IV infusion can't bring the steady state concentration immediately and it requires at least 4.32 half-lives to achieve 95% of required Css. On the other hand, IV bolus administration can achieve steady state immediately but it can't be maintained as the drug is eliminated from the body. So, in order to achieve steady state immediately which is then maintained for the desired time period, a combination of IV bolus dose is given as loading dose along with IV infusion. For a particular drug, steady state concentration depends on the infusion rate and it can be calculated as the ratio of rate of infusion to clearance of the drug. Similarly, loading dose is the ratio of rate of infusion to elimination rate constant.

0:00 Introduction
0:07 Steady state concentration
2:40 Solution to Working example 1
5:05 Solution to Working example 2
7:13 Solution to Working example 3
9:53 Calculation of loading dose