Assessment of the Physical Properties, Drug Loadability and Release Profile, and Biocompatibility of UniPearls® Microspheres.

Microspheres based transarterial chemoembolization is important for liver cancer treatment. UniPearls is a novel product of microspheres featuring a uniform particle size and independently developed in China. This study aimed to investigate the physical properties, drug loading and releasing ability, and biocompatibility of UniPearls. Various experiments were performed including: compression rupture, suspendability, simulated use, drug loading, drug releasing, cytotoxicity, mouse lymphoma assay (MLA), muscle implant, intradermal reaction, guinea pig maximization test (GPMT), and systemic toxicity. UniPearls or UniPearls extraction liquid was set as experimental group(s), while HepaSphere or related extraction liquid was set as control group(s). UniPearls showed no microsphere rupture after compression to 1 μm for 10 or 20 min, but some ruptures for 30 min, and microspheres were successfully suspended in a short time. In a 3-dimensional (3D) hepatic artery model, UniPearls exhibited no microsphere break, delivery block, shape change or unexpected catheter outflow during simulated experiment. The maximum loading rates of 40-100 mg doxorubicin and irinotecan were 100% and 97.4% by UniPearls, respectively; then the releasing rates at plateaus with different-dose doxorubicin and irinotecan ranged 34.0%-46.5% and 85.6%-91.8%, respectively. In vitro experiments revealed no cytotoxicity or impact on inducing gene mutation by UniPearls. In vivo experiments disclosed no local reaction, skin sensitization, obvious acute/subchronic systemic toxicity symptoms by UniPearls. Besides, the above indexes were not different between UniPearls and controls (HepaSphere or related extraction liquids). UniPearls serves as a good product of microspheres, benefiting from its satisfied physical properties, drug loadability, releasing ability and biocompatibility.