The present invention concerns new pharmaceutical formulations based on aqueous colloidal suspensions for sustained release of active ingredient(s) - AI - in particular, protein(s) and peptide(s), as well as the applications, especially therapeutic, of these formulations. This formulation comprises an aqueous colloidal suspension with low viscosity based on micrometric particles of amphiphilic polymer PO that is biodegradable, hydrosoluble and carrying hydrophobic groups (HG) - alpha-tocopherol- and ionizable hydrophilic groups (IG) - Glu -, ionized at least in part, said particles being suitable for spontaneously combining non-covalently with an AI at pH = 7.0 under isotonic conditions and with a size between 0.5 and 100 µm. This suspension contains multivalent ions (Mg++) with a polarity opposite that of IH groups of the PO, the ratio r fulfilling the formula (A) where - n is the valence of said multivalent ions - [MI] is the molar of multivalent ions, [IG] is the molar concentration of ionizable groups IG, is between 0.3 and 10.
