The recent insight in the release of anticancer drug loaded into PLGA microspheres

Preparation and release pattern study of long-term controlled release Blonanserin microspheres

To prepare a PLGA microsphere loaded with the antipsychotic Blonanserin without release leg period and released in a near-zero model for long time, in this study, 15 kDa and 75 kDa PLGA were chosen to be mixed with different ratios, and Blonanserin microspheres (Bn-MS) without significant differences in the particle size, drug loading capacity, and encapsulation rate were prepared by microfluidics. The release kinetic model was fitted to the release behavior by monitoring the changes in particle size and morphology during the Bn-MS release to investigate microspheres' in vitro release pattern. The results showed that the addition of appropriate ratios of mixed molecular weights to Bn-MS could eliminate the release hysteresis period. When the ratio of 15 kDa and 75 kDa was 1:9 (F3), the Bn-MS had a low burst release rate, moderate release rate, no release hysteresis period, a long release period of up to 35 days, and a stable release pattern close to the zero level. The results of the release mechanism study indicated that the hybrid PLGA improved the release behavior of the microspheres by adjusting the dissolution degradation rate of Bn-MS, which in turn affected the release mechanism of the microspheres.

Preparation and in vitro evaluation of pH and glutathione dual-responsive drug delivery system based on sodium carboxymethyl cellulose

Stimuli-responsive drug delivery systems based on sodium carboxymethyl cellulose (NaCMC) for drug release encounter inherent challenges. In this research, a novel pH and glutathione (GSH) dual-responsive system, CPT-S-S-NaCMC@ZIF-8/SP-PEG, was constructed. Firstly, the prodrug CPT-S-S-OH was synthesized and combined with NaCMC to form GSH-responsive micelles CPT-S-S-NaCMC, significantly enhancing the drug loading and grafting rates to 63.79 % and 91.99 %, respectively. Subsequently, zinc ions and dimethylimidazole can be assembled into porous materials (ZIF-8) on the surface of the micelles. This system exhibits dual pH-GSH responsiveness and effectively reduces the drug release from 84.76 % to 28.71 % at pH = 7.4. Moreover, incorporating pH-responsive spiropyran (SP)-modified polyethylene glycol (PEG) can reduce drug leakage to 16.09 % at pH = 7.4 and exhibit good fluorescence intensity at 722 nm.

The drug release of PLGA-based nanoparticles and their application in treatment of gastrointestinal cancers

The poly (lactic-co-glycolic acid) (PLGA) based nanoparticles have been applied for drug delivery due to their simple preparation, biodegradability, and ideal biocompatibility. In this study, the factors affecting the degradation of PLGA-based nanoparticles are reviewed, encompassing the ratio of PLA to PGA, relative molecular weight, crystallinity, and preparation process of PLGA nanoparticles. The drug release behavior of PLGA-based nanoparticles, such as the degradation environment, encapsulated drug properties of polymers, and drug loading rates, are also discussed. Since gastrointestinal cancer is one of the major global threats to human health, this paper comprehensively summarizes the application of PLGA nanoparticles in gastrointestinal cancers from diagnosis, chemotherapy, radiotherapy, and novel tumor treatment methods (immunotherapy, gene therapy, and photothermal therapy). Finally, the future application of PLGA-based drug delivery systems in treating gastrointestinal cancers is discussed. The bottleneck of application status and the prospect of PLGA-nanoparticles in gastrointestinal tumor application are presented. To truly realize the great and wide application of PLGA-based nanoparticles, collaborative progress in the field of nanomaterials and life sciences is needed.

Quantification of Microsphere Drug Release by Fluorescence Imaging with the FRET System

Accurately measuring drug and its release kinetics in both in vitro and in vivo environments is crucial for enhancing therapeutic effectiveness while minimizing potential side effects. Nevertheless, the real-time visualization of drug release from microspheres to monitor potential overdoses remains a challenge. The primary objective of this investigation was to employ fluorescence imaging for the real-time monitoring of drug release from microspheres in vitro, thereby simplifying the laborious analysis associated with the detection of drug release. Two distinct varieties of microspheres were fabricated, each encapsulating different drugs within PLGA polymers. Cy5 was selected as the donor, and Cy7 was selected as the acceptor for visualization and quantification of the facilitated microsphere drug release through the application of the fluorescence resonance energy transfer (FRET) principle. The findings from the in vitro experiments indicate a correlation between the FRET fluorescence alterations and the drug release profiles of the microspheres.

Advances on Delivery System of Active Ingredients of Dried Toad Skin and Toad Venom

Dried toad skin (TS) and toad venom (TV) are the dried skin of the Bufo bufo gargarizans Cantor and the Bufo melanostictus Schneider, which remove the internal organs and the white secretions of the skin and retroauricular glands. Since 2005, cinobufacini preparations have been approved by the State Food and Drug Administration for use as adjuvant therapies in the treatment of various advanced cancers. Meanwhile, bufalenolides has been identified as the main component of TS/TV, exhibiting antitumor activity, inducing apoptosis of cancer cells and inhibiting cancer cell proliferation or metastasis through a variety of signaling pathways. However, clinical agents frequently face limitations such as inherent toxicity at high concentrations and insufficient tumor targeting. Additionally, the development and utilization of these active ingredients are hindered by poor water solubility, low bioavailability, and rapid clearance from the bloodstream. To address these challenges, the design of a targeted drug delivery system (TDDS) aims to enhance drug bioavailability, improve targeting within the body, increase drug efficacy, and reduce adverse reactions. This article reviews the TDDS for TS/TV, and their active components, including passive, active, and stimuli-responsive TDDS, to provide a reference for advancing their clinical development and use.

Visualization and correlation of drug release of risperidone/clozapine microspheres in vitro and in vivo based on FRET mechanism

This study addresses the challenging task of quantitatively investigating drug release from PLGA microspheres after in vivo administration. The objective is to employ Förster resonance energy transfer (FRET) to visualize drug-encapsulated microspheres in both in vitro and in vivo settings. The primary goal is to establish a quantitative correlation between FRET fluorescence changes and microsphere drug release. The study selects drugs with diverse structures and lipid solubility to explore release mechanisms, using PLGA as the matrix material. Clozapine and risperidone serve as model drugs. FRET molecules, Cy5 and Cy5.5, along with Cy7 derivatives, create FRET donor-acceptor pairs. In vitro results show that FRET fluorescence changes align closely with microsphere drug release, particularly for the Cy5.5-Cy7 pair. In vivo experiments involve subcutaneous administration of microspheres to rats, tracking FRET fluorescence changes while collecting blood samples. Pharmacokinetic studies on clozapine and risperidone reveal in vivo absorption fractions using the Loo-Riegelman method. Correlating FRET and in vivo absorption data establishes an in vitro-in vivo relationship (IVIVR). The study demonstrates that FRET-based fluorescence changes quantitatively link to microsphere drug release, offering an innovative method for visualizing and monitoring release in both in vitro and in vivo settings, potentially advancing clinical applications of such formulations.

Nanomaterial-Based Drug Delivery Systems for Pain Treatment and Relief: From the Delivery of a Single Drug to Co-Delivery of Multiple Therapeutics

The use of nanomaterials in drug delivery systems for pain treatment is becoming increasingly common. This review aims to summarize how nanomaterial-based drug delivery systems can be used to effectively treat and relieve pain, whether via the delivery of a single drug or a combination of multiple therapeutics. By utilizing nanoformulations, the solubility of analgesics can be increased. Meanwhile, controlled drug release and targeted delivery can be realized. These not only improve the pharmacokinetics and biodistribution of analgesics but also lead to improved pain relief effects with fewer side effects. Additionally, combination therapy is frequently applied to anesthesia and analgesia. The co-encapsulation of multiple therapeutics into a single nanoformulation for drug co-delivery has garnered significant interest. Numerous approaches using nanoformulation-based combination therapy have been developed and evaluated for pain management. These methods offer prolonged analgesic effects and reduced administration frequency by harnessing the synergy and co-action of multiple targets. However, it is important to note that these nanomaterial-based pain treatment methods are still in the exploratory stage and require further research to be effectively translated into clinical practice.