The fitted curves generated by the nonlinear regression models
shown in Figs. 3 and 4 represent the kinetic release of D3 in simulated
intestinal fluid (SIF) at pH 6.8, with or without pancreatin,
respectively. At the end of the six hours of experiment, over 90%
of the free D3 was degraded, probably due to oxidation and free
radical formation, as explained above. However, Fig. 3A shows that
the blg/Lyso microspheres provided some protection to D3 for up to
four hours; following that, the release and/or degradation rate was
not statistically different from that of the free vitamin, as shown by
the scale on the equivalence test