A transdermal delivery system was designed to release a drug through a rate$-$controlling membrane. The drug concentration in the reservoir was saturated and kept at $5$ mcg$/$mL$.$ The membrane$/$reservoir partition coefficient is $100,$ and drug diffusion coefficient in membrane is $5$ x $10^-6$ cm$^2/$sec$.$ The membrane thinness is $1$ mm$,$ and its cross$-$sectional area is $10$ cm$^2.($Assume sink condition without lag time.$)$ Calculate the Permeability coefficient $($cm$/$s$)$: $-$ Continue from the question above, calculate the rate of diffusion$($mcg$/$s$)$: $-$ Continue from the question above, calculate for $24$ hours of constant controlled drug release, how much drug can be released across the membrane $($mcg$)$: