- #1
StheevilH
- 13
- 0
Okay I found some references and the equation I am after is
Q = 2 * C * (D * t / ∏)^(1/2)
where Q is the weight of drug released per unit area (hence unit is mg/cm^2)
C is the initial drug concentration
D is the diffusion coefficient (unit of cm^2 min^-1)
and t is release time in min.
What I am not sure about is the units.
Logically the concentration of drug would be in g/L.
but when I merge all the units together, I get something else.
This is my working.
The units on the right hand side should equals to Q.
= 2 (constant) * C (g/L) * [D (cm^2 * min^-1) * t (min) / ∏ (constant)]^(1/2)
only considering units (ie discard constants)
= [g * cm^[2*(1/2)] * min^(1/2)] / [L * min^(-1 * 1/2)]
= g * cm * min^(1/2) / L * min^(-1/2)
= g * cm * min^(1/4) / L
which does not equals to unit of Q (mg/cm^2).
The units given are all correct but is there something I am missing here?
Breaking rules of powers perhaps?
Thank you!
Q = 2 * C * (D * t / ∏)^(1/2)
where Q is the weight of drug released per unit area (hence unit is mg/cm^2)
C is the initial drug concentration
D is the diffusion coefficient (unit of cm^2 min^-1)
and t is release time in min.
What I am not sure about is the units.
Logically the concentration of drug would be in g/L.
but when I merge all the units together, I get something else.
This is my working.
The units on the right hand side should equals to Q.
= 2 (constant) * C (g/L) * [D (cm^2 * min^-1) * t (min) / ∏ (constant)]^(1/2)
only considering units (ie discard constants)
= [g * cm^[2*(1/2)] * min^(1/2)] / [L * min^(-1 * 1/2)]
= g * cm * min^(1/2) / L * min^(-1/2)
= g * cm * min^(1/4) / L
which does not equals to unit of Q (mg/cm^2).
The units given are all correct but is there something I am missing here?
Breaking rules of powers perhaps?
Thank you!