Solve simultaneous differential equations with imbedded functions and a parameter estimation - matlab

Question

The aim is to solve the below equations and plot m with time, i.e. dm/dt
k is unknown and needs to be estimated. For the parameter estimation, the below values for m versus t can be used. This is a dummy dataset, as I would like to get an idea if this problem is solvable. If needed, an initial guesstimate for k can be provided 6e-5 m2/bar.hr.
I have added an initial idea for the code, but not sure if my implementation of the A(H) and P(H) functions in the odes is correct. Also I need a way to estimate for k whilst fitting to the provided m vs t data.
function dydt = diffunTAR(~,y,k, h, A_H, P_H, rho_h, rho_o, wo)
dydt = zeros (2,1);
D = 2.64/1000 %mm/1000 to convert to m
r=D/2
rho_o = 1320 %kg/m3
rho_h = 1000 % kg/m3
wo=648/1000000 %weight component 1 in mg converted to kg
h= 1.5/1000 %1.5mm expressed in m
function A_H= pi*(D/2)^2 + (2/r)*(1+(rho_o/rho_h*y(2)))*(wo/rho_o);
end
function P_H = 5004.6*y(2) + 150.39;
end
%dV/dt
dydt(1)= (k/h)* function A_H* function P_H;
%dH/dt
dydt(2)= (rho_h*k/wo*h)*function A_H*function P_H;
end
tspan = linspace(0,21*24); %time in hrs for 21 days
y0 = [0 6.4800e-04];
[t,y]=ode45(#(t,y) diffunTAR(t,y, k, h, A_H0, rho_h, rho_o, wo), tspan, y0);
updated code after help
function dydt = diffunTAR(~,y,k,h,rho_h,rho_o,wo,L,r)
dydt = zeros (2,1);
%dV/dt
dydt(1)= k/h* AH * PH;
%dH/dt
dydt(2)= (rho_h*k/wo*h) * AH * PH;
AH
PH
function PH
(5004.6*y(2))+150.3;
end
function AH
pi*(r^2)+(2/r)*(1+(rho_o/rho_h*y(2)))*(wo/rho_o);
setInitialConditions (AH, 2*pi*(r)*L+2*pi*(r)^2);
end
end
D = 2.64/1000 %mm/1000 to convert to m
r=D/2
L = 10.6/100 %cm/100 to convert to m
wo=648/1000000 %weight osmotic tablets in mg converted to kg
k=6e-5 %guess for permeability
h= 1.5/1000 %1.5mm expressed in m
rho_o = 1320 %kg/m3
rho_h = 1000 % kg/m3
tspan = linspace(0,21*24); %time in hrs for 21 days
y0 = [0 6.4800e-04];
[t,y]=ode45(#(t,y) diffunTAR(t,y,k,h,rho_h,rho_o,wo,L,r), tspan, y0);