A two$-$layered controlled drug release device is to be designed to deliver a burst of drug immediately upon implantation and then a sustained release of drug for an additional two days. The initial burst should release $200mg(M_{bo})$ and then an additional $600mg(M_{so})$ should be released over the next two days. The device is layered as diagrammed here:

burst layen

sustained release

layer

These parameter definitions apply:

$\backslash$table$[[A,c{m}^2,$area of device$],[a,mmda{y}^{-1},$erosion rate of sustained release layer$],[C_{bo},mgc{m}^{-3},\backslash$table$[[$concentration of drug in burst layer$]]],[C_{so},mgc{m}^{-3},$concentration of drug in sustained release layer$],[d_b,mm,$thickness of burst layer$],[d_s,mm,$thickness of sustained release layer$],[M_b,mg,$mass of drug in burst layer$],[M_{bo},mg,$mass of drug in burst layer initially$],[M_s,mg,$mass of drug in sustained release layer$],[M_{so},mg,$mass of drug in sustained release layer initially$],[t,$day,time after device implantation$]]$

The area of the two layers must be the same.

$($a$)$ The available options for the burst layer and the sustained release layer are detailed in the tables below. Suggest a design $($pick one option for the burst layer and one option for the sustained released layer$)$ that meets the requirements specified above.

$\backslash$table$[[$Table $1.$ Options,burst layer design.$],[,(mm),(m\frac{g}{c}{m}^3),(c{m}^2),,,],[$Option$,d_b,C_{bo},A,,,],[$B$,0\mathrm{.}6,333,10,,,],[$C$,0\mathrm{.}8,417,,,,],[$D$,0\mathrm{.}8,500,,,,],[$E$,1\mathrm{.}2,333,,,,]]$

$\backslash$table$[[$Table $2.$ Options $-$ sustained release layer design.$],[,(mm),(m\frac{g}{c}{m}^3),(c{m}^2),$ day