Page 8 - controlled drug delievery
P. 8
Dose Calculation
The total amount of drug (Dt) in the MR dosage form consists of:
Dt = Di +Dm
Di: intial priming dose (released rapidly)
Dm: maintainance dose (slowly released, ideally at zero order rate)
Di = Cp . Vd (mg)
Cp : required plasma drug concentration (µg/L)
Vd : Volume of distribution (L)
During the maintainance phase
K0m (mg/h) = Rate in = Rate out = Cp .ClT
Rate out: rate of drug elimination from the body (mg/hr)
ClT : total drug clearance = volume of body fluids cleared from the drug/hr (L/hr)
Dm = K0m . Td (mg)
Td: time desired for sustained release from one dose (hrs)
