s Enteric-Coated Polymers Past and Present - A Review

Tablet coating has evolved over the years, and today, there are various types of coating for the delayed release of a drug. Drugs can be enteric-coated to provide delayed release, protect the active pharmaceutical ingredients, minimize undesirable effects, and modify the pharmacokinetic properties of a drug, which will have clinical impacts. Certain types of drugs need to be entericcoated for various reasons, such as gastric irritants or acid-liable drugs. This article will review ethylcellulose and polymethacrylate, their role in an enteric coating, and their process coating parameters. Ethylcellulose can provide a short delayed release; it can be modified by adding pHdependent polymers such as sodium alginate and hydroxypropyl methylcellulose phthalate for a long delayed release. On the other hand, polymethacrylate can also be employed to enteric coat drugs without additional polymers. Polymethacrylate, such as Eudragit®, comes in different grades with varying proportions of polymer ratio, allowing for targeted delayed drug release. These will impact which polymer to be employed. Upon choosing the coating material, modeling can also predict in vitro and in vivo correlation as enteric-coated products can have unpredictable in vivo pharmacokinetic profiles. Today, the trend is moving away from the traditional coating, and towards new polymers, and with digitalization, there is a focus to start using data from laboratory experiments to be integrated with computational modeling, artificial intelligence, and machine learning to accurately predict key process parameters and film properties for high-quality products.