MEGGLE Product Decision Flyer

MEGGLE has it.The right spray-dried lactose product for direct compression

Spray-drying (SD) opened the door for lactose in Direct Compression (DC) and had a major impact on tableting technology. After initial quality problems, SD lactose has become a very frequently used, robust excipient grade in pharmaceutical formulation design.

Nowadays, pharma grade lactose is manufactured first, and then converted into SD lactose, avoiding former browning due to the use of a contaminated mother liquor. SD lactose is an excellent example demonstrating the versatility of this material: Besides thermodynamically most stable polymorph α-lactose monohydrate, a precisely defined percentage of amorphous lactose is created in a tailored particle design process using a lactose suspension.

Important: Amount of amorphous lactose

The amount of amorphous lactose can be determined by the lactose dissolved before the atomization step. Generally, SD lactose grades expose between 10 to 15% amorphous lactose, and an aqueous lactose solution contains a majority of ß-anomer, especially at elevated temperatures. This ratio is basically not changed after dispersion, when due to rapid dehydration no formation of a structured crystal lattice is possible. Lactose molecules arrange more the less randomly containing some traces of water. Lack of an ordered structure is seen the reason for its adhesive, more plastically deforming compaction behavior, while sphenoidal, structure-giving, α-lactose monohydrate crystals (also denoted as “tomahawk”-shaped) tend more to consolidate by fragmentation.

Spray-drying: Modulation of porous particles

A combination of these two compaction behaviors favors synergistically tableting and simultaneously loadability of a compact. In a typical SD process a liquid or slurry is rapidly dispersed into a controlled drop size, and its physical shape is preserved by a hot, counter-flowing gas, streaming against the dispersing atomizer.  In SD lactose manufacture only aqueous systems are used, drying agent is just hot air. The formation of spherical aggregates of narrow particle size distribution (PSD) impacts powder technological aspects dramatically: Flowability of product is greatly enhanced by spherical shape of agglomerates and smooth surface enabling excellent tablet mass and content uniformity values. Besides that, SD also allows to modulate porosity of particles, which may be applied increasing compaction performance, as well as reducing lubricant sensitivity.

MEGGLE’s spray-dried lactose grades for direct compression are available under the trade names

FlowLac ® 90 and FlowLac® 100