Pharmaceutical preparations, namely, a drug delivery system comprising polymer-based oral capsules for the modified release of a wide variety of therapeutic agents for treating cystic fibrosis, iron irregularities, diarrhea, constipation, short bowel syndrome, asthma, psoriasis, ulcerative colitis, celiac disease, tumors, irritable bowel diseases, environmental enteropathy disorder, atopic dermatitis, allergic rhinitis, Crohn's disease, hemochromatosis, iron deficiency anemia, and wounds