Mannose-anchored N,N,N-trimethyl chitosan nanoparticles for pulmonary administration of etofylline.

Drug delivery to lungs via pulmonary administration offers potential for the development of new drug delivery systems. Here we fabricated the etofylline (ETO) encapsulated mannose-anchored N,N,N-trimethyl chitosan nanoparticles (Mn-TMC NPs). The prominent characteristics like biocompatibility, controlled release, targeted delivery, high penetrability, enhanced physical stability, and scalability mark Mn-TMC NPs as a viable alternative to various nanoplatform technologies for effective drug delivery. Mannosylation of TMC NPs leads to the evolution of new drug delivery vehicle with gratifying characteristics, and potential benefits in efficient drug therapy. It is widely accepted that following pulmonary administration, the introduction of mannose to the surface of drug nanocarriers provide selective macrophage targeting via receptor-mediated endocytosis. The fabricated Mn-TMC NPs exhibited particle size of 223.3 nm, PDI 0.490, and ζ-potential -19.1 mV, drug-loading capacity 76.26 ± 1.2%, and encapsulation efficiency of 91.75 ± 0.88%. Sustained drug release, biodegradation studies, stability, safety, and aerodynamic behavior revealed the effectiveness of prepared nanoformulation for pulmonary administration. In addition, the in vivo pharmacokinetic studies in Wistar rat model revealed a significant improvement in therapeutic efficacy of ETO, illustrating mannosylation a promising approach for efficient therapy of airway diseases following pulmonary administration.

Instability of common beans during storage causes hardening: The role of glass transition phenomena.

Long-term storage of common beans leads to loss of cooking quality and an ill-defined solution, appropriate storage, is recommended. Therefore, the polymer science theory of glasses that hypothesizes stability of a system below its glass transition temperature (Tg) was applied to determine bean stability during storage in relation to cooking behavior. Since composition influences Tg, powders of cotyledons and seed coats in addition to whole beans were equilibrated above different saturated salt solutions in order to generate materials with different moisture contents. A thermal mechanical compression test which measures compressibility changes in a system upon reaching its glass-rubber transition temperature region was conducted to obtain the Tg. A Tg-moisture relation was established, whose relevance was confirmed by storage and cooking experiments which showed development of hard-to-cook in beans stored above Tg but not below it. Therefore, this relation constitutes a stability map for storage of common beans.

Synthesis, characterization and antifungal efficacy of chitosan derivatives with triple quaternary ammonium groups.

A novel type of water soluble chitosan derivatives (TQCSPX) were synthesized including 3-aminopyridine (TQCSP1) and 3-Amino-4-methylpyridine (TQCSP2). The theoretical structures of TQCSPX were calculated by Gaussian 09 and confirmed by FT-IR, 1H NMR, 13C NMR, elemental analysis and XRD. The antifungal properties of TQCSPX against Phytophthora capsici (P. capsici), Rhizoctonia solani (R. solani), Fusarium oxysporum (F. oxysporum) and Fusarium solani (F. solani) were evaluated at concentrations ranging from 0.2mg/mL to 0.8mg/mL. Antifungal results indicated that the derivatives have significantly enhanced antifungal activity after quaternized compared with the original chitosan (CS). Moreover, TQCSP1 inhibited the growth of P. capsici with inhibitory indices of 91.94% at 0.8mg/mL. The experimental results demonstrated that the increasing number of the positive charge would improve the antifungal efficiency of chitosan, which may provide a novel direction for the development of fungicides.

Controlled synthesis of N,N,N-trimethyl chitosan for modulated bioadhesion and nasal membrane permeability.

In an experiment to explore the bioadhesion, biocompatibility, and membrane permeation properties, the controlled synthesis of N,N,N-trimethyl chitosan (TMC) was carried out by two-step reductive methylation of chitosan (CHT). Methylation was confirmed by (1)H NMR (δ=3.1 ppm) and FTIR analysis (CH stretch at 1,485 cm(-1)). The TMC was further characterized by DSC, TGA, XRD, HR-TEM, SEM, and elemental analysis. Findings revealed improved solubility, enhanced viscosity, increased swelling index and higher molecular weight of TMC over CHT. Comparative evaluation validated increased bioadhesion potential, and improved ex vivo biocompatibility of TMC compared to CHT. Increased bioadhesion of TMC NPs over CHT NPs can be attributed to the strong electrostatic interactions between cationic amino groups with anionic sialic and sulfonic acid moieties contained in the mucin of the nasal mucus. Ex vivo biocompatibility studies suggested that the NP formulations of both biopolymers were biocompatible and could be applied safely on the nasal epithelium. Ex vivo permeation studies executed on excised cattle nasal mucosa illustrated improved permeability of TMC NPs over CHT NPs. In the author's opinion, two-step reductive methylation of CHT could be an attractive strategy to improve its solubility, bioadhesion, and permeation characteristics without affecting biocompatibility across the mucosal surfaces.