Foamed Binder Technology

Foamed binder technology from The Dow Chemical Company can help you achieve faster, simpler, and safer wet granulation processing. Using familiar, proven METHOCEL* polymers, this technology greatly improves binder distribution in the formulation mix and yields a remarkable array of processing advantages.

Compared to conventional spray processing, foamed binder technology can shorten processing times by reducing water requirements.  It can improve reproducibility through more uniform binder distribution. Moreover, it eliminates spray nozzles and their many variables in granulation processing equipment.  Foam processing also offers better end point determinations and reduced equipment clean-up time.

While foamed binder processing offers many advantages, this technology doesn’t demand new equipment or radical changes in processing techniques.  You can very easily use it with familiar high shear, low shear, or fluid bed granulation equipment, in both laboratory- and production-scale settings. Our evaluations also show it yields familiar metrics for particle size distributions, solid dose physical properties, and dissolution profiles.

How foam binder granulation works

Foam granulation takes advantage of the tremendous increase in the liquid surface area and volume of polymeric binder foams to improve the distribution of the water/binder system throughout the powder bed of a solid dose pharmaceutical formulation.

A simple foam generation apparatus is used to incorporate air into a conventional water-soluble polymeric excipient binder such as METHOCEL hypromellose (hydroxypropyl methylcellulose).  The resulting foam has a consistency like shaving cream. Hypromellose polymers are ideal candidates for this technology because they are excellent film formers and create exceptionally stable foams.

In a small-scale laboratory setting or in a full-scale production setting, the foam generator can be connected directly to high-shear, low-shear, or fluid bed granulation equipment.

Extremely efficient binder delivery and particle coverage

The key to the effectiveness of foam binder performance is rapid and extremely efficient particle coverage. Compared to sprayed liquid binders, foamed binders offer much higher surface area, and they spread very rapidly and evenly over powder surfaces.  The foamed binders and the powder particles show excellent mutual flow through one another.

The foam binder also shows a low soak: spread ratio, so particle surfaces are quickly and completely covered.  By contrast, spraying is a cumulative process that begins with small liquid droplets “dappling” particle surfaces until enough binder liquid accumulates to initiate particle agglomeration.  Spraying requires considerably more water and processing time than a foamed binder to achieve particle agglomeration.

The foam binder technology also eliminates the need for spray nozzles and all of their attendant variables, such as nozzle configuration, distance from the moving powder bed, spray patterns, clogging, droplet size, and droplet distribution.  The dilute binder solutions are easy to handle in processing. Overall, foam binder processing is easier, faster, and allows safer handling of potent drug compounds.

®™*Trademark of The Dow Chemical Company ("Dow") or an affiliated company of Dow.