(M1030-08-53) Evaluation of Talc Alternative for EUDRAGIT^® E PO-Based Coatings

Purpose: Talc has traditionally been utilized as an anti-tacking agent in pharmaceutical coating applications, particularly in formulations containing EUDRAGIT^® polymers, to minimize adhesion during processing and storage. However, legal actions against manufacturers of talc-based products, alleging contamination with asbestos, a recognized carcinogen, have raised significant safety concerns. In response, the Risk Assessment Committee (RAC) of the European Chemicals Agency (ECHA) has recommended classifying talc as STOT RE 1, H372 (lungs, inhalation) and as a Presumed Carcinogen to humans of category 1B, H350 (May cause cancer)¹. This evolving landscape compels pharmaceutical companies to investigate talc alternatives to mitigate potential liability risks and comply with stringent safety regulations. This study aims to evaluate kaolin as a viable substitute for talc in EUDRAGIT® E PO-based coating systems.

Methods: Three distinct tablet cores were prepared for coating trials: black placebo tablets (for opacity evaluation), caffeine tablets (for disintegration and dissolution testing), and silica tablets (for moisture uptake studies). Coating dispersions were prepared with talc and talc-alternative formulation for EUDRAGIT® E PO coating system for immediate release and EUDRAGIT® E PO coating system for moisture protection application. The talc-alternative formulations utilized kaolin (Kaopolite® KR USP, Imerys) as a replacement for talc. Coating was performed in a perforated coating pan following established process parameters². Analytical methods included opacity evaluation using a spectrophotometer, disintegration testing across various media, dissolution performance assessment via USP Type 2 apparatus, and moisture uptake studies under controlled humidity conditions.

Results: The coating process for both talc and talc-alternative formulations was smooth, exhibiting no signs of sticking. Coated tablets displayed excellent gloss and comparable surface characteristics. Opacity measurements indicated L-values exceeding 94 for both formulations, confirming significant whiteness achieved at 6% w/w weight gain (as shown in figure 1 and 2). Disintegration times for EUDRAGIT® E PO immediate release formulations were under 10 minutes across all media, while EUDRAGIT® E PO moisture protection formulations also met this criterion in 0.1N HCl. Dissolution studies revealed that both talc and talc-alternative formulations achieved complete release within 30 minutes, confirming immediate release performance. Moisture uptake studies indicated no significant differences between talc-based and kaolin-based coatings, suggesting that kaolin effectively maintains moisture protection properties.

Conclusion: Kaolin found to be a promising alternative to talc in EUDRAGIT® E PO-based coatings, demonstrating comparable performance across all evaluated parameters. Kaolin is listed in the IIG database and also has GRAS status, which allows its use in pharmaceutical and nutraceutical formulations alleviates regulatory concerns, making it a suitable replacement for talc. This study underscores the potential for transitioning to talc alternatives in pharmaceutical development, aligning with evolving safety standards and regulatory expectations.

Fig 1: Comparison of coating build up between talc and talc-alternative EUDRAGIT® E PO coating system for immediate release

Fig 2: Comparison of coating build up between talc and talc-alternative EUDRAGIT® E PO coating system for moisture protection