Kinetics of drug decomposition. Part 60. Thermal decomposition of the mixture of aminophenazone, allobarbital and adiphenine hydrochloride in the solid state.

Kinetics of decomposition of a mixture of aminophenazone, allobarbital and adiphenine hydrochloride has been examined using accelerated testing at elevated temperatures (333-353 K). The reaction order, rate constants and activation parameters (Q10 degrees, EA, delta H#, delta S#, delta G) have been determined and compared for each component, in the presence of each component of the mixture and in the presence of two components of the mixture. The effect of individual components of the mixture on the rate of decomposition of the other components has been observed, the value of this effect has been determined using the rate constants obtained. The rate constants and times t10% for room temperature were calculated. The "shelf-life time" (t10%) was calculated from accelerated testing data at elevated temperature and compared with that obtained for Vegantalgin ragées in the mixture studied at 293 K.