Development of a small-scale spray-drying approach for amorphous solid dispersions (ASDs) screening in early drug development

Abstract

The present study details the development of a small-scale spray-drying approach for the routine screening of amorphous solid dispersions (ASDs). This strategy aims to overcome the limitations of standard screening methodologies like solvent casting and quench cooling to predict drug-polymer miscibility of spray-dried solid dispersions (SDSDs) and therefore to guarantee appropriate carrier and drug-loading (DL) selection. A DoE approach was conducted to optimize process conditions of ProCept 4M8-TriX spray-drying to maximize the yield from a 100 mg batch of Itraconazole/HPMCAS-LF and Itraconazole/Soluplus 40:60 (w/w). Optimized process parameters include: inlet temperature, pump speed, drying and atomizing airflows. Identified process conditions derived from the DoE analysis were further (i) tested with Itraconazole, Naproxen and seven polymers, (ii) adapted for small cyclone use, (iii) downscaled to 20 mg batch production. Drug-polymer miscibility was systematically characterized using modulated differential scanning calorimetry (mDSC). Spray-drying was identified as a well-suited screening approach: mean yield of 10.1 to 40.6% and 51.1 to 81.0% were obtained for 20 and 100 mg ASD productions, respectively. Additionally, this work demonstrates the interest to move beyond conventional screening approaches and integrate spray-drying during screening phases so that a greater prediction accuracy in terms of SDSDs miscibility and performance can be obtained.

Keywords: Amorphous solid dispersions; design of experiments; miscibility; polymers; quench cooling; screening; solvent casting; spray-dryer.