Figure 3: Nature Materials

Fig. 3: Fabrication and physicochemical properties of LuCI.

From: Therapeutic luminal coating of the intestine

Fig. 3

a, Schematic representations of the physical and chemical structures of sucralfate and LuCI. b, Reaction of sucralfate in high-concentration HCl solutions (0.3–0.6 N HCl in water) to form translucent water-immiscible translucent liquids (that is, paste) with different viscosities. c, Viscosity of the acidified sucralfate paste reacted in HCl solutions (0.3–0.6 N). The viscosity decreased with a higher concentration of the HCl. One-way ANOVA (n = 3 per arm, ***P < 0.0001). d, The number of hydroxy groups per number of aluminium (OH/Al) of LuCI fabricated using HCl solutions in different concentrations measured using a titration method. e, Reversible dehydration/hydration of LuCI to form a dried powder formulation that quickly forms a sticky paste in an aqueous environment. f, Viscosity of sucralfate and dehydrated LuCI in different simulated body fluids, which include simulated gastric fluid (SGF) (pH 1.0), simulated duodenal fluid (SDF) (pH 3.5) and simulated intestinal fluid (SIF) (pH 6.5). N/A, did not form paste. g, Change of rheological properties of dried LuCI powder rehydrated in different simulated gastrointestinal fluids. h, Relative barrier function of LuCI tested using glucose solutions in different simulated body fluids (120 g l–1). One-way ANOVA (n = 3 per arm, ***P < 0.0001). i, Schematic representation of complex coacervation in LuCI between anionic sucrose octasulfate and cationic LWM PAC. The two polyelectrolytes are bound via a strong electrostatic interaction to form a liquid that is insoluble in water. j, Change in viscosity of rehydrated LuCI in NaCl solutions with different ionic strengths. With increasing ionic strength, the viscosity of rehydrated LuCI pastes decreased due to partial masking of the charged groups in PAC and sucrose octasulfate of LuCI, and fully dissolved in NaCl solutions with a high ionic strength. This is a characteristic behaviour of complex coacervate systems. Sucralfate and LuCI fabricated using HCl solutions with concentrations lower than 0.3 N did not dissolve in NaCl solutions.