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131.
Azita Haddadi Effat Sadat Farboud Mohammad Erfan Reza Aboofazeli 《Journal of microencapsulation》2013,30(6):698-712
This work describes the formulation and characterization of urea-loaded microspheres prepared using various polymers such as ethyl cellulose (EC), cellulose acetate phthalate (CAP) and poly (D,L-lactic-co-glycolic acid) (PLGA), along with the utilization of a solvent evaporation technique. The effect of various formulation parameters (i.e. polymer type and concentration, vehicle type, polymer solution/vehicle volume ratio, drug/polymer ratio, homogenizer and stirrer speed, sonication time and speed, type of washing solution, drying and separation method) on the characteristics of microspheres was also evaluated. Results obtained indicated that, in the presence of urea, highest rate of EC microsphere production could be obtained at a drug/polymer ratio of 1:2 and a polymer solution/vehicle volume ratio of 1:50. In some cases, crystallization of urea was observed during the encapsulation process using cellulose derivative polymers. CAP microparticles showed a rough and tortuous surface while EC microparticles had a wider range of particle size. However, with the PLGA polymer, much better desired microparticles with a smaller size range of 1–3?µm were obtained. In general, PLGA microspheres were spherical in shape and possessed smooth surfaces with less pores in comparison with those obtained by the other polymers. The yield of particle production and the extent of urea encapsulation in PLGA particles were measured to be 68.87%?±?5.3 and 40.5%?±?3.4, respectively. The release study from PLGA microspheres revealed that up to 70% of the drug was released within a few days, through a four-stage release pattern. 相似文献
132.
Azita Haddadi Reza Aboofazeli Mohammad Erfan Effat Sadat Farboud 《Journal of microencapsulation》2013,30(6):379-386
This study describes the formulation and characterization of O/W and W/O creams containing urea-loaded microparticles prepared with poly (D, L-lactic-co-glycolic acid) (PLGA) in order to encapsulate and stabilize urea. The solvent evaporation method was used for preparing PLGA microparticles containing urea. The microparticles size was evaluated by laser light diffractometry. The resulting microparticles were then incorporated in O/W and W/O creams and stability and the release pattern from the creams was evaluated by UV-spectrophotometry. The particle size of PLGA microparticles was in the range of 1–5 µm and most microparticles had a particle size smaller than 3 µm. The encapsulation efficiency was calculated as 40.5%?±?3.4. This study also examined release pattern of urea which varied among different formulations. The results showed that the release from O/W creams followed Higuchi kinetics while the release from W/O creams showed the zero order kinetics and the creams containing microparticulated urea had slower release than free urea creams. 相似文献
133.
The stability of various biodegradable polyester polymers with different molecular weights and lactic/glycolic acids ratios were evaluated in simulated gastrointestinal fluids as an approach to apply microparticles for oral protein delivery on the basis of particle uptake mechanism. A common w/o/w emulsion solvent evaporation technique using dichloromethane for dissolving the polymer and polyvinyl alcohol as the stabilizer was used for encapsulation. Microspheres were incubated at 37°C in USP simulated fluids with a concentration of 20 mg mL?1 and also in the literature, which suggested fed or fasted simulated intestinal fluids for different times up to 24 h, while shaking at 75 rpm. The stability assessment was done by detecting pH alterations of the media, enzymatic assay of L-lactic acid, performing differential scanning calorimetric studies and observing the size and morphology of particles. Results showed that the three polymers, namely Resomers® R207, RG756 and RG505, could be suitable for the preparation of protein-loaded microspheres. 相似文献
134.
Matthew J. Landry Fiona M. Asigbee Sarvenaz Vandyousefi Erfan Khazaee Reem Ghaddar Jessica B. Boisseau Benjamin T. House Jaimie N. Davis 《Journal of the Academy of Nutrition and Dietetics》2019,119(5):760-768
Background
No studies have assessed the relationship between diet quality, using the Healthy Eating Index (HEI), and adiposity, physical activity, and metabolic disease risk factors in a Hispanic college population.Objective
To assess associations between diet quality and adiposity, metabolic health, and physical activity levels in a Hispanic college freshman population.Design
This was a cross-sectional study. Measurements were obtained during a 4-hour in-person visit and included demographic information via questionnaire, height, weight, waist circumference, body mass index, body fat via BodPod, hepatic fat, visceral adipose tissue (VAT) and subcutaneous adipose tissue via magnetic resonance imaging, glucose, insulin, homeostatic model assessment of insulin resistance (HOMA-IR), and lipids via blood draw from fasting subjects, physical activity (ie, step counts per day and time spent in different intensity levels) via 7-day accelerometry, and dietary intake via three to four 24-hour dietary recalls. Dietary quality was calculated using the HEI-2015.Participants/setting
Hispanic college freshmen (n=92), 18 to 19 years, 49% male, who were enrolled at University of Texas at Austin from 2014 to 2015.Main outcome measures
Main outcome measures were diet quality and adiposity, metabolic health, and physical activity levels.Statistical analyses performed
Linear regressions determined if dietary quality is related to adiposity, metabolic, and physical activity outcomes. A priori covariates included sex, body fat, and body mass index percentile (for metabolic models), and moderate and vigorous physical activity (MVPA, for adiposity and metabolic models).Results
The average HEI-2015 total score was 54.9±13.4. A 1-point increase in HEI score was associated with 1.5 mL lower VAT (P=0.013); 8 minutes per day higher light activity (P=0.008), and 107 more step counts per day (P=0.002); and 0.10 μg/mL lower insulin (P=0.046) and 0.5 U lower HOMA-IR (P<0.001).Conclusion
Results suggest that small improvements in diet quality may be positively associated with a reduction in metabolic disease risk, during a critical time period in a young person’s life. 相似文献135.
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139.
Amini Erfan Ahmadi Nariman Clifford Thomas G. Hugen Cory M. Bazargani Soroush T. Cai Jie Miranda Gus Sherrod Andy E. Daneshmand Siamak Djaladat Hooman 《International urology and nephrology》2019,51(3):435-441
International Urology and Nephrology - To assess the impact of carcinoma in situ (CIS) on oncologic outcomes in patients who underwent radical cystectomy, with a focus on those who received... 相似文献
140.