Simple pharmacokinetics with VBA

Here you find a simple model of pharmacokinetics with VBA:

Private Sub pharmacokinetic()

Dim Ka, F, A0, K, V, t, Tmax, cmax, t12 As Double

Ka = InputBox("Ka costant of absorption h-1", "input data")

K = InputBox("K costant of elimination h-1", "Input data ")

V = InputBox("Volume liter/kg", "input data")

F = InputBox("bioavailability", "input data")

A0 = InputBox("dose mg ", "input data")

dt = InputBox("interval of time h", "Input data ")

t = 0

j = 0

Do

j = j + 1

t = t + j * dt

c = F * A0 * Ka / V / (Ka - K) * (Exp(-K * t) - Exp(-Ka * t)) 'concentration profile for dosing oral A0

Cells(j, 1) = t

Cells(j, 2) = c

Loop While j < 8

r = Ka / K

Tmax = 1 / (Ka - K) * Log(r)

cmax = F * A0 / V * Exp(-K * Tmax) 'maximum concentration at tmax

t12 = Log(2) / K 'half life of drug

Cells(1, 10) = Tmax

Cells(1, 11) = cmax

Cells(1, 12) = t12

End Sub