In recent years, plant derived polymers have evoked tremendous interest in the field of drug delivery. In this work, a promising anticancer drug, paclitaxel, was precipitated in the basil seeds mucilage (BSM) using supercritical carbon dioxide (SC-CO2). The employed SC-CO2 process in this research is a combination of gas antisolvent and phase inversion techniques and consists of two steps: (1) casting solution preparation, a uniform mixture of BSM, water, paclitaxel and dimethyl sulfoxide (DMSO), (2) simultaneous generation and precipitation of nanoparticles in BSM structure using SC-CO2 as antisolvent. The effect of DMSO/water ratio (4 and 6 (v/v)), pressure (10-16 MPa) and CO2 addition rate (1-3 mL/min) on mean particle size (MPS), particle size distribution (PSD) and drug loading efficiency (DLE) were studied. Particle analyses were performed by scanning electron microscopy (SEM) and Zetasizer. High performance liquid chromatography was utilized for studying DLE. Nanoparticles of paclitaxel (MPS of 117-200 nm depending on process variables) with narrow PSD were successfully precipitated in BSM structure with DLE of 56.8-78.2%. The FTIR spectra confirmed that paclitaxel actually precipitated in basil seeds mucilage. Experimental results indicated that higher DMSO/water ratio, pressure and CO2 addition decreased MPS and DLE. (C) 2014 Elsevier B.V. All rights reserved.