Publications in July & August 2016 - drug delivery systems

Today´s topic is chitosan for drug delivery systems. In July and August 2016, 33 articles about chitosan combined with drug delivery systems were published. As might be expected, top publisher are China (13 articles), United States (5) and India (4). The articles investigated drug release by chitosan-based micro- or nanoparticles, hydrogels and nanocomposites. Thereby controlled release of cytostatics, proteins or peptides was mainly studied. (Source: www.gopubmed.org)

Chemotherapy for cancer treatment is still limited by several factors regarding target orientation and persistence of anti-cancer drugs.

Transferrin functionalized chitosan-PEG nanoparticles for targeted delivery of paclitaxel to cancer cells

Nag M.,Gajbhiye V., Kesharwani P., Jain N. K. et al. Colloids and Surface B: Biointerfaces, 148: 363-370, Epub August 2016. doi: 10.1016/j.colsurfb.2016.08.059.

The first study, published by authors from India and the USA, attempted to realize targeted delivery of paclitaxel (PTX), a cytostatic drug, by polyethylene glycol (PEG) modified chitosan nanoparticles (NPs). PTX-loaded chitosan (MW<100 kDa, DDA 75-85%) NPs were prepared by solvent evaporation method. NPs were PEGylated by coupling amine group on the NPs surface to the hydroxyl group of PEG. The PEG-NPs were functionalized with transferrin (Tf), which binds to surface receptors overexpressed on cancer cells. Receptor-mediated endocytosis leads to uptake of the nanoparticles and targeted delivery of the incorporated drug PTX. Creation of NP-PEG-Tf was carried out by coupling a carboxyl group of Tf and hydroxyl group present on the NP-PEG.

RESULTS:

• Uptake of PEGylated transferrin-coupled chitosan nanoparticles into cancer cells was higher compared to particles without transferrin
• Higher cytotoxicity and higher intracellular uptake of PTX-NPs-PEG-Tf to HOP-62 cells
• Retention time in the lung and the blood increased for Tf conjugated chitosan nanoparticles

Conclusion: PEGylated chitosan nanoparticles coupled with transferrin are a promising tool for target-site delivery of anti-cancer drugs like PTX. The investigated PTX-NP-PEG-Tf showed improved efficacy of PTX by enhancing intracellular uptake as well as lung and blood retention time.

Source: https://www.ncbi.nlm.nih.gov/pubmed/27632697

In Vivo Magnetic Resonance Imaging and Microwave Thermotherapy of Cancer Using Novel Chitosan Microcapsules

Tang S., Du Q., Liu T. et al. Nanoscale research letters. 11 (1): 334, Epub July 2016. doi: 10.1186/s11671-016-1536-0.

In cancer therapy, microwave (MW) thermotherapy enables effective ablation of large tumors by heat and has many advantages compared to other therapeutic approaches. The main goal is to prevent the integrity of surrounding healthy tissue. Ionic liquids (ILs) are highly suitable for heating by microwave irradiation. Application of the biocompatible and -degradable material chitosan is promising for encapsulation and delivery of ILs to the tumor. In this publication, chitosan-based (DDA = 80-95 %) microcapsules for MW thermotherapy of tumors and as contrast agent for improved tumor magnetic resonance (MR) imaging were developed. Chitosan/Fe₃O₄@IL microcapsules were intratumorally injected (200mg/kg) into mice with H22 tumors, followed by MW irradiation at ultralow power density (1.8 W/cm2) for 5 min.

RESULTS

for chitosan/Fe₃O₄@IL microcapsules:

• in vitro: desired temperature rise after MW irradiation, good biocompatibility, low cytotoxicity
• no organ toxicity in vivo
• complete elimination of H22 tumor cells in mice after MW thermotherapy
• in vivo imaging results prove applicability as efficient contrast agent

Conclusion: Successful development of chitosan/Fe₃O₄@IL microcapsules for application in MR imaging-guided MW thermotherapy. Microcapsules were biocompatible in vitro for tested concentration (max. 1000 mg/mL). MW irradiation led to H22 tumor destruction in mice. All in all, multifunctional chitosan particles are promising as tumor theranostic platforms.

Free fulltext available: Source: https://www.ncbi.nlm.nih.gov/pubmed/27422776