Degradation studies of hydrophilic, partially degradable and bioactive cements (HDBCs) incorporating chemically modified starch

The degradation rate in Hydrophilic, Degradable and Bioactive Cements (HDBCs) containing starch/cellulose acetate blends (SCA) is still low. In order to increase degradation, higher amounts of starch are required to exceed the percolation threshold. In this work, gelatinization, acetylation and methacrylation of corn starch were performed and assessed as candidates to replace SCA in HDBCs. Formulations containing methacrylated starch were prepared with different molar ratios of 2-hydroxyethyl methacrylate and methyl methacrylate in the liquid component and the amount of residual monomer released into water was evaluated. The concentration of reducing sugars, percentage of weight loss and morphologic analyses after degradation all confirmed increased degradation of HDBC with alpha-amylase, with the appearance of pores and voids from enzymatic action. Methacrylated starch therefore is a better alternative to be used as the solid component of HDBC then SCA, since it leads to the formation of cements with a lower release of toxic monomers and more prone to hydrolytic degradation while keeping the other advantages of HDBCs.The authors acknowledge to Foundation for Science and Technology (FCT), who supported this study through funds from project Concept2Cement (POCTI/CTM/60735/2004)

Community-Centered Responses to Ebola in Urban Liberia: The View from Below

The West African Ebola epidemic has demonstrated that the existing range of medical and epidemiological responses to emerging disease outbreaks is insufficient, especially in post-conflict contexts with exceedingly poor healthcare infrastructures. This study provides baseline information on community-based epidemic control priorities and identifies innovative local strategies for containing EVD in Liberia.In this study the authors analyzed data from the 2014 Ebola outbreak in Monrovia and Montserrado County, Liberia. The data were collected for the purposes of program design and evaluation by the World Health Organization (WHO) and the Government of Liberia (GOL), in order to identify: (1) local knowledge about EVD, (2) local responses to the outbreak, and (3) community based innovations to contain the virus. At the time of data collection, the international Ebola response had little insight into how much local Liberian communities knew about Ebola, and how communities managed the epidemic when they could not get access to care due to widespread hospital and clinic closures. Methods included 15 focus group discussions with community leaders from areas with active Ebola cases. Participants were asked about best practices and what they were currently doing to manage EVD in their respective communities, with the goal of developing conceptual models of local responses informed by local narratives. Findings reveal that communities responded to the outbreak in numerous ways that both supported and discouraged formal efforts to contain the spread of the disease. This research will inform global health policy for both this, and future, epidemic and pandemic responses

Probe Penetration Method to Characterize Low Solid High Viscous Pharmaceutical Gel Compositions

Objective: The objective was to develop a discriminatory analytical technique to evaluate rheological properties of low solid high viscous gel compositions used in the preparation of semi-solid pharmaceutical dosage forms. Background: Rheological properties of materials are frequently described in terms of viscosity, which is defined as resistance to flow. Compositions displaying strong gel consistency do not flow unless the applied stress exceeds certain value “Yield Stress”. In this study, we propose a Probe Penetration Method for better characterization of gels displaying yield stress when used at very low concentrations. Methods: Different types of carbomer solutions (carbomer homopolymer, copolymer, interpolymer, and polycarbophil) were prepared in water at different concentrations (0.1-1.0% w/w). Using sodium hydroxide, the pH of solutions was adjusted to 5.0-6.0, and the gel strength was measured using CT3-Texture Analyzer for non-neutralized and neutralized samples. The test records sample resistance to a penetrating stainless-steel probe (@ speed of 0.5mm/s). The test starts when the designated trigger load (10mN) is reached (at sample surface), then travelling 25mm distance representing sample center. Results: The control solutions, regardless of their concentrations, showed minimal differences in their gel strength values, 12-31mN. The results after neutralization demonstrated higher values and varied among different concentrations; carbomer homopolymer 18-196mN, copolymer 28-132mN, interpolymer 21-238mN, & polycarbophil 20-118mN. Conclusion: Given its discriminatory capability, the gel strength measurement by probe penetration method can be used in studying the rheological properties of highly viscous gel materials used at less than 1% concentrations. Grants: This study was supported by NSU Grant 33508

A Dual Mechanism to Deter Intravenous Drug Abuse Using Crosslinked Anionic Polymers

Objective: The objective was to evaluate the contribution of binding and swelling of two crosslinked anionic polymers (carboxymethyl starch, CMS; and carboxymethyl cellulose, CMC) in reducing the amount of free drug available for intravenous abuse in different extracting solvents. Background: CMS and CMC polymers can offer both swelling and binding properties in aqueous solutions. Binding to cationic opioid drugs and entrapping portion of the drug solution due to swelling are expected to significantly lower the amount of free drug available for injection. This study evaluated the contribution of the two mechanisms in total drug entrapment from drug solutions. Methods: CMS and CMC were mixed with Dextromethorphan HBr in 10.0 ml of common extracting solvents. Followed by centrifugation, the supernatant was measured for its volume and drug concentration (UV spectroscopy). The results were used to calculate the total drug entrapment, entrapment due to swelling and entrapment due to binding. Results: In most extracting solvents, drug entrapment due to binding with CMS and CMC were ≥ 25% and ≥ 40% higher than that due to swelling, respectively. In solvents containing ions, entrapment due to swelling was greater but not exceeding 15% and 5% for CMS and CMC, respectively. Conclusion: The binding is the primary contributor to total drug entrapment in all extracting solvents, except in those containing salts (sodium) and ionic moieties (carboxyl groups). Grants: This study was supported by NSU Grant 33508