Clear Coating
Clear coatings are transparent, polymer-based films that protect tablets from moisture and oxygen while enhancing mechanical strength and handling. Because clear coatings do not mask surface imperfections, the punch tip and tablet surfaces must be finely polished. Even minor tooling defects or roughness can be visible under the coating. For clear-coated tablets, tooling requires precision polishing and shallow, smooth engravings to prevent unwanted marks post-coating.
Aqueous Coating
Aqueous coatings use water as the solvent, offering a safer, eco-friendly alternative to solvent-based coatings. They provide benefits like faster processing and lower toxicity but can increase risks of sticking or picking during compression and coating. Tooling for aqueous-coated tablets should feature highly polished surfaces and may incorporate anti-stick treatments. Proper punch finishes help ensure smooth tablet ejection and minimize surface imperfections that affect coating quality.
Enteric Coating
Enteric coatings are specialized films designed to withstand stomach acid and dissolve only in the intestines, protecting acid-sensitive drugs or formulations that irritate the stomach lining. The brittle nature of enteric coatings means any sharp edges, deep engravings, or uneven tablet surfaces can cause cracking or flaking. Tooling for enteric-coated tablets must avoid aggressive embossing and promote gentle tablet shapes with uniform curvature. Smooth and consistent surface finishes are essential for coating adhesion and effective drug release.
Color Coating
Color coatings enhance tablet appearance, support brand recognition, and improve patient compliance. These coatings commonly use pigments or lake colors, requiring uniformity across batches. Deep or sharp engravings can trap excess pigment or create shadows, leading to color inconsistencies or mottling. Punches must have clean geometries and refined finishes, and consistent tablet size and shape are critical for flawless, even color coatings.
The Role of Tooling in Coated Tablet Success
Each coating type places specific demands on tablet tooling design. Factors such as surface polish, engraving depth, tip geometry, and overall tablet shape significantly influence coating performance. Improper tooling can cause coating defects like flaking, color variation, or compromised drug release profiles. Precision-engineered punches and dies ensure smoother coating operations, better adhesion, and superior aesthetic quality of the final product.
At Brijon Pharmatech LLP, we collaborate closely with formulators to deliver punches and dies tailored for all major coating types—clear, aqueous, enteric, and color coatings—ensuring consistent, high-quality results batch after batch.
Optimized tooling design is essential for pharmaceutical coating success, enhancing product performance, patient experience, and brand value.
