Automated process development with pure API filling using vacuum drum

In pharmaceutical development, dosing of pure active pharmaceutical ingredient (API) has proven to be essential for reducing API consumption and shortening early-stage development time, avoiding the need for excipients and compatibility studies. The vacuum drum filler, known for its precision in dosing down to 1 mg, is commonly employed for micro-dosing purposes, e.g., in the field of dry powder inhalation (DPI). In this study, however, it is desired to investigate the vacuum drum filler for its suitability in pure API filling. Automated Process Development (APD) integrates design of experiments (DoE) with automated execution to optimize processes efficiently. In this study, the APD method was investigated on the vacuum drum filling system to analyse the impact of various process parameters on the filling weight of capsules and the relative standard deviation (RSD) between the bores considering pure API. For this, two APIs were investigated: powdered paracetamol and micronized paracetamol. Notably, despite variations in vacuum and pressure, process parameters related to powder preparation in the chamber exerted the most significant influence. The 3-wire stirrer, located in the chamber on top of the vacuum drum, resulted in better filling weights and lower RSD with both powders. The APD method allowed to identify the parameters that minimized the RSD in the capsule filling of pure powdered paracetamol, emphasizing the need for tailored parameter optimization. Further investigation is needed to determine how to achieve optimal powder preparation in the chamber for micronized paracetamol.