Kinetics of the decomposition of racemic ibuprofen crystals were studied
by non-isothermal analysis. Thermogravimetric analysis revealed that ibuprofen
is thermally stable up to 152.6°C and the initial loss of mass was due to
evaporation only. Activation energy, pre-exponential factor, activation entropy
and Gibbs free energy for the decomposition of ibuprofen were determined using
the integral method of Coats-Redfern (CR). Geometrical contraction models were
found to be the best fits. The Arrheinus equation for the thermal decomposition
of ibuprofen is k = (1.1 × 107) e–79125/RT sec–1.
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