Square patch of length and with $50mm$

$x=\frac{\text{h}\text{a}\text{t}(P{)}_{BD}}{}$

$=lnn$ thic $.$

density of medication $=A_1{P}_m,p_1=100k\frac{g}{m^3}$

partion coefficient of $Q=0\mathrm{.}5$

interphase rondition $)=(0)=(0$

$D_{AP}=0\mathrm{.}1{10}^{-12}\frac{m^2}{s}{D}_{AS}=0\mathrm{.}2{10}^{-12}\frac{m}{s}$

Das $=0\mathrm{.}2{10}^{-12}\frac{m^2}{s}$

a$)$ differential form of the mass tronsfor equation at st$.$jl for patch and skin side

b$)$ Fick's low and simplify.

C$)$ mass flux $n_{AP}$ it $)=(0$

d$)$ mass concontration $P_{A,S},k=0||$ coefficient DAP, Das ilPils if PAisi is the uniform mass cenc. Of $A$ in the sk

f$)$ thickness of the skin that all the diag is consimad.