The invention relates to process for coating a solid, water-insoluble particulate matter, with a metal oxide comprising: (a) contacting the solid water-insoluble particulate matter with a cationic additive in an aqueous medium to obtain a dispersion of said particulate matter having a positive zeta potential； (b) coating the solid water-insoluble particulate matter by precipitation of a metal oxide salt onto the surface of the particulate matter, forming a metal oxide layer thereon； and (c) aging said coating layer. The invention further relates to coated particulate matter obtained by the process and to compositions comprising solid, water-insoluble particulate matter, coated by a metal oxide layer, the particulate matter being a dermatological active agent or a pesticide. The invention additionally relates to methods of treating a surface condition in a subject using compositions comprising solid, water insoluble dermatologically active agent, coated by a metal oxide layer.
