nonlinear pharmacokinetics because of saturating or depressing bio-clearance of RES. We further propose structural holism can be a watershed to improve the stealth effect; that is, the whole surface structure and geometry play important roles, rather than solely relying on a single factor such as maximizing repulsion force through polymer-based steric stabilization (e.g., PEGylation) or inhibiting immune attack through a bio-inspired component. Consequently, engineering delicate structural hierarchies to minimize attractive binding sites, that is, minimal charges/dipole and hydrophobic domain, becomes crucial. In parallel, the pragmatic implementation of the pseudo-stealth effect and dynamic modulation of the stealth effect are discussed for future development.

Facilitated encapsulation of a nonionic contrast agent for X-ray computed tomography into lipid vesicles by the multiple emulsification-solvent evaporation method

We studied the encapsulation of iohexol (Ihex), a nonionic contrast agent used for X-ray computational tomography, into lipid vesicles using the multiple emulsification-solvent evaporation method to formulate a nanosized contrast agent. This lipid vesicle preparation method consists of three steps: (1) primary emulsification for producing water-in-oil (W/O) emulsions containing fine water droplets that will be converted to the internal water phase of the lipid vesicles, (2) secondary emulsification for formulating multiple water-in-oil-in-water (W/O/W) emulsions encapsulating the fine water droplets containing Ihex, and (3) solvent evaporation to remove the oil phase solvent (n-hexane) and to form lipid bilayers surrounding the fine inner droplets, resulting in the formation of lipid vesicles encapsulating Ihex. As the diameter and Ihex concentration of the primary W/O emulsion droplets decreased, a higher Ihex encapsulation yield was obtained for the final lipid vesicles. The entrapment yield of Ihex in the final lipid vesicles varied significantly with the emulsifier (Pluronic® F-68) concentration in the external water phase of W/O/W emulsion, and the highest yield (65%) was obtained when the emulsifier concentration was 0.1 wt%. We also investigated the powderization of lipid vesicles encapsulating Ihex via lyophilization. The powderized vesicles were dispersed in water after rehydration and maintained their controlled diameters. The entrapment yield of Ihex in powderized lipid vesicles was maintained for over 1 month at 25 ˚C, while significant leakage of Ihex was observed in the lipid vesicles suspended in the aqueous phase.

Efficacy of regional cooling + oral dexamethasone for primary prevention of hand-foot syndrome associated with pegylated liposomal doxorubicin

PURPOSE

Pegylated liposomal doxorubicin (PLD)-induced hand-foot syndrome (HFS) frequently lowers the quality of life of ovarian cancer patients. Wrist and ankle cooling, having a limited preventive effect, has been the commonest supportive HFS care. In this study, we retrospectively assessed the primary preventive effect of a combination of regional cooling and oral dexamethasone therapy (cooling + oral Dex) on HFS.

METHODS

This study is a single-arm retrospective, observational study. Recurrent ovarian cancer patients were administered PLD ± bevacizumab. We retrospectively examined the efficacy of hands and feet cooling (from the start of PLD to the end) + oral Dex (day 1-5: 8 mg/day, day 6, 7: 4 mg/day) for primary HFS prevention.

RESULTS

This study included 74 patients. The initial dose of PLD was 50 mg/m² and 40 mg/m² for 32 (43.2%) and 42 (56.8%) patients, respectively. HFS of Grade ≥ 2 and Grade ≥ 3 developed in five (6.8%) and one (1.4%) patient(s), respectively. The incidence of ≥ Grade 2 and ≥ Grade 3 HFS was much lower than those reported in previous studies. Dose reduction was required in 13 patients (17.6%) mainly because of neutropenia or mucositis; there was no HFS-induced dose reduction. Meanwhile, PLD therapy was discontinued mainly because of interstitial pneumonia (4 patients) and HFS (one patient).

CONCLUSIONS

We demonstrated the efficacy of regional cooling and oral Dex for primary prevention of PLD-induced HFS. Although future prospective studies are needed to confirm its efficacy, this combination therapy can be considered for primary prevention of HFS in ovarian cancer patients on PLD.

A novel estrogen-targeted PEGylated liposome co-delivery oxaliplatin and paclitaxel for the treatment of ovarian cancer

Ovarian cancer is the second cause of death among gynecological malignancies. In this study, we designed a novel estrogen-targeted PEGylated liposome loaded with oxaliplatin and paclitaxel (ES-SSL-OXA/PTX) which could target estrogen receptor (ER) highly expressed on the surface of SKOV-3 cells to enhance therapeutic efficacy and reduce the side effects for SKOV-3 tumor therapy. ES-SSL-OXA/PTX was prepared by thin film hydration method and exhibited a uniform spherical morphology. Encapsulation efficiency (EE) were determined by HPLC method with the results of 44.10% for OXA and 65.85% for PTX. The mean particle size and polydispersity index (PDI) were 168.46 nm and 0.145, respectively. In vivo and in vitro targeting study confirmed that ES-SSL-OXA/PTX has optimum specific targeting ability. Meanwhile, In vitro and in vivo antitumor results of ES-SSL-OXA/PTX exhibited a superior antiproliferative effect on SKOV-3 cells and a stronger anti-tumor efficacy with the tumor inhibition rate of 85.24%. The pharmacokinetics results of ES-SSL-OXA/PTX showed a prolonged half-life time and a slowed clearance rate. The preliminary safety study of acute toxicity and long-term toxicity demonstrated ES-SSL-OXA/PTX exhibited a reduced toxicity profile. Based on the above results, ES-SSL-OXA/PTX could be a promising novel formulation for the treatment of ovarian cancer in future clinic.

A liposomal vaccine promotes strong adaptive immune responses via dendritic cell activation in draining lymph nodes

Subunit proteins provide a safe source of antigens for vaccine development especially for intracellular infections which require the induction of strong cellular immune responses. However, those antigens are often limited by their low immunogenicity. In order to achieve effective immune responses, they should be encapsulated into a stable antigen delivery system combined with an appropriate adjuvant. As such cationic liposomes provide an efficient platform for antigen delivery. In the present study, we describe a liposomal vaccine platform for co-delivery of antigens and adjuvants able to elicit strong antigen-specific adaptive immune responses. Liposomes are composed of the cationic lipid dimethyl dioctadecylammonium bromide (DDAB), cholesterol (CHOL) and oleic acid (OA). Physicochemical characterization of the formulations showed that their size was in the range of ∼250 nm with a positive zeta potential which was affected in some cases by the enviromental pH facilitating endosomal escape of potential vaccine cargo. In vitro, liposomes were effectively taken up by bone marrow dendritic cells (BMDCs) and when encapsulated IMQ they promoted BMDCs maturation and activation. Upon in vivo intramuscular administration, liposomes' active drainage to lymph nodes was mediated by DCs, B cells and macrophages. Thus, mice immunization with liposomes having encapsulated LiChimera, a previously characterized anti-leishmanial antigen, and IMQ elicited infiltration of CD11b^low DCs populations in draining LNs followed by increased antigen-specific IgG, IgG2a and IgG1 levels production as well as indcution of antigen-specific CD4⁺ and CD8⁺ T cells. Collectively, the present work provides a proof-of-concept that cationic liposomes composed of DDAB, CHOL and OA adjuvanted with IMQ provide an efficient delivery platform for protein antigens able to induce strong adaptive immune responses via DCs targeting and induction of maturation.

The Post-insertion Method for the Preparation of PEGylated Liposomes

PEGylation is a crucial process for decorating the surface of liposomes with polyethylene glycol (PEG) for clinical use. This process endows the liposomes extended circulation time and improved stability in vivo. The post-insertion method is one of the well-established techniques for PEGylation. This method requires only one-step incubation to accomplish the transfer of PEGylated lipids from PEGylated lipid-based micelles into the membranes of preformed liposomes.

Self-assembled hyaluronic acid-coated nanocomplexes for targeted delivery of curcumin alleviate acute kidney injury

Acute kidney injury (AKI) is a pathological process with high morbidity, and drug resistance is easy to occur due to untargeted drug therapy. Curcumin can repair acute kidney injury. The expression of the CD44 receptor in renal tubular epithelial cells is abnormally elevated during AKI, and hyaluronic acid (HA) has the ability to bind specifically to the CD44 receptor. In this study, we developed a hyaluronic acid-coated liposome (HALP) nanocomplexes that targeted renal epithelial cells and its effect of relieving AKI was investigated. HALP was formed by self-assembly through the electrostatic interaction of curcumin-loaded cationic liposomes (LP) with hyaluronic acid and responds to the release of curcumin in the acidic microenvironment of lesions to treat AKI. HALP had good stability and biocompatibility. The in vitro results showed that compared to LP, HALP exhibited higher antioxidant, anti-inflammatory, and anti-apoptotic capacities. The AKI model suggested that HALP could not only target and accumulate in the injured kidney but also had an excellent ability to reduce the inflammatory response, which decreased tubular necrosis and restored kidney function.

Liposomal Amphotericin B for Treatment of Leishmaniasis: From the Identification of Critical Physicochemical Attributes to the Design of Effective Topical and Oral Formulations

The liposomal amphotericin B (AmB) formulation, AmBisome^®, still represents the best therapeutic option for cutaneous and visceral leishmaniasis. However, its clinical efficacy depends on the patient's immunological status, the clinical manifestation and the endemic region. Moreover, the need for parenteral administration, its side effects and high cost significantly limit its use in developing countries. This review reports the progress achieved thus far toward the understanding of the mechanism responsible for the reduced toxicity of liposomal AmB formulations and the factors that influence their efficacy against leishmaniasis. It also presents the recent advances in the development of more effective liposomal AmB formulations, including topical and oral liposome formulations. The critical role of the AmB aggregation state and release rate in the reduction of drug toxicity and in the drug efficacy by non-invasive routes is emphasized. This paper is expected to guide future research and development of innovative liposomal formulations of AmB.

Multimodal imaging distribution assessment of a liposomal antibiotic in an infectious disease model

Liposomes are promising targeted drug delivery systems with the potential to improve the efficacy and safety profile of certain classes of drugs. Though attractive, there are unique analytical challenges associated with the development of liposomal drugs including human dose prediction given these are multi-component drug delivery systems. In this study, we developed a multimodal imaging approach to provide a comprehensive distribution assessment for an antibacterial drug, GSK2485680, delivered as a liposomal formulation (Lipo680) in a mouse thigh model of bacterial infection to support human dose prediction. Positron emission tomography (PET) imaging was used to track the in vivo biodistribution of Lipo680 over 48 h post-injection providing a clear assessment of the uptake in various tissues and, importantly, the selective accumulation at the site of infection. In addition, a pharmacokinetic model was created to evaluate the kinetics of Lipo680 in different tissues. Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) was then used to quantify the distribution of GSK2485680 and to qualitatively assess the distribution of a liposomal lipid throughout sections of infected and non-infected hindlimb tissues at high spatial resolution. Through the combination of both PET and MALDI IMS, we observed excellent correlation between the Lipo680-radionuclide signal detected by PET with the GSK2485680 and lipid component signals detected by MALDI IMS. This multimodal translational method can reduce drug attrition by generating comprehensive biodistribution profiles of drug delivery systems to provide mechanistic insight and elucidate safety concerns. Liposomal formulations have potential to deliver therapeutics across a broad array of different indications, and this work serves as a template to aid in delivering future liposomal drugs to the clinic.

Development of Ulvan-Containing Liposomes as Antibacterial Drug Delivery Platforms

Liposomes, due to their safety profile and targeting ability, are among the most studied nanocarriers as antimicrobial delivery systems. However, due to lack of stability and the non-specific interaction of liposomes with cells and proteins, their use is relatively limited. Aiming to overcome these drawbacks, it was envisaged that incorporation of ulvan, a bioactive marine sulfated polysaccharide isolated from green algae, in liposomes could improve their physicochemical properties and overall stability. Thus, we initially studied the interactions of ulvan with neutral, negatively, and positively charged lipids using Differential Scanning Calorimetry and subsequently, based on the obtained results, we prepared the respective ulvan–containing neutral and charged liposomes, where ulvan interacts with both lipid chains and polar groups in the liposomal bilayer. In a further step, we entrapped in the liposomes fusidic acid, used as a model antibacterial drug, and proceeded with the evaluation of their antibacterial activity against Staphylococcus aureus. The physicochemical properties (size and ζ-potential), stability, morphology, and entrapment efficiency of the prepared liposomal formulations were determined.

In vitro and in vivo activity of thermosensitive liposomes loaded with doxorubicin and cisplatin

Thermosensitive liposomes loaded with cisplatin and doxorubicin composed of DPPC, DSPC, and DPPE-PEG5000 with different ratios were prepared by thin film hydration method. The Differential Scanning Calorimetry (DSC) curves showed that the liposomes composed of DPPC-DSPC-DPPE-PEG5000 with phospholipid ratio 95:5:0.05 w/w were a suitable formulation as thermosensitive liposomes with a DSC peak at 42.1 °C. The effect of doxorubicin and cisplatin encapsulated non-thermosensitive and thermosensitive liposomes on cellular proliferation and IC50 in SKBR3 & MDA-MB-231 breast cancer and PC-3 & LNcaP prostate cancer cell lines was investigated. The results showed that doxorubicin loaded into thermosensitive liposomes showed 20-fold decrease in the IC50 at 42 °C while comparing it with the same at 37 °C. Also, the results showed a more than 35-fold and 12-fold decrease in the IC50 of cisplatin thermosensitive liposomes at 42 °C, while compared with free cisplatin and cisplatin thermosensitive liposomes at any temperature. The in vivo results showed that the effect of doxorubicin encapsulated thermosensitive liposomes at hyperthermic conditions during the treatment as the tumor growth inhibition was measured 1.5-fold higher than any of the liposomal formulations of doxorubicin. It was also noticed that the tumor volume reduced to 150 mm³ in doxorubicin thermosensitive liposomes (G8) after 3 weeks during the treatment, but increased to 196 mm³ after 4 weeks. The Kaplan-Meir curve showed the 100% survival of the animals from G8 (thermosensitive liposomes containing doxorubicin plus hyperthermia) after 12 weeks. The flow cytometry data revealed more than 25% apoptotic cells and 6.25% necrotic cells in the tumor cells from the tissues of the G8 group of the animals. The results clearly indicate the superior efficacy of doxorubicin and cisplatin containing thermosensitive liposomes treatment during hyperthermia.

Lipid-Nanoparticle-Based Delivery of CRISPR/Cas9 Genome-Editing Components

Gene editing mediated by CRISPR/Cas9 systems is due to become a beneficial therapeutic option for treating genetic diseases and some cancers. However, there are challenges in delivering CRISPR components which necessitate sophisticated delivery systems for safe and effective genome editing. Lipid nanoparticles (LNPs) have become an attractive nonviral delivery platform for CRISPR-mediated genome editing due to their low immunogenicity and application flexibility. In this review, we provide a background of CRISPR-mediated gene therapy, as well as LNPs and their applicable characteristics for delivering CRISPR components. We then highlight the challenges of CRISPR delivery, which have driven the significant development of new, safe, and optimized LNP formulations in the past decade. Finally, we discuss considerations for using LNPs to deliver CRISPR and future perspectives on clinical translation of LNP-CRISPR gene editing.

Formulation of Amphotericin B in PEGylated Liposomes for Improved Treatment of Cutaneous Leishmaniasis by Parenteral and Oral Routes

Liposomal amphotericin B (AmB) or AmBisome® is the most effective and safe therapeutic agent for visceral leishmaniasis (VL), but its clinical efficacy is limited in cutaneous leishmaniasis (CL) and HIV/VL co-infection. The aim of this work was to develop a formulation of AmB in PEGylated liposomes and compare its efficacy to AmBisome® in a murine model of CL. Formulations of AmB in conventional and PEGylated liposomes were characterized for particle size and morphology, drug encapsulation efficiency and aggregation state. Those were compared to AmBisome® in Leishmania amazonensis-infected BALB/c mice for their effects on the lesion size growth and parasite load. The conventional and PEGylated formulations showed vesicles with 100–130 nm diameter and low polydispersity, incorporating more than 95% of AmB under the non-aggregated form. Following parenteral administration in the murine model of CL, the PEGylated formulation of AmB significantly reduced the lesion size growth and parasite load, in comparison to control groups, in contrast to conventional liposomal AmB. The PEGylated formulation of AmB was also effective when given by oral route on a 2-day regimen. This work reports for the first time that PEGylated liposomal AmB can improve the treatment of experimental cutaneous leishmaniasis by both parenteral and oral routes.

New Cysteine-Containing PEG-Glycerolipid Increases the Bloodstream Circulation Time of Upconverting Nanoparticles

Upconverting nanoparticles have unique spectral and photophysical properties that make them suitable for development of theranostics for imaging and treating large and deep-seated tumors. Nanoparticles based on NaYF₄ crystals doped with lanthanides Yb³⁺ and Er³⁺ were obtained by the high-temperature decomposition of trifluoroacetates in oleic acid and 1-octadecene. Such particles have pronounced hydrophobic properties. Therefore, to obtain stable dispersions in aqueous media for the study of their properties in vivo and in vitro, the polyethylene glycol (PEG)-glycerolipids of various structures were obtained. To increase the circulation time of PEG-lipid coated nanoparticles in the bloodstream, long-chain substituents are needed to be attached to the glycerol backbone using ether bonds. To prevent nanoparticle aggregation, an L-cysteine-derived negatively charged carboxy group should be included in the lipid molecule.

Experimental and Theoretical Insights on Chemopreventive Effect of the Liposomal Thymoquinone Against Benzo[a]pyrene-Induced Lung Cancer in Swiss Albino Mice

Purpose

Thymoquinone (TQ), a phytoconstituent of Nigella sativa seeds, has been studied extensively in various cancer models. However, TQ’s limited water solubility restricts its therapeutic applicability. Our work aims to prepare the novel formulation of TQ and assess its chemopreventive potential in chemically induced lung cancer animal model.

Methods

The polyethylene glycol coated DOPE/CHEMS incorporating TQ-loaded pH-sensitive liposomes (TQPSL) were prepared and characterized. Mice were exposed to benzo[a]pyrene (BaP) thrice a week for 4 weeks to induce lung cancer. TQPSL was administered three times a week for 21 weeks, starting 2 weeks before the first dose of BaP.

Results

The prepared TQPSL revealed 85% entrapment efficiency with 128 nm size and −19.5 mv ζ-potential showing high stability of the formulation. The pretreatment of TQPSL showed the recovery in BaP-modulated relative organ weight of lungs, cancer marker enzymes, and antioxidant enzymes in the serum. The histopathological analysis of the tissues showed that TQPSL protected the malignancy in the lungs. The flow cytometry data revealed the induction of apoptosis and decreased intracellular ROS by TQPSL. Molecular docking was performed to predict the TQ’s affinity for eight possible anticancer drug targets linked to lung cancer etiology. The data assisted to identify the serine/threonine-protein kinase BRAF as the most suitable target of TQ with binding energy −6.8 kcal/mol.

Conclusion

The current findings demonstrated the potential of TQPSL and its possible therapeutic targets of lung cancer. To our knowledge, this is the first research to outline the development of TQ formulation against lung cancer considering its low solubility as well as pulmonary delivery challenges.

Withania somnifera: Progress towards a Pharmaceutical Agent for Immunomodulation and Cancer Therapeutics

Chemotherapy is one of the prime treatment options for cancer. However, the key issues with traditional chemotherapy are recurrence of cancer, development of resistance to chemotherapeutic agents, affordability, late-stage detection, serious health consequences, and inaccessibility. Hence, there is an urgent need to find innovative and cost-effective therapies that can target multiple gene products with minimal adverse reactions. Natural phytochemicals originating from plants constitute a significant proportion of the possible therapeutic agents. In this article, we reviewed the advances and the potential of Withania somnifera (WS) as an anticancer and immunomodulatory molecule. Several preclinical studies have shown the potential of WS to prevent or slow the progression of cancer originating from various organs such as the liver, cervix, breast, brain, colon, skin, lung, and prostate. WS extracts act via various pathways and provide optimum effectiveness against drug resistance in cancer. However, stability, bioavailability, and target specificity are major obstacles in combination therapy and have limited their application. The novel nanotechnology approaches enable solubility, stability, absorption, protection from premature degradation in the body, and increased circulation time and invariably results in a high differential uptake efficiency in the phytochemical’s target cells. The present review primarily emphasizes the insights of WS source, chemistry, and the molecular pathways involved in tumor regression, as well as developments achieved in the delivery of WS for cancer therapy using nanotechnology. This review substantiates WS as a potential immunomodulatory, anticancer, and chemopreventive agent and highlights its potential use in cancer treatment.

A drift on liposomes to proliposomes: recent advances and promising approaches

Liposomes are nano-structured vesicles, made up of phospholipids that provide active ingredients at the site of action at a predetermined rate and add the advantage of the sustained-release formulation. Liposomes have stability issues that tend to agglomerate and fuse upon storage, which reflects their drawback. Hence to overcome the aggregation, fusion, hydrolysis, and/or oxidation problems associated with liposomes a new technology named Proliposomes has been introduced. Proliposomes are defined as carbohydrate carriers coated with phospholipids, which upon addition of water generate liposomes. The objective of the review is to cover the concept of proliposomes for pulmonary or alveolar delivery of drugs and compare it with that of liposomes; highlight the methods used for preparations along with the characterization parameters. This is the first systematic review that covers the categorization of liposomes, characteristic methods, and recent examples of drugs from 2015 to 2021, supplied in form of proliposomes to the macrophages as well as others and offers an advantage over the free drug by offering a prolonged drug release and sufficient bioavailability in addition to overcome the stability issues related to liposomes. Since this is a very new technology and many scientists are continuously working in this field to make the drug available for clinical trials and ultimately in the market for the targeted delivery of drugs with better storage life.HIGHLIGHTSProliposomes as an alternative to overwhelm the stability and storage-related issues of liposomes.Anhydrous carbohydrate carriers are utilized for proliposomal preparation.Inhaled delivery of drugs as solid lipid nanoparticles offers a significant impact on pulmonary tract infections, particularly in cystic fibrosis.Size of liposomes attained after proliposome hydrolysis is critical for drug delivery via respiration.

Biocompatible Nanomaterials as an Emerging Technology in Reproductive Health; a Focus on the Male

A growing body of research has confirmed that nanoparticle (NP) systems can enhance delivery of therapeutic and imaging agents as well as prevent potentially damaging systemic exposure to these agents by modifying the kinetics of their release. With a wide choice of NP materials possessing different properties and surface modification options with unique targeting agents, bespoke nanosystems have been developed for applications varying from cancer therapeutics and genetic modification to cell imaging. Although there remain many challenges for the clinical application of nanoparticles, including toxicity within the reproductive system, some of these may be overcome with the recent development of biodegradable nanoparticles that offer increased biocompatibility. In recognition of this potential, this review seeks to present recent NP research with a focus on the exciting possibilities posed by the application of biocompatible nanomaterials within the fields of male reproductive medicine, health, and research.

Surface-engineered liposomes for dual-drug delivery targeting strategy against Methicillin-resistant Staphylococcus aureus (MRSA)

This study focused on the encapsulation of vancomycin (VAN) into liposomes coated with a red blood cell membrane with a targeting ligand, daptomycin–polyethylene glycol–1,2-distearoyl-sn-glycero-3-phosphoethanolamine, formed by conjugation of DAPT and N-hydroxysuccinimidyl-polyethylene glycol-1,2-distearoyl-sn-glycero-3-phosphoethanolamine. This formulation is capable of providing controlled and targeted drug delivery to the bacterial cytoplasm. We performed MALDI-TOF, NMR and FTIR analyses to confirm the conjugation of the targeting ligand via the formation of amide bonds. Approximately 45% of VAN could be loaded into the aqueous cores, whereas 90% DAPT was detected using UV–vis spectrophotometry. In comparison to free drugs, the formulations controlled the release of drugs for > 72 h. Additionally, as demonstrated using CLSM and flow cytometry, the resulting formulation was capable of evading detection by macrophage cells. In comparison to free drugs, red blood cell membrane–DAPT–VAN liposomes, DAPT liposomes, and VAN liposomes reduced the MIC and significantly increased bacterial permeability, resulting in > 80% bacterial death within 4 h. Cytotoxicity tests were performed in vitro and in vivo on mammalian cells, in addition to hemolytic activity tests in human erythrocytes, wherein drugs loaded into the liposomes and RBCDVL exhibited low toxicity. Thus, the findings of this study provide insight about a dual antibiotic targeting strategy that utilizes liposomes and red blood cell membranes to deliver targeted drugs against MRSA.

Controlling the Biological Fate of Liposomal Spherical Nucleic Acids Using Tunable Polyethylene Glycol Shells

Liposomal spherical nucleic acids (LSNAs) modified with polyethylene glycol (PEG) units are studied in an attempt to understand how the circulation time and biodistribution of the constructs can be manipulated. Specifically, the effect of (1) PEG molecular weight, (2) PEG shell stability, and (3) PEG modification method (PEG in both the core and shell versus PEG in the shell only) on LSNA blood circulation, biodistribution, and in vivo cell internalization in a syngeneic, orthotopic triple-negative breast cancer mouse model is studied. Generally, high PEG molecular weight extends blood circulation lifetime, and a more lipophilic anchor stabilizes the PEG shell and improves circulation and tumor accumulation but at the cost of cell uptake efficiency. The PEGylation strategy has a minor effect on in vitro properties of LSNAs but significantly alters in vivo cell uptake. For example, surface-only PEG in one design contributed to higher in vivo cell internalization than its counterpart with PEG both in the shell and core. Taken together, this work provides guidelines for designing LSNAs that exhibit maximal in vivo cancer cell uptake characteristics in the context of a breast cancer model.

EDTA-Gradient Loading of Doxorubicin into Ferrocene-Containing Liposomes: Effect of Lipid Composition and Visualization of Triggered Release by Cryo-TEM

Efficient delivery of therapeutic compounds to their sites of action has been a ubiquitous concern throughout the history of human medicine. The tumor microenvironment offers a variety of endogenous stimuli that may be exploited by a responsive nanocarrier, including heterogeneities in redox potential. In the early stages of the design of such responsive delivery systems, it is necessary to develop a comprehensive understanding of the biophysical mechanism by which the stimulus response occurs, as well as how the response may change from the inclusion of cargo compounds. We describe the optimization of lipid compositions for liposomes containing synthetic ferrocene-appended lipids to achieve highly efficient loading of doxorubicin via an ethylenediaminetetraacetic acid (EDTA) gradient. Liposomes containing ferrocenylated phospholipid are shown to be unstable to the loading conditions, while those including a ferrocenylated alkylammonium amphiphile obtain a near-quantitative loading efficiency. Calorimetric studies demonstrate that this instability is the consequence of the relative degree of lipid hydrolysis that occurs under the acidic loading conditions. Drug-loaded liposomes of the optimized composition are studied by cryo-TEM; the presence of doxorubicin aggregates is observed inside vesicles, and doxorubicin release, as well as the changes in membrane structure resulting from oxidant treatment, is also observed by cryogenic transmission electron microscopy (cryo-TEM). These results further demonstrate the potential of ferrocene lipids in the design of redox-responsive nanocarriers and begin to explore their possible role as probes of membrane dynamics.

Cationic Liposomes as Vectors for Nucleic Acid and Hydrophobic Drug Therapeutics

Cationic liposomes (CLs) are effective carriers of a variety of therapeutics. Their applications as vectors of nucleic acids (NAs), from long DNA and mRNA to short interfering RNA (siRNA), have been pursued for decades to realize the promise of gene therapy, with approvals of the siRNA therapeutic patisiran and two mRNA vaccines against COVID-19 as recent milestones. The long-term goal of developing optimized CL-based NA carriers for a broad range of medical applications requires a comprehensive understanding of the structure of these vectors and their interactions with cell membranes and components that lead to the release and activity of the NAs within the cell. Structure-activity relationships of lipids for CL-based NA and drug delivery must take into account that these lipids act not individually but as components of an assembly of many molecules. This review summarizes our current understanding of how the choice of the constituting lipids governs the structure of their CL-NA self-assemblies, which constitute distinct liquid crystalline phases, and the relation of these structures to their efficacy for delivery. In addition, we review progress toward CL-NA nanoparticles for targeted NA delivery in vivo and close with an outlook on CL-based carriers of hydrophobic drugs, which may eventually lead to combination therapies with NAs and drugs for cancer and other diseases.

Induction of Spontaneous Liposome Adsorption by Exogenous Surface Modification with Cell-Penetrating Peptide-Conjugated Lipids

The use of amphiphilic molecules such as poly(ethylene glycol)-conjugated phospholipid (PEG-lipid) enables incorporation into liposome surfaces by exogenous addition as a result of the self-assembly with lipids. This technique can be applicable for manipulation of both liposomes and cells. In this study, we aimed to characterize Tat peptide (YGRKKRRQRRR)-conjugated PEG-lipids when used to exogenously surface modify liposomes (size: ca. 100 nm). We earlier reported that cells, which were surface modified with Tat peptides conjugated to PEG-lipids could attach spontaneously to material surfaces without any chemical modification. Here, we synthesized different types of Tat-PEG-lipids by combining PEG of different molecular weights (5 and 40 kDa) with different lipids with three acyl chains (myristoyl, palmitoyl, and stearoyl, respectively) and then studied the spontaneous adsorption of modified liposomes onto a substrate surface induced by the different Tat-PEG-lipids. The amount of adsorbed liposomes strongly depended on the number of incorporated Tat-PEG-lipid moieties: a decrease in both the PEG and the acyl chain lengths led to adsorption of higher amounts of liposomes. Furthermore, when a collagenase-cleavable amino acid sequence was inserted between the Tat sequence and the PEG segment, adsorbed liposomes could be harvested from the substrate by collagenase treatment with no difference in desorption efficiency between the different Tat-PEG-lipids. Thus, Tat-PEG-lipid can be a suitable tool for the manipulation of liposomes and cells.

A Critical Review of the Use of Surfactant-Coated Nanoparticles in Nanomedicine and Food Nanotechnology

Surfactants, whose existence has been recognized as early as 2800 BC, have had a long history with the development of human civilization. With the rapid development of nanotechnology in the latter half of the 20th century, breakthroughs in nanomedicine and food nanotechnology using nanoparticles have been remarkable, and new applications have been developed. The technology of surfactant-coated nanoparticles, which provides new functions to nanoparticles for use in the fields of nanomedicine and food nanotechnology, is attracting a lot of attention in the fields of basic research and industry. This review systematically describes these "surfactant-coated nanoparticles" through various sections in order: 1) surfactants, 2) surfactant-coated nanoparticles, application of surfactant-coated nanoparticles to 3) nanomedicine, and 4) food nanotechnology. Furthermore, current progress and problems of the technology using surfactant-coated nanoparticles through recent research reports have been discussed.

Liposome technologies towards colorectal cancer therapeutics

Colorectal cancer (CRC) is the third most common cancer and the fourth most common deadly cancer worldwide. After treatment with curative intent recurrence rates vary with staging 0-13% in Stage 1, 11-61% in S2 and 28-73% in Stage 3. The toxicity to healthy tissues from chemotherapy and radiotherapy and drug resistance severely affect the quality of life and cancer specific outcomes of CRC patients. To overcome some of these limitations, many efforts have been made to develop nanomaterial-based drug delivery systems. Among these nanocarriers, liposomes represented one of the most successful candidates in delivering targeted oncological treatment, improving safety profile and therapeutic efficacy of encapsulated drugs. In this review we will discuss liposome design with a particular focus on the targeting feature and triggering functions. We will also summarise the recent advances in liposomal delivery system for CRC treatment in both the preclinical and clinical studies. We will finally provide our perspectives on the liposome technology development for the future clinical translation. STATEMENT OF SIGNIFICANCE: Conventional treatments for colorectal cancer (CRC) severely affect the therapeutic effects for advanced patients. With the development of nanomedicines, liposomal delivery system appears to be one of the most promising nanocarriers for CRC treatment. In last three years several reviews in this area have been published focusing on the preclinical research and drug delivery function, which is a fairly narrow focus in the field of liposome technology for CRC therapy. Our review presented the most recent advances of the liposome technology (both clinical and preclinical applications) for CRC with strong potential for further clinical translation. We believe it will attract lots of attention from various audiences, including researchers, clinicians and the industry.

Improving the bioavailability and bioactivity of garlic bioactive compounds via nanotechnology

This review highlights main bioactive compounds and important biological functions especially anticancer effects of the garlic. In addition, we review current literature on the stability and bioavailability of garlic components. Finally, this review aims to provide a potential strategy for using nanotechnology to increase the stability and solubility of garlic components, providing guidelines for the qualities of garlic products to improve their absorption and prevent their early degradation, and extend their circulation time in the body. The application of nanotechnology to improve the bioavailability and targeting of garlic compounds are expected to provide a theoretical basis for the functional components of garlic to treat human health. We review the improvement of bioavailability and bioactivity of garlic bioactive compounds via nanotechnology, which could promisingly overcome the limitations of conventional garlic products, and would be used to prevent and treat cancer and other diseases in the near future.

Liposomal Nanomedicine: Applications for Drug Delivery in Cancer Therapy

The increasing prevalence of cancer, a disease in which rapid and uncontrollable cell growth causes complication and tissue dysfunction, is one of the serious and tense concerns of scientists and physicians. Nowadays, cancer diagnosis and especially its effective treatment have been considered as one of the biggest challenges in health and medicine in the last century. Despite significant advances in drug discovery and delivery, their many adverse effects and inadequate specificity and sensitivity, which usually cause damage to healthy tissues and organs, have been great barriers in using them. Limitation in the duration and amount of these therapeutic agents' administration is also challenging. On the other hand, the incidence of tumor cells that are resistant to typical methods of cancer treatment, such as chemotherapy and radiotherapy, highlights the intense need for innovation, improvement, and development in antitumor drug properties. Liposomes have been suggested as a suitable candidate for drug delivery and cancer treatment in nanomedicine due to their ability to store drugs with different physical and chemical characteristics. Moreover, the high flexibility and potential of liposome structure for chemical modification by conjugating various polymers, ligands, and molecules is a significant pro for liposomes not only to enhance their pharmacological merits but also to improve the effectiveness of anticancer drugs. Liposomes can increase the sensitivity, specificity, and durability of these anti-malignant cell agents in the body and provide remarkable benefits to be applied in nanomedicines. We reviewed the discovery and development of liposomes focusing on their clinical applications to treat diverse sorts of cancers and diseases. How the properties of liposomal drugs can be improved and their opportunity and challenges for cancer therapy were also considered and discussed.

Coarse-grained simulation of the self-assembly of lipid vesicles concomitantly with novel block copolymers with multiple tails

We carried out a series of coarse-grained molecular dynamics liposome-copolymer simulations with varying extent of copolymer concentration in an attempt to understand the effect of copolymer structure and concentration on vesicle self-assembly and stability. For one particular case molecular dynamics simulation data was successfully verified against experimental NMR results enhancing the credulity in the simulation methodology. The study focused on a new class of promising copolymers based on ethylene oxide (EO) chains and short blocks of aliphatic double chains that mimic lipid tails. The lipid mimetic units are based on 1,3-didodecyloxy-2-glycidylglycerol (DDGG) and 1,3-didodecyloxy-propane-2-ol (DDP). The conducted simulations indicate that multiple lipid anchor-bearing copolymers lead to stable hybrid liposome formations. Single lipid bearing might incur liposome-stabilizing potential for relatively small ethylene oxide chains but fails dramatically in combination with a longer EO-based moiety. The consistency of the theoretical evidence with experimental NMR observation for certain cases provides confidence for the relevance of the methodology in eliciting the factors governing liposome-polymer stability which is of fundamental and practical significance.

Towards the Development of Long Circulating Phosphatidylserine (PS)- and Phosphatidylglycerol (PG)-Enriched Anti-Inflammatory Liposomes: Is PEGylation Effective?

The anionic phospholipids (PLs) phosphatidylserine (PS) and phosphatidylglycerol (PG) are endogenous phospholipids with anti-inflammatory and immunomodulatory activity. A potential clinical use requires well-defined systems and for several applications, a long circulation time is desirable. Therefore, we aimed the development of long circulating liposomes with intrinsic anti-inflammatory activity. Hence, PS- and PG-enriched liposomes were produced, whilst phosphatidylcholine (PC) liposomes served as control. Liposomes were either formulated as conventional or PEGylated formulations. They had diameters below 150 nm, narrow size distributions and composition-dependent surface charges. Pharmacokinetics were assessed non-invasively via in vivo fluorescence imaging (FI) and ex vivo in excised organs over 2 days. PC liposomes, conventionally formulated, were rapidly cleared from the circulation, while PEGylation resulted in prolongation of liposome circulation robustly distributing among most organs. In contrast, PS and PG liposomes, both as conventional or PEGylated formulations, were rapidly cleared. Non-PEGylated PS and PG liposomes did accumulate almost exclusively in the liver. In contrast, PEGylated PS and PG liposomes were observed mainly in liver and spleen. In summary, PEGylation of PS and PG liposomes was not effective to prolong the circulation time but caused a higher uptake in the spleen.

Novel Pancreatic Cancer Therapy Targeting Cell Surface Glycans by Liposomes Modified with rBC2LCN Lectin

INTRODUCTION

Since the outermost layer of cancer cells is covered with various glycans, targeting these groups may serve as an effective strategy in cancer therapy. We previously reported that fucosylated glycans are specifically expressed on pancreatic cancer cells, and that a protein specifically binding to these glycans, namely rBC2LCN lectin, is a potential guiding drug carrier. In the present study, a novel type of glycan-targeting nanoparticle was developed by modifying the surface of doxorubicin-containing liposomes with rBC2LCN lectin. The efficiency and specificity of this formulation, termed Lec-Doxosome, were examined in vitro and in vivo in human pancreatic cancer models.

METHODS

Lec-Doxosome was prepared by a post-insertion method based on the insertion of rBC2LCN lectin into the liposomal surface via a lipid linker. The in vitro cellular binding, uptake, and cytotoxicity of Lec-Doxosome were compared with the corresponding parameters in the unmodified liposomes by applying to human pancreatic cancer cell line (Capan-1) with affinity for rBC2LCN lectin. For the in vivo assay, Lec-Doxosome was intravenously injected once per week for a total of 3 weeks into mice bearing subcutaneous tumors.

RESULTS

The in vitro application of Lec-Doxosome resulted in a 1.2- to 1.6-fold higher intracellular doxorubicin accumulation and a 1.5-fold stronger cytotoxicity compared with the respective rates of accumulation and cytotoxicity in the unmodified liposomes. In vivo, Lec-Doxosome reduced the mean tumor weight (368 mg) compared with that in mice treated with unmodified liposomes (456 mg), without causing any additional adverse events.

CONCLUSION

It was demonstrated from the results obtained herein that rBC2LCN lectin is a potent modifier, as a means for boosting the efficiency of nanoparticles in the targeting of cancer cell surface glycans.

Effect of the ammonium salt anion on the structure of doxorubicin complex and PEGylated liposomal doxorubicin nanodrugs

BACKGROUND

In Doxil®, PEGylated nanoliposomes are created by hydration of the lipids in ammonium sulfate, and are remotely loaded with doxorubicin by a transmembrane ammonium gradient. The ammonium sulfate is then removed from the external aqueous phase, surrounding the liposomes, and replaced by an isoosmotic sucrose solution in 10 mM histidine buffer at pH 6.5.

METHODS

We prepared PEGylated liposomal doxorubicin (PLD) with a series of ammonium monovalent salts that after remote loading became the intraliposome doxorubicin counteranions. We analyzed the liposomes by solution X-ray scattering, differential scanning calorimetry, and electron micropscopy.

RESULTS

PLDs prepared with sulfonic acid derivatives as counteranion exhibited chemical and physical stabilities. We determined the effect of these ammonium salt counteranions on the structure, morphology, and thermotropic behavior of the PEGylated nanoliposomes, formed before and after doxorubicin loading, and the bulk properties of the doxorubicin-counteranion complexes. By comparing the structure of the doxorubicin complexes in the bulk and inside the nanoliposomes, we revealed the effect of confinement on the structure and doxorubicin release rate for each of the derivatives of the ammonium sulfonic acid counteranions.

CONCLUSIONS

We found that the extent and direction of the doxorubicin confinement effect and its release rate were strongly dependent on the type of counteranion. The counteranions, however, neither affected the structure and thermotropic behavior of the liposome membrane, nor the thickness and density of the liposome PEG layers. In an additional study, it was demonstrated that PLD made with ammonium-methane sulfonate exhibit a much lower Hand and Foot syndrome.

GENERAL SIGNIFICANCE

The structure, physical state, and pharmacokinetics of doxorubicin in PEGylated nanoliposomes, prepared by transmembrane remote loading using gradients of ammonium salts, strongly depend on the counteranions.

Nanoparticle-Induced Complement Activation: Implications for Cancer Nanomedicine

Nanoparticle-based anticancer medications were first approved for cancer treatment almost 2 decades ago. Patients benefit from these approaches because of the targeted-drug delivery and reduced toxicity, however, like other therapies, adverse reactions often limit their use. These reactions are linked to the interactions of nanoparticles with the immune system, including the activation of complement. This activation can cause well-characterized acute inflammatory reactions mediated by complement effectors. However, the long-term implications of chronic complement activation on the efficacy of drugs carried by nanoparticles remain obscured. The recent discovery of protumor roles of complement raises the possibility that nanoparticle-induced complement activation may actually reduce antitumor efficacy of drugs carried by nanoparticles. We discuss here the initial evidence supporting this notion. Better understanding of the complex interactions between nanoparticles, complement, and the tumor microenvironment appears to be critical for development of nanoparticle-based anticancer therapies that are safer and more efficacious.

Doxorubicin-loaded pH-sensitive micelles: A promising alternative to enhance antitumor activity and reduce toxicity

Doxorubicin (DOX) is an anthracycline antibiotic widely used in the treatment of cancer, however, it is associated with the occurrence of adverse reactions that limits its clinical use. In this context, the encapsulation of DOX in micelles responsive to pH variations has shown to be a strategy for tumor delivery of the drug, with the potential to increase therapeutic efficacy and to reduce the toxic effects. In addition, radiolabeling nanoparticles with a radioactive isotope is of great use in preclinical studies, since it allows the in vivo monitoring of the nanostructure through the acquisition of quantitative images. Therefore, this study aimed to develop, characterize, and evaluate the antitumor activity of a pH-sensitive micelle composed of DSPE-PEG₂₀₀₀, oleic acid, and DOX. The micelles had a diameter of 13 nm, zeta potential near to neutrality, and high encapsulation percentage. The critical micellar concentration (CMC) was 1.4 × 10^-5 mol L^-1. The pH-sensitivity was confirmed in vitro through a drug release assay. Cytotoxicity studies confirmed that the encapsulation of DOX into the micelles did not impair the drug cytotoxic activity. Moreover, the incorporation of DSPE-PEG₂₀₀₀-DTPA into the micelles allowed it radiolabeling with the technetium-99 m in high yield and stability, permitting its use to monitor antitumor therapy. In this sense, the pH-sensitive micelles were able to inhibit tumor growth significantly when compared to non-pH-sensitive micelles and the free drug. in vivo toxicity evaluation in the zebrafish model revealed significantly lower toxicity of pH-sensitive micelles compared to the free drug. These results indicate that the developed formulation presents itself as a promising alternative to potentiate the treatment of tumors.

Innovational combination of hetero-bifunctional N-PEG quinoline scaffolds derivatives with improved anticancer activity against breast and colon cancer cell lines and P-glycoprotein, cytochrome p450 enzyme activity prediction

Polyethylene glycol (PEG) is a polymer that is widely used as a carrier for drug delivery systems (DDS). A library of N-PEGylated quinoline derivatives of PEG molecular weight 200 was prepared rapidly after the activation of PEGs using maleic anhydride. Quinoline with a polymer backbone is essential as new material. PEG is a water-soluble nonionic polymer approved by food and drug organizations for medicine applications. Because of its nontoxic grapheme, it is widely utilized in numerous biochemical, cosmetic, pharmaceutical, and industrialized applications. The modern SwissADME is a web tool that stretches free admittance to a pool of hasty, yet solid, clarifying models for physicochemical properties, pharmacokinetics, and therapeutic science. The present facile synthetic strategy can be a practical approach for incorporating polymeric carriers conjugated with drug moieties, either in the backbone of the polymer or as a terminal and pendant group on the polymer chains.

Sterically stabilized liposomes targeting P21 (RAC1) activated kinase-1 and secreted phospholipase A2 suppress prostate cancer growth and metastasis

Metastatic prostate cancer (PCa) has a very high mortality rate in men, in Western countries and lacks reliable treatment. The advanced-stage PCa cells overexpress P21 (RAC1) activated kinase-1 (PAK1) and secreted phospholipase A2 (sPLA2) suggesting the potential utility of pharmacologically targeting these molecules to treat metastatic PCa. The small molecule, inhibitor targeting PAK1 activation-3 (IPA3) is a highly specific allosteric inhibitor of PAK1; however, it is metabolically unstable once in the plasma thus, limiting its utility as a chemotherapeutic agent. In the present study, the efficacy and specificity of IPA3 were combined with the stability and the sPLA2-targeted delivery method of two sterically stabilized liposomes [sterically stabilized long-circulating liposomes (SSL)-IPA3 and sPLA2 responsive liposomes (SPRL)-IPA3, respectively] to inhibit PCa growth and metastasis. It was found that twice-a-week administration of either SSL-IPA3 or SPRL-IPA3 for 3 weeks effectively suppressed the growth of PC-3 cell tumor xenografts implanted in athymic nude mice. Both drug formulations also inhibited the metastasis of intravenously administered murine RM1 PCa cells to the lungs of C57BL/6 mice. Whereas the twice-a-week administration of SSL-IPA3 significantly inhibited the spontaneous PCa metastasis to the lungs in Transgenic Adenocarcinoma of the Mouse Prostate mice, the administration of free IPA3 had no significant therapeutic benefit. The results present two novel IPA3 encapsulated liposomes to treat metastatic PCa.