Liposomes like advanced drug carriers: from fundamentals to pharmaceutical applications

AIMS

There are around 24 distinct lipid vesicles described in the literature that are similar to vesicular systems such as liposomes. Liposome-like structures are formed by combining certain amphiphilic lipids with a suitable stabiliser. Since their discovery and classification, self-assembled liposome-like structures as active drug delivery vehicles captured researchers' curiosity.

METHODOLOGY

This comprehensive study included an in-depth literature search using electronic databases such as PubMed, ScienceDirect and Google Scholar, focusing on studies on liposome and liposomes like structure, discussed in literature till 2024, their sizes, benefits, drawback, method of preparation, characterisation and pharmaceutical applications.

RESULTS

Pharmacosomes, cubosomes, ethosomes, transethosomes, and genosomes, all liposome-like structures, have the most potential due to their smaller size with high loading capacity, ease of absorption, and ability to treat inflammatory illnesses. Genosomes are futuristic because of its affinity for DNA/gene transport, which is an area of focus in today's treatments.

CONCLUSION

This review will critically analyse the composition, preparation procedures, drug encapsulating technologies, drug loading, release mechanism, and related applications of all liposome-like structures, highlighting their potential benefits with enhanced efficacy over each other and over traditional carriers by paving the way for exploring novel drug delivery systems in the Pharma industry.

Current development of theragnostic nanoparticles for women's cancer treatment

In the biomedical industry, nanoparticles (NPs-exclusively small particles with size ranging from 1-100 nanometres) are recently employed as powerful tools due to their huge potential in sophisticated and enhanced cancer theragnostic (i.e. therapeutics and diagnostics). Cancer is a life-threatening disease caused by carcinogenic agents and mutation in cells, leading to uncontrolled cell growth and harming the body's normal functioning while affecting several factors like low levels of reactive oxygen species, hyperactive antiapoptotic mRNA expression, reduced proapoptotic mRNA expression, damaged DNA repair, and so on. NPs are extensively used in early cancer diagnosis and are functionalized to target receptors overexpressing cancer cells for effective cancer treatment. This review focuses explicitly on how NPs alone and combined with imaging techniques and advanced treatment techniques have been researched against 'women's cancer' such as breast, ovarian, and cervical cancer which are substantially occurring in women. NPs, in combination with numerous imaging techniques (like PET, SPECT, MRI, etc) have been widely explored for cancer imaging and understanding tumor characteristics. Moreover, NPs in combination with various advanced cancer therapeutics (like magnetic hyperthermia, pH responsiveness, photothermal therapy, etc), have been stated to be more targeted and effective therapeutic strategies with negligible side effects. Furthermore, this review will further help to improve treatment outcomes and patient quality of life based on the theragnostic application-based studies of NPs in women's cancer treatment.

Preparation, characterization, and Co-delivery of cisplatin and doxorubicin-loaded liposomes to enhance anticancer Activities

Ovarian cancer stands as a leading cause of cancer-related deaths among women globally. This malignancy has hindered successful treatment attempts due to its inherent resistance to chemotherapy agents. The utilization of cisplatin and doxorubicin-loaded liposomes emerges as a strategically advantageous approach in the realm of biomedical applications. This strategy holds promise for augmenting drug efficacy, mitigating toxicity, refining pharmacokinetics, and facilitating versatile drug delivery while accommodating combination therapies. In pursuit of scholarly investigations, the eminent databases, including PubMed/MEDLINE, ScienceDirect, Scopus, and Google Scholar, were meticulously scrutinized. Within this study, a nano-liposomal formulation was meticulously designed to serve as a co-delivery system. This system was optimized by varying lipid concentrations, hydration time, and DSPC: cholesterol molar ratios to efficiently encapsulate and load doxorubicin (DOX) and cisplatin (CIS) to overcome drug resistance problems. The Lipo (CIS + DOX) formulation underwent rigorous characterization including dimensions, entrapment efficiencies and drug release kinetics. Notably, the entrapment efficiency of cisplatin and doxorubicin loaded liposomal nanoparticles was an impressive 85.29 ± 1.45 % and 73.62 ± 1.70 %, respectively. Furthermore, Lipo (CIS + DOX) drug release kinetics exhibited pH-dependent properties, with lower drug release rates at physiological pH (7.4) than acidic (pH 5.4). Subsequent cytotoxicity assays revealed the enhanced biocompatibility of dual-drug liposomes with HFF cells compared to free drug combinations. Impressively, CIS and DOX-loaded liposomes induced significant cytotoxicity against A2780 in comparison to free drugs and combinatorial free drugs. Furthermore, the CIS and DOX-loaded liposome showed induced apoptotic potential and cell cycle arrest in A2780 compared to CIS, DOX, and their combination (CIS + DOX). Combining CIS and DOX via liposomal nanoparticles introduces a promising therapeutic avenue for addressing ovarian cancer. These nano-scale carriers hold the potential for attenuating the untoward effects of singular drugs and their attendant toxicities.

Multicompartment colloid systems with lipid and polymer membranes for biomedical applications

Multicompartment structures have the potential for biomedical applications because they can act as multifunctional systems and provide simultaneous delivery of drugs and diagnostics agents of different types. Moreover, some of them mimic biological cells to some extent with organelles as separate sub-compartments. This article analyses multicompartment colloidal structures with smaller sub-units covered with lipid or polymer membranes that provide additional protection for the encapsulated substances. Vesosomes with small vesicles encapsulated in the inner pools of larger liposomes are the most studied systems to date. Dendrimer molecules are enclosed by a lipid bilayer shell in dendrosomes. Capsosomes, polymersomes-in-polymer capsules, and cubosomes-in-polymer capsules are composed of sub-compartments encapsulated within closed multilayer polymer membranes. Janus or Cerberus emulsions contain droplets composed of two or three phases: immiscible oils in O/W emulsions and aqueous polymer or salt solutions that are separated into two or three phases and form connected droplets in W/O emulsions. In more cases, the external surface of engulfed droplets in Janus or Cerberus emulsions is covered with a lipid or polymer monolayer. eLiposomes with emulsion droplets encapsulated into a bilayer shell have been given little attention so far, but they have very great prospects. In addition to nanoemulsion droplets, solid lipid nanoparticles, nanostructured lipid carriers and inorganic nanoparticles can be loaded into eLiposomes. Molecular engineering of the external membrane allows the creation of ligand-targeted and stimuli-responsive multifunctional systems. As a result, the efficacy of drug delivery can be significantly enhanced.

Review on Different Vesicular Drug Delivery Systems (VDDSs) and Their Applications

BACKGROUND

Colloidal dispersions, also known as vesicular drug delivery systems (VDDSs), are highly ordered assemblies composed of one or more concentric bilayers formed by the self-assembly of amphiphilic building blocks in the presence of water.

OBJECTIVE

VDDSs are important to target the entrapped drugs at specific sites inside the body, control the drug release, enhance the drug bioavailability, and reduce undesired side effects.

METHODS

There are different types of VDDSs suitable for the entrapment of both hydrophilic and lipophilic drugs. According to the patent composition, VDDSs are classified into lipid-based and nonlipid- based VDDSs.

RESULTS

There are different types of VDDSs which include liposomes, ethosomes, transferosomes, ufasomes, colloidosomes, cubosomes, niosomes, bilosomes, aquasomes, etc. Conclusion: This review article aims to address the different types of VDDSs, their advantages and disadvantages, and their therapeutic applications.

Self-assembly of a 5-fluorouracil and camptothecin dual drug dipeptide conjugate

Nano-formulated, combinatory therapeutics that control the spatiotemporal aspects of drug release have potential to overcome many of the challenges faced in cancer therapy. Herein, we describe a peptide nanotube functionalized with two anticancer drugs, 5-fluoruracil (5-FU) and camptothecin (CPT). The nanotube was formed via peptide self-assembly, which positioned 5-FU on the surface at the aqueous interface; whereas, CPT was sequestered within the hydrophobic walls. Thus, two different release profiles were observed: rapid release of 5-FU, followed by slower, sustained production of CPT. This profile emerged from the rapid hydrolytic cleavage of 5-FU at the aqueous/nanotube interface, which produced a smaller nanotube comprised of the peptide fragment.

Biocatalytic self-assembled synthetic vesicles and coacervates: From single compartment to artificial cells

Compartmentalization is an intrinsic feature of living cells that allows spatiotemporal control over the biochemical pathways expressed in them. Over the years, a library of compartmentalized systems has been generated, which includes nano to micrometer sized biomimetic vesicles derived from lipids, amphiphilic block copolymers, peptides, and nanoparticles. Biocatalytic vesicles have been developed using a simple bag containing enzyme design of liposomes to multienzymes immobilized multi-vesicular compartments for artificial cell generation. Additionally, enzymes were also entrapped in membrane-less coacervate droplets to mimic the cytoplasmic macromolecular crowding mechanisms. Here, we have discussed different types of single and multicompartment systems, emphasizing their recent developments as biocatalytic self-assembled structures using recent examples. Importantly, we have summarized the strategies in the development of the self-assembled structure to improvise their adaptivity and flexibility for enzyme immobilization. Finally, we have presented the use of biocatalytic assemblies in mimicking different aspects of living cells, which further carves the path for the engineering of a minimal cell.

Multicompartment systems: A putative carrier for combined drug delivery and targeting

In this review, we discuss recent developments in multicompartment systems commonly referred to as vesosomes, as well as their method of preparation, surface modifications, and clinical potential. Vesosomal systems are able to entrap more than one drug moiety and can be customized for site-specific delivery. We focus in particular on the possible reticuloendothelial system (RES) - mediated accumulation of vesosomes, and their application in tumor targeting, as areas for further investigation.

Exploring New Horizons in Liquid Compartmentalization via Microfluidics

Spatial organization of cellular processes is crucial to efficiently regulate life's essential reactions. Nature does this by compartmentalization, either using membranes, such as the cell and nuclear membrane, or by liquid-like droplets formed by aqueous liquid-liquid phase separation. Aqueous liquid-liquid phase separation can be divided in two different phenomena, associative and segregative phase separation, of which both are studied for their membraneless compartmentalization abilities. For centuries, segregative phase separation has been used for the extraction and purification of biomolecules. With the emergence of microfluidic techniques, further exciting possibilities were explored because of their ability to fine-tune phase separation within emulsions of various compositions and morphologies and achieve one of the simplest forms of compartmentalization. Lately, interest in aqueous liquid-liquid phase separation has been revived due to the discovery of membraneless phases within the cell. In this Perspective we focus on segregative aqueous phase separation, discuss the theory of this interesting phenomenon, and give an overview of the evolution of aqueous phase separation in microfluidics.

Metallo-Liposomes Derived from the [Ru(bpy)3]2+ Complex as Nanocarriers of Therapeutic Agents

The obtaining of nanocarriers of gene material and small drugs is still an interesting research line. Side-effects produced by the toxicity of several pharmaceutics, the high concentrations needed to get therapeutic effects, or their excessive use by patients have motivated the search for new nanostructures. For these reasons, cationic metallo-liposomes composed by phosphatidylcholine (PC), cholesterol (CHO) and RuC1C19 (a surfactant derived from the metallic complex [Ru(bpy)3]2+) were prepared and characterized by using diverse techniques (zeta potential, dynamic light scattering and electronic transmission microscopy –TEM-). Unimodal or bimodal populations of spherical aggregates with small sizes were obtained depending on the composition of the liposomes. The presence of cholesterol favored the formation of small aggregates. ct-DNA was condensed in the presence of the liposomes investigated. In-vitro assays demonstrated the ability of these nanoaggregates to internalize into different cell lines. A positive gene transfection into human bone osteosarcoma epithelial cells (U2OS) was also observed. The RuC1C19 surfactant was used as sensor to quantify the binding of DNA to the liposomes. Doxorubicin was encapsulated into the metallo-liposomes, demonstrating their ability to be also used as nanocarriers of drugs. A relationship between then encapsulation percentage of the antibiotic and the composition of the aggregates has been established.

Lipid nanovesicles for biomedical applications: 'What is in a name'?

Vesicles, generally defined as self-assembled structures formed by single or multiple concentric bilayers that surround an aqueous core, have been widely used for biomedical applications. They can either occur naturally (e.g. exosomes) or be produced artificially and range from the micrometric scale to the nanoscale. One the most well-known vesicle is the liposome, largely employed as a drug delivery nanocarrier. Liposomes have been modified along the years to improve physicochemical and biological features, resulting in long-circulating, ligand-targeted and stimuli-responsive liposomes, among others. In this process, new nomenclatures were reported in an extensive literature. In many instances, the new names suggest the emergence of a new nanocarrier, which have caused confusion as to whether the vesicles are indeed new entities or could simply be considered modified liposomes. Herein, we discussed the extensive nomenclature of vesicles based on the suffix "some" that are employed for drug delivery and composed of various types and proportions of lipids and others amphiphilic compounds. New names have most often been selected based on changes of vesicle lipid composition, but the payload, structural complexity (e.g. multicompartment) and new/improved proprieties (e.g. elasticity) have also inspired new vesicle names. Based on this discussion, we suggested a rational classification for vesicles.

Co-delivery of 5-fluorodeoxyuridine and doxorubicin via gold nanoparticle equipped with affibody-DNA hybrid strands for targeted synergistic chemotherapy of HER2 overexpressing breast cancer

Combination chemotherapy is still of great importance as part of the standard clinical care for patients with HER2 positive breast cancer. As an attractive component, gold nanoparticles (AuNPs) have been extensively studied as biosafety nanomaterials, but they are rarely explored as drug nanocarriers for targeted co-delivery of multiple chemotherapeutics. Herein, a novel affibody-DNA hybrid strands modified AuNPs were fabricated for co-loading nucleoside analogue (5-fluorodeoxyuridine, FUdR) and anthracycline (doxorubicin, Dox). FUdRs were integrated into DNA hybrid strands decorated on AuNPs by DNA solid phase synthesis, and Dox molecules were intercalated into their duplex regions. Affibody molecules coupled to the DNA hybrid strands were distributed the surface of AuNPs, giving them targeting for HER2. The new dual-drug-containing affibody-DNA-AuNPs (Dox@affi-F/AuNPs) owned compact and stable spherical nanostructures, and precise drug loading. Cytotoxicity tests demonstrated that these nanoparticles caused a higher inhibition in HER2 overexpressing breast cancer cells, and showed better synergistic antitumor activity than simple mixture of the two drugs. The related mechanistic studies proved that Dox@affi-F/AuNPs achieved a remarkable combined antitumor activity of Dox and FUdR by promoting more cells to enter apoptosis pathway. Our work provided a nanomedicine platform for targeted co-delivery of nucleoside analog therapeutics and anthracycline anticancer drugs to achieve synergistic treatment of HER2⁺ cancer.

Oleic Acid Copolymer as A Novel Upconversion Nanomaterial to Make Doxorubicin-Loaded Nanomicelles with Dual Responsiveness to pH and NIR

Oleic acid (OA) as main component of plant oil is an important solvent but seldom used in the nanocarrier of anticancer drugs because of strong hydrophobicity and little drug release. In order to develop a new type of OA nanomaterial with dual responses to pH and near infrared light (NIR) to achieve the intelligent delivery of anticancer drugs. The novel OA copolymer (mPEG-PEI-(NBS, OA)) was synthesized by grafting OA and o-nitrobenzyl succinate (NBS) onto mPEGylated polyethyleneimine (mPEG-PEI) by amidation reaction. It was further conjugated with NaYF₄:Yb³⁺/Er³⁺ nanoparticles, and encapsulated doxorubicin (DOX) through self-assembly to make upconversion nanomicelles with dual response to pH and NIR. Drug release behavior of DOX, physicochemical characteristics of the nanomicelles were evaluated, along with its cytotoxic profile, as well as the degree of cellular uptake in A549 cells. The encapsulation efficiency and drug loading capacity of DOX in the nanomicelles were 73.84% ± 0.58% and 4.62% ± 0.28%, respectively, and the encapsulated DOX was quickly released in an acidic environment exposed to irradiation at 980 nm. The blank nanomicelles exhibited low cytotoxicity and excellent biocompatibility by MTT assay against A549 cells. The DOX-loaded nanomicelles showed remarkable cytotoxicity to A549 cells under NIR, and promoted the cellular uptake of DOX into the cytoplasm and nucleus of cancer cells. OA copolymer can effectively deliver DOX to cancer cells and achieve tumor targeting through a dual response to pH and NIR.

A pre-formulation strategy for the liposome encapsulation of new thioctic acid conjugates for enhanced chemical stability and use as an efficient drug carrier for MPO-mediated atherosclerotic CVD treatment

Lipoyl-apocynin and lipoyl-sesamol are bio-active conjugates of thioctic acid, synthesized using a benign chemical approachviathe combination of thioctic acid and the powerful bio-phytonutrients, apocynin and sesamol, respectively.

Design, Preparation, and Characterization of Novel Calix[4]arene Bioactive Carrier for Antitumor Drug Delivery

An amphiphilic and bioactive calix[4]arene derivative 8 (CA) is designed and successfully synthesized from tert-butyl calix[4] arene 1 by sequential inverse F-C alkylation, nitration, O-alkylation, esterification, aminolysis, reduction, and acylation reaction. The blank micelles of FA-CA and doxorubicin (DOX) loaded micelles FA-CA-DOX are prepared subsequently undergoing self-assembly and dialysis of CA and DSPE-PEG₂₀₀₀-FA. The drug release kinetics curve of the encapsulated-DOX micelle demonstrates a rapid release under mild conditions, indicating the good pH-responsive ability. Furthermore, the cytotoxicity of DOX-loaded micelle respect to the blank micelle against seven different human carcinoma (A549, HeLa, HepG2, HCT116, MCF-7, MDA-MB231, and SW480) cells has been also investigated. The results confirm the more significant inhibitory effect of DOX-loaded micelle than those of DOX and the blank micelles. The CDI calculations show a synergistic effect between blank micelles and DOX in inducing tumor cell death. In conclusion, FA-CA micelles reported in this work was a promising drug delivery vehicle for tumor targeting therapy.