Topical Ophthalmic Liposomes Dual-Modified with Penetratin and Hyaluronic Acid for the Noninvasive Treatment of Neovascular Age-Related Macular Degeneration.

Introduction: Since intrinsic ocular barrier limits the intraocular penetration of therapeutic protein through eye drops, repeated intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF) agents are the standard therapy for neovascular age-related macular degeneration (nAMD), which are highly invasive and may cause particular ocular complications, leading to poor patient compliance. Methods: Using Penetratin (Pen) as the ocular penetration enhancer and hyaluronic acid (HA) as the retina-targeting ligand, a dual-modified ophthalmic liposome (Penetratin hyaluronic acid-liposome/Conbercept, PenHA-Lip/Conb) eye drop was designed to non-invasively penetrate the ocular barrier and deliver anti-VEGF therapeutic agents to the targeted intraocular tissue. Results: PenHA-Lip effectively penetrates the ocular barrier and targets the retinal pigment epithelium via corneal and non-corneal pathways. After a single topical administration of conbercept-loaded PenHA-Lip (PenHA-Lip/Conb), the intraocular concentration of conbercept peaked at 18.74 ± 1.09 ng/mL at 4 h, which is 11.55-fold higher than unmodified conbercept. In a laser-induced choroidal neovascularization (CNV) mouse model, PenHA-Lip/Conb eye drops three times daily for seven days inhibited CNV formation and progression without any significant tissue toxicity and achieved an equivalent effect to a single intravitreal conbercept injection. Conclusion: PenHA-Lip efficiently and safely delivered conbercept to the posterior eye segment and may be a promising noninvasive therapeutic option for nAMD.

Degradable gene delivery systems based on Pluronics-modified low-molecular-weight polyethylenimine: preparation, characterization, intracellular trafficking, and cellular distribution.

BACKGROUND: Cationic copolymers consisting of polycations linked to nonionic amphiphilic block polymers have been evaluated as nonviral gene delivery systems, and a large number of different polymers and copolymers of linear, branched, and dendrimeric architectures have been tested in terms of their suitability and efficacy for in vitro and in vivo transfection. However, the discovery of new potent materials still largely relies on empiric approaches rather than a rational design. The authors investigated the relationship between the polymers' structures and their biological performance, including DNA compaction, toxicity, transfection efficiency, and the effect of cellular uptake. METHODS: This article reports the synthesis and characterization of a series of cationic copolymers obtained by grafting polyethyleneimine with nonionic amphiphilic surfactant polyether-Pluronic(®) consisting of hydrophilic ethylene oxide and hydrophobic propylene oxide blocks. Transgene expression, cytotoxicity, localization of plasmids, and cellular uptake of these copolymers were evaluated following in vitro transfection of HeLa cell lines with various individual components of the copolymers. RESULTS: Pluronics can exhibit biological activity including effects on enhancing DNA cellular uptake, nuclear translocation, and gene expression. The Pluronics with a higher hydrophilic-lipophilic balance value lead to homogeneous distribution in the cytoplasm; those with a lower hydrophilic-lipophilic balance value prefer to localize in the nucleus. CONCLUSION: This Pluronic-polyethyleneimine system may be worth exploring as components in the cationic copolymers as the DNA or small interfering RNA/microRNA delivery system in the near future.

A thermo-sensitive PLGA-PEG-PLGA hydrogel for sustained release of docetaxel.

The aim of this study was to investigate the suitability of poly-(d,l-lactic acid-co-glycolic acid) (PLGA)-polyethylene glycol (PEG)-PLGA triblock copolymer as a matrix material for a sustained-release system for docetaxel (DTX). The copolymers were synthesized by ring-opening polymerization reaction and characterized by (1)H-NMR and gel permeation chromatography. The DTX-loaded formulations were prepared, characterized. And the antitumor efficacy and the pharmacokinetics of DTX-loaded copolymer on A-549 lung tumor-bearing BALB/cA mice were investigated. The results showed that DTX-loaded copolymer highly increased the solubility of DTX by more than 3000-fold. And copolymer concentration as well as drug loading level exerted appreciable influence on the drug release behavior. Further, the pharmacokinetic test showed that DTX-loaded copolymer could be with the sustained-release nature for over 3 weeks, which correlated well with the in vitro release. Additionally, one intratumoral injection of the thermo-sensitive hydrogel containing DTX was comparable to three intravenous injections of DTX injection in inhibiting the tumor growth in A-549 lung tumor-bearing BALB/cA mice with a less toxic manner. PLGA-PEG-PLGA could thus provide a promising alternate locally delivered vehicle for DTX to achieve prolonged exposure having greater efficacy in inhibiting tumor growth with lower toxicity.

Second-generation aptamer-conjugated PSMA-targeted delivery system for prostate cancer therapy.

BACKGROUND: miR-15a and miR-16-1 have been identified as tumor suppressor genes in prostate cancer, but their safe and effective delivery to target cells is key to the successful use of this therapeutic strategy. RNA aptamer A10 has been used as a ligand, targeting prostate cancer cells that express prostate-specific membrane antigen (PSMA). Compared with A10, the binding of the second-generation RNA aptamer, A10-3.2, to PSMA is more efficient. METHODS: A10-3.2 was investigated as a PSMA-targeting ligand in the design of a polyamidoamine (PAMAM)-based microRNA (miR-15a and miR-16-1) vector to prostate cancer cells. Using polyethyleneglycol (PEG) as a spacer, PAMAM was conjugated to aptamer (PAMAM-PEG-APT) and used as a vehicle for miRNA target delivery. RESULTS: Luciferase assays of pGL-3 expression against PC3 (PSMA(-)) and LNCaP (PSMA(+)) cells demonstrated that the transfection efficiency of the synthesized DNA/PAMAM-PEG-APT complex was higher than that of the DNA/PAMAM-PEG complex. In addition, cell viability assays of LNCaP (PSMA(+)) cells showed that, with a N/P ratio of 15:1, the IC(50) value of miRNA/PAMAM-PEG-APT was approximately 4.7-fold lower than that of miRNA/PAMAM-PEG. CONCLUSION: This PSMA-targeted system may prove useful in widening the therapeutic window and allow for selective killing of prostate cancer cells.

Penetration and distribution of PLGA nanoparticles in the human skin treated with microneedles.

This study was designed to investigate the penetration and the distribution of poly(d,l-lactic-co-glycolic acid) (PLGA) nanoparticles in the human skin treated with microneedles. Fluorescent nanoparticles were prepared to indicate the transdermal transport process of the nanoparticles. Permeation study was performed on Franz-type diffusion cells in vitro. The distribution of nanoparticles was visualized by confocal laser scanning microscopy (CLSM) and quantified by high performance liquid chromatography (HPLC). CLSM images showed that nanoparticles were delivered into the microconduits created by microneedles and permeated into the epidermis and the dermis. The quantitative determination showed that (i) the permeation of nanoparticles into the skin was enhanced by microneedles, but no nanoparticle reached the receptor solution; (ii) much more nanoparticles deposited in the epidermis than those in the dermis; (iii) the permeation was in a particle size-dependent manner; and (iv) the permeation increased with the nanoparticle concentration increasing until a limit value was reached. These results suggested that microneedles could enhance the intradermal delivery of PLGA nanoparticles. The biodegradable nanoparticles would sustain drug release in the skin and supply the skin with drug over a prolonged period. This strategy would prove to be useful for topical drug administration.