Highly Soluble Glimepiride and Irbesartan Co-amorphous Formulation with Potential Application in Combination Therapy

One-third of the population of the USA suffers from metabolic syndrome (MetS). Treatment of patients with MetS regularly includes drugs prescribed simultaneously to treat diabetes and cardiovascular diseases. Therefore, the development of novel multidrug formulations is recommended. However, the main problem with these drugs is their low solubility. The use of binary co-amorphous systems emerges as a promising strategy to increase drug solubility. In the present study, irbesartan (IBS) and glimepiride (GMP), class II active pharmaceutical ingredients (API), widely used in the treatment of arterial hypertension and diabetes, were selected to develop a novel binary co-amorphous system with remarkable enhancement in the dissolution of both APIs. The phase diagram of IBS-GMP was constructed and co-amorphous systems were prepared by melt-quench, in a wide range of compositions. Dissolution profile (studied at pH 1.2 and 37°C for mole fractions 0.01, 0.1, and 0.5) demonstrated that the x_GMP = 0.01 formulation presents the highest enhancement in its dissolution. GMP went from being practically insoluble to reach 3.9 ± 0.9 μg/mL, and IBS showed a 12-fold increment with respect to the dissolution of its crystalline form. Infrared studies showed that the increase in the dissolution profile is related to the intermolecular interactions (hydrogen bonds), which were dependent of composition. Results of structural and thermal characterization performed by XRD and DSC showed that samples have remained in amorphous state for more than 10 months of storage. This work contributes to the development of a highly soluble co-amorphous drugs with potential used in the treatment of MetS.