Compatibility studies between isosorbide mononitrate and selected excipients used in the development of extended release formulations.

Techniques of thermal and isothermal stress testing (IST) were used to evaluate the compatibility of isosorbide mononitrate (IMN) with selected excipients used in the development of extended release formulations. In the first phase of the study, differential scanning calorimeter (DSC) was used as a tool to detect any interaction. In the next phase, excipients defined in the prototype formula were tested for their compatibility with IMN using IST. Based on the results, cellulose acetate and MCC were found to show interaction with IMN. Results of IST demonstrated incompatibility between IMN and cellulose acetate. All the excipients defined in the prototype formula were found to be compatible with IMN. Using the excipients that were found to be compatible with IMN, formulations were optimized. The optimized formulation was found to be stable after 3 months of storage at accelerated stability conditions (40 degrees C and 75% RH). In conclusion, tools of DSC, and IST were successfully employed to evaluate the compatibility of IMN with selected excipients.