Ensuring quality control in HME, a quantitative analysis of hydrocortisone filament using a portable Raman spectrometer

3D printing is a breakthrough in drug development, offering advantages like personalized medication and the ability to create complex drug formulations. Ensuring safety and efficacy of these printed medications requires rigorous quality control, for which Raman spectroscopy is a powerful tool. This technique can be integrated into the hot melt extrusion (HME) process or the printing process itself, analyzing the drug-content in filament after its production and before it is melted and formed into the final dosage form. This project focused on developing a quantitative analytical method using a portable Raman spectrometer to measure the concentration of hydrocortisone (HCT) in a filament. This filament acts as a pharmaceutical ink, designed for printing solid oral forms for individualized dosing. Following ICH guidelines, a validated method for HCT quantification in solution was established. This method was then successfully adapted for direct quantification of HCT within the filament composed of 20 % HCT and excipients. The initial step involved defining a specific spectral region unique to HCT. Preprocessing methods were optimized, including smoothing, baseline correction, derivatives and Extended Multiplicative Signal Correction, used to mitigate unwanted spectral variations. The method proved highly accurate for the target HCT concentration across three filament batches, achieving a mean absolute error of 2.96 %. This project highlights the value of using a portable Raman probe to control the quality of the filament either at the output of HME or directly at the point of care, in order to verify the quality of the received filament.