The invention relates to process for coating a solid, water-insolubleparticulate matter, with a metal oxide comprising: (a) contacting the solidwater-insoluble particulate matter with a cationic additive in an aqueousmedium to obtain a dispersion of said particulate matter having a positivezeta potential； (b) coating the solid water-insoluble particulate matter byprecipitation of a metal oxide salt onto the surface of the particulatematter, forming a metal oxide layer thereon； and (c) aging said coating layer.The invention further relates to coated particulate matter obtained by theprocess and to compositions comprising solid, water-insoluble particulatematter, coated by a metal oxide layer, the particulate matter being adermatological active agent or a pesticide. The invention additionally relatesto methods of treating a surface condition in a subject using compositionscomprising solid, water insoluble dermatologically active agent, coated by ametal oxide layer.
