Partial Differential Equation

I need to solve for Ca, for the for the following partial derivative equation.

where Dab is a variable representing Drug diffusivity

and r is the radius of a scaffold used for drug diffusivity

and Ca which represents the concentration of the Drug

Solve for Ca ------ Ca

Cylindrical:l I (rdirection), Unsteadystate, with generation > Start with general mass transfer equation: 091 (1 0 06A 1 626A OZCA) =D (1" )+ + + R at AB 1" 6r or r 2662 622 A , Cancel out terms not relevant to the problem: 66 ()66A 1 62A =D (r) + 13 AB (Tar r2 692+ Steady State No transfer along 9 N0 transfer along z