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.