Direct fluorescent labeling for efficient biological assessment of inhalable particles

<p>Labeling of aerosol particles with a radioactive, magnetic, or optical tracer has been employed to confirm particle localization in cell compartments, which has provided useful evidence for correlating toxic effects of inhaled particles. However, labeling requires several physicochemical steps to identify functionalities of the inner or outer surfaces of particles, and moreover, these steps can cause changes in size, surface charge, and bioactivity of the particles, resulting in misinterpretations regarding their toxic effects. This study addresses this challenging issue with a goal of introducing an efficient strategy for constantly supplying labeled aerosol particles in a single-pass configuration without any pre- or post-physicochemical batch treatments of aerosol particles. Carbon black (CB, simulating combustion-generated soot) or calcium carbonate (CC, simulating brake-wear fragments) particles were constantly produced via spark ablation or bubble bursting, respectively. These minute particles were incorporated with fluorescein isothiocyanate-poly(ethylene glycol) 2-aminoethyl ether acetic acid solution at the orifice of a collison atomizer to fabricate hybrid droplets. The droplets successively entered a diffusion dryer containing 254-nm UV irradiation; therefore, the droplets were dynamically stiffened by UV to form fluorescent probes on particles during solvent extraction in the dryer. Particle size distributions, morphologies, and surface charges before and after labeling were measured to confirm fluorescence labeling without significant changes in the properties. <i>In vitro</i> assays, including confocal imaging, were conducted to confirm the feasibility of the labeling approach without inducing significant differences in bioactivity compared with untreated CB or CC particles.</p

Formulation, Characterization and Optimization of Valsartan Self-Microemulsifying Drug Delivery System Using Statistical Design of Experiment

The aim of the present research was to systematically investigate the main, interaction and the quadratic effects of formulation variables on the performance of self-microemulsifying drug delivery system (SMEDDS) of valsartan using design of experiment. A 17-run Box-Behnken design (BBD) with 3-factors and 3-levels, including 5 replicates at the centre point, was used for fitting a 2nd-order response surface. After the preliminary screening, Labrafil M 2125 CS as oil, Tween 20 as surfactant and Capryol 90 as co-surfactant were taken as independent variables. The dependent factors (responses) were particle size, polydispersity index (PDI), dissolution after 15 min and equilibrium solubility. Coefficients were estimated by regression analysis and the model adequacy was checked by an F -test and the determination coefficient (R). All the responses were optimized simultaneously by using desirability function. Our results demonstrated marked main and interaction effects of independent factors on responses. The optimized formulation consisted of 26.8% (w/w) oil, 60.1% (w/w) surfactant and 13.1% (w/w) co-surfactant, and showed average micelle size of 90.7 nm and 0.246 PDI, 91.2% dissolution after 15 min and 226.7 mg/g equilibrium solubility. For the optimized formulation, predicted value and experimental value were in close agreement. After oral administration, the optimized formulation gave more than 2-fold higher area under curve (AUC) and about 6-fold higher Cmax in rats than valsartan powder (

Development and optimization of self-nanoemulsifying drug delivery system with enhanced bioavailability by Box-Behnken design and desirability function

The aim of our study was to characterize and optimize a self-nanoemulsifying drug delivery system (SNEDDS) formulation by a three-factor, three-level Box-Behnken design (BBD) combined with a desirability function. The independent factors were the amounts of Capryol PGMC (X), Tween 20 (X), and Transcutol HP (X). The dependent variables were droplet size (Y), equilibrium solubility (Y), and cumulative percentage of drug released in 15 min (Y) from the SNEDDS formulation. The responses were fitted to a second-order quadratic model and statistical validation of the fitted models was carried out by analysis of variance. Various response surface graphs and contour plots were constructed to understand the effects of different factor level combinations on the responses. The optimized SNEDDS formulation consisting of Capryol PGMC-Tween 20-Transcutol HP at proportions of 5:58.4:40 (w/w) was prepared and a comparison of the predicted values and experimental values was found to be in close agreement. Furthermore, an in vivo pharmacokinetic study of the optimized SNEDDS formulation showed a 2.2-fold increase in relative oral bioavailability compared with that of the suspension. In conclusion, the BBD demonstrated its effectiveness in optimizing the SNEDDS formulation and in understanding the effects of formulation variables on the performance of SNEDDS

Development of raloxifene-solid dispersion with improved oral bioavailability via spray-drying technique

The purpose of this study was to develop a raloxifene-loaded solid dispersion with enhanced dissolution rate and bioavailability via spray-drying technique. Solid dispersions of raloxifene (RXF) were prepared with PVP K30 at weight ratios of 1:4, 1:6 and 1:8 using a spray-drying method, and characterized by differential scanning calorimetry, X-ray powder diffraction, scanning electron microscopy, and solubility and dissolution tests. The bioavailability of the solid dispersion in rats was also evaluated compared to those of RXF powder and commercial product. Results showed that the RXF-loaded solid dispersion was in amorphous form with increased solubility and dissolution rate. The absorption of RXF from solid dispersion resulted in approximately 2.6-fold enhanced bioavailability compared to pure drug. Moreover, RXF-loaded solid dispersion gave similar AUC, C and T values to the commercial product, suggesting that it was bioequivalent to the commercial product in rats. These findings suggest that an amorphous solid dispersion of RXF could be a viable option for enhancing the oral bioavailability of RXF

Folate-targeted nanostructured chitosan/chondroitin sulfate complex carriers for enhanced delivery of bortezomib to colorectal cancer cells

Folate-targeting self-assembled nanoparticles (NPs) using biocompatible and biodegradable natural polymers chitosan (Cs) and chondroitin sulfate (Chs) were developed to address the major challenge in cancer treatment, the selective delivery of nanoparticles to the target site. In this study, we successfully incorporated a hydrophobic drug, bortezomib (Bor), into folic acid (FA)-conjugated Cs/Chs self-assembled NPs (Bor/Cs/Chs-FA) for colorectal cancer therapy. The particle size and polydispersity index of Bor/Cs/Chs-FA were ∼196.5 ± 1.2 nm and ∼0.21 ± 0.5, respectively. A pH-dependent release profile was observed, facilitating cancer cell-targeted drug release under an acidic tumor microenvironment. Moreover, in vitro data revealed enhanced cellular uptake and apoptosis in folate receptor-expressing colorectal cancer cells (HCT-116 and HT-29) as compared to that in lung cancer cells (A549), which do not express folate receptors. Furthermore, intravenous administration of Bor/Cs/Chs-FA in a HCT-116 bearing xenograft mouse model showed that the NPs were a safe and effective drug delivery system. The results suggest that folate-targeted nanoparticle can be effectively applied for efficient chemotherapy of colorectal cancer. Keywords: Bortezomib, Chitosan chondroitin sulfate, Colorectal cancer, Folic aci