Skyepharma publishes White Paper on press-coated tablets

Fully featured CDMO Skyepharma Productions S.A.S. (Skyepharma) has published a White Paper exploring hitherto unappreciated technicalities of press-coating tablets.

The paper sheds new insights onto the influence of layer thickness (distance between the surface of core outer tablet surface) and the press-coating process on overall press-coated tablet attributes, particularly the final structure and properties of the core, which are likely to affect its dissolution profile.

Effects on tablet core

The paper is based on original research by Skyepharma scientist Léo Picart, as part of his PhD thesis at University of Bordeaux. His work on press-coated tablets and their compression process, revealing new design parameters that are critical in development and manufacture of this type of tablet, has been published as a peer-reviewed paper in the International Journal of Pharmaceutics, marking a significant new milestone for Skyepharma.

A significant finding of the paper is that, contrary to previous assumptions, the press-coating process can modify the tablet core itself, increasing diameter by up to +15% and decreasing thickness by as much as -30%. Core density was found to fluctuate during coating-compression: first decreasing at low pressure before increasing at high pressures. Since loss of density is normally associated with ruptures in powder compaction, this raises new questions about overall tablet integrity and mechanical resistance that was also investigated in the present study.

Numerical modeling

Using numerical modeling, the paper investigates the influence of parameters including in layer thickness and core diameter on stress and density.

It concludes that compression of the coating can have severe effects for core structure, especially with brittle materials. It also observes that, due to opening of the barrier being due to mechanical action of core swelling, a fractured core might play a key role in the release profile of the active ingredient, although it may not be visible from the exterior of the press-coated tablet.

It also discusses influence of the thickness of coating layer on observed changes and how reducing layer thickness can cause higher deformations and more important strength loss.

Research-driven manufacturing

The study provides new insights into the compression and coating processes, reinforcing Skyepharma’s manufacturing expertise.

Through research and academic partnership, Skyepharma continues to generate knowledge on the pharmaceutical processes to be reinvested in its development and increase capacity to meet target product specifications.

Léo Picart’s ongoing research into effects of layer thickness and core diameter of overall tablet properties reveal that these under-investigated parameters can now be highlighted as critical to high quality process, advancing Skyepharma press-coated tablet technology. His studies are expected to generate further articles in due course.