Preformulation is an important stage of the rational development of pharmaceutical dosage forms where several features should be evaluated such as compatibility between drug and excipients, stability, storage conditions and miscibility, especially for liquid and semi-solid formulations . Miscibility is related to the identity of excipients and to their concentrations. Excess amounts of drug in lipid-core DDS such as NLC and solid lipid nanoparticles (SLN) can result in the expulsion of the API from the matrix and, thus, formulation instability . Beyond the compounds themselves, their proportions and interactions are crucial to understand the miscibility.