There are a few reasons why it is important to add only one third of the diluent to the medication bottle at first and save the remaining two-thirds until after the medication has been vigorously shaken.
First, adding only a small amount of diluent at first allows you to better control the final volume of the solution. This is important because the final volume of the solution will determine the concentration of the medication, and it is important to ensure that the solution has the correct concentration.
Second, adding only a small amount of diluent at first allows you to more easily mix the medication and diluent together. This is because adding all of the diluent at once can make it difficult to mix the two substances together thoroughly. By adding only a small amount of diluent at first and then shaking the bottle vigorously, you can ensure that the medication and diluent are well mixed.
Finally, adding only a small amount of diluent at first can help to prevent the solution from foaming or frothing. This is because when a medication is mixed with a diluent, it can cause the solution to foam or froth, which can make it difficult to accurately measure the final volume of the solution. By adding only a small amount of diluent at first, you can help to prevent the solution from foaming or frothing, which can make it easier to accurately measure the final volume of the solution.
