Development of Novel Octanoyl Chitosan Nanoparticles for Improved Rifampicin Pulmonary Delivery: Optimization by Factorial Design

A novel hydrophobic chitosan derivative, octanoyl chitosan (OC) with improved organic solubility was synthesized, characterized, and employed for the preparation of rifampicin (Rif) encapsulated nanoparticle formulations for pulmonary delivery. OC was characterized to confirm acyl group substitution and cytotoxicity in A549 epithelial lung cells. OC nanoparticles were produced by the double emulsion solvent evaporation technique without cross-linking and characterized for particle size distribution, morphology, crystallinity, thermal stability, aerosol delivery, and drug release rate. OC was successfully synthesized with substitution degree of 44.05 ± 1.75%, and solubility in a range of organic solvents. Preliminary cytotoxicity studies of OC showed no effect on cell viability over a period of 24 h on A549 cell lines. OC nanoparticles were optimized using a 32full factorial design. An optimized batch of OC nanoparticles, smooth and spherical in morphology, had mean hydrodynamic diameter of 253 ± 19.06 nm (PDI 0.323 ± 0.059) and entrapment efficiency of 64.86 ± 7.73% for rifampicin. Pulmonary deposition studies in a two-stage impinger following aerosolization of nanoparticles from a jet nebulizer gave a fine particle fraction of 43.27 ± 4.24%. In vitro release studies indicated sustained release (73.14 ± 3.17%) of rifampicin from OC nanoparticles over 72 h, with particles demonstrating physical stability over 2 months. In summary, the results confirmed the suitability of the developed systems for pulmonary delivery of drugs with excellent aerosolization properties and sustained-release characteristics. © 2018, American Association of Pharmaceutical Scientists

Self-propagating molecular assemblies as interlayers for efficient inverted bulk-heterojunction solar cells

Here we report the first use of self-propagating molecule-based assemblies (SPMAs) as efficient electron-transporting layers for inverted organic photovoltaic (OPV) cells. P3HT-PCBM cells functionalized with optimized SPMAs exhibit power conversion efficiencies approaching 3.6% (open circuit voltage = 0.6 V) vs 1.5% and 2.4% for the bare ITO and Cs2CO3-coated devices, respectively. The dependence of cell response parameters on interlayer thickness is investigated, providing insight into how to further optimize device performance. © 2010 American Chemical Society

Can molecular profiling enhance radiotherapy? Impact of personalized targeted gold nanoparticles on radiosensitivity and imaging of adenoid cystic carcinoma

Personalized molecular profiling has an established role in selection of treatment for metastatic disease; however, its role in improving radiosensitivity and functional imaging has not been evaluated. In the current study, we examined molecular profiling as a tool for designing personalized targeted gold nanoparticles (GNP) to serve as dual-modal tumor radiosensitizers and functional imaging enhancers. To this end, molecular profiling of a patient's salivary gland adenoid cystic carcinoma (ACC) was performed, and anaplastic lymphoma kinase (ALK) mutation was detected. The extracted tumor was subcutaneously injected into mice, which were then treated either with radiation, the specific ALK inhibitor crizotinib, or a combination of therapies. One of these combinations, namely, ALK-targeted GNP (via crizotinib coating), was found to enhance radiation treatment, as demonstrated by a significant decrease in tumor volume over 24 days. In parallel, ALK-targeted GNP substantially augmented tumor visualization via computed tomography. The mechanism of radiosensitivity enhancement was mostly related to a diminished cell repair mechanism in tumors, as demonstrated by proliferating cell nuclear antigen staining. These findings indicate that personalized molecular profiling is an effective technique for enhancing cancer theranostics