Microbubbles coupled to methotrexate-loaded liposomes for ultrasound-mediated delivery of methotrexate across the blood–brain barrier

Abstract

Methotrexate (MTX) is the single most effective agent for the treatment of primary central nervous system lymphoma. Currently, the delivery of MTX to the brain is achieved by high systemic doses, which cause severe long-term neurotoxicity, or intrathecal administration, which is highly invasive and may lead to infections or hemorrhagic complications. Acoustically active microbubbles have been developed as drug carriers for the noninvasive and brain-targeted delivery of therapeutics. However, their application is limited by their low drug-loading capacity. To overcome this limitation, we prepared microbubbles coupled to MTX-loaded liposomes using ZHIFUXIAN, a novel type of microbubbles with a superior safety profile and long circulation time. MTX-liposome-coupled microbubbles had a high drug-loading capacity of 8.91%±0.86%, and their size (2.64±0.93 μm in diameter) was suitable for intravenous injection. When used with ultrasound, they showed more potent in vitro cytotoxicity against Walker-256 cancer cells than MTX alone or MTX-loaded liposomes. When Sprague-Dawley rats were exposed to sonication, administration of these MTX-liposome-coupled microbubbles via the tail vein led to targeted disruption of the blood–brain barrier without noticeable tissue or capillary damage. High-performance liquid chromatography analysis of the brain MTX concentration showed that MTX delivery to the brain followed the order of MTX-liposome-coupled microbubbles + ultrasound (25.3±2.4 μg/g) > unmodified ZHIFUXIAN + MTX + ultrasound (18.6±2.2 μg/g) > MTX alone (6.97±0.75 μg/g) > MTX-liposome-coupled microbubbles (2.92±0.39 μg/g). Therefore, treatment with MTX-liposome-coupled microbubbles and ultrasound resulted in a significantly higher brain MTX concentration than all other treatments ( P <0.01). These results suggest that MTX-liposome-coupled microbubbles may hold great promise as new and effective therapies for primary central nervous system lymphoma and other central nervous system malignancies.

Epidermal growth factor receptor-targeted sonoporation with microbubbles enhances therapeutic efficacy in a squamous cell carcinoma model

“…Many researchers have focused on establishing the sonoporation system as an effective non-viral drug delivery method. Sonoporation strategies have also been developed with various types of MBs for targeted delivery [ 25 , 26 ]. Liao et al demonstrated that the combination of EGFR-targeting MBs and US exposure effectively eliminates tumor cells in vivo [ 27 ].…”

Ultrasound-Triggered Effects of the Microbubbles Coupled to GDNF Plasmid-Loaded PEGylated Liposomes in a Rat Model of Parkinson's Disease

“…Animals were anesthetized and placed supine on a positioning sled for MRI. Brain ultrasound treatment was conducted under the following settings: 1 MHz, 20% duty cycle, and an ultrasound intensity of 2 W/cm 2 (Wang et al, 2014 ). After injecting PLs-MBs (0.01 ml/kg body weight) and PLs-GDNF-MBs (0.01 ml/kg body weight) into the tail vein for 30 min, FUS was performed.…”

“…Thus, coupling gene-loaded liposomes to the microbubble surface is adopted (Lentacker et al, 2010 ). This approach takes full advantage of the high DNA-carrying capacity of PLs and the ultrasound-mediated BBB disruption effect of MBs (Wang et al, 2014 ).…”

Opening the Blood-Brain Barrier and Improving the Efficacy of Temozolomide Treatments of Glioblastoma Using Pulsed, Focused Ultrasound with a Microbubble Contrast Agent

“…Thirty Wistar rats (200 ± 20 g; Huafukang Biotechnology Company, Beijing, China) were fed pellet feed for a week in cages before the experiment. The rats were divided equally into three groups: (a) non-mCEUS control group; (b) continuous launch of mCEUS [ 18 ]; and (c) intermittent mCEUS launches (400-ms interval) [ 18 ]. Before undergoing mCEUS, the rats were anesthetized by intraperitoneal injection of pentobarbital sodium (3%, 30 mg/kg).…”

“…Microbubble contrast suspension containing 8 μ l (45 μ g) of sulfur hexafluoride per ml (Third Military Medical University) was injected (1 ml/kg, both mCEUS groups) via the tail vein [ 18 ]. Continuous or intermittent mCUES was applied to each rat for a period of 10 min via a Philips IE33 (USA) ultrasonic diagnostic machine with an S5-1 probe (harmonic frequency, 1.7/3.3 MHz; mechanical index, 0.8 mI; and treatment time, 10 min) [ 19 ].…”