Applying active pharmaceutical ingredients to biocompatible substrates using 2D printing technology is an innovative and effective way to customise the dosage of active pharmaceutical ingredients to each individual. This treatment modality could address the challenges that arise in particular in the treatment of chronic diseases, in the treatment of children and the elderly, and in the treatment of high-potency active substances and/or active substances with a narrow therapeutic window. Another important advantage of 2D printing technology is the possibility to prepare the dosage form immediately prior to dispensing to the patient by dispersing the dry particles in the base ink medium and printing them on biocompatible substrates. Therefore, the aim of our research work was to prepare simvastatin dry particles by spray-drying which are suitable for dispersion in the ink media and remain sufficiently physicochemically stable over the entire shelf life. Three different emulsions were produced with lactose, calcium silicate and a combination of lactose and nanocellulose as anti-adhesives. The particles were prepared by spray-drying of the emulsions and the conversion of simvastatin to an amorphous form which was verified by differential scanning calorimetry and Fourier transform infrared spectroscopy. Particles were prepared without and with the addition of ascorbic acid in order to verify the effect of the antioxidant on the chemical stability of simvastatin in the particles. The particles were dispersed in three media containing different proportions of propylene glycol and water. A stability study was carried out for one month, where both dry and dispersed particles were stored at 25 °C and 40 % RH and at 40 °C and 75 % RH. The samples were analysed by ultra-high performance liquid chromatography and the particle content of simvastatin was determined. We found that the addition of ascorbic acid had a significant effect on the chemical stability of the particles prepared using lactose and a combination of lactose and nanocellulose. These particles show satisfactory chemical stability after 1 month of storage. The fresh and dispersed particles were measured for size by laser diffraction and their morphological properties were evaluated by scanning electron microscopy. We were interested in the influence of the sampling location, the used anti-adhesive, the medium and the storage temperature on the size of the dispersed particles, since it is crucial to avoid unwanted lubrication of the printer head nozzles. It can be confirmed that the particles with the combination of lactose and nanocellulose, which contain an antioxidant and are dispersed in the most viscous medium, show the appropriate size and physico-chemical stability.
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