Role of templating agents in the spray drying and postcrystallization of lactose for the production of highly porous powders

Abstract

ABSTRACTIn this work, we report a method using templating techniques in spray drying to fabricate porous lactose with flower-like shapes. Three templating agents, including boric acid, citric acid, and ascorbic acid, have been used and compared for the production of flower-like lactose. The role of templating agents has been found to be significant in spray drying and postcrystallization of lactose. After spray drying, the boric acid (with a smaller size) is more likely to diffuse to the core of spray-dried particles than the other two templating acids. The morphology, pore structure, and crystallinity of the flower-like lactose have been found to be related to the use of different templating agents. The Brunauer–Emmet–Teller surface areas of the flower-like lactose are 29, 24, and 25 m2/g, respectively, for boric acid, citric acid, and ascorbic acid, as the templating agents. From the Barrett–Joyner–Halenda analysis, the citric acid-templated flower-like lactose has more large pores (radius > 61.8 Å), while the boric acid-templated lactose has more pores with a size of 28.2 Å (radius) and the ascorbic acid-templated lactose has more pores with a size of 15.2 Å (radius).