Vol. 7, Issue 2, Part I (2025)

A tablet is defined as a solid unit dosage form, and one of the major reasons for coating such dosage forms is to modify the drug-release profile and improve the bioavailability of the active pharmaceutical ingredients (APIs). Tablets containing APIs can be coated with a thin polymeric film to provide multiple advantages. Typically, horizontal rotating pans are used during coating, and the coating solution is applied onto the tablet surface through spraying systems. Tablet coating offers benefits such as masking bitter taste and unpleasant odors, providing physical and chemical protection, and shielding the product from environmental factors. Additionally, coating helps in targeting the drug to a specific site of action. Traditional coating techniques include sugar coating, film coating, and enteric coating. The main goal behind developing new coating technologies is to overcome the limitations associated with solvent-based coatings. These modern methods allow the coating material to be applied directly to the dosage form without using solvents. This review summarizes conventional tablet coating techniques, recent technological advancements, and the key components involved in tablet coating.

Conventional tablets are solid oral dosage forms containing an active pharmaceutical ingredient (API) along with necessary excipients. They are generally manufactured using direct compression, wet granulation, or dry granulation techniques. These tablets are formulated to disintegrate and release the drug either immediately or in a controlled manner, depending on their design. Tablet coating plays an essential role in pharmaceutical formulation by enhancing therapeutic effectiveness, improving patient compliance, and increasing product stability. This review highlights the major aspects of tablet coating, including its types, components, and recent technological developments. It discusses coating materials such as polymers, plasticizers, and colorants, emphasizing their importance in modifying drug release, masking unpleasant taste, and improving appearance. Recent innovations such as film coating, enteric coating, and nanotechnology-based approaches for greater accuracy and functionality are also explored.