Composite silica-hyaluronic acid (Si-HA) micro particles were synthesized, employing tetraethyl orthosilicate (TEOS) in the presence of linear HA and a crosslinker, divinyl sulfone (DVS) via a water-in-oil microemulsion polymerization technique. Porous HA (PHA) hydrogel particles were generated after removal of silica particles upon treatment of HA composites with hydrofluoric acid (FIF). Furthermore, HA particles were quaternized (QHA) by chemical modification using 3-chloro-2-hydroxypropyl trimethyl ammonium chloride as a quarternization agent. The size of HA based particles were ranged between 1.26 and 2.95 mu m. The PHA particles have a surface area of 2.7 m(2)/g confirmed by the surface area measurements. Modified HA particles were used in the absorption and release studies of two model drugs in PBS, trimethoprim (TMP) and sodium diclofenac (SDF) which are acidic and basic in nature, respectively. The ability to control the size, charge and porosity of the HA particles which showed almost linear drug release profiles. (C) 2012 Elsevier Inc. All rights reserved.