3D printed scaffolds as delivery devices for nanocrystals: A proof of concept loading Atorvastatin with enhanced properties for sublingual route of administration.

Increasing the solubility of drugs is a recurrent objective of pharmaceutical research, and one of the most widespread strategies today is the formulation of nanocrystals (NCs). Beyond the many advantages of formulating NCs, their incorporation into solid dosage forms remains a challenge that limits their use. In this work, we set out to load Atorvastatin NCs (ATV-NCs) in a delivery device by combining 3D scaffolds with an "in situ" loading method such as freeze-drying. When comparing two infill patterns for the scaffolds at two different percentages, the one with the highest NCs load was chosen (Gyroid 20 % infill pattern, 13.8 ± 0.5 mg). Colloidal stability studies of NCs suggest instability in acidic media, and therefore, the system is postulated for use as a sublingual device, potentially bypassing stomach and hepatic first-pass effects. An ad hoc dissolution device was developed to mimic the release of actives. The nanometric size and properties acquired in the process were maintained, mainly in the dissolution rate and speed, achieving 100 % dissolution of the content in 180 s. Based on these results, the proof of concept represents an innovative approach to converting NCs suspensions into solid dosage forms.

Thermally self-assembled biodegradable poly(casein-g-N-isopropylacrylamide) unimers and their application in drug delivery for cancer therapy.

In this work, we report the synthesis of graft copolymers based on casein and N-isopropylacrylamide, which can self-assemble into biodegradable micelles of approximately 80 nm at physiological conditions. The obtained copolymers were degraded by trypsin, an enzyme that is overexpressed in several malignant tumors. Moreover, graft copolymers were able to load doxorubicin (Dox) by ionic interaction with the casein component. In vitro release experiments showed that the in situ assembled micelles can maintain the cargo at plasma conditions but release Dox immediately after their exposition at pH 5.0 and trypsin. Cellular uptake and cytotoxicity assays revealed the efficient delivery to the nucleus and antiproliferative efficacy of Dox in the breast cancer cell line MDA231. Both delivery and therapeutic activity were enhanced in presence of trypsin. Overall, the prepared micelles hold a great potential for their utilization as dual responsive trypsin/pH drug delivery system.