Square patch of length and with $50mm$

$=lnm$ thic.

density of medication $=A_1{P}_m,p_1,=100k{g}^2{m}^3$

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

Interphase rondition $)=(0)=(0$

$D_{AP}=0-1{10}^{-12}\frac{m^2}{s}$

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

a$)$ differential form of themass tronsfor equatm at st$.$ It for patch and skin side

b$)$ Fick's low and simplify.

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

d$)$ mass concontration $P_{A,S},lx=0||$

e$)$ total mass conc difference between the patch and the skin. Q Asp P P$,$ P$,$ i $-P_{\text{A}\text{i}\text{s}}$ coefficient $D_{AP},D_{AS}$ i LP$,$LS if $P_{\text{A}\text{i}\text{s}\text{i}}$ is the uniform mass cenc. Of $A$ in the $sk$

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