Factors Affecting the Acoustic In Vitro Release of Calcein from PEGylated Liposomes.

Typical methods used in cancer treatment, including chemotherapy, are debilitating because of the various adverse side effects experienced by cancer patients. The free drug injected into the patient at given doses affects both healthy and cancerous cells. Therefore, novel methods are being researched to ensure the selectivity of the treatment. The purpose of this study is to test the release of a model fluorescent drug, calcein, from echogenic stealth liposomes, triggered by lowfrequency pulsed ultrasound. Several experimental parameters related to the ultrasound (US) and the investigated liposomes were varied in order to examine their effect on the acoustic release. Upon analysis of experimental results, the study concluded that release can be maximized by optimizing the sonication frequency, power density, and US pulse duration. When a non-isothermal chamber is used to conduct the experiments, it is important to have longer 'Off' than 'On' US periods in order to avoid overheating the liposomes. Applying such pulsation pattern can also be utilized to achieve slower release rates, which safely meet the desired drug levels at the end of the session. Our study also concluded that optimizing the liposome concentration is vital to delivering desired drug doses. Additionally, the type of lipids used in the synthesis should be carefully selected to produce stable yet acoustically sensitive liposomes capable of releasing at desired rates.

Improving the Efficacy of Anticancer Drugs via Encapsulation and Acoustic Release.

Conventional chemotherapeutics lack the specificity and controllability, thus may poison healthy cells while attempting to kill cancerous ones. Newly developed nano-drug delivery systems have shown promise in delivering anti-tumor agents with enhanced stability, durability and overall performance; especially when used along with targeting and triggering techniques. This work traces back the history of chemotherapy, addressing the main challenges that have encouraged the medical researchers to seek a sanctuary in nanotechnological-based drug delivery systems that are grafted with appropriate targeting techniques and drug release mechanisms. A special focus will be directed to acoustically triggered liposomes encapsulating doxorubicin.

Ultrasound-guided Pulsed Radiofrequency in the Management of Thoracic Postherpetic Neuralgia: A Randomized, Double-blinded, Controlled Trial.

OBJECTIVES: This study was designed to evaluate the efficacy and safety of ultrasound-guided pulsed radiofrequency (PRF) for the intercostal nerves (ICNs) in the management of thoracic postherpetic neuralgia. METHODS: After 2 weeks of treatment by pregabalin 150 mg/12 hours, patients were randomly allocated into 2 groups. The PRF group, after ultrasound-guided localization of the ICN of the affected thoracic dermatome, sensory stimulation of the ICN was tested. Thereafter, the patient received 2 cycles PRF at 42°C temperature, for 120 seconds. The sham group, after stimulation, the same time was spent to mimic PRF. The same procedures were repeated to the upper and lower adjacent ICNs. Pain intensity using Visual Analogue Scale (VAS), and total analgesics consumption were assessed at the baseline, every 2 weeks for 6 months then after 9 and 12 months. The duration of effective pain relief was recorded. Quality of life was evaluated using self-evaluation questionnaires (SF-36) at baseline then after 1, 3, 6, and 12 months. RESULTS: PRF group expressed a significant decrease on the VAS throughout the study period. VAS<30 was reported in the PRF group until the 22nd week. Pregabalin and acetaminophen consumption was significantly lower in the PRF group. The 8 domains of the SF-36 revealed a significant improvement in the PRF group when compared with the sham group throughout the study period except for the physical role which displayed nonsignificant improvement. CONCLUSIONS: Ultrasound-guided PRF for ICNs in combination with pharmacotherapy seems to be a safe and effective treatment modality for postherpetic neuralgia.

The use of ultrasound to release chemotherapeutic drugs from micelles and liposomes.

Several drug delivery systems have been investigated to reduce the side effects of chemotherapy by encapsulating the therapeutic agent in a nanosized carrier until it reaches the tumor site. Many of these particles are designed to be responsive to the mechanical and thermal perturbations delivered by ultrasound. Once the nanoparticle reaches the desired location, ultrasound is applied to release the chemotherapy drug only in the vicinity of the targeted (cancer) site, thus avoiding any detrimental interaction with healthy cells in the body. Studies using liposomes and micelles have shown promising results in this area, as these nanoparticles with simple, yet effective structures, showed high efficiency as drug delivery vehicles both in vitro and in vivo. This article reviews the design and application of two novel nanosized chemotherapeutic carriers (i.e. micelles and liposomes) intended to be actuated by ultrasound.