Using differential ricati equation for computing control in ode45

I have generated differential riccati equation using method mentioned at https://www.mathworks.com/matlabcentral/answers/94722-how-can-i-solve-the-matrix-riccati-differential-equation-within-matlab.

However now I want to use this differential riccati equation to compute control using ode45. I know u = -R\B'*P*x but I am not sure how to select the appropriate P in this case, since time is not certain in ode45