Effect of substrates on naproxen-polyvinylpyrrolidone solid dispersions formed via the drop printing technique

Solid dispersions have been used to improve the bioavailability of poorly water-soluble drugs. However, drug solid-state phase, compositional uniformity, and scale-up problems are issues that need to be addressed. To allow for highly controllable products, the drop printing (DP) technique can provide precise dosages and predictable compositional uniformity of active pharmaceutical ingredients in two-/three-dimensional structures when integrated with edible substrates. With different preparation conditions, DP was conducted to fabricate naproxen (NAP)-polyvinylpyrrolidone solid dispersions with chitosan and hydroxypropyl methylcellulose films as the substrate. Scanning electron microscopy, X-ray diffraction, second harmonic generation microscopy, and atomic force microscopy analyses were performed to characterize the microstructure and spatial distribution of NAP in the solid dispersions. The results identified that composition, temperature, and substrate type all had an impact on morphology and crystallization of samples. The surface energy approach was combined with classical nucleation theory to evaluate the affinity between the nucleus of NAP and substrates. Finally, the collective results of the drug were correlated to the release profile of NAP within each sample.