Physical characterization of surface-modified liposomes by incorporation of gangliosides designed for immunotherapies

New Nanocarrier System for Liposomes Coated with Lactobacillus acidophilus S-Layer Protein to Improve Leu-Gln-Pro-Glu Absorption through the Intestinal Epithelium

The present study describes the development of a novel liposome nanocarrier system. The liposome was coated with Lactobacillus acidophilus CICC 6074 S-layer protein (SLP) to improve the intestinal absorption of the cholesterol-lowering peptide Leu-Gln-Pro-Glu (LQPE). The SLP-coated liposomes were prepared and characterized with morphology, particle size, zeta potential, membrane stability, Fourier transform infrared spectroscopy, and dual-channel surface plasma resonance. The results showed that SLP could successfully self-assemble on liposomes. Then, LQPE liposomes and SLP-coated LQPE liposomes (SLP-L-LQPE) were prepared. SLP-L-LQPE not only showed better sustained release properties and gastrointestinal tolerance in vitro but also increased the retention time in mice intestine. Transepithelial transport experiment indicates that the transshipment of LQPE increased significantly after being embedded by liposomes and coated with SLP. The research provides a theoretical basis for the study of SLP-coated liposomes and a potential drug delivery system for improving the intestinal absorption of peptides.

Cationic Polymethacrylate-Modified Liposomes Significantly Enhanced Doxorubicin Delivery and Antitumor Activity

Liposome (LP) encapsulation of doxorubicin (DOX) is a clinically validated method for cancer drug delivery, but its cellular uptake is actually lower than the free DOX. Therefore, we modified DOX-LP with a cationic polymer (Eudragit RL100; ER) to improve its cellular uptake and antitumor activity. The resulting DOX-ERLP was a 190 nm nanoparticle that was absorbed efficiently and caused cancer cell death in 5 hrs. Growth as measured by the MTT assay or microscopic imaging demonstrated that DOX-ERLP has at least a two-fold greater potency than the free DOX in inhibiting the growth of a DOX resistant (MCF7/adr) cell and an aggressive liver cancer H22 cell. Further, its in vivo efficacy was tested in H22-bearing mice, where four injections of DOX-ERLP reduced the tumor growth by more than 60% and caused an average of 60% tumor necrosis, which was significantly better than the DOX and DOX-LP treated groups. Our work represents the first use of polymethacrylate derivatives for DOX liposomal delivery, demonstrating the great potential of cationic polymethacrylate modified liposomes for improving cancer drug delivery.

Liposomes in drug delivery: a patent review (2007 - present)

INTRODUCTION

Drug therapy is frequently limited by the widespread biodistribution of the active agents and the little specificity for non-healthy cells. Therefore, inadequate drug concentrations result into the site of action, and severe toxicity may also arise. To address the problem, liposome-based medicines have tried to improve pharmacotherapy.

AREAS COVERED

The review provides an updated revision of the lately published patents covering recent advances in liposome-based drug delivery. They are principally related to the control of drug biodistribution by using stealth, stimuli-sensitive and/or liposomal structures surface modified for ligand-mediated delivery. The contribution further highlights liposome-based theranosis.

EXPERT OPINION

Liposomes have received great attention given their biocompatibility, biodegradability and targetability. From 2007 to present date, patent publications related to their use in drug delivery have shown the move towards more stable structures with optimized drug delivery capabilities, further combining passive and active targeting concepts to gain control of the in vivo fate. However, the introduction of all these liposomal structures in the disease arena is still a challenge. Two key aspects are the difficulty of identifying easy and economic synthesis conditions which can be scaled up in the pharmaceutical industry, and the need for complementary investigations illustrating risks of toxicity/immunogenicity.