--- title: "Budesonide Enteric Capsules (Part III): Engineering Analysis of Efficient Coating for Hard Capsules" date: 2025-12-30T03:31:22Z modified: 2025-12-30T05:15:14Z permalink: "https://www.chinacanaan.com/blog/budesonide-enteric-capsules-part-iii-engineering-analysis-of-efficient-coating-for-hard-capsules/" type: post status: publish excerpt: "" wpid: 5141 categories: - Blog - Coating - News - Technology featured_image: "https://www.chinacanaan.com/wp-content/uploads/2025/12/企业微信截图_17670716625794.png" timestamp: 2025-12-30T05:15:14Z tags: - Blog - Coating - News - Technology --- In the manufacture of budesonide enteric capsules, **pellet coating establishes the foundation for targeted drug delivery**. The **enteric coating of hard capsules**, however, represents the **final protective barrier**, ensuring that the dosage form passes safely through the gastric environment and reaches the intended intestinal site. In industrial practice, questions frequently arise: - Why do some enteric capsules exhibit **premature release in the stomach**? - Why does **dissolution performance vary within and between batches**? These issues are closely linked to the **uniformity and process stability of hard capsule enteric coating**. _Related articles:_ – Budesonide Enteric Capsules (Part I): Fluid-Bed Drug Layering and Coating Analysis – Budesonide Enteric Capsules (Part II): Micro-Pellet Filling & Hard Capsule Sealing Explained ## **Why Hard Capsule Enteric Coating Is a Critical Process Step**? Compared with conventional enteric-coated tablets, enteric-coated hard capsules offer greater formulation and process flexibility. They are particularly suitable for APIs such as budesonide, which are sensitive to compression or require complex release profiles. ![](https://www.chinacanaan.com/wp-content/uploads/2025/12/7218a847-3178-41f6-9df7-403c69b72d3d.png) ### **Manufacturing Process of Budesonide Enteric Capsules** #### **Drug Layering on Pellet Cores** Micronized budesonide is dispersed in a hydroxypropyl methylcellulose (HPMC) solution to prepare a drug-layering suspension. The suspension is layered onto **sugar pellet cores**, resulting in **drug-loaded pellets**. #### **Seal Coating** Citric acid and hydroxypropyl methylcellulose are formulated into a seal coating solution. The seal coating is applied to the drug-loaded pellets to obtain **sealed pellets**, providing protection for the drug layer and preparing the surface for subsequent functional coatings. #### **Sustained-Release Coating** A sustained-release coating dispersion is prepared by blending hydroxypropyl methylcellulose, an aqueous polyethylene glycol solution, and **ethylcellulose aqueous dispersion (Surelease®, Type B)**. The coating is layered onto the sealed pellets and cured to form **sustained-release pellets**. #### **Capsule Filling** The sustained-release pellets are filled into **size 1 hydroxypropyl methylcellulose (HPMC) hard capsules**. #### **Enteric Coating of Capsules** The filled capsules are enteric-coated using a blended system of **methacrylic acid–methyl methacrylate copolymers** in ratios of **1:1 and 1:2** (**EUDRAGIT® L 100 and EUDRAGIT® S 100**), resulting in **budesonide enteric capsules**. Source: Patent CN120053463A Taking **Nefecon® (marketed as TARPEYO®)** as an example: - The hard capsule is **enteric-coated**, allowing it to remain intact during gastric transit; - Under the pH conditions of the **distal ileum**, the capsule shell dissolves, releasing **hundreds of triple-layer coated pellets**; - The pellets subsequently provide **sustained release of budesonide**, achieving high local drug concentrations at the affected **Peyer’s patches**, thereby intervening upstream in the pathogenesis of **IgA nephropathy**. This **dual-release design — delayed capsule opening combined with sustained pellet release** — is essential for achieving **localized therapeutic action with minimal systemic side effects**. ## **Process Challenges in Enteric Coating of Hard Capsules** ### **Coating Uniformity as a Critical Determinant of Release Performance** Non-uniform coating is a **primary cause of inconsistent release behavior** in enteric-coated capsules. In industrial manufacturing, coating uniformity can be evaluated at two levels: - **Inter-capsule uniformity**: variation in coating thickness between individual capsules; - **Intra-capsule uniformity**: variation in coating thickness across different surfaces of a single capsule. Insufficient control of coating uniformity may result in: - **Premature release under gastric conditions**, compromising targeted delivery; - **Delayed or accelerated release**, leading to reduced consistency in therapeutic performance. Coating uniformity is influenced by multiple interacting factors, including **capsule size and geometry, pan rotation speed, batch load, pan design, and baffle configuration**. ![](https://www.chinacanaan.com/wp-content/uploads/2025/12/f43e3372-11b2-4204-a369-0d6d82062c33-1-1024x683.png) ## **Three Key Engineering Measures for Precise Release Control** To address the coating challenges associated with budesonide capsules, **Canaan BGX Series High-efficiency Coater** is engineered around **three critical process elements**, providing stable and reliable performance for enteric capsule coating. Customized Multi-Configuration Impellers for Three-Dimensional Capsule FlowBased on the physical properties of hard capsules, Canaan applies **customized multi-configuration impellers**. Through optimized blade angles, capsules undergo radial movement combined with axial turnover, generating a three-dimensional convective flow pattern and ensuring uniform coating without dead zones. ![](https://www.chinacanaan.com/wp-content/uploads/2025/12/d3a6117e-02b0-433e-9574-e6fd32b9ff90-1024x256.jpg) ![](https://www.chinacanaan.com/wp-content/uploads/2025/12/da8b1134-7d40-474c-9e69-329c8cc3bde7-1024x153.jpg) Schematic of Customized Impeller Design ![](https://www.chinacanaan.com/wp-content/uploads/2025/12/0e85fdeb-32ff-42b6-82ea-195c2207db82-1024x457.jpg) Schematic of Capsule Coating Spray and Finished ProductAutomated Spray Gun Adjustment for Consistent AtomizationDuring capsule coating, as the coating weight increases, the bed height rises and the distance between the capsules and the spray guns decreases. Such changes may lead to variations in droplet distribution and coating uniformity. **Canaan** **BGX Series Coater** is equipped with an **automated spray gun adjustment mechanism**, which dynamically regulates the **height and angle of the spray guns** during operation. This ensures **stable atomization conditions throughout the process** and prevents non-uniform coating caused by distance variation. High-Precision Process Control to Prevent Coating DefectsThe system is operated via the **TechproM V4 control platform**, which integrates digital process control with real-time sensing to achieve **precise closed-loop regulation of critical parameters**: **Negative Pressure:** ±10 Pa **Temperature:** ±1 °C (up to ±0.5 °C under stable steam conditions) **Humidity:** ±0.5 g/kg **Airflow:** ±3 % Combined with internationally recognized control valve components, the system significantly reduces the risk of coating defects such as powder loss, sticking, and orange peel formation. ## **From Lab Trials to Mass Production: Canaan Delivers Proven Process Pathways** Canaan **Solid Dosage Form R&D Center** is equipped with a complete platform ranging from **small-scale trials to pilot-scale production**, providing customers with: - Development and **optimization of enteric coating processes for hard capsules**; - Integrated process validation linking **pellet drug layering, capsule filling, and capsule coating**; - Case-based **process solutions derived from validated experience**, reducing project timelines and scale-up risks. The manufacture of budesonide enteric capsules represents a **highly coordinated process chain**, spanning **pellet coating → capsule filling → capsule coating**. Leveraging extensive expertise and accumulated case experience in solid dosage form equipment, Canaan has supported multiple pharmaceutical manufacturers from **laboratory trials to full-scale production lines**. Canaan continues to collaborate with pharmaceutical partners to **overcome challenges in high-end solid dosage form industrialization**, ensuring that **precision drug delivery is not only designed, but reliably manufactured**. Welcome to **Canaan Solid Dosage Form **R&D Center**** to observe **budensonide capsule coating trials firsthand**. ![](https://www.chinacanaan.com/wp-content/uploads/2025/12/蓝色小人-1-1024x481.gif)