Degradation in basic conditions
The drug was found to be relatively stable in basic degradation conditions as compare to acidic degradation conditions. OP was observed to be degraded to about 95% in basic conditions, when
treated with 0.1N NaOH as well as with 1.0N NaOH for 1 h at room temperature (≈25ºC). The degradation rate constant and half life for OP in 0.1N NaOH were 0.001121% min-1 and 618.6 min,
respectively. The drug was following linear degradation pattern in the case of 0.1N NaOH. The degradation rate constant and half life for OP in 1.0N NaOH were 0.01033 % min-1 and 67.13 min,
respectively. The degradation pattern was one-phase exponential decay in the case of 1.0N NaOH as shown in the Figure 3b.