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

Oncoplastic breast consortium recommendations for mastectomy and whole breast reconstruction in the setting of post-mastectomy radiation therapy

Aim Demand for nipple- and skin- sparing mastectomy (NSM/SSM) with immediate breast reconstruction (BR) has increased at the same time as indications for post-mastectomy radiation therapy (PMRT) have broadened. The aim of the Oncoplastic Breast Consortium initiative was to address relevant questions arising with this clinically challenging scenario. Methods A large global panel of oncologic, oncoplastic and reconstructive breast surgeons, patient advocates and radiation oncologists developed recommendations for clinical practice in an iterative process based on the principles of Delphi methodology. Results The panel agreed that surgical technique for NSM/SSM should not be formally modified when PMRT is planned with preference for autologous over implant-based BR due to lower risk of long-term complications and support for immediate and delayed-immediate reconstructive approaches. Nevertheless, it was strongly believed that PMRT is not an absolute contraindication for implant-based or other types of BR, but no specific recommendations regarding implant positioning, use of mesh or timing were made due to absence of high-quality evidence. The panel endorsed use of patient-reported outcomes in clinical practice. It was acknowledged that the shape and size of reconstructed breasts can hinder radiotherapy planning and attention to details of PMRT techniques is important in determining aesthetic outcomes after immediate BR. Conclusions The panel endorsed the need for prospective, ideally randomised phase III studies and for surgical and radiation oncology teams to work together for determination of optimal sequencing and techniques for PMRT for each patient in the context of BR

Oncoplastic Breast Consortium consensus conference on nipple-sparing mastectomy.

Purpose Indications for nipple-sparing mastectomy (NSM) have broadened to include the risk reducing setting and locally advanced tumors, which resulted in a dramatic increase in the use of NSM. The Oncoplastic Breast Consortium consensus conference on NSM and immediate reconstruction was held to address a variety of questions in clinical practice and research based on published evidence and expert panel opinion. Methods The panel consisted of 44 breast surgeons from 14 countries across four continents with a background in gynecology, general or reconstructive surgery and a practice dedicated to breast cancer, as well as a patient advocate. Panelists presented evidence summaries relating to each topic for debate during the in-person consensus conference. The iterative process in question development, voting, and wording of the recommendations followed the modified Delphi methodology. Results Consensus recommendations were reached in 35, majority recommendations in 24, and no recommendations in the remaining 12 questions. The panel acknowledged the need for standardization of various aspects of NSM and immediate reconstruction. It endorsed several oncological contraindications to the preservation of the skin and nipple. Furthermore, it recommended inclusion of patients in prospective registries and routine assessment of patient-reported outcomes. Considerable heterogeneity in breast reconstruction practice became obvious during the conference. Conclusions In case of conflicting or missing evidence to guide treatment, the consensus conference revealed substantial disagreement in expert panel opinion, which, among others, supports the need for a randomized trial to evaluate the safest and most efficacious reconstruction techniques

Risk assessment of nitrate transport through subsurface layers and groundwater using experimental and modeling approach

Landfills are one of the main point sources of groundwater pollution. This research mainly aims to assess the risk of nitrate (NO-3) transport from the unlined landfill to subsurface layers and groundwater using experimental results and the SESOIL model. Samples from 12 groundwater wells downstream of the landfill were collected and analyzed in 2008, 21 years after the landfill construction. The average NO-3 concentration in the wells was 54 mg/L, slightly higher than the World Health Organization (NO-350 mg/L) standards. SESOIL model was used to predict the NO-3 concentration at the bottom of the unsaturated zone. Results indicated that the current mean NO-3 concentration at the bottom of the unsaturated zone is 75 mg/L. the model predicted that the level of NO3 will increased up to 325 mg/L within 30 years. Accordingly, the NO-3 concentration in groundwater wells near the landfill area is expected to gradually increase with time. Although the current risk associated with the NO-3 level might not be harm to adults, however, it might pose severe risks to both adults and infants in the near future due to NO-3 leaching. Urgent mitigation measures such as final cell cover (cap), lining system and vertical expansion should be considered at the landfill to protect the public health in the area. © 2017, © 2017 Informa UK Limited, trading as Taylor & Francis Group