Multivesicular liposome (MVL) sustained delivery of a novel synthetic cationic GnRH antagonist for prostate cancer treatment

Pressure-sensitive multivesicular liposomes as a smart drug-delivery system for high-altitude pulmonary edema

Changes in bodily fluid pressures, such as pulmonary artery pressure, play key roles in high-altitude pulmonary edema (HAPE) and other disorders. Smart delivery systems releasing a drug in response to these pressures might facilitate early medical interventions. However, pressure-responsive delivery systems are unavailable. We here constructed hydrostatic pressure-sensitive multivesicular liposomes (PSMVLs) based on the incomplete filling of the internal vesicle space with neutral lipids. These liposomes were loaded with amlodipine besylate (AB), a next-generation calcium channel inhibitor, to treat HAPE on time. AB-loaded PSMVLs (AB-PSMVLs) were destroyed, and AB was released through treatment under hydrostatic pressure of at least 25 mmHg. At 25 mmHg, which is the minimum pulmonary artery pressure value in HAPE, 38.8% of AB was released within 1 h. In a mouse HAPE model, AB-PSMVLs concentrated in the lung and released AB to diffuse into the vascular wall. Intravenously injected AB-PSMVLs before HAPE modeling resulted in a stronger protection of lung tissues and respiratory function and lower occurrence of pulmonary edema than treatment with free drug or non-pressure-sensitive AB-loaded liposomes. This study offers a new strategy for developing smart drug delivery systems that respond to changes in bodily fluid pressures.

Impact of particle size of multivesicular liposomes on the embolic and therapeutic effects in rabbit VX2 liver tumor

Transcatheter arterial chemoembolization (TACE) is usually considered more efficacious in the local treatment of parenchyma-sparing hepatocellular carcinoma (HCC). At present, embolic agents commonly used in TACE, include DC pellets, Hepasphere, Lipiodol, etc. Except that iodine oil is a viscous fluid embolic agent, other solid microsphere particles used clinically range from 70 to 700 µm, among which 100 to 300 µm is the most commonly used. With the technology development of micro-invasive interventional therapy, the specific distal embolization through TACE to occlude tumor arterial blood supply in patients with HCC is also required more accurately. Effective terminal embolization is considered to be a preferred option for TACE therapy due to significantly improving the survival rate of patients and preserving liver function. In this article, we prepared the multifunctional multivesicular liposomes (IVO-DOX-MVLs) (<100 µm) that can simultaneously encapsulate ioversol and doxorubicin based on the high-phase transition temperature (T_m) lipid ingredients, and evaluated its local artery embolization and therapeutic effect in rabbit VX-2 tumor model. The influence of particle size on occlusion and therapeutic effect of MVLs on rabbit VX-2 liver tumor models were well evaluated, including the tumor volume change, tumor growth rate, and necrosis rate, which were evaluated by magnetic resonance (MR). MVL samples with average particle size distribution of 50-60 µm exhibited fewer off-target embolization. Through TACE, IVO-DOX-MVLs were directly transported to the tumor tissues, playing roles of embolization performance, CT imaging effect, and local tumor killing effect. The feasibility of MVLs as a multifunctional embolic agent in its clinical application can be further improved by optimization of lipid composition and preparation process.

Preparation of nano-sized multi-vesicular vesicles (MVVs) and its application in co-delivery of doxorubicin and curcumin

Multi-vesicular vesicles (MVVs) offer structural advantages in terms of drug encapsulation and physiological stability. In this study, we address the challenge of preparing small-sized MVVs for drug delivery. The nano-sized MVVs (∼120 nm) loaded with doxorubicin (DOX) and curcumin (CUR) (DOX/CUR@MVVs) were successfully prepared using a glass bead combined with a thin film dispersion method. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis confirmed the independent non-homocentric vesicle structures of DOX/CUR@MVVs with homogeneous particle sizes. The experimental results showed high encapsulation rates of DOX and CUR in DOX/CUR@MVVs, reaching 82.5 ± 0.75 % and 85.9 ± 0.69 %, respectively. Moreover, the MVVs exhibited good biosafety and sustained release properties. Notably, the bioavailability of DOX and CUR in DOX/CUR@MVVs was enhanced compared to free DOX and CUR, with increases of 4.2 and 2.1 times, respectively. And the half-life of DOX and CUR was extended by 10 times in DOX/CUR@MVVs. In vivo antitumor experiments demonstrated that nano-sized DOX/CUR@MVVs significantly improved the antitumor activity while reducing the toxic side effects of DOX. Overall, the successful preparation of nano-sized DOX/CUR@MVVs and their potent and low-toxic antitumor effects provide a critical experimental reference for the combined antitumor therapy of MVVs and liposomes.

Hypermethylation of the Promoter Region of miR-23 Enhances the Metastasis and Proliferation of Multiple Myeloma Cells via the Aberrant Expression of uPA

Multiple myeloma has a long course, with no obvious symptoms in the early stages. However, advanced stages are characterized by injury to the bone system and represent a severe threat to human health. The results of the present work indicate that the hypermethylation of miR-23 promoter mediates the aberrant expression of uPA/PLAU (urokinase plasminogen activator, uPA) in multiple myeloma cells. miR-23, a microRNA that potentially targets uPA’s 3’UTR, was predicted by the online tool miRDB. The endogenous expressions of uPA and miR-23 are related to disease severity in human patients, and the expression of miR-23 is negatively related to uPA expression. The hypermethylation of the promoter region of miR-23 is a promising mechanism to explain the low level of miR-23 or aberrant uPA expression associated with disease severity. Overexpression of miR-23 inhibited the expression of uPA by targeting the 3’UTR of uPA, not only in MM cell lines, but also in patient-derived cell lines. Overexpression of miR-23 also inhibited in vitro and in vivo invasion of MM cells in a nude mouse model. The results therefore extend our knowledge about uPA in MM and may assist in the development of more effective therapeutic strategies for MM treatment.

Ultrasound-Mediated Cancer Therapeutics Delivery using Micelles and Liposomes: A Review

BACKGROUND

Existing cancer treatment methods have many undesirable side effects that greatly reduce the quality of life of cancer patients.

OBJECTIVE

This review will focus on the use of ultrasound-responsive liposomes and polymeric micelles in cancer therapy.

METHODS

This review presents a survey of the literature regarding ultrasound-triggered micelles and liposomes using articles recently published in various journals, as well as some new patents in this field.

RESULTS

Nanoparticles have proven promising as cancer theranostic tools. Nanoparticles are selective in nature, have reduced toxicity, and controllable drug release patterns making them ideal carriers for anticancer drugs. Numerous nanocarriers have been designed to combat malignancies, including liposomes, micelles, dendrimers, solid nanoparticles, quantum dots, gold nanoparticles, and, more recently, metal-organic frameworks. The temporal and spatial release of therapeutic agents from these nanostructures can be controlled using internal and external triggers, including pH, enzymes, redox, temperature, magnetic and electromagnetic waves, and ultrasound. Ultrasound is an attractive modality because it is non-invasive, can be focused on the diseased site, and has a synergistic effect with anticancer drugs.

CONCLUSION

The functionalization of micellar and liposomal surfaces with targeting moieties and the use of ultrasound as a triggering mechanism can help improve the selectivity and enable the spatiotemporal control of drug release from nanocarriers.

Multivesicular liposome: A lipid-based drug delivery system for efficient drug delivery

The advancement of delivery tools for therapeutic agents has brought several novel formulations with increased drug loading, sustained release, targeted delivery, and prolonged efficacy. Amongst the several novel delivery approaches, multivesicular liposome has gained potential interest because this delivery system possesses the above advantages. In addition, this multivesicular liposomal delivery prevents degradation of the entrapped drug within the physiological environment while administered. The special structure of the vesicles allowed successful entrapment of hydrophobic and hydrophilic therapeutic agents, including proteins and peptides. Furthermore, this novel formulation could maintain the desired drug concentration in the plasma for a prolonged period, which helps to reduce the dosing frequencies, improve bioavailability, and safety. This tool could also provide stability of the formulation, and finally gaining patient compliance. Several multivesicular liposomes received approval for clinical research, while others are at different stages of laboratory research. In this review, we have focused on the preparation of multivesicular liposomes along with their application in different ailments for the improvement of the performance of the entrapped drug. Moreover, the challenges of delivering multivesicular vesicles have also been emphasized. Overall, it could be inferred that multivesicular liposomal delivery is a novel platform of advanced drug delivery with improved efficacy and safety.

Modeling of Anti-cancer Drug Release Kinetics from Liposomes and Micelles: A review

Nanocarriers, such as liposomes and micelles, were developed to enhance the delivery of therapeutic drugs to malignant tissues. Internal or external stimuli can be applied to achieve spatiotemporal controlled release from these carriers. This will result in enhancing their therapeutic efficacy while reducing toxicity. Mathematical modeling is used to simulate drug release from nanocarriers; this will facilitate and optimize the development and design of desirable nanocarriers in a systematic manner, rather than a trial-and-error approach. This review summarizes nine mathematical models often used to simulate drug release from nanocarriers and reviews studies which employed these models to simulate drug release from conventional as well as temperature-, pH-, and ultrasound-triggered micelles and liposomes.

Preparation of giant lipid vesicles with controllable sizes by a modified hydrophilic polydimethylsiloxane microarray chip

This paper presents an accessible method to prepare giant lipid vesicles (GLVs) with controllable sizes based on the quick formation of patterned lipid films. Lipid solutions naturally penetrate into arrayed micro-apertures on a modified hydrophilic Polydimethylsiloxane (PDMS) chip, and excess lipid films on the surface are removed by a glass slide. Three main factors, the depth and diameter of the micro-apertures and concentration of the lipid solution, were investigated to obtain an optimal preparation condition. Based on this condition, the formed GLVs have a controllable size and narrow size distribution (the standard deviation < 5 μm). By controlling the diameter of the micro-aperture and concentration of the lipid solution, GLVs with various sizes (23, 48, 66 and 82 μm) can be formed.

IN VITRO RELEASE KINETICS MODEL FITTING OF LIPOSOMES: AN INSIGHT

Liposomes are emerging cargoes for bioactive delivery owing to their widely accepted biocompatible and biodegradable nature. It is always a challenge to control the release of payload for effective delivery to the site of interest. Over the couple of decennia, mathematical modeling of release process is a need of time whether the drug remains in the circulation or reaches at the target site. For establishing a better in vitro - in vivo correlation, release kinetics models viz. Peppas, Higuchi, Weibull, Zero Order and First order including mechanistic models like All-or-None, Toroidal, and Biomembrane models etc. are continuously exploited to predict drug release profile. Most of these models rely on the diffusion equations based on the composition of liposomes and conditions of release. Here, we summarized the crucial reports exploring these models and associated interventions to know the underlying physicochemical release phenomenon. Such mathematical model fitting can be a promising approach to deduce release/delivery process to help in designing the safe and efficacious ("Smart") liposomes.

Recent developments in protein and peptide parenteral delivery approaches

Discovery of insulin in the early 1900s initiated the research and development to improve the means of therapeutic protein delivery in patients. In the past decade, great emphasis has been placed on bringing protein and peptide therapeutics to market. Despite tremendous efforts, parenteral delivery still remains the major mode of administration for protein and peptide therapeutics. Other routes such as oral, nasal, pulmonary and buccal are considered more opportunistic rather than routine application. Improving biological half-life, stability and therapeutic efficacy is central to protein and peptide delivery. Several approaches have been tried in the past to improve protein and peptide in vitro/in vivo stability and performance. Approaches may be broadly categorized as chemical modification and colloidal delivery systems. In this review we have discussed various chemical approaches such as PEGylation, hyperglycosylation, mannosylation, and colloidal carriers including microparticles, nanoparticles, liposomes, carbon nanotubes and micelles for improving protein and peptide delivery. Recent developments on in situ thermosensitive gel-based protein and peptide delivery have also been described. This review summarizes recent developments on some currently existing approaches to improve stability, bioavailability and bioactivity of peptide and protein therapeutics following parenteral administration.