Novel chitosan derivative for temperature and ultrasound dual-sensitive liposomal microbubble gel

In-situ gel injection of poloxamer-based metamizole provides long-acting antipyretic effects

Metamizole easily decomposes in the body and has a short action time and low bioavailability. Hence, frequent injection administrations are needed to maintain its plasma concentration. This study aimed to design and develop an in-situ gel based on poloxamer 407 and 188 to assess its long-acting antipyretic effects. The in-situ gel-forming systep00m with optimum sol-gel transition temperature of 35.9 °C to 36.3 °C could be formed using a combination of P407 at a ratio of 21-23% (w/v) and P188 at a ratio of 2-4% (w/v). In vitro erosion test showed that the in-situ gel's erosion curve and the metamizole release rate both reached about 90% at 6 h, revealing a good linear relationship between the in-situ gel erosion and the drug release. In vitro release test with dialysis tube showed that the release of metamizole from the in-situ gel was remarkably slower than that from the metamizole solution. Approximately 85% of metamizole was released in the dialysis tube within 7 h, implying a good sustained release effect. Pharmacodynamic study showed that the in-situ gel injection extended the action time of metamizole relative to that when using the metamizole solution. Pharmacokinetic study revealed that the in-situ gel significantly increased the blood serum half-life and area under the curve), contributing to a sustained release and improved bioavailability. This study demonstrated that in-situ gel injection could prolong the action of metamizole in the body to reduce the number of administration times and has good clinical application.

Review of Curcumin Physicochemical Targeting Delivery System

Curcumin (CUR), as a traditional Chinese medicine monomer extracted from the rhizomes of some plants in Ginkgo and Araceae, has shown a wide range of therapeutic and pharmacological activities such as anti-tumor, anti-inflammatory, anti-oxidation, anti-virus, anti-liver fibrosis, anti-atherosclerosis, and anti-Alzheimer’s disease. However, some issues significantly affect its biological activity, such as low aqueous solubility, physico-chemical instability, poor bioavailability, and low targeting efficacy. In order to further improve its curative effect, numerous efficient drug delivery systems have been carried out. Among them, physicochemical targeting preparations could improve the properties, targeting ability, and biological activity of CUR. Therefore, in this review, CUR carrier systems are discussed that are driven by physicochemical characteristics of the microenvironment (eg, pH variation of tumorous tissues), affected by external influences like magnetic fields and vehicles formulated with thermo-sensitive materials.

Multifunctionalized Microscale Ultrasound Contrast Agents for Precise Theranostics of Malignant Tumors

In ultrasonography, ultrasound contrast agents (UCAs) that possess high acoustic impedance mismatch with the bulk medium are frequently employed to highlight the borders between tissues by enhanced ultrasound scattering in a clinic. Typically, the most common UCA, microbubble, is generally close in size to a red blood cell (<∼10 μm). These microscale UCAs cannot be directly entrapped into the target cells but generate several orders of magnitude stronger echo signals than the nanoscale ones. And their large containment and high ultrasound responsiveness also greatly facilitate to perform combined treatments, e.g., drug delivery and other imaging techniques. So multifunctionalized microscale UCAs appear on this scene and keep growing toward a promising direction for precise theranostics. In this review, we systematically summarize the new advances in the principles and preparations of multifunctionalized microscale UCAs and their medical applications for malignant tumors.

Optimization of Preparation Conditions for Lysozyme Nanoliposomes Using Response Surface Methodology and Evaluation of Their Stability

The main purpose of this study was to optimize the preparation of lysozyme nanoliposomes using response surface methodology and measure their stability. The stabilities of lysozyme nanoliposomes in simulated gastrointestinal fluid (SGF), simulated intestinal fluid (SIF), as well as pH, temperature and sonication treatment time were evaluated. Reverse-phase evaporation method is an easy, speedy, and beneficial approach for nanoliposomes’ preparation and optimization. The optimal preparative conditions were as follows: phosphatidylcholine-to-cholesterol ratio of 3.86, lysozyme concentration of 1.96 mg/mL, magnetic stirring time of 40.61 min, and ultrasound time of 14.15 min. At the optimal point, encapsulation efficiency and particle size were found to be 75.36% ± 3.20% and 245.6 nm ± 5.2 nm, respectively. The lysozyme nanoliposomes demonstrated certain stability in SGF and SIF at a temperature of 37 °C for 4 h, and short sonication handling times were required to attain nano-scaled liposomes. Under conditions of high temperature, acidity and alkalinity, lysozyme nanoliposomes are unstable.

Nanocarriers for the delivery of active ingredients and fractions extracted from natural products used in traditional Chinese medicine (TCM)

Traditional Chinese medicine (TCM) has been practiced for thousands of years with a recent increase in popularity. Despite promising biological activities of active ingredients and fractions from TCM, their poor solubility, poor stability, short biological half-life, ease of metabolism and rapid elimination hinder their clinical application. Therefore, overcoming these problems to improve the therapeutic efficacy of TCM preparations is a major focus of pharmaceutical sciences. Recently, nanocarriers have drawn increasing attention for their excellent and efficient delivery of active TCM ingredients or fractions. This review discusses problems in the delivery of active TCM ingredients or fractions; focuses on recent advances in nanocarriers that represent potential solutions to these problems, including lipid-based nanoparticles and polymeric, inorganic, and hybrid nanocarriers; and discusses unanswered questions in the field and criteria for the development of better nanocarriers for the delivery of active TCM ingredients or fractions to be focused on in future studies.

Dual thermoresponsive and pH-responsive self-assembled micellar nanogel for anticancer drug delivery

In this article, we prepared a dual thermoresponsive and pH-responsive self-assembled micellar nanogel for anticancer drug delivery by using a degradable pH-responsive ketal derivative, mPEG2000-Isopropylideneglycerol (mPEG-IS, PI) polymer. The purpose of this study is to develop an injectable dual-responsive micellar nanogel system which has a sol-gel phase transition by the stimulation of body temperature with improved stability and biocompatibility as a controlled drug delivery carrier for cancer therapy. The pH-responsive PI was designed with pH-responsive ketal group as hydrophobic moieties and PEG group as hydrophilic moieties. The PI micelles encapsulated paclitaxel (PTX) was fabricated. Then, the PI micelles were formed in a thermo-nanogel. The micellar nanogel could improve the solubility and stability of PTX. The physiochemical properties of PI micelles and micellar nanogel were characterized. The results showed that dual-responsive micellar nanogel could carry out sol-gel transition at 37 °C. The PI polymer can spontaneously self-assemble into micellar structure with size of 100-200 nm. The dual-responsive micellar nanogel could be degraded under lower pH condition. The test in vitro PTX release showed that dual-responsive micellar nanogel could release about 70% for 70 h under pH 5.0 while about 10% release at pH 7.4 and pH 9.0. The dual-responsive micellar nanogel was of lower cytotoxicity and suppressed tumor growth most efficiently. The micellar nanogel will be a new potential dual-responsive drug delivery system for cancer therapy.