They may also comprise mineral or organic fillers such as silica or clays, binders such as vinylpyrrolidone, oils or waxes, polyalkylene glycols or polyalkylene glycol derivatives, lubricants, for instance polyol stearates or alkali metal or alkaline-earth metal stearates, and also colorants or matting agents, for instance titanium oxides, each of these additives possibly being present at a concen