Jerry Klinzing ^a
a Oral Formulation Sciences and Technology, Merck
Rahway, NJ, 07065

Purpose. Reducing and eliminating defects associated with debossed tablets is critical for a successful commercial product. Poorly designed debossing can lead to film coating problems such as bridging or abrasion defects causing illegible branding markings. The design, position, and tablet geometry are critical factors when designing the debossing and crucial for reducing and eliminating these types of tableting defects. To date most work has been done computationally and experimentally on simple tablet geometries with idealized debossing features. This work aims to highlight the need to thoughtfully design and locate the debossing features in order to develop the most robust tablet.

Methods. Tablets were produced with three different cup depth profiles matching that listed in the Tablet Specification Manual for 14/32” diameter shallow, standard, and deep concavity. On each tooling design, four different debossed features were studied with varied parameters such as stroke depth, stroke width, and stroke radius. Finite element analysis was performed for all three designs, along with a design where the debossed feature was varied at different distances from the apex of the tablet. Experimentally, tablets were produced and density gradients were measured via x-ray microcomputed tomography.

Results. It was found that stroke depth plays a significant role on the local density gradients around the debossed features. In addition, an increase in cup depth also exasperates the low-density regions around the debossed features. Defects around the debossing were analyzed after friability and examined through imaging.

Conclusions. Proper design of debossing features on tablets is critical for a successful commercial product. This work helps further the understanding of how finite element modeling can be used to optimize tablet shapes and debossing features without the need for timely and costly experimentation.