[ Eq(Derivative(x1, t), (-(k1*x6 + k10*x8))*x1 + k6*x5),
  Eq(Derivative(x2, t), (-k2)*x5*x2 + k7*x6),
  Eq(Derivative(x3, t), (-(k3*x6 + k4*x8))*x3 + k8*x7),
  Eq(Derivative(x4, t), (-k5)*x7*x4 + k9*x8),
  Eq(Derivative(x5, t), (k1*x6 + k10*x8)*x1 - k6*x5),
  Eq(Derivative(x6, t), k2*x5*x2 - k7*x6),
  Eq(Derivative(x7, t), (k3*x6 + k4*x8)*x3 - k8*x7),
  Eq(Derivative(x8, t), k5*x7*x4 - k9*x8) ]