CMC (400–800 cps, 2% solution at 20°C), HA (Mw 400,000–800,000) and HPMC (1390 cps, 2% solution at 20°C) were purchased from Abaran Materias Primas (Madrid, Spain). Timabak (TB) was purchased from Thea (Madrid, Spain); Timoftol (TF) and Timolol Sandoz (TL) were supplied by Frosst (Madrid, Spain). TM powder was provided by Sigma-Aldrich (Madrid, Spain). Phosphate-buffered saline (PBS), rendered isotonic with NaCl (pH 7.2), was prepared with ultrapure water (milliQ; Millipore Iberica SA, Madrid, Spain).