Track: Formulation and Delivery - Chemical - Formulation - Excipients
Category: Poster Abstract
Low-Cost Enteric Spray Coating System for Dietary Supplements
Purpose: Commercial spray-coating systems are very expensive, space-consuming, and overscaled for the small batches needed in many academic pharmaceutical labs. Such systems are overkill for the small numbers of capsules needed in enteric-coating formulation prototyping, dissolution testing, animal studies, and preliminary clinical studies with natural products. Thus, there is a need for small-scale equipment to produce small numbers (10 to 200) of dosage units. The purpose of this project is to design, build, and test an inexpensive, compact, and useful spray-coating system for small-scale enteric coating of capsules. Methods: The system comprised a magnetic stirrer, a peristaltic pump (set at 1ml/min), an X-flow nebulizer, a heat gun, a sample rotator, and a custom-fashioned spray bowl. A commercially-available food-grade enteric coating (based on shellac and sodium alginate) was dispersed in water and pumped through the X-flow nebulizer, sprayed by nitrogen, and directed at HPMC capsules inside the spray bowl. Meanwhile, the spray bowl was rotated as the hot air dried the capsule coating. Methylene blue was added to the coating mixture to facilitate visual monitoring of the coating process. The empty HPMC capsules were filled with sucrose and sodium fluorescein, for facile detection of capsule content leakage or release. Additionally, the small-scale dip-coating procedure previously described by Dodds & Podczcek with Eudragit L100 was used to provide an enteric coating for another set of HPMC capsules filled with sucrose and fluorescein. Fluorescein release was determined on a fluorescent plate reader with excitation at 485nm, emission at 528nm. Results: The cost of the entire system was < $2000, and the system can be operated on a benchtop or inside of a standard chemical fume hood. Our preliminary results indicated that the food-grade spray-coating provided resistance to the simulated gastric fluid, as did the dip-coating system. Further experiments are needed to optimize the thickness and uniformity of application of the spray coating, and to demonstrate gastro-resistance and intestinal release. Conclusion: The low-cost small-scale spray coater may be used for preformulation studies in the development of enteric-coated dietary supplement prototypes. It could also be used for small-scale clinical study formulations of natural products in academic settings. References: Dodds R, Podczeck F. Using a small-scale capsule dip coater to produce gastro-resistant hard capsules. Tablets & Capsules. 2008;2008:1-7.1.