Thermal Decomposition Kinetics of Ibuprofen and Naproxen Drugs Incorporated in Cellulose Acetate Matrices

The suitable combination of active pharmaceutical molecules and polymer matrices is a key factor for the development of systems for controlled release. The proper choice of the bioactive species/polymer pair depends strongly on the dispersion capacity and the interaction established between the bioactive species in the polymer matrix. Solid dispersions composed of cellulose acetate (CA) with either naproxen (NPX) or ibuprofen (IBF) are separately evaluated by Thermogravimetry Analysis in decomposition kinetics studies. Ozawa's isoconversional method is used to calculate the Estimated Activation Energy (Eα) values. Eα indicated strong intermolecular interactions between the drugs and the CA matrix that is responsible for the increase in thermal stabilities of the drugs when they are combined with the polymer matrix. Differential scanning calorimetry analyses and solubility parameters showed CA has better compatibility with NPX compared to IBF. Therefore, this work brings exciting information for systems based on CA. Moreover, the approach is promising for the development of new materials, especially those of pharmaceutical relevance.