The use of oil-in-water emulsions for controlled lipid release is of increasing relevance for poorly water-soluble drugs and gained major interest for treating obesity. In this conceptual study, we highlight the relevance of interfacial rheology combined with neutron reflectivity measurements in designing emulsion systems with stimuli-responsive biopolymers to generate specific lipid digestion kinetics. Stimuli-responsive biopolymers change their mechanical and emulsion stabilization properties at specific physicochemical conditions present in the human environment. We used whey protein isolate because of its sensitivity to pH, methylcellulose because of its sensitivity to temperature, and nanocrystalline cellulose because of its sensitivity to ionic strength [1]. The biopolymer-dependent effects on gastric lipolysis and gastric emulsion structuring, more precisely droplet size and viscosity, during digestion and resulting pancreatic lipolysis was investigated in-vitro. In order to establish a valid in-vitro/in-vivo correlation, emulsion structures formed during gastric digestion in-vitro were validated by in-vivo magnetic resonance imaging experiments visualizing emulsion structuring and stomach emptying [2]. In parallel, in-vivo lipid sensing and release patterns were investigated by repetitive measurements of measuring plasma triglycerides and cholecystocinin concentrations in healthy human volunteers. By taking all relevant physicochemical and mechanical processes of human digestion into account, we are thus able to propose design concepts for food and drug delivery systems [3].
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