Development and evaluation of Thymol/PVP solid dispersion: comparative physicochemical properties and bronchodilation activity

Asthma is a chronic respiratory disease characterized by airway inflammation. Thymol is a monocyclic monoterpene that commonly occurs in the essential oils of the Lamiaceae family and exhibits a bronchodilatory effect. In this study, polyvinylpyrrolidone (PVP) was used as a polymeric carrier for thymol to enhance its physicochemical properties. A thymol-PVP solid dispersion was successfully prepared and evaluated. Differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD) analyses indicated the transformation of thymol from its crystalline form to an amorphous form. Dissolution studies showed enhanced release of thymol from the formulation compared to pure thymol. The formulation produced a significantly greater tracheal relaxation compared to thymol alone, most likely due to its rapid dissolution. This study showed that improving the physicochemical properties of thymol through formulation may provide a promising and better therapeutic approach in the development of drugs to address respiratory disorders such as asthma.