Ever wondered why some tablets don’t dissolve in the stomach but instead release their active ingredients precisely in the intestines? That controlled behavior is achieved through Enteric Coating.
In pharmaceutical production, enteric coating is not just about formulation; it’s a manufacturing challenge. For procurement specialists sourcing tablet coating machines, understanding the interplay between polymers, process parameters, and equipment is essential to ensure ROI and GMP compliance.
This comprehensive guide serves as your hub for mastering enteric coating technology. We will cover the mechanism, materials, and machinery, while directing you to our deep-dive resources for specific technical details.
Jianpai High-Efficiency Coating System: Ensuring precise temperature and spray control required for consistent enteric coating.
What Is Enteric Coating? (The Mechanism)
Enteric coating is a pH-sensitive protective film applied to oral solid dosage forms. The coating withstands the acidic environment of the stomach (pH 1–3) and dissolves only in the higher pH of the small intestine (pH 5.5–7.5).
Why use it?
Protection: Prevents acid-sensitive drugs (like PPIs) from degrading in the stomach.
Safety: Prevents irritating drugs (like Aspirin) from damaging the stomach lining.
Targeting: Delivers drugs directly to the intestine for better absorption.
Film Coating vs. Enteric Coating: What’s the difference? While standard film coating is for aesthetics, enteric coating is functional. If you are unsure which one your production line needs, read our detailed comparison: [Film Coating vs Enteric Coating – Key Differences & Selection Guide]
Key Polymers Used in Enteric Coating
The success of enteric coating depends entirely on the polymer selection. Different polymers dissolve at different pH levels, allowing formulators to target specific areas of the digestive tract.
Common Polymers at a Glance
Polymer Name
Solubility pH
Source
Typical Use
CAP (Cellulose Acetate Phthalate)
> 6.0
Synthetic
General enteric coating
Eudragit® L & S
> 5.5 – 7.0
Synthetic
Precise intestinal targeting
HPMCP
> 5.0 – 5.5
Semi-synthetic
Pellets and tablets
Deep Dive into Materials: Not all polymers work with every machine. To learn about the pros, cons, and equipment compatibility of these materials, check out our guide: [Common Enteric Coating Materials: A Procurement Guide]
The Enteric Coating Process Explained
Applying an enteric layer is more complex than standard film coating. It requires precise thermodynamic control to prevent defects like “orange peel” or “twinning.”
The 4-Step Process:
Core Preparation: Tablets must be hard enough to withstand the tumbling of the coating pan.
Solution Preparation: Dissolving polymers in solvents (or water for aqueous systems).
Spraying & Drying: The critical phase where the Automatic Tablet Coating Machine sprays the solution while hot air dries it instantly.
Curing: A final heating stage to ensure film integrity.
You can have the best polymer formula in the world, but if your tablet coating machine has poor airflow or clogged spray guns, the batch will fail.
Enteric coating requires:
Precise Temperature Control: To prevent polymer degradation.
High-Efficiency Drying: To handle the slower evaporation rates of enteric solutions.
Anti-Bearding Spray Guns: To prevent nozzle clogging during long runs.
Equipment Selection Guide: Are you upgrading your production line? Don’t buy the wrong size or type. Read our expert advice for procurement: [How to Choose a Tablet Coating Machine for 2026]
Troubleshooting: Common Problems in Enteric Coating
Even with good equipment, things can go wrong. Issues like cracking, peeling, and color variation are common headaches for production managers.
Case Study: Reducing Stomach Irritation A generic drug manufacturer faced customer complaints about gastric irritation from an analgesic. By switching to a CAP-based enteric coating and upgrading to a Jianpai High-Efficiency Coating Machine, they achieved a perfect acid-resistant barrier, reducing complaints by 90% while increasing throughput.
Conclusion
Understanding enteric coating is essential for pharmaceutical manufacturers and procurement professionals. Beyond formulation, success relies on selecting GMP-compliant tablet coating machines, pill coating machines, or fluid bed coaters that deliver consistent, defect-free results.
JIANPAI offers high-quality tablet coating solutions for film, enteric, and sugar coating applications. Partnering with a reliable equipment supplier helps improve coating quality, reduce production risks, and ensure long-term manufacturing success.
Frequently Asked Questions (FAQ)
Q1: What is the main purpose of enteric coating? A: To protect tablets from stomach acid and enable controlled intestinal release.
Q2: Which machine is best for enteric coating? A: A perforated pan Automatic Film Coating Machine with precise PLC control is recommended over traditional sugar pans.
Q3: Can water-based enteric coatings be used? A: Yes, aqueous enteric coatings are safer and greener, but they require a machine with excellent drying efficiency to prevent defects.
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