Relative bioavailability of ertugliflozin tablets containing the amorphous form versus tablets containing the cocrystal form.

OBJECTIVES: Ertugliflozin is a selective sodium-glucose cotransporter 2 inhibitor approved for the treatment of type 2 diabetes in adults. In its natural form, ertugliflozin exists as an amorphous solid with physicochemical properties that prevent commercial manufacture. The commercial product was developed as an immediate-release tablet, consisting of an ertugliflozin-L-pyroglutamic acid cocrystal of 1 : 1 molar stoichiometry as the active pharmaceutical ingredient. The ertugliflozin cocrystal may partially dissociate when exposed to high humidity for extended periods, leading to the formation of free amorphous ertugliflozin. Therefore, a study was conducted to estimate the relative bioavailability of ertugliflozin when administered in non-commercial formulated tablets containing the amorphous form vs. the cocrystal form. MATERIALS AND METHODS: In this phase 1, open-label, randomized, two-period, two-sequence, single-dose crossover study, 16 healthy subjects received 15 mg immediate-release ertugliflozin in its amorphous and cocrystal forms under fasted conditions, separated by a washout period of ≥ 7 days. Blood samples were collected post-dose for 72 hours to determine plasma ertugliflozin concentrations. RESULTS: Mean ertugliflozin plasma concentration-time profiles were nearly superimposable following administration of the amorphous and cocrystal forms. The 90% confidence intervals for the geometric mean ratios for AUCinf and Cmax were wholly contained within the pre-specified criteria for similarity (70 - 143%), as well as the acceptance range for bioequivalence (80 - 125%). Most adverse events were mild in intensity. CONCLUSION: Any dissociation of ertugliflozin to the amorphous form that occurs in tablets containing the cocrystal will not have any clinically meaningful impact on the oral bioavailability of ertugliflozin.

General principles of pharmaceutical solid polymorphism: a supramolecular perspective.

The diversity of solid-state forms that an active pharmaceutical ingredient (API) may attain relies on the repertoire of non-covalent interactions and molecular assemblies, the range of order, and the balance between entropy and enthalpy that defines the free energy landscape. It is recognized that crystallization is associated with molecular recognition events that lead to self-assembly, and that pharmaceutical function and thermodynamic stability can be altered with a slight change in the interacting molecules or their molecular network motifs. Our current understanding of pharmaceutical solids in terms of molecular recognition and complementarity provides new insights into the design and function of single and fully miscible, multiple-component solids with varying degrees of order, from amorphous to crystalline states, and in this way is leading the path to supramolecular pharmaceutics. This review describes pharmaceutical solids in terms of supramolecular chemistry and crystal engineering concepts, and discusses the events that control crystallization and solid phase transformations.

PH-induced nanosegregation of ritonavir to lyotropic liquid crystal of higher solubility than crystalline polymorphs.

Birefringent spherical vesicles of ritonavir (RTV) are formed by increasing the pH of aqueous solutions from 1 to 3 or to 7 and by addition of water to ethanol solutions at room temperature. Increasing the pH creates supersaturation levels of 30-400. Upon this change in pH, the solutions become translucent, implying that some kind of RTV assembly was formed. Small spherical vesicles of narrow size distribution are detectable only after a few hours by optical microscopy. The vesicles show similar X-ray diffraction patterns and differential scanning calorimetry (DSC) behavior to amorphous RTV prepared by melt-quenching crystalline RTV. Examination by polarized optical microscopy suggests that these are lyotropic liquid crystalline (LLC) assemblies. Small-angle X-ray scattering and synchrotron X-ray diffraction further support the presence of orientational order that is associated with a nematic structure. RTV self-organizes into various phases as a result of the supersaturation created in aqueous solutions. The LLC vesicles do not fuse but slowly transform to the polymorphs of RTV (in days), Form I and finally Form II. Amorphous RTV in aqueous suspension also undergoes a transformation to a mesophase of similar morphology. Transformation pathways are consistent with measured dissolution rates and solubilities: amorphous > LLC >> Form I > Form II. The dissolution and solubility of LLC is slightly lower than that of the amorphous phase and about 20 times higher than that of Form II. RTV also self-assembles at the air/water interface as indicated by the decrease in surface tension of aqueous solutions. This behavior is similar to that of amphiphilic molecules that induce LLC formation.