Compositions for oral administration and processes of preparing the same are described. In particular, compositions in the form of bilayer tablets including B vitamins for modified delivery are described. The bilayer multi-B vitamin tablets offer immediate release of a first set of B vitamins, such as riboflavin (B2) and cyanocobalamin (B12) followed by controlled release of a second set of B vitamins, such as folic acid, biotin, niacinamide (B3), pyridoxine (B6), pantothenic acid (B5) and thiamine (B1).說明了用於口服給藥的組成物及其製備方法。尤其,說明了包括B族維生素之呈雙層錠劑形式以供修飾遞送的組成物。該雙層複合B族維生素錠劑提供了一第一組B族維生素,例如核黃素(B2)與氰鈷胺素(B12)之立即釋放,接著一第二組B族維生素,例如葉酸、生物素、菸鹼醯胺(B3)、吡哆素(B6)、泛酸(B5)與硫胺素(B1)之控制釋放。