A Solid-State Approach to Enable Early Development Compounds: Selection and Animsal Bioavailability Studies of an Itraconazole Amorphous Solid Dispersion

Abstract

A solid-state approach to enable compounds in preclinical development is used by identifying an amorphous solid dispersion in a simple formulation to increase bioavailability. Itraconazole (ITZ) was chosen as a model crystalline compound displaying poor aqueous solubility and low bioavailability. Solid dispersions were prepared with different polymers (PVP K-12, K29/32, K90; PVP VA S-630; HPMC-P 55; and HPMC-AS HG) at varied concentrations (1:5, 1:2, 2:1, 5:1 by weight) using two preparation methods (evaporation and freeze drying). Physical characterization and stability data were collected to examine recommended storage, handling, and manufacturing conditions. Based on generated data, a 1:2 (w/w) ITZ/HPMC-P dispersion was selected for further characterization, testing, and scale-up. Thermal data and computational analysis suggest that it is a possible solid nanosuspension. The dispersion was successfully scaled using spray drying, with the materials exhibiting similar physical properties as the screening samples. A simple formulation of 1:2 (w/w) ITZ/HPMC-P dispersion in a capsule was compared to crystalline ITZ in a capsule in a dog bioavailability study, with the dispersion being significantly more bioavailable. This study demonstrated the utility of using an amorphous solid form with desirable physical properties to significantly improve bioavailability and provides a viable strategy for evaluating early drug candidates.