Fabrication of sub-micron protein-chitosan electrostatic complexes for encapsulation and pH-Modulated delivery of model hydrophilic active compounds

AbstractElectrostatic sub-micron complexes of a protein (sodium caseinate (NaCAS) or bovine serum albumin (BSA)) and a polysaccharide (chitosan) were fabricated by associative phase separation and investigated for use in encapsulation and pH-triggered delivery applications. Various factors have been studied with respect to the extent of complexing and the size and morphology of the complexes produced, including protein type and the biopolymer mixing ratio. The effect of applying ultrasound has been considered with a view to comminuting precipitates produced under low shear to the colloidal scale to form coacervates. A simple model is suggested to explain how the biopolymer mixing ratio influences the ability for application of ultrasound to convert macroscopically phase-separated complex precipitates into coacervates. Different factors, both from a formulation and processing viewpoint, were studied with respect to encapsulation efficiency (EE) of model hydrophilic actives: fluorescein, rhodamine B, and riboflavin. Release of fluorescein and rhodamine B was measured as function of pH in order to investigate the pH-responsive molecular release capability of the fabricated structures. It is envisaged this work will add to the current tool-box of pH-responsive molecular delivery approaches, including those in the areas of foods, pharmaceuticals, and agrochemicals

Processing effects during rotating membrane emulsification

AbstractIn this study, a rotating membrane emulsification setup incorporating a 6.1μm pore diameter SPG membrane was used to produce O/W emulsions of average droplet sizes between 23.4 and 216.6μm. All emulsions consisted of 10vol% of sunflower oil or silicone oil stabilised by 1wt% Tween 20. The transmembrane pressure (0.1–1.8bar), rotational speeds (100–2000RPM) annular gap width (5–45mm), dispersed and continuous phase viscosity were all investigated as to their effect on emulsion droplet size and dispersed phase flux. Modification of the dispersed phase flow properties alters the droplet size with four regions being suggested; a decrease in size (as droplet coalescence is minimised), a plateau (size-stable zone), a gradual increase in size (due to transfer of mass via droplet neck) and then a rapid increase (due to jetting). The importance of Taylor vortices development was seen with larger droplets formed in their absence; typically at low rotational speeds, narrow vessel diameters and more viscous continuous phases. It was concluded that the flow behaviour of each phase requires careful consideration to understand the likely formation mechanism(s) during operation. Across the pressure and viscosity ranges investigated, the dispersed phase flux ranged between 50 and 12,500Lm−2h−1 and pore activity was within the range of 0.5–2.7%

Food-grade Pickering emulsions stabilised with solid lipid particles

Aqueous dispersions of tripalmitin particles (with a minimum size of 130 nm) were produced, via a hot sonication method, with and without the addition of food-grade emulsifiers.</p

Case Report Short Stature in Chronic Kidney Disease Treated with Growth Hormone and an Aromatase Inhibitor

We describe an alternative strategy for management of severe growth failure in a 14-year-old child who presented with advanced chronic kidney disease close to puberty. The patient was initially treated with growth hormone for a year until kidney transplantation, followed immediately by a year-long course of an aromatase inhibitor, anastrozole, to prevent epiphyseal fusion and prolong the period of linear growth. Outcome was excellent, with successful transplant and anticipated complete correction of height deficit. This strategy may be appropriate for children with chronic kidney disease and short stature who are in puberty