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

• Developing a new production process for highly-porous and crystalline lactose particles
• Using carbohydrate sugars as non-acidic templating materials
• Significant effect of templating sugars concentration on porosities of lactose particles
• Significant effect of carbohydrate sugars on the degrees of lactose crystallinity

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 m2/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.

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