Solubility and limiting activity coefficient of simvastatin in different organic solvents

Thermal Stability of Simvastatin under Different Atmospheres

“…1), which is traditionally prepared by direct alkylation of lovastatin, a similar statin obtained as a secondary metabolite from the filamentous fungus Aspergillus terreus. [7][8][9] Thermal stability studies of crystalline 10,11 and amorphous [11][12][13][14] SV from ambient temperature (∼298 K) to the melting point (∼412 K) 10,11,[15][16][17][18][19] are scarce, and, to the best of our knowledge, a detailed characterization of degradation products has not yet been reported. 20 This information is, however, very important for various aspects of SV use, such as the reliable definition of storage conditions or the development of new formulations that imply heating.…”

Enantiotropy of Simvastatin as a Result of Weakened Interactions in the Crystal Lattice: Entropy-Driven Double Transitions and the Transient Modulated Phase as Seen by Solid-State NMR Spectroscopy

“…One can deduce from these entropy changes that the extent of disorder is increased more significantly upon the phase transition from Form II to Form I. Still, the respective disorder needs to be limited only to certain molecular segments as long as the melting of Form I into liquid is accompanied by a significantly larger entropy change of 77.96 J·mol −1 ·K −1 [ 17 ].…”

Linking Aggregation in Solution, Solvation, and Solubility of Simvastatin: An Experimental and MD Simulation Study

“…The deviations are, however, unlikely to be due to polymorphism or solvate formation, because all measurements were performed above 275 K and, in this case, only form I should exist in equilibrium with the solution, as observed in this work. Moreover, because the solubility determinations by Nti-Gyabaah et al 21 relied on HPLC analysis, where the solution is not taken to dryness, the observed discrepancies can also not be justified by the occurrence of gels. This conclusion is further reinforced by the fact that the results by Aceves-Hernandez et al, 20 which were also based on HPLC analysis, and those by Yan et al, 22 which were obtained by the solid residue method, are in agreement with those reported in this work, where both the solid residue and UV−vis spectroscopy methods were used.…”

“…, for T ≈ 278−318 K. 21,22 The reliability of these data is difficult to assess, since the discrepancies found between the mole fraction solubilities determined in different laboratories reach ∼70% in the case of alcohols 20,21 and >100% for acetates. 21,22 The studies in ethanol and ethyl acetate performed here contributed to resolve these large discrepancies. The solubility in acetone, which appears to be the most convenient solvent to produce well-formed crystals, 16 is to the best of our knowledge reported for the first time.…”