Enteric-Coated Polymers Past and Present - A Review

Abstract

Abstract: 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 enteric-coated 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 pa-rameters. Ethylcellulose can provide a short delayed release; it can be modified by adding pH-dependent 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 pre-dict in vitro and in vivo correlation as enteric-coated products can have unpredictable in vivo phar-macokinetic 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 experi-ments to be integrated with computational modeling, artificial intelligence, and machine learning to accurately predict key process parameters and film properties for high-quality products.