Spray Drying in the Pharmaceutical Industry

The Oak Crest Institute of Science is making use of high efficiency spray drying techniques common in the pharmaceutical industry to create high quality powders from liquid samples (1). Spray drying uses an atomizing spray nozzle to control the size of particles that are to be dried. As hot air drives water from samples, evaporative cooling prevents overheating of the particles, resulting in a pure powder form of the original liquid sample. This drying method is advantageous in a variety of industries due to  its single step process and high powder purity and yields. Here, we demonstrate the effectiveness of this technique by spray drying lactose, a common component in pharmaceutical applications, such as the formulation of tablets and capsules (2).

Buchi Mini Spray Dryer B-290 at Oak Crest.

Collection vial with lactose powder after spray drying.

SEM of lactose powder before spray drying at 200x magnification.

SEM of lactose powder before spray drying at 900x magnification.

SEM of lactose powder after spray drying at 200x magnification.

SEM of lactose powder after spray drying at 900x magnification.

A lactose powder was dissolved as a 10% solution and spray dried, yielding 83% sample recovery. Imaging in the scanning electron microscope (SEM)(3) illustrates the difference in powder structure between the original lactose stock and after spray drying. While the original powder consists of large particles with variable size and shape, dissolution and spray drying of the same original material produces uniform round particles with a much tighter size distribution (approximately 1-6 µm in diameter). The change in particle size and surface area can dramatically change the rate of dissolution (4), which is an important factor in the formulation of pharmaceuticals (5).