Nanophox particle size analyzer

Particle size distribution of the synthesized NPs was analyzed using dynamic light scattering on DynaPro-TC-04 DLS instrument (Protein Solutions, Wyatt Technology, Santa Barbara, CA) the size distribution of as-synthesized NPs was also observed by Nanophox particle size analyzer (Sympatec GmbH, Clausthal-Zellerfeld, Germany). To evaluate the stability and surface charge of the as synthesized 5-FU NPs, zeta potential was determined using DTS software (Malvern Instruments, Worcestershire, UK) based on M3-PALS technology following a method standardized in our laboratory^{38 (link)}. 5-FU NPs were suspended in phosphate buffer (10 mM, pH 7.4) and thoroughly mixed in a cyclo-mixer for 1 min and used for zeta sizing as well as surface charge determination.

The determination of the size of the labeled nanocolloids was carried out by spectroscopy on a Nanophox particle size analyzer (“Sympatec GmbH”, Germany), and also by a technique, based on measuring the activity of the suspension before and after filtering it successively through filters with predetermined pore sizes: 220, 100, and 50 nm. Three samples were taken with a volume of 5 μl from each initial solution and filtrates for the subsequent measurement of their activity. Calculations of the yield of products with different particle sizes were determined according to the formulas given below: $$C_{220}=\frac{A_{\mathit{vc}}-A_1}{A_{\mathit{vc}}};C_{100}=\frac{A_1-A_2}{A_1};C_{50}=\frac{A_2-A_3}{A_2},$$
where A_vc is the activity of the initial suspension prior to filtration; A₁ is the activity measured after filtration through a 220 nm filter; A₂ is the activity after filtration through 100 nm filter; A₃ is the activity measured after filtration through 50 nm filter.
In parallel, determination of the radiochemical purity (RCP) of preparations by thin layer chromatography method was carried out.