Ricerc@Sapienza

The effects that an increase of environmental pH has on the triple helix of scleroglucan (Sclg)
and on the Sclg/borax hydrogel are reported. Rheological experiments show that the hydrogel is less
sensitive to pH increase than Sclg alone, while at pH = 14 a dramatic viscosity decrease takes place for
both systems. This effect is evidenced also by the reduced water uptake and anisotropic elongation
detected, at pH = 14, by the swelling behaviour of tablets prepared with the Sclg/borax system.

pH-sensitive nonionic surfactant vesicles (niosomes) by polysorbate-20 (Tween-20) or polysorbate-20 derivatized by glycine (added as pH sensitive agent), were developed to deliver Ibuprofen (IBU) and Lidocaine (LID). For the physical-chemical characterization of vesicles (mean size, size distribution, zeta potential, vesicle morphology, bilayer properties and stability) dynamic light scattering (DLS), small angle X-ray scattering and fluorescence studies were performed.