Effective Targeting of Colon Cancer Cells with Piperine Natural Anticancer Prodrug Using Functionalized Clusters of Hydroxyapatite Nanoparticles

Targeted drug delivery offers great opportunities for treating cancer. Here, we developed a novel anticancer targeted delivery system for piperine (Pip), an alkaloid prodrug derived from black pepper that exhibits anticancer effects. The tailored delivery system comprises aggregated hydroxyapatite nanoparticles (HAPs) functionalized with phosphonate groups (HAP-Ps). Pip was loaded into HAPs and HAP-Ps at pH 7.2 and 9.3 to obtain nanoformulations. The nanoformulations were characterized using several techniques and the release kinetics and anticancer effects investigated in vitro. The Pip loading capacity was >20%. Prolonged release was observed with kinetics dependent on pH, surface modification, and coating. The nanoformulations fully inhibited monolayer HCT116 colon cancer cells compared to Caco2 colon cancer and MCF7 breast cancer cells after 72 h, whereas free Pip had a weaker effect. The nanoformulations inhibited ~60% in HCT116 spheroids compared to free Pip. The Pip-loaded nanoparticles were also coated with gum Arabic and functionalized with folic acid as a targeting ligand. These functionalized nanoformulations had the lowest cytotoxicity towards normal WI-38 fibroblast cells. These preliminary findings suggest that the targeted delivery system comprising HAP aggregates loaded with Pip, coated with gum Arabic, and functionalized with folic acid are a potentially efficient agent against colon cancer.

A simple time-resolved fluorescence assay for quantitative determination of DOTA chelator

DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate) is one of the preeminent metal chelator applied for diagnostic and therapeutic purposes, however to date there is no versatile and reliable nonradioisotopic method for its precise determination. In this technical note, we present a novel and sensitive fluorimetric assay for quantitative determination of DOTA based on the luminescence quenching of the highly luminescent europium ions complex with trioctyl phosphine oxide and naphthoyl trifluoroacetone sensitizing activators. The assay is carried out in two simple steps and enables the determination of DOTA in the nanomolar range providing a superior tool compared to commonly applied spectrophotometric assay with Arsenazo-III reagent.