3D printed matrix solid forms: Can the drug solubility and dose customisation affect their controlled release behaviour?

The use of 3D printing in pharmaceutics has grown over the last years, along with the number of studies on the impact of the composition of these formulations on their pharmaceutical and biopharmaceutical properties. Recently, we reported the combined effect of the infill percentage and the presence of a pore former on the drug release behaviour of 3D printed matrix solid forms prepared by fused deposition modelling. However, there are some open questions about the effect of the drug solubility and the size of these dosage forms on their controlled release properties. Therefore, we produced poly(Ɛ-caprolactone) filaments containing different soluble forms of dexamethasone (free acid, DEX; acetate ester, DEX-A; and phosphate salt, DEX-P), which showed suitable mechanical properties and printability. 3D printed solid forms were produced in two different sizes. The formulations composed of DEX-P released about 50% of drug after 10 h, while those containing DEX or DEX-A released about 9%. The drug release profiles from the 3D printed forms containing the same drug form but with different sizes were almost completely overlapped. Therefore, these 3D printed matrix solid forms can have their drug content customised by adjusting their size, without changing their controlled release behaviour.