function dz = model(t, z, c)
              dz(1) = ..
              dz(2) = ..

%p0 = Initial Value of Parameters
A = [];
b = [];
Aeq = [];
beq = [];
nlcon  = ode45(@(t,z)model(t,z,x), tSpan, z0); % Is this correct?
p = fmincon(@objective,p0,A,b,Aeq,beq,lb,ub,nlcon);

function cost = objective(c,expZ,tSpan,z0)
sol = ode45(@(t,z)model(t,z,c), tSpan, z0); % Is this step required?
ModelZ = sol(end,:)%  the solutions obtained from model at end point of tSpan
cost = ModelZ-expZ; %expZ contains steady state values of z1,z2..