The invention relates to a stable pharmaceutical compositions and a process for the preparation of the same, which is used for the prevention and treatment of osteoporosis and osteoarthritis comprising a combination of a therapeutically effective amount of Calcitriol a therapeutically effective amount of elemental Calcium a therapeutically effective amount of elemental Zinc along with suitable pharmaceutically acceptable excipients wherein Calcitriol is present in a dosage unit that physically separates it from other therapeutic components.