Spray drying and post-processing production of highly-porous lactose particles using sugars as templating agents

The possibility of using different carbohydrate sugars, such as maltose, sucrose, glucose, and fructose, as templating agents to produce highly-porous lactose particles with high degrees of crystallinity in a new templating process has been investigated. The new production process includes spray drying of the lactose (core material) solutions containing different types of ethanol-soluble templating sugars and then removing the templates in a post-treatment process involving ethanol-washing the spray-dried particles. Gravimetric moisture sorption tests and modulated scanning calorimetry (MDSC) have been used to study the effect of different concentrations of templating sugars on in-process crystallization of lactose during the spray-drying step and its effect on the BET surface areas of the final processed particles after ethanol washing. The results showed significant reductions in process yield and glass-transition temperatures of the spray-dried powders and considerable increases in the degree of crystallinity of the lactose in spray-dried powders, as the templating-sugar concentrations were increased. Spray-dried powders containing sucrose and maltose as templating materials had lower degrees of crystallinity, which resulted in higher porosities and BET surface areas of around 20 +/- 1 and 18.2 +/- 0.6 m(2)/g, respectively. The results of this study have implications in choosing the proper processing conditions (type of templating agent and its concentration) to control in-process crystallization of lactose during spray-drying to produce highly-porous engineered particles. (C) 2015 Elsevier B.V. All rights reserved.