Tablettose – MEGGLE’s agglomerated lactose grades for direct compression

Tablettose - Technical brochure by MEGGLE_Figure 6 — Tablettose - Technical brochure by MEGGLE

General information

Direct compression (DC) tablet manufacture is a popular choice because it provides the least complex, most cost effective process to produce tablets compared to other tablet manufacturing approaches. Manufacturers can blend APIs with excipients and compress, making dosage forms simple to produce [1, 2].

DC technology and the use of modern tableting equipment require that excipients and APIs form a compactible mixture with excellent flowability and low particle segregation tendency [3].

In the pharmaceutical industry, lactose is one of the most commonly used excipients; however, like many other excipients, lactose may not be suitable for direct compression without modification due to insufficient powder flow or/and compaction properties (figure 1).

The brittle alpha-lactose monohydrate compactibility is strongly dependent on the powder surface area before compaction and the fragmentation produced during the compaction event. The binding capacity increases with increasing powder surface area, suggesting that the smaller the lactose particles become, the more compactibility improves. While the small particles offer relatively good dry binding properties, poor flowability makes milled alpha-lactose monohydrate sieve fractions show good flow properties, but very poor compressability [4].

For these reasons, MEGGLE developed directly compressable, agglomerated alpha-lactose monohydrate in the mid 1970s, combining the good flowability of coarse lactose and good compactibility of fine milled lactose. The product is marketed as the brand name Tablettose®. Tablettose® is manufactured by a continuous spray agglomeration process. Water is used as the binder and is sprayed onto fluidized fine milled lactose particles, creating liquid bridges to form agglomerated lactose. The added water is later evaporated and the liquid bridges are maintained. With this process, no amorphous lactose is produced, resulting in a very stable, non-hygroscopic, pure alpha-lactose monohydrate powder.

Particle size distribution (PSD)

Figure 2 shows typical particle size distribution data (obtained by laser diffraction) for MEGGLE’s agglomerated lactose grades Tablettose®. Tablettose® 80 and Tablettose® 100 exhibit similar particle size distributions. Comparatively, Tablettose® 70 demonstrates a narrower particle size distribution due to fewer fines.

Figure 3 depicts the specified PSD range and typical average values by mechanical sieve shaker. These parameters are constantly monitored through in-process control (IPC) testing and are part of Tablettose®’s particle size distribution specification.

Functional related characteristics

Powder flow

It is well known that particle size and shape influence powder flowability. Particles less than 100 μm tend to be more cohesive and less freely flowing, whereas larger, denser particles tend to be more freely flowing. Particle morphology also significantly affects powder flow characteristics. Figure 7 demonstrates that particle shape and structure are as important as particle size distribution for powder flowability. Due to its “blackberry” or “popcorn” structure, agglomerated lactose has a nearly spherical shape, resulting in a lower flowability index (powder through an orifice) compared to sieved (SpheroLac® 100) or milled (GranuLac® 70) lactose.

See the full brochure on “Tablettose®“ here

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