A binary mixture as equal mass ratio of bisoprolol fumarate and calcium hydrogen phosphate anhydrous was placed in an open quartz Petri dish and kept at 80[degrees]C for 72 hours.
The next step in this part of the experiment was to set the binary mixture of bisoprolol fumarate and calcium hydrogen phosphate exposed at a temperature of 80[degrees]C for 121 hours in an open Petri dish.
According to the previous experimental data obtained from the thermal degradation, another experimental setup was performed by introducing an equimolar amount of bisoprolol fumarate and calcium hydrogen phosphate. The binary mixture was subjected to stress conditions as presented in Section 2.5.3 (thermal degradation study B).
The result of the analysis showed the increase of the proportion for the unidentified impurity with RRT 0.95 with temperature, in combination with calcium hydrogen phosphate.