The invention relates to: a controlled-release pharmaceutical formulation comprising at least one active ingredient dispersed in matrix comprising at least one slow-release excipient comprising association at least of one glycogen and at least of one alginate with alkaline-earth metal salts, and preparation process thereof. The invention also relates to: slow-release excipient comprising association at least of one glycogen and at least of one alginate with alkaline-earth metal salts, preparation process thereof, and application thereof at slow-release pharmaceutical formulations preparation.