Equilibrium solubility using shake-flask method of JM-20: a synthetic molecule with neuroprotective action

Abstract

Context: Drug solubility is one of the most important physicochemical properties for the development of new pharmaceutical products, which, in our study, is a new synthetic molecule, which has been shown to have a potential neuroprotective effect in rat. Aims: To evaluate the equilibrium solubility of JM-20 within the physiological pH range and aqueous chemical stability. Methods: It was performed at pH 1.2, 4.5 and 6.8 at 37 ± 0.5°C for 27 h by the method of the saturated flasks. HPLC and FTIR were used for the study of aqueous stability and to evaluate the molecular structure of the non-ionized fraction by DSC/TGA. Results: Concentrations calculated at pH 1.2 were higher than at pH 4.5 and pH 6.8. A retention time greater than pH 4.5 and 6.8 after 24 h was detected in the aqueous stability study at pH 1.2, in addition to other peaks in these chromatograms. Analyses by FT-IR and DSC/TGA demonstrated the absence of polymorphism in the dissociated fraction of saturated solutions. Conclusions: The JM-20 presented at 6 hours its maximum steady state of solubility, being inferior to pH 4.5 and 6.8. It is corroborated by the qualitative analysis by HPLC, that the compound is chemically unstable from 24 h to pH 4.5 and 6.8. By FT-IR and DSC/TG it was elucidated that the fractions of the molecule not dissociated, did not undergo structural changes in it, and it is inferred that there is no polymorphism.

Keywords

• polymorphs
• saturation shake-flask method
• solubility