Lactose

Most oral solid dosage forms are mainly lactose, which makes it the material that decides how a blending and compression line behaves.

Grades are different materials

• Sieved crystalline grades flow well and compact poorly.
• Milled grades are fine, cohesive and improve content uniformity with potent actives.
• Spray-dried grades are designed for direct compression and flow like a granulate.

Hopper geometry, feeder type and blender choice all follow from this, so a grade change is a process change rather than a purchasing decision.

Segregation in blends

A coarse excipient with a fine active separates during transfer, and the result is content uniformity failure at the press.

Short transfers, minimal free fall, mass flow hoppers and particle size matching between excipient and active are the practical controls.

Sieving and lump control

Lactose arriving from storage carries agglomerates, and the sieve before the blender is both a quality step and a foreign body control.

Containment and cleaning

The excipient itself is benign, but it shares equipment with actives that are not.

Contained charging, documented cleaning validation and sampling that proves the result belong to the lactose line as much as to the active line.

Dust explosion

Lactose dust is combustible, and mills, sieves and collectors in a pharmaceutical plant need the same protection logic as in food production.

What to establish before buying equipment

• Grade and supplier, with flow properties measured on the delivered lot.
• Particle size relationship between excipient and active.
• Required blend uniformity and the sampling plan.
• Cleaning validation approach for shared equipment.

Lactose is a pharmaceutical excipient, so storage is about preserving a specified material rather than just keeping it dry.

Grades differ widely: crystalline, milled and spray-dried lactose behave almost like different materials, and the grade is chosen for its compression or flow behaviour. Moisture changes both.

• Control humidity; lactose takes up water and the fine grades cake.
• Keep grades strictly separate, including in the equipment between campaigns.
• Protect agglomerated grades from mechanical handling that breaks them down.

Gentleness, cleanability and traceability set the equipment.

Spray-dried grades owe their flow to agglomerates that conveying can destroy, so velocity is a quality parameter. Vacuum transfer is the normal choice, both for containment and because it treats the material more gently than a long pressure line.

• Vacuum conveying at modest velocity.
• Cleaning validation designed in, including the receiver filter and discharge valve.
• Gravimetric dosing where the formulation tolerance demands it.

Lactose dust is combustible, and in a pharmaceutical plant the controls are both safety and quality.

• Explosion protection on collectors and vessels, from measured values for the grade.
• Containment appropriate to what else is in the blend, not to the lactose itself.
• Cross-contamination control, which in practice is the dominant daily concern.

Lactose is also an allergen consideration where products are used by people with intolerance, which affects labelling and line segregation.