Preparation, characterisation and evaluation of loading paclitaxel into debranched corn starch

As a pivotal biological and renewable resource, corn starch has extensive industrial applications. This study aims to investigate the debranched corn starch (DS) as a natural carrier for loading the high-melting-point hydrophobic anti-cancer drug paclitaxel (PTX) via efficient molecular interactions for the first time, resulting in a new loading system debranched corn starch-paclitaxel (DS–PTX). DS with a high degree of polymerisation was mainly involved in the loading process, resulting in a higher drug loading (DL, 34.9 % ± 0.72 %). PTX loaded into DS–PTX was successfully isolated for the first time and characterised to exist as nanostrip crystals with an average length and an average diameter of 870 ± 290 and 160 ± 20 nm, respectively, differing from raw PTX. DS–PTX was verified to be a weak V-type crystalline structure comprising H-bonds, van der Waals forces and hydrophobic interactions between PTX and DS. In vitro digestion experiments confirmed that DS–PTX substantially decreased the release of PTX in artificial gastric juice (AGJ). After 24 h of digestion in artificial intestinal fluid (AIF), the cumulative release of PTX from DS–PTX (94.8 % ± 0.91 %) reached its peak compared to other starch-based oral loading systems, indicating nearly complete digestion and a substantial increase in the solubility of nano-PTX. The cytotoxicity of DS–PTX to normal cells was lower than that of raw PTX. DS–PTX was believed as efficient molecular interactions, nearly complete digestion and high security. Utilising the DS carrier to load high-melting-point hydrophobic drugs could open new avenues for the application of corn starch. • DS was successfully loaded with the anti-cancer drug PTX via molecular interactions. • PTX loaded into DS was isolated and characterised to exist as nanostrip crystals. • Release of DS–PTX was higher than other starch-based oral loading systems in digestive solution.