A polymer sphere of $0\mathrm{.}2$ cm radius, containing a therapeutic protein at a concentration of $0\mathrm{.}1$ mg$/$ml$,$ is introduced into a large volume of buffer. The protein diffuses from the polymer into the buffer. The volume of the buffer is large enough so that the protein concentration can be considered zero. The diffusion coefficient of the protein is $5$ x $10-10$ cm$2/$s$.$ The aim is to determine the concentration profile in the steady state, and it can be assumed that at a dimensionless radius of $0\mathrm{.}8$ the protein concentration of the sphere reaches $0\mathrm{.}5\%$ of the initial concentration in the polymer.