The pharmaceutical industry as well as European and US governing agencies have indicated the need for more accurate, high resolution, characterization of complex drug materials, nanomedicines, to facilitate their development and eventual approval. In particular, accurately measuring the size, zeta-potential, and concentration of nanomedicines is desired. Herein we demonstrate the comprehensive and high resolution analysis capabilities of tunable resistive pulse sensing (TRPS) on the most widely approved nanomedicines to-date, liposomal particles. The number-based size distribution, concentration and volume fraction of liposomes formed by extrusion through a 100 nm or 200 nm Nucleopore filter membrane are shown as well as how freeze-thaw aggregation changes individual liposomes and the overall size distribution. In addition, the simultaneous size and zeta-potential analysis capabilities of TRPS is used to characterize the homogeneity and difference between liposomes made with and without the addition of PEGylated phospholipids.
Keywords: Coulter counter, particle characterization, pore sensor, TRPS, qNano.