Solid solution polymorphs afford two highly soluble co-drug forms of tolbutamide and chlorpropamide

The search for solid solutions of class-two insulin secretagogues, tolbutamide and chlorpropamide, reveals a rare case of monotropic polymorphism for the mixed crystals. At any stoichiometry, two crystal forms are isolated that are kinetically stable at room temperature from a few months to over a year. Dissolution tests certify the solubility advantage of the solid solutions over the pure drugs as well as their physical mixture, suggesting a potential application as a highly soluble co-drug formulation. Tolbutamide and chloropropamide form two co-drug solid solutions that show a rare case of monotropic polymorphism at any composition. Both forms are kinetically stable and with faster dissolution rate than the pure drugs.

Automated summary

The search for solid solutions of class-two insulin secretagogues tolbutamide and chlorpropamide reveals a rare case of monotropic polymorphism for the mixed crystals. The solid solutions exhibit superior solubility advantage over pure drugs, suggesting potential applications as highly soluble co-drug formulations.