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

In vitro influence of dietary protein and fructooligosaccharides on metabolism of canine fecal microbiota

BACKGROUND: The present in vitro study investigated whether the utilization of fructooligosaccharides (FOS) may influence canine fecal microbial population in presence of diets differing in their protein content and digestibility. Fresh fecal samples were collected from five adult dogs, pooled, and incubated for 24 h with the undigested residue of three diets: 1, Low protein high digestibility diet (LP HD, crude protein (CP) 229 g/kg); 2, High protein high digestibility diet (HP HD, CP 304 g/kg); 3, High protein low digestibility diet (HP LD, CP 303 g/kg) that had been previously subjected to enzymatic digestion. In the in vitro fermentation study, there were six treatments: 1) LP HD; 2) HP HD 3) HP LD; 4) LP HD + FOS; 5) HP HD + FOS; 6) HP LD + FOS. Fructooligosaccharides were added at the final concentration of 1.5 g/L. Samples of fermentation fluid were collected at 6 and 24 h of incubation. RESULTS: Values of pH were reduced by FOS at 6 and 24 h (P < 0.001); conversely, low protein digestibility and high dietary protein level resulted in higher pH at both sampling times (P < 0.001). At 24 h, FOS lowered ammonia (−10 %; P < 0.001) and resulted (P < 0.05) in higher concentrations of total volatile fatty acids (VFA) (+43 %), acetic acid (+14 %), propionic acid (+75 %) and n-butyric acid (+372 %). Conversely, at 24 h, low protein digestibility resulted (P < 0.01) in lower concentrations of acetic acid (−26 %), propionic acid (−37 %) and total VFA (−21 %). Putrescine concentrations were increased at 6 and 24 h of fermentation by low protein digestibility (+21 and 22 %, respectively; P < 0.05) and FOS (+18 and 24 %, respectively; P < 0.01). After 24 h of fermentation, high dietary protein level resulted in lower counts of lactobacilli and enterococci (−0.5 and −0.7 log cells/mL, respectively; P < 0.05) whereas low protein digestibility tended to increase counts of C. perfringens (+0.2 log cells/mL; P = 0.07). CONCLUSIONS: Results from the present study showed that diets rich in protein may exert negative influences on the canine intestinal ecosystem, slightly increasing the presence of ammonia and reducing counts of lactobacilli and enterococci. Moreover, the presence of poorly digestible protein resulted in lower concentrations of VFA. Conversely, administration of FOS may improve metabolism of canine intestinal microbiota, reducing ammonia concentrations and enhancing VFA production

Poly(vinyl chloride) membrane electrodes for the determination of the antibiotic tiamulin

New polymeric electrodes responding to tiamulin hydrogen fumarate were constructed by incorporating tiamulin tetraphenylborate and tiamulin phosphotungstate ion-pair complexes into PVC membranes, with the latter giving the best linear and Nernstian response. The electrodes exhibited a linear response over the concentration range 10(-2)-10(-6) mol l(-1). The pH did not affect the response of the electrodes within the range 2-8. Direct potentiometry was used to assay tiamulin hydrogen fumarate in pharmaceutical formulations and in the bulk form. The results were compared with those obtained with non-aqueous titration for the antibiotic in the bulk form and with HPLC for commercial formulations.13345746

Fundamentos para processos gerenciais na prática do cuidado Fundamento para el proceso generencial en las prácticas del cuidado Fundaments for managing process in care practices

Apresenta-se uma reflexão sobre elementos que estruturam o processo de trabalho em saúde e o agir do enfermeiro. Abordam-se o processo de trabalho em saúde, as tecnologias em saúde e o gerenciamento do cuidado como construtos que fundamentam a reflexão, com o objetivo de auxiliar na ampliação da visibilidade dos atos do enfermeiro. Ressalta-se a importância da utilização desses fundamentos para o exercício de práticas do cuidado nos processos gerenciais.<br>El presente trabajo constituye una reflexión sobre los elementos que estructuran el proceso del trabajo en salud y el actuar del enfermero. Se aborda el proceso del trabajo en salud, las tecnologías en salud y el gerenciamiento del cuidado como constructores que fundamentan la reflexión, con el objetivo de ayudar a la ampliación de la visibilidad de los actos del enfermero. Se resalta la importancia de la utilización de estos fundamentos en el ejercicio de las prácticas del cuidado en los procesos gerenciales.<br>A reflection on the elements that structure the process of the nurse's work with health and his/her action. The study deals with health work, technologies in health and the management of care as pillars that serve as bases for the reflection, with the aim of helping the enlargement of the visibility of the nurse's acts. The importance of those fundaments for the exercise of care practices in the managing processes is highlighted