NOVEL SMART pH SENSITIVE CHITOSAN GRAFTED ALGINATE HYDROGEL MICROCAPSULES FOR ORAL PROTEIN DELIVERY: II. EVALUATION OF THE SWELLING BEHAVIOR

Objective: The main objective of this study is to evaluate the swelling behavior of pH sensitive chitosan (CS) grafted alginate (ALG) hydrogel microcapsules and compared with a simple alginate-chitosan mixed polyelectrolyte complex (PEC) to show the benefits of the used covalently grafting technique. In addition, the behavior of the swelling process under physiological conditions to stimulate gastric, colonic and intestinal medium for grafted PEC microcapsules will be investigated as well.Methods: The new pH sensitive hydrogel microcapsules were prepared using grafting to†technique. Swelling studies were conducted in buffer saline solutions with different pHs using wet beads. In addition; the sensitivity of the grafted microcapsules to the change of pH in the simulated gastric fluid (SGF; pH 1.2), (SIF; pH 6.8) and (SCF; pH 7.4) was investigated.Results: It was observed from the swelling studies that sharp phase transition was recognized between pH 3–4. While this transition became broader and recognized between pH 3.0-7.4, where the maximum value of the equilibrium swelling degree was varied depending on the variation of CS concentration from 0.1% to 0.5%, both grafted and mixed microcapsules exhibit higher swelling degree at high pH 6.8 (120%, 100%) respectively.Conclusion: It was clear from all swelling studies that the grafting technique may be a suitable way for large-scale production of pH sensitive alginate–chitosan microcapsules as a potential system for site-specific oral delivery of protein drugs to different regions of the intestinal tract.Â

NOVEL SMART pH SENSITIVE CHITOSAN GRAFTED ALGINATE HYDROGEL MICROCAPSULES FOR ORAL PROTEIN DELIVERY: I. PREPARATION AND CHARACTERIZATION

Objectives: Preparation and characterization of a new pH sensitive chitosan (CS) grafted alginate (ALG) hydrogel microcapsules for the oral delivery of protein.Methods: The pH sensitive hydrogel microcapsules were prepared for the first time using grafting to†technique. Firstly, alginate was activated using Ï-Benzoquinone (PBQ) as a coupling agent to graft Chitosan chains later on. Both of activated and grafted alginate microcapsules were characterized by Fourier transform-Infra red spectroscopy (FT-IR), thermal gravimetric analysis (TGA) and the morphological structures were investigated using Scanning electron microscopy (SEM) examination.Results: It was found that the optimum conditions affecting the activation process and also the swelling degree of the prepared hydrogel microcapsules were 2% ALG, 0.04M PBQ pH10, 45 °C for 2h. In addition, the grafting process depends on the attached amount of PBQ and CS concentration. Maximum grafting efficiency (GE %) and chitosan add-on percentage were 98.6% and 14.8% respectively using 0.3% CS at 40 °C for 3h.Conclusions: Novel pH sensitive hydrogel microcapsules were prepared via grafting of chitosan molecules on to activated alginate backbone. The formulated microcapsules can be applied as a new pH sensitive carrier for protein drugs. Â

Bisphenol A Detection in Various Brands of Drinking Bottled Water in Riyadh, Saudi Arabia Using Gas Chromatography/Mass Spectrometer

Purpose: To assess whether bisphenol A contamination occurred in seven brands of bottled drinking water in Riyadh, Saudi Arabia.Methods: Liquid-liquid extraction (using dichloromethane) was used to analytically extract bisphenol A from drinking water bottles and a gas chromatograph-mass spectrometer was employed for its detection using a splitless capillary column and helium as the carrier gas.Results: The concentration of bisphenol A (BPA) was high in all the bottled water brands tested. The mean concentration of BPA of the bottled water stored indoors (4.03 ng/L) was significantly lower than that stored outdoors (7.5 ng/L).Conclusion: Our results show that significant amounts of BPA leached from bottle containers into the water. Long storage of bottled water under direct sunlight should be avoided to reduce the risk of human exposure to BPA

Distinguishing post-treatment changes from recurrent disease in cholangiocarcinoma: a case report

<p>Abstract</p> <p>Introduction</p> <p>Three-dimensional techniques for radiotherapy have expanded possibilities for partial volume liver radiotherapy. Characteristic, transient radiographic changes can occur in the absence of clinical radiation-induced liver disease after hepatic radiotherapy and must be distinguished from local recurrence.</p> <p>Case presentation</p> <p>In this report, we describe computed tomography changes after chemoradiotherapy for cholangiocarcinoma as an example of collaboration to determine the clinical significance of the radiographic finding.</p> <p>Conclusion</p> <p>Because of improved three-dimensional, conformal radiotherapy techniques, consultation across disciplines may be necessary to interpret post-treatment imaging findings.</p

Influence of helium-ion bombardment on the optical properties of ZnO nanorods/p-GaN light-emitting diodes

Light-emitting diodes (LEDs) based on zinc oxide (ZnO) nanorods grown by vapor-liquid-solid catalytic growth method were irradiated with 2-MeV helium (He+) ions. The fabricated LEDs were irradiated with fluencies of approximately 2 × 1013 ions/cm2 and approximately 4 × 1013 ions/cm2. Scanning electron microscopy images showed that the morphology of the irradiated samples is not changed. The as-grown and He+-irradiated LEDs showed rectifying behavior with the same I-V characteristics. Photoluminescence (PL) measurements showed that there is a blue shift of approximately 0.0347 and 0.082 eV in the near-band emission (free exciton) and green emission of the irradiated ZnO nanorods, respectively. It was also observed that the PL intensity of the near-band emission was decreased after irradiation of the samples. The electroluminescence (EL) measurements of the fabricated LEDs showed that there is a blue shift of 0.125 eV in the broad green emission after irradiation and the EL intensity of violet emission approximately centered at 398 nm nearly disappeared after irradiations. The color-rendering properties show a small decrease in the color-rendering indices of 3% after 2 MeV He+ ions irradiation

Effect of Mitomycin - C and Triamcinolone on Preventing Urethral Strictures

Urethral stricture is a common disease with high recurrence rate. Several manipulations were defined to prevent the recurrence but the results were disappointing. This study aimed to evaluate the efficacy of triamcinolone and mitomycin-C on urethral stricture formation and their effect on inhibition of urethral fibrosis. A total of 24 New Zealand rabbits were divided into 3 groups. Urethras of rabbits were traumatized with pediatric resectoscope. Resection area was irrigated with 10mL saline, swapped with a cotton wool soaked with 0.5mg/mL MMC and injected by 40mg triamcinolone in groups 1, 2 and 3 respectively. Retrograde urethrogram was performed at 28th day of procedure and the urethra was removed for histopathologic evaluation. There were significant differences in urethral diameters and in lumen reduction rate between the control and study groups (p< 0.001). Compared to control group, all treatment groups showed mild fibrosis, less collagen bundle irregularity, and lower numbers of fibroblasts (p= 0.003). The Tunnel assay showed that the number of apoptotic cells in the submucosal connective tissue was quantitatively higher in control groups (p= 0.034). In the view of efficacy and safety, MMC and triamcinolone have the potential to replace the use of stents, clean intermittent catheterization, or long term catheters following internal urethrotomy. There were no statistically significant differences between two agents in terms of preventing urethral stricture formation in the present study. Mitomycin C and triamcinolone decreased the recurrence rates of urethral stricture