Hardik L. Patel

  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.  

  Hydrogel nanoparticles have gained considerable attention in recent years as one of the most promising nanoparticulate drug delivery systems owing to their unique potentials via combining the characteristics of a hydrogel system with a nanoparticle. Therefore, it seems that the pharmacy world will benefit from the hydrophilicity, flexibility, versatility, high water absorptivity, and biocompatibility of these particles and all the advantages of the NPs, mainly long life span in circulation and the possibility of being actively or passively targeted to the desired bio-phase. Several polymeric hydrogel nanoparticulate systems have been prepared and characterized in recent years, based on both natural and synthetic polymers, each with its own advantages and drawbacks. Several cross linking methods have been used in the way to form the hydrogel matrix structures. The remainder of this text presents various types of nanogels prepared and characterized, using a classification based on the type of polymeric materials used in preparation of the NPs.   Key words: Hydrogel, Nanoparticles, Hydrogel nanoparticles, Nanogels, Hydrogel.