Critical material attributes (CMAs) of strip films loaded with poorly water-soluble drug nanoparticles: III. Impact of drug nanoparticle loading

Polymer strip films have emerged as a robust platform for poorly water-soluble drug delivery. However, the common conception is that films cannot exceed low drug loadings, mainly due to poor drug stability, slow release, and film brittleness. This study explores the ability to achieve high loadings of poorly water-soluble drug nanoparticles in strip films while retaining good mechanical properties and enhanced dissolution rate. Aqueous suspensions containing up to 30 wt% griseofulvin nanoparticles were prepared via wet stirred media milling and incorporated into hydroxypropyl methylcellulose (HPMC) films. Griseofulvin loading in films was adjusted to be between 9 and 49 wt% in HPMC-E15 films and 30 and 73 wt% in HPMC-E4M films by varying the mixing ratio of HPMC solution-to-griseofulvin suspension. All films exhibited good content uniformity and nanoparticle redispersibility up to 50 wt% griseofulvin, while E4M films above 50 wt% griseofulvin had slightly worse content uniformity and poor nanoparticle redispersibility. Increasing drug loading in films generally required more time to achieve 100% release during dissolution, although polymer–drug clusters dispersed from E4M films above 50 wt% griseofulvin, resulting in similar dissolution profiles. While all films exhibited good tensile strength, a significant decrease in percent elongation was observed above 40–50 wt% GF, resulting in brittle films.