Suitability of various excipients as carrier and coating materials for liquisolid compacts

Context: The liquisolid technology is a promising technique for the release enhancement of poorly soluble drugs. With this approach, liquids such as solutions or suspensions of poorly soluble drugs in a non-volatile liquid vehicle are transformed into acceptably flowing and compressible powders. As fast-release liquisolid compacts require a high amount of liquid vehicle, more effective tableting excipients for liquid adsorption are needed to reduce tablet weight. Objective: The aim of this study was to investigate the suitability of various novel tableting excipients as carrier and coating materials for liquisolid compacts. Materials and methods: Liquisolid compacts containing the liquid drug tocopherol acetate (TA) as model drug and various excipients were prepared. The effect of liquid drug content on the flowability and tabletability of the liquisolid powder blends as well as the disintegration of the liquisolid compacts was studied. From this data, the maximum liquid adsorption capacity of the respective mixtures of carrier and coating materials could be determined. Results and discussion: The liquid adsorption capacity depends on the specific surface area of the investigated excipients. Fujicalin (R) and especially Neusilin (R) are more effective carrier materials for liquid adsorption than Avicel (R), which is often used for liquisolid systems. Moreover, Florite (R) and Neusilin (R) turned out to be more suitable as coating materials than the commonly used Aerosil (R) due to their better tableting properties. Conclusion: If Neusilin (R) is used as carrier and coating material instead of Avicel (R) (carrier material) and Aerosil (R) (coating material), the TA adsorption capacity is increased by a factor of 7.