Continuous low-dose feeding of highly active pharmaceutical ingredients in hot-melt extrusion

Context: Manufacturing solid low-dose pharmaceutical products has always the homogeneity challenge. In continuous manufacturing, there is the additional challenge of feeding active pharmaceutical ingredient (API) dry powder at low rates. This paper presents a method for feeding API particles into a continuous extrusion process using a suspension. The challenges for feeding and the product homogeneity are both addressed. Objective: The objective of this study is to demonstrate the feasibility of manufacturing low-dose extrudates by feeding the API particles in a diluted anti-solvent suspension. Materials and methods: Extrudates with an Ibuprofen content of 0.021% and 0.043% (w/w) were prepared by feeding a 0.9% w/w suspension of Ibuprofen particles into a Coperion extruder. Results and discussion: The homogeneity (RSD) of extrudates was tested during a time span of 30 min and had values between 2% and 7%. Conclusion: Feeding particles in an anti-solvent suspension offers a simple feeding option for API and minor components which yield products of desired homogeneity. The liquid feeding approach offers a simplified process with enhanced process control possibilities.