Bio pharmaceutics

Maintainance dose calculation

1. Presentation on Maintenance dose Prepared by: Imran Ahammad Chowdhury

2. Maintenance Dose Definition: Maintenance dose is the dose of a drug administered just to replace the drug that has been eliminated from the body during the dosing interval , so as to maintain the steady state drug in the body. It is denoted by Q. Derivation of Maintenance dose: The maintenance dose range can be calculated by the familiar plateau principle equation.

3. The equation is: Q = ---------------------(I) Where, Q = maintenance dose; = concentration of drug at steady state level; = elimination rate constant; = volume of distribution. Equation (1) can be written as follows: Q = [ since = effective drug concentration ] But = Total amount of drug in the body at (EDC) level, i.e. So that, Q = --------------------(II)  

4. Alternatively, since is the total clearance Q = (EDC)----------------(III) So the equation shows that , the maintenance dose rate will have to be higher , if is higher. From this equation can be calculate the maintenance dose of the drug. THE END