Formulations for enteric delivery of therapeutic agents

A method for orally administering a therapeutic agent, the method comprising

• providing a formulation comprising the therapeutic agent, and
• orally administering the formulation to a subject in need thereof,
• wherein the formulation comprises a plurality of nanoparticles, the nanoparticles comprising a pH-sensitive polymer and a therapeutic agent or a combination of therapeutic agents, the therapeutic agent having a molecular weight from about 1000 to about 10000 Daltons, wherein the polymer is insoluble at acidic pH and soluble at neutral or alkaline pH and wherein the pH-sensitive polymer is selected from the group consisting of a copolymer of methacrylic acid and an acrylic or methacrylic ester, methacrylic acid-methylmethacrylate copolymer, methacrylic acid-ethyl acrylate copolymer, a cellulose derivative, cellulose acetate phthalate, cellulose acetate succinate, cellulose acetate trimellitate, hydroxypropyl methylcellulose phthalate, hydroxypropyl methylcellulose acetate succinate, and combinations thereof;
• wherein a suspension of the nanoparticles is made by a process comprising dissolving the therapeutic agent and suspending the pH-sensitive polymer in an aqueous medium in which the therapeutic agent is soluble and associating the dissolved therapeutic agent and the suspended pH-sensitive polymer in the aqueous medium by adjusting the pH between about 5.5 and about 8 so as to form nanoparticles having a mean particle size of 50 nm or less with mixing alone and without the use of sonication, heat, or any other input of external energy;
• wherein the therapeutic agent and pH-sensitive polymer do not dissociate from the nanoparticles at acidic pH, with the proviso that the nanoparticles do not contain two different polymers, one polymer present in a core structure and the other polymer present in a shell structure and associated with the therapeutic agent.