Impaction

  Coatings are an essential part in the formulation of pharmaceutical dosage form to achieve superior aesthetic quality (e.g., color, texture, mouth feel, and taste masking), physical and chemical protection for the drugs in the dosage forms, and modification of drug release characteristics. Most film coatings are applied as aqueous- or organic-based polymer solutions. Solventless coatings are the alternative coating technologies for solid pharmaceutical dosage forms in which coating materials are directly coated onto solid dosage forms without using any solvent and then cured by various methods to form a coat. As a result, these technologies can overcome the disadvantages which are caused by solvents in conventional liquid coating. This review discusses and compares six solventless coating methods - Compression coating, Powder / dry coating, Hot-melt coating, Supercritical fluid spray coating, Magnetically Assisted Impaction Coating’ (MAIC), Solventless photo curable coating that can be used to coat the pharmaceutical dosage forms. Powder coating also called as dry coating which include plasticizer-dry coating, electrostatic-dry-coating, heat-dry-coating and plasticizer-electrostatic-heat-dry-coating. This review summarizes the fundamental principles and coating processes of various solventless coating technologies.